2024
Ziadeh, C. P. ; S. B. Ziadeh; B. H. Aflague; M. A. Townley; M. P. Ayres; A. R. Contosta;; Garnas, J. R.
Distinct communities under the snow: describing characteristics of subnivium arthropod communities Journal Article
In: Environmental Entomology, 2024.
@article{Ziadeh.2024,
title = {Distinct communities under the snow: describing characteristics of subnivium arthropod communities},
author = {Ziadeh, C. P.; S. B. Ziadeh; B. H. Aflague; M. A. Townley; M. P. Ayres; A. R. Contosta; and J. R. Garnas},
url = {https://www.sciencefriday.com/segments/insect-ecosystem-between-snow-and-soil/},
doi = {10.1093/ee/nvae017},
year = {2024},
date = {2024-04-04},
urldate = {2024-04-04},
journal = {Environmental Entomology},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Karsten, M. ; A. Collop; J. Terblanche; S. Clusella-Trullas; J. R. Garnas; P. Bradicich
Testing hypotheses of invasion pathways of the ladybird Harmonia axyridis into and across South Africa Journal Article
In: Biological Invasions, 2024.
@article{karsten.2024,
title = {Testing hypotheses of invasion pathways of the ladybird Harmonia axyridis into and across South Africa},
author = {Karsten, M.; A. Collop; J. Terblanche; S. Clusella-Trullas; J. R. Garnas; P. Bradicich},
doi = {10.1007/s10530-024-03274-w},
year = {2024},
date = {2024-03-22},
urldate = {2024-03-22},
journal = {Biological Invasions},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
JR, Morrison E; Duong T; Garnas
A high-quality draft genome sequence of Neonectria faginata, causative agent of beech bark disease of Fagus grandifolia Journal Article
In: Microbiol Resource Announcements, vol. 13, iss. 2, pp. e0104823, 2024.
@article{morrison.2024,
title = {A high-quality draft genome sequence of Neonectria faginata, causative agent of beech bark disease of Fagus grandifolia},
author = {Morrison E; Duong T; Garnas JR},
doi = {10.1128/mra.01048-23},
year = {2024},
date = {2024-02-01},
urldate = {2024-02-01},
journal = {Microbiol Resource Announcements},
volume = {13},
issue = {2},
pages = {e0104823},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2023
Kanaskie, C. R. ; K. J. Dodds; F. M. Stephen; J. R. Garnas
In: Environmental Entomology, vol. 53, iss. 1, pp. 143–156, 2023.
@article{kanaskie.2023,
title = {Southern pine beetle (Coleoptera: Curculionidae) and its associated insect community: similarities and key differences between northeastern and southeastern pine forests},
author = {Kanaskie, C. R.; K. J. Dodds; F. M. Stephen; J. R. Garnas},
doi = {10.1093/ee/nvad112.},
year = {2023},
date = {2023-12-15},
urldate = {2023-12-15},
journal = {Environmental Entomology},
volume = { 53},
issue = {1},
pages = {143–156},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Garnas, Jeff; Lombardero, FJ; Ayres, M. P.
Forest Insect Population Dynamics Book Chapter
In: Allison, Jeremy; Paine, Timothy D; Slippers, Bernard; Wingfield, Michael J. (Ed.): Forest Entomology and Pathology, Volume 1: Entomology, vol. 1, Chapter 5, Springer, 1, 2023, ISBN: 978-3-031-11552-3 978-3-031-11553-0.
@inbook{19900,
title = {Forest Insect Population Dynamics},
author = {Jeff Garnas and FJ Lombardero and M. P. Ayres},
editor = {Jeremy Allison and Timothy D Paine and Bernard Slippers and Michael J. Wingfield},
url = {https://link.springer.com/10.1007/978-3-031-11553-0_5},
doi = {10.1007/978-3-031-11553-0_5},
isbn = {978-3-031-11552-3 978-3-031-11553-0},
year = {2023},
date = {2023-07-01},
urldate = {2023-07-01},
booktitle = {Forest Entomology and Pathology, Volume 1: Entomology},
volume = {1},
publisher = {Springer},
edition = {1},
chapter = {5},
organization = {Springer},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Kanaskie, CR; Schmeelk, TC; Cancelliere, JA; Garnas, JR
In: The Coleopterists Bulletin , vol. 77, iss. 2, pp. 248-251 , 2023.
@article{nokey,
title = {New Records of Southern Pine Beetle (Dendroctonus frontalis Zimmermann; Coleoptera: Curculionidae) in New York, New Hampshire, and Maine, USA Indicate Northward Range Expansion},
author = {CR Kanaskie and TC Schmeelk and JA Cancelliere and JR Garnas
},
url = {https://bioone.org/journals/the-coleopterists-bulletin/volume-77/issue-2/0010-065X-77.2.248/New-Records-of-Southern-Pine-Beetle-Dendroctonus-frontalis-Zimmermann-Coleoptera/10.1649/0010-065X-77.2.248.full},
doi = {10.1649/0010-065X-77.2.248},
year = {2023},
date = {2023-07-01},
urldate = {2023-07-01},
journal = {The Coleopterists Bulletin },
volume = {77},
issue = {2},
pages = {248-251 },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2022
Fitza, K. N.; Garnas, Jeff R.; Slippers, B
Fitness consequences of lineage interbreeding in the nematode Deladenus siricidicola, biological control agent of the European woodwasp, Sirex noctilio Journal Article
In: Biological Control, vol. 169, pp. 104875, 2022.
@article{Fitza:2021,
title = {Fitness consequences of lineage interbreeding in the nematode Deladenus siricidicola, biological control agent of the European woodwasp, Sirex noctilio},
author = {K. N. Fitza and Jeff R. Garnas and B Slippers},
year = {2022},
date = {2022-01-01},
journal = {Biological Control},
volume = {169},
pages = {104875},
abstract = {Deladenus siricidicola is a principal biological control agent used to suppress populations of the globally invasive pine pest, the woodwasp Sirex noctilio. Previous studies have reported low genetic diversity in D. siricidicola populations in biological control programs in the Southern Hemisphere and identified two additional, distinct lineages in North America and Spain. In this study, we tested the ability of these three lineages to interbreed and produce viable offspring. We used microsatellite markers to confirm admixture in offspring. Secondly, we compared growth rates among parental and admixed replicates on four isolates of the Amylostereum areolatum fungus on which nematodes typically feed in their asexual, non-parasitic phase. We show that all the lineages were capable of interbreeding and that admixture was asymmetric (i.e., skewed towards one of the parents). The offspring from one of the crosses showed significant variation in growth rate on different isolates of A. areolatum, compared to the parental isolates, but specifically on the slowest growing fungal isolate. Our results pave the way for the strategic introduction of genetic diversity into biological control programs and also inform expectations of accidental introductions of D. siricidicola into new regions. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Deladenus siricidicola is a principal biological control agent used to suppress populations of the globally invasive pine pest, the woodwasp Sirex noctilio. Previous studies have reported low genetic diversity in D. siricidicola populations in biological control programs in the Southern Hemisphere and identified two additional, distinct lineages in North America and Spain. In this study, we tested the ability of these three lineages to interbreed and produce viable offspring. We used microsatellite markers to confirm admixture in offspring. Secondly, we compared growth rates among parental and admixed replicates on four isolates of the Amylostereum areolatum fungus on which nematodes typically feed in their asexual, non-parasitic phase. We show that all the lineages were capable of interbreeding and that admixture was asymmetric (i.e., skewed towards one of the parents). The offspring from one of the crosses showed significant variation in growth rate on different isolates of A. areolatum, compared to the parental isolates, but specifically on the slowest growing fungal isolate. Our results pave the way for the strategic introduction of genetic diversity into biological control programs and also inform expectations of accidental introductions of D. siricidicola into new regions.
2021
Dittrich-Schroder, Gudrun; Garnas, Jeff R.; Arriagada-Cares, Daniela; Ahumada, Rodrigo; Hurley, Brett P.; Lawson, Simon A.; Slippers, Bernard
Global diversity and introduction history of Glycaspis brimblecombei reflects a history of bridgeheads and distinct invasions Journal Article
In: Frontiers in Forests and Global Change, vol. 4, 2021.
@article{Dittrich:2021,
title = {Global diversity and introduction history of Glycaspis brimblecombei reflects a history of bridgeheads and distinct invasions},
author = {Gudrun Dittrich-Schroder and Jeff R. Garnas and Daniela Arriagada-Cares and Rodrigo Ahumada and Brett P. Hurley and Simon A. Lawson and Bernard Slippers},
url = {https://www.frontiersin.org/articles/10.3389/ffgc.2021.783603/full},
year = {2021},
date = {2021-01-01},
journal = {Frontiers in Forests and Global Change},
volume = {4},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Krivak-Tetley, Flora E.; Lantschner, M. Victoria; Lombardero, Maria; Garnas, Jeff R.; Hurley, Brett P.; Villacide, José M.; Slippers, Bernard; Corley, Juan C.; Liebhold, Andrew M.; Ayres, Matthew P.
2021.
@journal{24723,
title = {Aggressive tree killer or natural thinning agent? Assessing the impacts of a globally important forest insect},
author = {Flora E. Krivak-Tetley and M. Victoria Lantschner and Maria Lombardero and Jeff R. Garnas and Brett P. Hurley and José M. Villacide and Bernard Slippers and Juan C. Corley and Andrew M. Liebhold and Matthew P. Ayres},
url = {https://www.sciencedirect.com/science/article/pii/S0378112720314973},
year = {2021},
date = {2021-01-01},
journal = {Forest Ecology and Management},
abstract = {Invasive insects and pathogens are prominent tree mortality agents in forests around the world, and the magnitude of their impacts is increasing. Comparative studies across multiple populations can be helpful for the development of new insights and innovative management strategies. We used the Sirex woodwasp, Sirex noctilio Fabricius, as a model system to compare invasion impacts across a range of ecological contexts around the globe: native woodwasps colonizing native trees, invasive woodwasps in non-native plantation trees, and invasive woodwasps attacking native trees. Across 133 stands of eight pine species on four continents, tree mortality associated with S. noctilio attack was positively correlated with stand basal area and stand density, and was mostly confined to smaller, suppressed trees. Larger average tree size and greater distances between trees were linked to lower levels of tree mortality. To more deeply assess the impacts of tree loss due to this pest, we examined mortality in vigorous trees, defined as those with a stem diameter greater than or equal to 90% of the mean diameter for trees in the stand. Sirex noctilio- related mortality in vigorous trees was rare, with one exception where Pinus contorta stands in Argentina lost as many as 300 vigorous trees ha-1. Pine species varied dramatically in their susceptibility to S. noctilio: for example, these losses in P. contorta were in stark contrast to very low mortality in P. ponderosa, the other pine species grown in Argentina. Surprisingly, location did not alter patterns in the influence of stand basal area on tree susceptibility for individual species. Most notably, Pinus radiata had the same relationship between basal area and tree mortality when grown in Spain (where S. noctilio is native and not considered a meaningful forest pest) and South Africa (where S. noctilio is a problematic invasive). Our findings suggest that the availability of optimal pine hosts is a key driver of S. noctilio-related tree mortality across continents and management regimes. Important variables that influence host availability include species- specific susceptibility and environmental and management-related factors that promote or limit the number of stressed trees present both within stands and across the regional forest or plantation landscape. },
keywords = {},
pubstate = {published},
tppubtype = {journal}
}
Invasive insects and pathogens are prominent tree mortality agents in forests around the world, and the magnitude of their impacts is increasing. Comparative studies across multiple populations can be helpful for the development of new insights and innovative management strategies. We used the Sirex woodwasp, Sirex noctilio Fabricius, as a model system to compare invasion impacts across a range of ecological contexts around the globe: native woodwasps colonizing native trees, invasive woodwasps in non-native plantation trees, and invasive woodwasps attacking native trees. Across 133 stands of eight pine species on four continents, tree mortality associated with S. noctilio attack was positively correlated with stand basal area and stand density, and was mostly confined to smaller, suppressed trees. Larger average tree size and greater distances between trees were linked to lower levels of tree mortality. To more deeply assess the impacts of tree loss due to this pest, we examined mortality in vigorous trees, defined as those with a stem diameter greater than or equal to 90% of the mean diameter for trees in the stand. Sirex noctilio- related mortality in vigorous trees was rare, with one exception where Pinus contorta stands in Argentina lost as many as 300 vigorous trees ha-1. Pine species varied dramatically in their susceptibility to S. noctilio: for example, these losses in P. contorta were in stark contrast to very low mortality in P. ponderosa, the other pine species grown in Argentina. Surprisingly, location did not alter patterns in the influence of stand basal area on tree susceptibility for individual species. Most notably, Pinus radiata had the same relationship between basal area and tree mortality when grown in Spain (where S. noctilio is native and not considered a meaningful forest pest) and South Africa (where S. noctilio is a problematic invasive). Our findings suggest that the availability of optimal pine hosts is a key driver of S. noctilio-related tree mortality across continents and management regimes. Important variables that influence host availability include species- specific susceptibility and environmental and management-related factors that promote or limit the number of stressed trees present both within stands and across the regional forest or plantation landscape.
Morrison, Eric; Kasson, Matthew; Heath, Jeremy; Garnas, JR
Pathogen and endophyte assemblages co-vary with beech bark disease progression, tree decline, and regional climate Journal Article
In: Frontiers in Forests and Global Change, 2021.
@article{24277,
title = {Pathogen and endophyte assemblages co-vary with beech bark disease progression, tree decline, and regional climate},
author = {Eric Morrison and Matthew Kasson and Jeremy Heath and JR Garnas},
url = {https://www.frontiersin.org/articles/10.3389/ffgc.2021.673099/},
year = {2021},
date = {2021-01-01},
journal = {Frontiers in Forests and Global Change},
abstract = {Plant-pathogen interactions are often considered in a pairwise manner with minimal consideration of the impacts of the broader endophytic community on disease progression and/or outcomes for disease agents and hosts. Community interactions may be especially relevant in the context of disease complexes (i.e, interacting or functionally redundant causal agents) and decline diseases (where saprobes and weak pathogens synergize the effects of primary infections and hasten host mortality). Here we describe the bark endophyte communities associated with a widespread decline disease of American beech, beech bark disease (BBD), caused by an invasive scale insect (Cryptococcus fagisuga) and two fungal pathogens, Neonectria faginata and N. ditissima. We show that the two primary fungal disease agents co-occur more broadly than previously understood (35.5% of infected trees), including within the same 1-cm diameter phloem samples. The two species appear to have contrasting associations with climate and stages of tree decline, wherein N. faginata was associated with warmer and N. ditissima with cooler temperatures. Neonectria ditissima showed a positive association with tree crown dieback – no such association was observed for N. faginata. Further, we identify fungal endophytes that may modulate disease progression as entomopathogens, mycoparasites, saprotrophs and/or additional pathogens, including Clonostachys rosea and Fusarium babinda. These fungi may alter the trajectory of disease via feedbacks with the primary disease agents or by altering symptom expression or rates of tree decline across the range of BBD.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Plant-pathogen interactions are often considered in a pairwise manner with minimal consideration of the impacts of the broader endophytic community on disease progression and/or outcomes for disease agents and hosts. Community interactions may be especially relevant in the context of disease complexes (i.e, interacting or functionally redundant causal agents) and decline diseases (where saprobes and weak pathogens synergize the effects of primary infections and hasten host mortality). Here we describe the bark endophyte communities associated with a widespread decline disease of American beech, beech bark disease (BBD), caused by an invasive scale insect (Cryptococcus fagisuga) and two fungal pathogens, Neonectria faginata and N. ditissima. We show that the two primary fungal disease agents co-occur more broadly than previously understood (35.5% of infected trees), including within the same 1-cm diameter phloem samples. The two species appear to have contrasting associations with climate and stages of tree decline, wherein N. faginata was associated with warmer and N. ditissima with cooler temperatures. Neonectria ditissima showed a positive association with tree crown dieback – no such association was observed for N. faginata. Further, we identify fungal endophytes that may modulate disease progression as entomopathogens, mycoparasites, saprotrophs and/or additional pathogens, including Clonostachys rosea and Fusarium babinda. These fungi may alter the trajectory of disease via feedbacks with the primary disease agents or by altering symptom expression or rates of tree decline across the range of BBD.
2020
Mutitu, Eston K.; Hoareau, Thierry B.; Hurley, Brett P.; Garnas, Jeff R.; Wingfield, Michael J.; Slippers, Bernard
Reconstructing early routes of invasion of the bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae): cities as bridgeheads for global pest invasions Journal Article
In: Biological Invasions, 2020, ISBN: 1573-1464.
@article{19894,
title = {Reconstructing early routes of invasion of the bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae): cities as bridgeheads for global pest invasions},
author = {Eston K. Mutitu and Thierry B. Hoareau and Brett P. Hurley and Jeff R. Garnas and Michael J. Wingfield and Bernard Slippers},
isbn = {1573-1464},
year = {2020},
date = {2020-04-01},
journal = {Biological Invasions},
abstract = {Insect pest invasions pose a major threat to agriculture, forestry and many natural ecosystems. Thaumastocoris peregrinus is an invasive sap-sucking pest of significant economic importance to Eucalyptus forestry that has recently invaded several countries worldwide. In this study we identify the origin and retrace the invasion history of T. peregrinus. We analysed samples from six locations in Africa, South America and Australia using microsatellites markers and a combination of clustering methods and scenario testing using Approximate Bayesian Clustering. We detected clear genetic substructure differentiating African and South American samples, with representatives of both present in Australia. The Australian population from New South Wales showed substantially higher genetic diversity than the Queensland source, which could indicate that this region could be part of the core range and evolutionary origin of the species. Africa and South America were colonised by independent introductions that occurred more or less concurrently. The study illustrates the impact of the bridgehead effect on global invasions following an outbreak or ‘invasion’ within a city in the native range of the insect.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Insect pest invasions pose a major threat to agriculture, forestry and many natural ecosystems. Thaumastocoris peregrinus is an invasive sap-sucking pest of significant economic importance to Eucalyptus forestry that has recently invaded several countries worldwide. In this study we identify the origin and retrace the invasion history of T. peregrinus. We analysed samples from six locations in Africa, South America and Australia using microsatellites markers and a combination of clustering methods and scenario testing using Approximate Bayesian Clustering. We detected clear genetic substructure differentiating African and South American samples, with representatives of both present in Australia. The Australian population from New South Wales showed substantially higher genetic diversity than the Queensland source, which could indicate that this region could be part of the core range and evolutionary origin of the species. Africa and South America were colonised by independent introductions that occurred more or less concurrently. The study illustrates the impact of the bridgehead effect on global invasions following an outbreak or ‘invasion’ within a city in the native range of the insect.
Garnas, Jeff R.; Vann, Katie; Hurley, Brett P
Biotic and abiotic effects on density, body size, sex ratio, and survival in immature stages of the European woodwasp, Sirex noctilio Journal Article
In: Ecology and Evolution, 2020.
@article{21631,
title = {Biotic and abiotic effects on density, body size, sex ratio, and survival in immature stages of the European woodwasp, Sirex noctilio},
author = {Jeff R. Garnas and Katie Vann and Brett P Hurley},
url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.6966},
year = {2020},
date = {2020-01-01},
journal = {Ecology and Evolution},
abstract = {Resource quality can have direct or indirect effects on female oviposition choice, offspring growth and survival, and ultimately on body size and sex ratio. We examined these patterns in Sirex noctilio Fabricus, the globally invasive European pine woodwasp, in South African Pinus patula plantations. We studied how tree position as well as natural variation in biotic and abiotic factors influenced sex-specific density, larval size, tunnel length, male proportion, and survival across development. Twenty infested trees divided into top, middle, and bottom sections were sampled at three time points during larval development. We measured moisture content, bluestain fungal colonization, and co-occurring insect density and counted, measured, and sexed all immature wasps. A subset of larval tunnels was measured to assess tunnel length and resource use efficiency (tunnel length as a function of immature wasp size). Wasp density increased from the bottoms to the tops of trees for both males and females. However, the largest individuals and the longest tunnels were found in bottom sections. Male bias was strong (~10:1) and likewise differed among sections, with the highest proportion in the middle and top sections. Sex ratios became more strongly male biased due to high female mortality, especially in top and middle sections. Biotic and abiotic factors such as colonization by Diplodia sapinea, weevil (Pissodes sp.) density, and wood moisture explained modest residual variation in our primary mixed effects models (0%–22%). These findings contribute to a more comprehensive understanding of sex-specific resource quality for S. noctilio and of how variation in key biotic and abiotic factors can influence body size, sex ratio, and survival in this economically important woodwasp.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Resource quality can have direct or indirect effects on female oviposition choice, offspring growth and survival, and ultimately on body size and sex ratio. We examined these patterns in Sirex noctilio Fabricus, the globally invasive European pine woodwasp, in South African Pinus patula plantations. We studied how tree position as well as natural variation in biotic and abiotic factors influenced sex-specific density, larval size, tunnel length, male proportion, and survival across development. Twenty infested trees divided into top, middle, and bottom sections were sampled at three time points during larval development. We measured moisture content, bluestain fungal colonization, and co-occurring insect density and counted, measured, and sexed all immature wasps. A subset of larval tunnels was measured to assess tunnel length and resource use efficiency (tunnel length as a function of immature wasp size). Wasp density increased from the bottoms to the tops of trees for both males and females. However, the largest individuals and the longest tunnels were found in bottom sections. Male bias was strong (~10:1) and likewise differed among sections, with the highest proportion in the middle and top sections. Sex ratios became more strongly male biased due to high female mortality, especially in top and middle sections. Biotic and abiotic factors such as colonization by Diplodia sapinea, weevil (Pissodes sp.) density, and wood moisture explained modest residual variation in our primary mixed effects models (0%–22%). These findings contribute to a more comprehensive understanding of sex-specific resource quality for S. noctilio and of how variation in key biotic and abiotic factors can influence body size, sex ratio, and survival in this economically important woodwasp.
Stauder, Cameron M.; Garnas, Jeff R.; Morrison, Eric W.; Salgado-Salazar, Catalina; Kasson, Matt T.
Characterization of mating type genes in heterothallic Neonectria species with emphasis on N. coccinea, N. ditissima, and N. faginata Journal Article
In: Mycologia, vol. 112, no. 5, pp. 880-894, 2020.
@article{19897,
title = {Characterization of mating type genes in heterothallic Neonectria species with emphasis on N. coccinea, N. ditissima, and N. faginata},
author = {Cameron M. Stauder and Jeff R. Garnas and Eric W. Morrison and Catalina Salgado-Salazar and Matt T. Kasson},
url = {https://www-tandfonline-com/doi/full/10.1080/00275514.2020.1797371},
year = {2020},
date = {2020-01-01},
journal = {Mycologia},
volume = {112},
number = {5},
pages = {880-894},
abstract = {Neonectria ditissima and N. faginata are canker pathogens involved in an insect-fungus disease complex of American beech (Fagus grandifolia) commonly known as beech bark disease (BBD). In Europe, both N. ditissima and N. coccinea are involved in BBD on European beech (Fagus sylvatica). Field observations across the range of BBD indicate that new infections occur primarily via ascospores. Both heterothallic (self-sterile) and homothallic (self-fertile) mating strategies have been reported for Neonectria fungi. As such, investigations into mating strategy are important for understanding both the disease cycle and population genetics of Neonectria. This is particularly important in the U.S. given that over time N. faginata dominates the BBD pathosystem despite high densities of non-beech hosts for N. ditissima. This study utilized whole-genome sequences of BBD-associated Neonectria spp. along with other publicly available Neonectria and Corinectria genomes and in vitro mating assays to characterize mating type (MAT) loci and confirm thallism for select members of Neonectria and Corinectria. MAT gene-specific primer pairs were developed to efficiently characterize the mating types of additional single ascospore strains of N. ditissima, N. faginata, and N. coccinea and several other related species lacking genomic data. In vitro mating assays were used in combination with molecular results to confirm thallism. These assays also comfirmed the sexual compatibility among N. ditissima strains from different plant hosts. Maximum likelihood phylogenetic analysis of both MAT1-1-1 and MAT1-2-1 sequences recovered trees with similar topology to previously published phylogenies of Neonectria and Corinectria. The results of this study indicate that all Neonectria and Corinectria tested are heterothallic based on our limited sampling and, as such, thallism cannot help explain the inevitable dominance of N. faginata in the BBD pathosystem.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Neonectria ditissima and N. faginata are canker pathogens involved in an insect-fungus disease complex of American beech (Fagus grandifolia) commonly known as beech bark disease (BBD). In Europe, both N. ditissima and N. coccinea are involved in BBD on European beech (Fagus sylvatica). Field observations across the range of BBD indicate that new infections occur primarily via ascospores. Both heterothallic (self-sterile) and homothallic (self-fertile) mating strategies have been reported for Neonectria fungi. As such, investigations into mating strategy are important for understanding both the disease cycle and population genetics of Neonectria. This is particularly important in the U.S. given that over time N. faginata dominates the BBD pathosystem despite high densities of non-beech hosts for N. ditissima. This study utilized whole-genome sequences of BBD-associated Neonectria spp. along with other publicly available Neonectria and Corinectria genomes and in vitro mating assays to characterize mating type (MAT) loci and confirm thallism for select members of Neonectria and Corinectria. MAT gene-specific primer pairs were developed to efficiently characterize the mating types of additional single ascospore strains of N. ditissima, N. faginata, and N. coccinea and several other related species lacking genomic data. In vitro mating assays were used in combination with molecular results to confirm thallism. These assays also comfirmed the sexual compatibility among N. ditissima strains from different plant hosts. Maximum likelihood phylogenetic analysis of both MAT1-1-1 and MAT1-2-1 sequences recovered trees with similar topology to previously published phylogenies of Neonectria and Corinectria. The results of this study indicate that all Neonectria and Corinectria tested are heterothallic based on our limited sampling and, as such, thallism cannot help explain the inevitable dominance of N. faginata in the BBD pathosystem.
2019
Wondafrash, Mesfin; Slippers, Bernard; Hurley, Brett P.; Garnas, Jeff R.
Local antagonism and resource partitioning among two invasive pine plantation pest Journal Article
In: Agricultural and Forest Entomology, vol. 21, pp. 276-285, 2019.
@article{RN23857,
title = {Local antagonism and resource partitioning among two invasive pine plantation pest},
author = {Mesfin Wondafrash and Bernard Slippers and Brett P. Hurley and Jeff R. Garnas},
year = {2019},
date = {2019-01-01},
journal = {Agricultural and Forest Entomology},
volume = {21},
pages = {276-285},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fitza, Katrin N. E.; Garnas, Jeff R.; Lombardero, Maria J.; Ayres, Matthew P.; Krivak-Tetley, Flora E.; Ahumada, Rodrigo; Hurley, Brett P.; Wingfield, Michael J.; Slippers, Bernard
The global diversity of Deladenus siricidicola in native and non-native populations Journal Article
In: Biological Control, vol. 132, pp. 57-65, 2019, ISSN: 10499644.
@article{RN23854,
title = {The global diversity of Deladenus siricidicola in native and non-native populations},
author = {Katrin N. E. Fitza and Jeff R. Garnas and Maria J. Lombardero and Matthew P. Ayres and Flora E. Krivak-Tetley and Rodrigo Ahumada and Brett P. Hurley and Michael J. Wingfield and Bernard Slippers},
doi = {10.1016/j.biocontrol.2019.01.014},
issn = {10499644},
year = {2019},
date = {2019-01-01},
journal = {Biological Control},
volume = {132},
pages = {57-65},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Queffelec, Josephine; Wooding, Amy; Greeff, Jaco; Garnas, Jeff R.; Hurley, Brett P; Wingfield, Michael J; Slippers, Bernard
Potential mechanisms that influence sex ratio variation in the invasive Hymenopteran Sirex noctilio in South Africa Journal Article
In: Ecology and Evolution, vol. 14, pp. 7966-7973, 2019.
@article{RN20843,
title = {Potential mechanisms that influence sex ratio variation in the invasive Hymenopteran Sirex noctilio in South Africa},
author = {Josephine Queffelec and Amy Wooding and Jaco Greeff and Jeff R. Garnas and Brett P Hurley and Michael J Wingfield and Bernard Slippers},
year = {2019},
date = {2019-01-01},
journal = {Ecology and Evolution},
volume = {14},
pages = {7966-7973},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Mutitu, Eston K.; Hoareau, Thierry B.; Hurley, Brett P.; Garnas, Jeffrey R.; Wingfield, Michael J.; Slippers, Bernard
Reconstructing routes of invasion of the Bronze Bug Thaumastocoris peregrinus ﴾Hemiptera: Thaumastocoridae﴿ Journal Article
In: Biological Invasions, vol. 22, pp. 2325–2335, 2019.
@article{RN22372,
title = {Reconstructing routes of invasion of the Bronze Bug Thaumastocoris peregrinus ﴾Hemiptera: Thaumastocoridae﴿},
author = {Eston K. Mutitu and Thierry B. Hoareau and Brett P. Hurley and Jeffrey R. Garnas and Michael J. Wingfield and Bernard Slippers},
url = {https://doi.org/10.1007/s10530-020-02258-w},
year = {2019},
date = {2019-01-01},
journal = {Biological Invasions},
volume = {22},
pages = {2325–2335},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2018
Burgess, Treena; McDougall, Keith; Scott, Peter; Hardy, Giles; Garnas, Jeff
Predictors of Phytophthora diversity and community composition in natural areas across diverse Australian ecoregions Journal Article
In: Ecography, vol. 42, no. 1, pp. 1-14, 2018.
@article{7108,
title = {Predictors of Phytophthora diversity and community composition in natural areas across diverse Australian ecoregions},
author = {Treena Burgess and Keith McDougall and Peter Scott and Giles Hardy and Jeff Garnas},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ecog.03904?af=R},
year = {2018},
date = {2018-01-01},
journal = {Ecography},
volume = {42},
number = {1},
pages = {1-14},
abstract = {Comprehensive understanding of the patterns and drivers of microbial diversity at a landscape scale is in its infancy, despite the recent ease by which soil communities can be characterized using massively parallel amplicon sequencing. Here we report on a comprehensive analysis of the drivers of diversity distribution and composition of the ecologically and economically important Phytophthora genus from 414 soil samples collected across Australia. We assessed 22 environmental and seven categorical variables as potential predictors of Phytophthora species richness, αandβ diversity, including both phylogenetically and non-phylogenically explicit methods. In addition, we classified each species as putatively native or introduced and examined the distribution with respect to putative origin. The two most widespread species, P. multivora and P. cinamomi, are introduced, though five of the ten most widely distributed species are putatively native. Introduced taxa comprised over 54% of Australia’s Phytophthora diversity and these species are known pathogens of annual and perennial crop habitats as well as urban landscapes and forestry. Patterns of composition were most strongly predicted by bioregion (R2=0.29) and ecoregion (R2=0.26) identity; mean precipitation of warmest quarter, mean temperature of the wettest quarter and latitude were also highly significant and described approximately 21%, 14% and 13% of variation in NMDS composition, respectively. We also found statistically significant evidence for phylogenetic over-dispersion with respect to key climate variables.This study provides a strong baseline for understanding biogeographical patterns in this important genus as well the impact of key plant pathogens and invasive Phytophthora species in natural ecosystems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Comprehensive understanding of the patterns and drivers of microbial diversity at a landscape scale is in its infancy, despite the recent ease by which soil communities can be characterized using massively parallel amplicon sequencing. Here we report on a comprehensive analysis of the drivers of diversity distribution and composition of the ecologically and economically important Phytophthora genus from 414 soil samples collected across Australia. We assessed 22 environmental and seven categorical variables as potential predictors of Phytophthora species richness, αandβ diversity, including both phylogenetically and non-phylogenically explicit methods. In addition, we classified each species as putatively native or introduced and examined the distribution with respect to putative origin. The two most widespread species, P. multivora and P. cinamomi, are introduced, though five of the ten most widely distributed species are putatively native. Introduced taxa comprised over 54% of Australia’s Phytophthora diversity and these species are known pathogens of annual and perennial crop habitats as well as urban landscapes and forestry. Patterns of composition were most strongly predicted by bioregion (R2=0.29) and ecoregion (R2=0.26) identity; mean precipitation of warmest quarter, mean temperature of the wettest quarter and latitude were also highly significant and described approximately 21%, 14% and 13% of variation in NMDS composition, respectively. We also found statistically significant evidence for phylogenetic over-dispersion with respect to key climate variables.This study provides a strong baseline for understanding biogeographical patterns in this important genus as well the impact of key plant pathogens and invasive Phytophthora species in natural ecosystems.
Burgess, Treena I.; Tan, Yu Pei; Garnas, Jeff; Edwards, Jacqueline; Scarlett, Kelly A.; Shuttleworth, Lucas A.; Daniel, Rosalie; Dann, Elizabeth K.; Parkinson, Louisamarie E.; Dinh, Quang; Shivas, Roger G.; Jami, Fahimeh
Current status of the Botryosphaeriaceae in Australia Journal Article
In: Australasian Plant Pathology, 2018, ISBN: 1448-6032.
@article{5559,
title = {Current status of the Botryosphaeriaceae in Australia},
author = {Treena I. Burgess and Yu Pei Tan and Jeff Garnas and Jacqueline Edwards and Kelly A. Scarlett and Lucas A. Shuttleworth and Rosalie Daniel and Elizabeth K. Dann and Louisamarie E. Parkinson and Quang Dinh and Roger G. Shivas and Fahimeh Jami},
url = {http://link.springer.com/article/10.1007/s13313-018-0577-5},
doi = {10.1007/s13313-018-0577-5},
isbn = {1448-6032},
year = {2018},
date = {2018-01-01},
journal = {Australasian Plant Pathology},
abstract = {The Botryosphaeriales, and in particular the Botryosphaeriaceae, are a well-studied group of fungi best known for the canker diseases they cause on woody hosts especially in stressed or damaged trees. Australian Plant Pathology herbaria contain many records for this group, but due to considerable taxonomic changes over the past decade, many of the species names have since been reclassified. In this article we used all published records with available sequence data of the Botryosphaeriaceae in Australia to examine the distribution and host range of these taxa. There are 24 genera encompassing 222 species in the Botryosphaeriaceae; 9 genera and 62 species have been recorded in Australia. Some genera such as Neoscytalidium are only found in warm, humid climates while Dothiorella species are more common in temperate climates. There were species, such as Lasiodiplodia theobromae, Neofusicoccum parvum and Botryosphaeria dothidea, which had a wide host range with many records. However, there were also several species found only in one location on a single host. While systematic data collection is still required, the information presented here provides a baseline of species present in Australia and will underpin future studies into this group of important pathogens.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Botryosphaeriales, and in particular the Botryosphaeriaceae, are a well-studied group of fungi best known for the canker diseases they cause on woody hosts especially in stressed or damaged trees. Australian Plant Pathology herbaria contain many records for this group, but due to considerable taxonomic changes over the past decade, many of the species names have since been reclassified. In this article we used all published records with available sequence data of the Botryosphaeriaceae in Australia to examine the distribution and host range of these taxa. There are 24 genera encompassing 222 species in the Botryosphaeriaceae; 9 genera and 62 species have been recorded in Australia. Some genera such as Neoscytalidium are only found in warm, humid climates while Dothiorella species are more common in temperate climates. There were species, such as Lasiodiplodia theobromae, Neofusicoccum parvum and Botryosphaeria dothidea, which had a wide host range with many records. However, there were also several species found only in one location on a single host. While systematic data collection is still required, the information presented here provides a baseline of species present in Australia and will underpin future studies into this group of important pathogens.
Asbjornsen, Heidi; Campbell, John L.; D’Amato, Anthony W.; Garnas, Jeff; Gunn, John S.; Iverson, Louis R.; Ontl, Todd A.; Peters, Mathew W.; Shannon, P. Danielle
Forest management options for addressing drought in the Midwest and Northeast U.S. Booklet
2018.
@booklet{5558,
title = {Forest management options for addressing drought in the Midwest and Northeast U.S.},
author = {Heidi Asbjornsen and John L. Campbell and Anthony W. D’Amato and Jeff Garnas and John S. Gunn and Louis R. Iverson and Todd A. Ontl and Mathew W. Peters and P. Danielle Shannon},
editor = {US Forest Service},
year = {2018},
date = {2018-01-01},
journal = {Forests and Drought},
month = {01},
keywords = {},
pubstate = {published},
tppubtype = {booklet}
}
Garnas, Jeff
Rapid evolution of insects to global environmental change: conceptual issues and empirical gaps Journal Article
In: Current Opinions in Insect Science, vol. 29, pp. 93–101, 2018.
@article{5560,
title = {Rapid evolution of insects to global environmental change: conceptual issues and empirical gaps},
author = {Jeff Garnas},
url = {https://www-sciencedirect-com/science/article/pii/S2214574517301979},
year = {2018},
date = {2018-01-01},
journal = {Current Opinions in Insect Science},
volume = {29},
pages = {93–101},
abstract = {Understanding how insects will respond both ecologically and evolutionarily to complex and interacting factors linked to global change is an important challenge that underpins our ability to produce better predictive models and to anticipate and manage ecosystem-scale disruption in the Anthropocene. Insects have the capacity to rapidly adapt to changing conditions via a variety of mechanisms which include both phenotypically plastic and evolutionary responses that interact in important ways. This short review comments on the current state of knowledge surrounding rapid evolution in insects and highlights conceptual and empirical gaps. Emphasis is placed on the need to consider direct and indirect community-level feedbacks via both ecological and evolutionary mechanisms when examining the consequences of global change, with particular focus on insects and their facultative and obligate symbionts.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Understanding how insects will respond both ecologically and evolutionarily to complex and interacting factors linked to global change is an important challenge that underpins our ability to produce better predictive models and to anticipate and manage ecosystem-scale disruption in the Anthropocene. Insects have the capacity to rapidly adapt to changing conditions via a variety of mechanisms which include both phenotypically plastic and evolutionary responses that interact in important ways. This short review comments on the current state of knowledge surrounding rapid evolution in insects and highlights conceptual and empirical gaps. Emphasis is placed on the need to consider direct and indirect community-level feedbacks via both ecological and evolutionary mechanisms when examining the consequences of global change, with particular focus on insects and their facultative and obligate symbionts.
2017
Wondafrash, Mesfin; Slippers, Bernard; Garnas, J.; Hurley, Brett
Parasitoid assemblage associated with a North American pine weevil in South Africa Journal Article
In: Agricultural and Forest Entomology, 2017.
@article{2608,
title = {Parasitoid assemblage associated with a North American pine weevil in South Africa},
author = {Mesfin Wondafrash and Bernard Slippers and J. Garnas and Brett Hurley},
year = {2017},
date = {2017-01-01},
journal = {Agricultural and Forest Entomology},
abstract = { 1 The weevil Pissodessp. was first reported as an introduced pest on exotic Pinusspp.inSouthAfricain1942.ItisonlyrecentlythatthenativewaspPycnetronpixPrinsloowas described fromSouth Africaas a parasitoidof thisweevil.2 We estimated the frequency and distribution of the association between P. pix andPissodessp., as well as the occurrence of possible other natural enemies. Parasitoidswere reared from Pissodes-infested Pinus radiata D. Don and Pinus patula Schiedeex Schltdl. & Cham logs collected frommajor Pinus-growing regions.3 The identity of parasitoids was confirmed using morphological and molecular tech-niques. Parasitismwas confirmed by analyzing gut content sequences of parasitoids.4 Pycnetron pix was found parasitizing Pissodes sp. throughout major Pinus-growingprovinces of the country. Another native parasitoid, Cratocnema sp., is reported forthe first time as a parasitoid of Pissodes sp. Rhopalicus tutela (Walker), a knownparasitoid of Pissodes spp. in their native range, was also detected and confirmed tobe ofEuropean origin.5 Althoughcharacterizedbyanerraticdistributionandalowparasitismrate,anaccruingsuite of natural enemies was documented, suggesting that there is potential foraugmentative biological control of Pissodessp. inSouth Africa.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1 The weevil Pissodessp. was first reported as an introduced pest on exotic Pinusspp.inSouthAfricain1942.ItisonlyrecentlythatthenativewaspPycnetronpixPrinsloowas described fromSouth Africaas a parasitoidof thisweevil.2 We estimated the frequency and distribution of the association between P. pix andPissodessp., as well as the occurrence of possible other natural enemies. Parasitoidswere reared from Pissodes-infested Pinus radiata D. Don and Pinus patula Schiedeex Schltdl. & Cham logs collected frommajor Pinus-growing regions.3 The identity of parasitoids was confirmed using morphological and molecular tech-niques. Parasitismwas confirmed by analyzing gut content sequences of parasitoids.4 Pycnetron pix was found parasitizing Pissodes sp. throughout major Pinus-growingprovinces of the country. Another native parasitoid, Cratocnema sp., is reported forthe first time as a parasitoid of Pissodes sp. Rhopalicus tutela (Walker), a knownparasitoid of Pissodes spp. in their native range, was also detected and confirmed tobe ofEuropean origin.5 Althoughcharacterizedbyanerraticdistributionandalowparasitismrate,anaccruingsuite of natural enemies was documented, suggesting that there is potential foraugmentative biological control of Pissodessp. inSouth Africa.
Burgess, Treena I.; White, Diane; McDougall, Keith M.; Garnas, Jeff; Dunstan, William A.; Catal`a, Santiago; Carnegie, Angus J.; Worboys, Stuart; Cahill, David; Vettraino, Anna-Maria; Stukely, Michael J. C.; Liew, Edward C. Y.; Paap, Trudy; Bose, Tanay; Migliorini, Duccio; Williams, Briony; Brigg, Frances; Crane, Colin; Rudman, Timothy; Hardy, Giles E. St J.
Distribution and diversity of Phytophthora across Australia Journal Article
In: Pacific Conservation Biology, vol. 23, pp. 1-13, 2017, ISSN: 1038-2097.
@article{RN26702,
title = {Distribution and diversity of Phytophthora across Australia},
author = {Treena I. Burgess and Diane White and Keith M. McDougall and Jeff Garnas and William A. Dunstan and Santiago Catal`a and Angus J. Carnegie and Stuart Worboys and David Cahill and Anna-Maria Vettraino and Michael J. C. Stukely and Edward C. Y. Liew and Trudy Paap and Tanay Bose and Duccio Migliorini and Briony Williams and Frances Brigg and Colin Crane and Timothy Rudman and Giles E. St J. Hardy},
url = {http://dx.doi.org/10.1071/PC16032},
doi = {10.1071/pc16032},
issn = {1038-2097},
year = {2017},
date = {2017-01-01},
journal = {Pacific Conservation Biology},
volume = {23},
pages = {1-13},
abstract = {The introduction and subsequent impact of Phytophthora cinnamomi within native vegetation is one of the major conservation issues for biodiversity in Australia. Recently, many new Phytophthora species have been described from Australia’s native ecosystems; however, their distribution, origin, and potential impact remain unknown. Historical bias in Phytophthora detection has been towards sites showing symptoms of disease, and traditional isolation methods show variable effectiveness of detecting different Phytophthora species. However, we now have at our disposal new techniques based on the sampling of environmental DNA and metabarcoding through the use of high-throughput sequencing. Here, we report on the diversity and distribution of Phytophthora in Australia using metabarcoding of 640 soil samples and we compare the diversity detected using this technique with that available in curated databases. Phytophthora was detected in 65% of sites, and phylogenetic analysis revealed 68 distinct Phytophthora phylotypes. Of these, 21 were identified as potentially unique taxa and 25 were new detections in natural areas and/or new introductions to Australia. There are 66 Phytophthora taxa listed in Australian databases, 43 of which were also detected in this metabarcoding study. This study revealed high Phytophthora richness within native vegetation and the additional records provide a valuable baseline resource for future studies. Many of the Phytophthora species now uncovered in Australia’s native ecosystems are newly described and until more is known we need to be cautious with regard to the spread and conservation management of these new species in Australia’s unique ecosystems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The introduction and subsequent impact of Phytophthora cinnamomi within native vegetation is one of the major conservation issues for biodiversity in Australia. Recently, many new Phytophthora species have been described from Australia’s native ecosystems; however, their distribution, origin, and potential impact remain unknown. Historical bias in Phytophthora detection has been towards sites showing symptoms of disease, and traditional isolation methods show variable effectiveness of detecting different Phytophthora species. However, we now have at our disposal new techniques based on the sampling of environmental DNA and metabarcoding through the use of high-throughput sequencing. Here, we report on the diversity and distribution of Phytophthora in Australia using metabarcoding of 640 soil samples and we compare the diversity detected using this technique with that available in curated databases. Phytophthora was detected in 65% of sites, and phylogenetic analysis revealed 68 distinct Phytophthora phylotypes. Of these, 21 were identified as potentially unique taxa and 25 were new detections in natural areas and/or new introductions to Australia. There are 66 Phytophthora taxa listed in Australian databases, 43 of which were also detected in this metabarcoding study. This study revealed high Phytophthora richness within native vegetation and the additional records provide a valuable baseline resource for future studies. Many of the Phytophthora species now uncovered in Australia’s native ecosystems are newly described and until more is known we need to be cautious with regard to the spread and conservation management of these new species in Australia’s unique ecosystems.
Olivier-Espejel, S.; Hurley, B. P.; Garnas, J.
Assessment of beetle diversity, community composition and potential threats to forestry using kairomone-baited traps Journal Article
In: Bulletin of Entomological Research, vol. 107, pp. 106-117, 2017, ISBN: 1475-2670 (Electronic)0007-4853 (Linking), (Olivier-Espejel, SHurley, B PGarnas, JENG2016/08/23 06:00Bull Entomol Res. 2016 Aug 22:1-12.).
@article{191,
title = {Assessment of beetle diversity, community composition and potential threats to forestry using kairomone-baited traps},
author = {S. Olivier-Espejel and B. P. Hurley and J. Garnas},
url = {https://dx.doi.org/10.1017/S0007485316000699},
isbn = {1475-2670 (Electronic)0007-4853 (Linking)},
year = {2017},
date = {2017-01-01},
journal = {Bulletin of Entomological Research},
volume = {107},
pages = {106-117},
abstract = {Traps designed to capture insects during normal movement/dispersal, or via attraction to non-specific (plant) volatile lures, yield by-catch that carries valuable information about patterns of community diversity and composition. In order to identify potential native/introduced pests and detect predictors of colonization of non-native pines, we examined beetle assemblages captured in intercept panel traps baited with kairomone lures used during a national monitoring of the woodwasp, Sirex noctilio, in Southern Africa. We identified 50 families and 436 morphospecies of beetles from nine sites sampled in both 2008 and 2009 and six areas in 2007 (trap catch pooled by region) across a latitudinal and elevational gradient. The most diverse groups were mainly those strongly associated with trees, known to include damaging pests. While native species dominated the samples in terms of richness, the dominant species was the introduced bark beetle Orthotomicus erosus (Curculionidae: Scolytinae) (22 +/- 34 individuals/site). Four Scolytinae species without previous records in South Africa, namely Coccotrypes niger, Hypocryphalus robustus (formerly Hypocryphalus mangiferae), Hypothenemus birmanus and Xyleborus perforans, were captured in low abundances. Communities showed temporal stability within sites and strong biogeographic patterns across the landscape. The strongest single predictors of community composition were potential evaporation, latitude and maximum relative humidity, while the strongest multifactor model contained elevation, potential evaporation and maximum relative humidity. Temperature, land use variables and distance to natural areas did not significantly correlate with community composition. Non-phytophagous beetles were also captured and were highly diverse (32 families) perhaps representing important beneficial insects.},
note = {Olivier-Espejel, SHurley, B PGarnas, JENG2016/08/23 06:00Bull Entomol Res. 2016 Aug 22:1-12.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Traps designed to capture insects during normal movement/dispersal, or via attraction to non-specific (plant) volatile lures, yield by-catch that carries valuable information about patterns of community diversity and composition. In order to identify potential native/introduced pests and detect predictors of colonization of non-native pines, we examined beetle assemblages captured in intercept panel traps baited with kairomone lures used during a national monitoring of the woodwasp, Sirex noctilio, in Southern Africa. We identified 50 families and 436 morphospecies of beetles from nine sites sampled in both 2008 and 2009 and six areas in 2007 (trap catch pooled by region) across a latitudinal and elevational gradient. The most diverse groups were mainly those strongly associated with trees, known to include damaging pests. While native species dominated the samples in terms of richness, the dominant species was the introduced bark beetle Orthotomicus erosus (Curculionidae: Scolytinae) (22 +/- 34 individuals/site). Four Scolytinae species without previous records in South Africa, namely Coccotrypes niger, Hypocryphalus robustus (formerly Hypocryphalus mangiferae), Hypothenemus birmanus and Xyleborus perforans, were captured in low abundances. Communities showed temporal stability within sites and strong biogeographic patterns across the landscape. The strongest single predictors of community composition were potential evaporation, latitude and maximum relative humidity, while the strongest multifactor model contained elevation, potential evaporation and maximum relative humidity. Temperature, land use variables and distance to natural areas did not significantly correlate with community composition. Non-phytophagous beetles were also captured and were highly diverse (32 families) perhaps representing important beneficial insects.
Mbenoun, M; Garnas, JR; Wingfield, M; Boyogueno, A; Roux, J
Metacommunity analyses of Ceratocystidaceae fungi across heterogeneous African savanna landscapes Journal Article
In: Fungal Ecology, vol. 28, pp. 76-85, 2017.
@article{190,
title = {Metacommunity analyses of Ceratocystidaceae fungi across heterogeneous African savanna landscapes},
author = {M Mbenoun and JR Garnas and M Wingfield and A Boyogueno and J Roux},
url = {www.sciencedirect.com/science/article/pii/S175450481630126X},
year = {2017},
date = {2017-00-01},
journal = {Fungal Ecology},
volume = {28},
pages = {76-85},
abstract = {Metacommunity theory offers a powerful framework to investigating the structure and dynamics of ecological communities. We use Ceratocystidaceae fungi as an empirical system to explore the potential of metacommunity principles to explain the incidence of putative fungal tree pathogens in natural ecosystems. The diversity of Ceratocystidaceae fungi was evaluated on elephant-damaged trees across the Kruger National Park of South Africa. Multivariate statistics were then used to assess the influence of landscapes, tree hosts and nitidulid beetle associates as well as isolation by distance on fungal community structure. Eight fungal and six beetle species were recovered on trees representing several plant genera. The distribution of Ceratocystidaceae fungi was highly heterogeneous across landscapes. Both tree host and nitidulid vector emerged as key factors contributing to this heterogeneity, while isolation by distance showed little influence. Our results are consistent with a model of metacommunity dynamics combining species sorting and patch dynamics processes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Metacommunity theory offers a powerful framework to investigating the structure and dynamics of ecological communities. We use Ceratocystidaceae fungi as an empirical system to explore the potential of metacommunity principles to explain the incidence of putative fungal tree pathogens in natural ecosystems. The diversity of Ceratocystidaceae fungi was evaluated on elephant-damaged trees across the Kruger National Park of South Africa. Multivariate statistics were then used to assess the influence of landscapes, tree hosts and nitidulid beetle associates as well as isolation by distance on fungal community structure. Eight fungal and six beetle species were recovered on trees representing several plant genera. The distribution of Ceratocystidaceae fungi was highly heterogeneous across landscapes. Both tree host and nitidulid vector emerged as key factors contributing to this heterogeneity, while isolation by distance showed little influence. Our results are consistent with a model of metacommunity dynamics combining species sorting and patch dynamics processes.
2016
Wondafrash, M.; Slippers, B.; Garnas, J.; Roux, G.; Foit, J.; Langor, D. W.; Hurley, B. P.
In: Biological Invasions, vol. 18, pp. 2283-2297, 2016, ISBN: 1387-3547, (Dr7zdTimes Cited:0Cited References Count:69).
@article{194,
title = {Identification and genetic diversity of two invasive Pissodes spp. Germar (Coleoptera: Curculionidae) in their introduced range in the southern hemisphere},
author = {M. Wondafrash and B. Slippers and J. Garnas and G. Roux and J. Foit and D. W. Langor and B. P. Hurley},
url = {http:/dx.doi.org/10.1007/s10530-016-1159-5},
isbn = {1387-3547},
year = {2016},
date = {2016-08-01},
journal = {Biological Invasions},
volume = {18},
pages = {2283-2297},
abstract = {During the first half of the twentieth century, two accidental cases of introduction of Pissodes weevils were recorded from the southern hemisphere. The weevils in South Africa were identified as the deodar weevil (Pissodes nemorensis) and those in South America as the small banded pine weevil (Pissodes castaneus). Wide distribution of the two species in their invasive range, general difficulty in identifying some Pissodes spp., and the varying feeding and breeding behaviours of the species in South Africa has necessitated better evidence of species identity and genetic diversity of both species and population structure of the species in South Africa. Barcoding and the Jerry-to-Pat region of the COI gene were investigated. Morphometric data of the South African species was analysed. Our results confirmed the introduction of only one Pissodes species of North American origin to South Africa. However, this species is not P. nemorensis, but an unrecognized species of the P. strobi complex or a hybrid between P. strobi and P. nemorensis. Only P. castaneus, of European origin, was identified from South America. We identified ten mitochondrial DNA haplotypes from South Africa with evidence of moderate genetic structure among geographic populations. Terminal leader and bole-feeding weevils did not differ at the COI locus. A single haplotype was identified from populations of P. castaneus in South America. Results of the present study will have implications on quarantine, research and management of these insect species.},
note = {Dr7zdTimes Cited:0Cited References Count:69},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
During the first half of the twentieth century, two accidental cases of introduction of Pissodes weevils were recorded from the southern hemisphere. The weevils in South Africa were identified as the deodar weevil (Pissodes nemorensis) and those in South America as the small banded pine weevil (Pissodes castaneus). Wide distribution of the two species in their invasive range, general difficulty in identifying some Pissodes spp., and the varying feeding and breeding behaviours of the species in South Africa has necessitated better evidence of species identity and genetic diversity of both species and population structure of the species in South Africa. Barcoding and the Jerry-to-Pat region of the COI gene were investigated. Morphometric data of the South African species was analysed. Our results confirmed the introduction of only one Pissodes species of North American origin to South Africa. However, this species is not P. nemorensis, but an unrecognized species of the P. strobi complex or a hybrid between P. strobi and P. nemorensis. Only P. castaneus, of European origin, was identified from South America. We identified ten mitochondrial DNA haplotypes from South Africa with evidence of moderate genetic structure among geographic populations. Terminal leader and bole-feeding weevils did not differ at the COI locus. A single haplotype was identified from populations of P. castaneus in South America. Results of the present study will have implications on quarantine, research and management of these insect species.
Garnas, Jeff R.; Auger-Rozenberg, M. A.; Roques, Alain; Bertelsmeier, Cleo; Wingfield, Michael J.; Saccaggi, Davina L.; Roy, Helen E.; Slippers, Bernard
Complex patterns of global spread in invasive insects: eco-evolutionary and management consequences Journal Article
In: Biological Invasions, vol. 18, pp. 935-952, 2016, ISBN: 1387-35471573-1464.
@article{185,
title = {Complex patterns of global spread in invasive insects: eco-evolutionary and management consequences},
author = {Jeff R. Garnas and M. A. Auger-Rozenberg and Alain Roques and Cleo Bertelsmeier and Michael J. Wingfield and Davina L. Saccaggi and Helen E. Roy and Bernard Slippers},
url = {http://dx.doi.org/10.1007/s10530-016-1082-9},
isbn = {1387-35471573-1464},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {935-952},
abstract = {The advent of simple and affordable tools for molecular identification of novel insect invaders and assessment of population diversity has changed the face of invasion biology in recent years. The widespread application of these tools has brought with it an emerging understanding that patterns in biogeography, introduction history and subsequent movement and spread of many invasive alien insects are far more complex than previously thought. We reviewed the literature and found that for a number of invasive insects, there is strong and growing evidence that multiple introductions, complex global movement, and population admixture in the invaded range are commonplace. Additionally, historical paradigms related to species and strain identities and origins of common invaders are in many cases being challenged. This has major consequences for our understanding of basic biology and ecology of invasive insects and impacts quarantine, management and biocontrol programs. In addition, we found that founder effects rarely limit fitness in invasive insects and may benefit populations (by purging harmful alleles or increasing additive genetic variance). Also, while phenotypic plasticity appears important post-establishment, genetic diversity in invasive insects is often higher than expected and increases over time via multiple introductions. Further, connectivity among disjunct regions of global invasive ranges is generally far higher than expected and is often asymmetric, with some populations contributing disproportionately to global spread. We argue that the role of connectivity in driving the ecology and evolution of introduced species with multiple invasive ranges has been historically underestimated and that such species are often best understood in a global context.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The advent of simple and affordable tools for molecular identification of novel insect invaders and assessment of population diversity has changed the face of invasion biology in recent years. The widespread application of these tools has brought with it an emerging understanding that patterns in biogeography, introduction history and subsequent movement and spread of many invasive alien insects are far more complex than previously thought. We reviewed the literature and found that for a number of invasive insects, there is strong and growing evidence that multiple introductions, complex global movement, and population admixture in the invaded range are commonplace. Additionally, historical paradigms related to species and strain identities and origins of common invaders are in many cases being challenged. This has major consequences for our understanding of basic biology and ecology of invasive insects and impacts quarantine, management and biocontrol programs. In addition, we found that founder effects rarely limit fitness in invasive insects and may benefit populations (by purging harmful alleles or increasing additive genetic variance). Also, while phenotypic plasticity appears important post-establishment, genetic diversity in invasive insects is often higher than expected and increases over time via multiple introductions. Further, connectivity among disjunct regions of global invasive ranges is generally far higher than expected and is often asymmetric, with some populations contributing disproportionately to global spread. We argue that the role of connectivity in driving the ecology and evolution of introduced species with multiple invasive ranges has been historically underestimated and that such species are often best understood in a global context.
Hui, Cang; Richardson, David M.; Landi, Pietro; Minoarivelo, Henintsoa O.; Garnas, JR; Roy, Helen E.
Defining invasiveness and invasibility in ecological networks Journal Article
In: Biological Invasions, vol. 18, pp. 971-983, 2016.
@article{188,
title = {Defining invasiveness and invasibility in ecological networks},
author = {Cang Hui and David M. Richardson and Pietro Landi and Henintsoa O. Minoarivelo and JR Garnas and Helen E. Roy},
url = {http://dx.doi.org/10.1007/s10530-016-1076-7},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {971-983},
abstract = {The success of a biological invasion is context dependent, and yet two key concepts—the invasiveness of species and the invasibility of recipient ecosystems—are often defined and considered separately. We propose a framework that can elucidate the complex relationship between invasibility and invasiveness. It is based on trait-mediated interactions between species and depicts the response of an ecological network to the intrusion of an alien species, drawing on the concept of community saturation. Here, invasiveness of an introduced species with a particular trait is measured by its per capita population growth rate when the initial propagule pressure of the introduced species is very low. The invasibility of the recipient habitat or ecosystem is dependent on the structure of the resident ecological network and is defined as the total width of an opportunity niche in the trait space susceptible to invasion. Invasibility is thus a measure of network instability. We also correlate invasibility with the asymptotic stability of resident ecological network, measured by the leading eigenvalue of the interaction matrix that depicts trait-based interaction intensity multiplied by encounter rate (a pairwise product of propagule pressure of all members in a community). We further examine the relationship between invasibility and network architecture, including network connectance, nestedness and modularity. We exemplify this framework with a trait-based assembly model under perturbations in ways to emulate fluctuating resources and random trait composition in ecological networks. The maximum invasiveness of a potential invader (greatest intrinsic population growth rate) was found to be positively correlated with invasibility of the recipient ecological network. Additionally, ecosystems with high network modularity and high ecological stability tend to exhibit high invasibility. Where quantitative data are lacking we propose using a qualitative interaction matrix of the ecological network perceived by a potential invader so that the structural network stability and invasibility can be estimated from the literature or from expert opinion. This approach links network structure, invasiveness and invasibility in the context of trait-mediated interactions, such as the invasion of insects into mutualistic and antagonistic networks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The success of a biological invasion is context dependent, and yet two key concepts—the invasiveness of species and the invasibility of recipient ecosystems—are often defined and considered separately. We propose a framework that can elucidate the complex relationship between invasibility and invasiveness. It is based on trait-mediated interactions between species and depicts the response of an ecological network to the intrusion of an alien species, drawing on the concept of community saturation. Here, invasiveness of an introduced species with a particular trait is measured by its per capita population growth rate when the initial propagule pressure of the introduced species is very low. The invasibility of the recipient habitat or ecosystem is dependent on the structure of the resident ecological network and is defined as the total width of an opportunity niche in the trait space susceptible to invasion. Invasibility is thus a measure of network instability. We also correlate invasibility with the asymptotic stability of resident ecological network, measured by the leading eigenvalue of the interaction matrix that depicts trait-based interaction intensity multiplied by encounter rate (a pairwise product of propagule pressure of all members in a community). We further examine the relationship between invasibility and network architecture, including network connectance, nestedness and modularity. We exemplify this framework with a trait-based assembly model under perturbations in ways to emulate fluctuating resources and random trait composition in ecological networks. The maximum invasiveness of a potential invader (greatest intrinsic population growth rate) was found to be positively correlated with invasibility of the recipient ecological network. Additionally, ecosystems with high network modularity and high ecological stability tend to exhibit high invasibility. Where quantitative data are lacking we propose using a qualitative interaction matrix of the ecological network perceived by a potential invader so that the structural network stability and invasibility can be estimated from the literature or from expert opinion. This approach links network structure, invasiveness and invasibility in the context of trait-mediated interactions, such as the invasion of insects into mutualistic and antagonistic networks.
Hajek, Ann E.; Hurley, Brett P.; Kenis, Marc; Garnas, Jeffrey R.; Bush, Samantha J.; Wingfield, Michael J.; Lenteren, Joop C. Van; Cock, Matthew J. W.
Exotic biological control agents: a solution or contribution to arthropod invasions? Journal Article
In: Biological Invasions, vol. 18, pp. 953-969, 2016.
@article{186,
title = {Exotic biological control agents: a solution or contribution to arthropod invasions?},
author = {Ann E. Hajek and Brett P. Hurley and Marc Kenis and Jeffrey R. Garnas and Samantha J. Bush and Michael J. Wingfield and Joop C. Van Lenteren and Matthew J. W. Cock},
url = {http://dx.doi.org/10.1007/s10530-016-1075-8},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {953-969},
abstract = {Biological control is a valuable and effective strategy for controlling arthropod pests and has been used extensively against invasive arthropods. As one approach for control of invasives, exotic natural enemies from the native range of a pest are introduced to areas where control is needed. Classical biological control began to be used in the late 1800s and its use increased until, beginning in 1983, scientists began raising significant concerns and questions about nontarget and indirect effects that can be caused by these introductions. In recent years, similar issues have been raised about augmentative use of exotic natural enemies. Subsequently, international guidelines, national regulations and scientific methods being used for exotic natural enemies in biological control have changed to require appropriate specificity testing, risk assessment and regulatory oversight before exotic natural enemies can be released. National and international standards aimed at minimizing risk have increased awareness and promoted more careful consideration of the costs and benefits associated with biological control. The barriers to the implementation of classical and augmentative biological control with exotic natural enemies now are sometimes difficult and, as a consequence, the numbers of classical biological control programs and releases have decreased significantly. Based in part on this new, more careful approach, classical biological control programs more recently undertaken are increasingly aimed at controlling especially damaging invasive arthropod pests that otherwise cannot be controlled. We examine evidence for these revised procedures and regulations aimed at increasing success and minimizing risk. We also discuss limitations linked to the apparent paucity of post-introduction monitoring and inherent unpredictability of indirect effects.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Biological control is a valuable and effective strategy for controlling arthropod pests and has been used extensively against invasive arthropods. As one approach for control of invasives, exotic natural enemies from the native range of a pest are introduced to areas where control is needed. Classical biological control began to be used in the late 1800s and its use increased until, beginning in 1983, scientists began raising significant concerns and questions about nontarget and indirect effects that can be caused by these introductions. In recent years, similar issues have been raised about augmentative use of exotic natural enemies. Subsequently, international guidelines, national regulations and scientific methods being used for exotic natural enemies in biological control have changed to require appropriate specificity testing, risk assessment and regulatory oversight before exotic natural enemies can be released. National and international standards aimed at minimizing risk have increased awareness and promoted more careful consideration of the costs and benefits associated with biological control. The barriers to the implementation of classical and augmentative biological control with exotic natural enemies now are sometimes difficult and, as a consequence, the numbers of classical biological control programs and releases have decreased significantly. Based in part on this new, more careful approach, classical biological control programs more recently undertaken are increasingly aimed at controlling especially damaging invasive arthropod pests that otherwise cannot be controlled. We examine evidence for these revised procedures and regulations aimed at increasing success and minimizing risk. We also discuss limitations linked to the apparent paucity of post-introduction monitoring and inherent unpredictability of indirect effects.
Fitza, Katrin N. E.; Tabata, Masanobu; Kanzaki, Natsumi; Kimura, Koki; Garnas, Jeff; Slippers, Bernard
Host specificity and diversity of Amylostereum associated with Japanese siricids Journal Article
In: Fungal Ecology, vol. 24, pp. 76-81, 2016, ISBN: 17545048.
@article{184,
title = {Host specificity and diversity of Amylostereum associated with Japanese siricids},
author = {Katrin N. E. Fitza and Masanobu Tabata and Natsumi Kanzaki and Koki Kimura and Jeff Garnas and Bernard Slippers},
url = {htttp://dx.doi.org/10.1016/j.funeco.2016.08.005},
isbn = {17545048},
year = {2016},
date = {2016-01-01},
journal = {Fungal Ecology},
volume = {24},
pages = {76-81},
abstract = {The mutualism between siricid woodwasps and Amylostereum fungal symbionts has long been considered to be species-specific. Recent studies from North America have challenged this assumption, where native siricids and the introduced Sirex noctilio are clearly swapping symbionts. Whether this pattern is a consequence of invasion or an underappreciated property of siricid biology is unknown. Here we show that the native Japanese siricid, Sirex nitobei, carries both Amylostereum areolatum and Amylostereum chailletii, rather than only A. areolatum as long assumed. Furthermore, all samples from a Urocerus sp. unexpectedly carried, A. chailletii and not Amylostereum laevigatum. Vegetative compatibility group tests revealed extensive clonality, with one VCG present amongst three A. areolatum isolates and six VCGs present amongst 61 A. chailletii isolates. These results contribute to the understanding of insect-fungal fidelity in the siricid-Amylostereum association and, together with other studies, suggest that host tree influences Amylostereum species occurrence, perhaps more strongly than wasps.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The mutualism between siricid woodwasps and Amylostereum fungal symbionts has long been considered to be species-specific. Recent studies from North America have challenged this assumption, where native siricids and the introduced Sirex noctilio are clearly swapping symbionts. Whether this pattern is a consequence of invasion or an underappreciated property of siricid biology is unknown. Here we show that the native Japanese siricid, Sirex nitobei, carries both Amylostereum areolatum and Amylostereum chailletii, rather than only A. areolatum as long assumed. Furthermore, all samples from a Urocerus sp. unexpectedly carried, A. chailletii and not Amylostereum laevigatum. Vegetative compatibility group tests revealed extensive clonality, with one VCG present amongst three A. areolatum isolates and six VCGs present amongst 61 A. chailletii isolates. These results contribute to the understanding of insect-fungal fidelity in the siricid-Amylostereum association and, together with other studies, suggest that host tree influences Amylostereum species occurrence, perhaps more strongly than wasps.
Hurley, Brett P.; Garnas, Jeff; Wingfield, Michael J.; Branco, Manuela; Richardson, David M.; Slippers, Bernard
Increasing numbers and intercontinental spread of invasive insects on eucalypts Journal Article
In: Biological Invasions, vol. 18, pp. 921-933, 2016.
@article{189,
title = {Increasing numbers and intercontinental spread of invasive insects on eucalypts},
author = {Brett P. Hurley and Jeff Garnas and Michael J. Wingfield and Manuela Branco and David M. Richardson and Bernard Slippers},
url = {http://dx.doi.org/10.1007/s10530-016-1081-x},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {921-933},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wingfield, Michael J.; Garnas, Jeff R.; Hajek, Ann; Hurley, Brett P.; Beer, Z. Wilhelm De; Taeru,
Novel and co-evolved associations between insects and microorganisms as drivers of forest pestilence Journal Article
In: Biological Invasions, vol. 18, pp. 1045-1056, 2016.
@article{193,
title = {Novel and co-evolved associations between insects and microorganisms as drivers of forest pestilence},
author = {Michael J. Wingfield and Jeff R. Garnas and Ann Hajek and Brett P. Hurley and Z. Wilhelm De Beer and Taeru},
url = {http://dx.doi.org/10.1007/s10530-016-1084-7},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {1045-1056},
abstract = {Some of the most devastating diseases of trees involve associations between forest insects and microorganisms. Although a small number of native insect-microorganism symbioses can cause tree mortality, the majority of associations with tree health implications involve one or more exotic organisms. Here, we divide damaging symbioses between forest insects and microorganisms into four categories based on the native/exotic status of the species involved: (1) insect and microorganism are native; (2) insect is native, microorganism is exotic; (3) insect is exotic, microorganism is native; and (4) insect and microorganism are both exotic. For each category, we describe several well-researched examples of forest insect symbioses and discuss some of the consequences of the types of interactions within each category. We then discuss priorities for research on forest insect symbioses that could help to further elucidate patterns in the complexity of such interactions in the context of invasion biology. We argue that a nuanced understanding of insect-pathogen relationships is lacking, even for the few well-studied examples. Because novel associations between insects, microorganisms, and trees are increasing with globalization, such symbioses and their potential to negatively impact forest ecosystems demand focused research in the future.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Some of the most devastating diseases of trees involve associations between forest insects and microorganisms. Although a small number of native insect-microorganism symbioses can cause tree mortality, the majority of associations with tree health implications involve one or more exotic organisms. Here, we divide damaging symbioses between forest insects and microorganisms into four categories based on the native/exotic status of the species involved: (1) insect and microorganism are native; (2) insect is native, microorganism is exotic; (3) insect is exotic, microorganism is native; and (4) insect and microorganism are both exotic. For each category, we describe several well-researched examples of forest insect symbioses and discuss some of the consequences of the types of interactions within each category. We then discuss priorities for research on forest insect symbioses that could help to further elucidate patterns in the complexity of such interactions in the context of invasion biology. We argue that a nuanced understanding of insect-pathogen relationships is lacking, even for the few well-studied examples. Because novel associations between insects, microorganisms, and trees are increasing with globalization, such symbioses and their potential to negatively impact forest ecosystems demand focused research in the future.
Hill, M. P.; Bertelsmeier, C; Clusella-Trullas, S; Garnas, JR; Robertson, M. P; Terblanche, J. S
Predicted decrease in global climate suitability masks regional complexity of invasive fruit fly species response to climate change Journal Article
In: Biological Invasions, vol. 18, pp. 883-891, 2016.
@article{187,
title = {Predicted decrease in global climate suitability masks regional complexity of invasive fruit fly species response to climate change},
author = {M. P. Hill and C Bertelsmeier and S Clusella-Trullas and JR Garnas and M. P Robertson and J. S Terblanche},
url = {http://dx.doi.org/10.1007/s10530-016-1078-5},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {883-891},
abstract = {Climate change affects the rate of insect invasions as well as the abundance, distribution and impacts of such invasions on a global scale. Among the principal analytical approaches to predicting and understanding future impacts of biological invasions are Species Distribution Models (SDMs), typically in the form of correlative Ecological Niche Models (ENMs). An underlying assumption of ENMs is that species–environment relationships remain preserved during extrapolations in space and time, although this is widely criticised. The semi-mechanistic modelling platform, CLIMEX, employs a top-down approach using species ecophysiological traits and is able to avoid some of the issues of extrapolation, making it highly applicable to investigating biological invasions in the context of climate change. The tephritid fruit flies (Diptera: Tephritidae) comprise some of the most successful invasive species and serious economic pests around the world. Here we project 12 tephritid species CLIMEX models into future climate scenarios to examine overall patterns of climate suitability and forecast potential distributional changes for this group. We further compare the aggregate response of the group against species-specific responses. We then consider additional drivers of biological invasions to examine how invasion potential is influenced by climate, fruit production and trade indices. Considering the group of tephritid species examined here, climate change is predicted to decrease global climate suitability and to shift the cumulative distribution poleward. However, when examining species-level patterns, the predominant directionality of range shifts for 11 of the 12 species is eastward. Most notably, management will need to consider regional changes in fruit fly species invasion potential where high fruit production, trade indices and predicted distributions of these flies overlap.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Climate change affects the rate of insect invasions as well as the abundance, distribution and impacts of such invasions on a global scale. Among the principal analytical approaches to predicting and understanding future impacts of biological invasions are Species Distribution Models (SDMs), typically in the form of correlative Ecological Niche Models (ENMs). An underlying assumption of ENMs is that species–environment relationships remain preserved during extrapolations in space and time, although this is widely criticised. The semi-mechanistic modelling platform, CLIMEX, employs a top-down approach using species ecophysiological traits and is able to avoid some of the issues of extrapolation, making it highly applicable to investigating biological invasions in the context of climate change. The tephritid fruit flies (Diptera: Tephritidae) comprise some of the most successful invasive species and serious economic pests around the world. Here we project 12 tephritid species CLIMEX models into future climate scenarios to examine overall patterns of climate suitability and forecast potential distributional changes for this group. We further compare the aggregate response of the group against species-specific responses. We then consider additional drivers of biological invasions to examine how invasion potential is influenced by climate, fruit production and trade indices. Considering the group of tephritid species examined here, climate change is predicted to decrease global climate suitability and to shift the cumulative distribution poleward. However, when examining species-level patterns, the predominant directionality of range shifts for 11 of the 12 species is eastward. Most notably, management will need to consider regional changes in fruit fly species invasion potential where high fruit production, trade indices and predicted distributions of these flies overlap.
Roques, Alain; Auger-Rozenberg, Marie-Anne; Blackburn, Tim M.; Garnas, JR; Pyšek, Petr; Rabitsch, Wolfgang; Richardson, David M.; Wingfield, Michael J.; Liebhold, Andrew M.; Duncan, Richard P.
Temporal and interspecific variation in rates of spread for insect species invading Europe during the last 200 years Journal Article
In: Biological Invasions, vol. 18, pp. 907-920, 2016.
@article{192,
title = {Temporal and interspecific variation in rates of spread for insect species invading Europe during the last 200 years},
author = {Alain Roques and Marie-Anne Auger-Rozenberg and Tim M. Blackburn and JR Garnas and Petr Pyšek and Wolfgang Rabitsch and David M. Richardson and Michael J. Wingfield and Andrew M. Liebhold and Richard P. Duncan},
url = {http://dx.doi.org/10.1007/s10530-016-1080-y},
year = {2016},
date = {2016-01-01},
journal = {Biological Invasions},
volume = {18},
pages = {907-920},
abstract = {Globalization is triggering an increase in the establishment of alien insects in Europe, with several species having substantial ecological and economic impacts. We investigated long-term changes in rates of species spread following establishment. We used the total area of countries invaded by 1171 insect species for which the date of first record in Europe is known, to estimate their current range radius (calculated as [invaded area]0.5/π). We estimated initial rates of radial spread and compared them among different groups of insects for all years (1800–2014) and for a subset of more recent decades (1950–2014). Accidentally introduced species spread faster than intentionally introduced species. Considering the whole period 1800–2014, spread patterns also differ between feeding guilds, with decreasing spread rates over residence time in herbivores but not in detritivores or parasitic species. These decreases for herbivorous species appeared mainly in those associated with herbaceous plants and crops rather than woody plants. Initial spread rate was significantly greater for species detected after 1990, roughly 3–4 times higher than for species that arrived earlier. We hypothesize that the political changes in Europe following the collapse of the Iron Curtain in 1989, and the further dismantling of customs checkpoints within an enlarged European Union (EU) have facilitated the faster spread of alien insect species. Also, the number of species first recorded in the Eastern Bloc of the politically-divided Europe before 1989 was lower than for the rest of Europe. A detailed analysis of six recent invaders indicated a dominant role of long-distance translocations related to human activities, especially with the plant trade, in determining rates of spread.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Globalization is triggering an increase in the establishment of alien insects in Europe, with several species having substantial ecological and economic impacts. We investigated long-term changes in rates of species spread following establishment. We used the total area of countries invaded by 1171 insect species for which the date of first record in Europe is known, to estimate their current range radius (calculated as [invaded area]0.5/π). We estimated initial rates of radial spread and compared them among different groups of insects for all years (1800–2014) and for a subset of more recent decades (1950–2014). Accidentally introduced species spread faster than intentionally introduced species. Considering the whole period 1800–2014, spread patterns also differ between feeding guilds, with decreasing spread rates over residence time in herbivores but not in detritivores or parasitic species. These decreases for herbivorous species appeared mainly in those associated with herbaceous plants and crops rather than woody plants. Initial spread rate was significantly greater for species detected after 1990, roughly 3–4 times higher than for species that arrived earlier. We hypothesize that the political changes in Europe following the collapse of the Iron Curtain in 1989, and the further dismantling of customs checkpoints within an enlarged European Union (EU) have facilitated the faster spread of alien insect species. Also, the number of species first recorded in the Eastern Bloc of the politically-divided Europe before 1989 was lower than for the rest of Europe. A detailed analysis of six recent invaders indicated a dominant role of long-distance translocations related to human activities, especially with the plant trade, in determining rates of spread.
2015
Nadel, R. L.; Wingfield, M. J.; Scholes, M. C.; Garnas, J. R.; Lawson, S. A.; Slippers, B.
Population dynamics of Thaumastocoris peregrinus in Eucalyptus plantations of South Africa Journal Article
In: Journal of Pest Science, vol. 88, pp. 97-106, 2015, ISBN: 1612-4758, (Cc0pwTimes Cited:1Cited References Count:53).
@article{183,
title = {Population dynamics of Thaumastocoris peregrinus in Eucalyptus plantations of South Africa},
author = {R. L. Nadel and M. J. Wingfield and M. C. Scholes and J. R. Garnas and S. A. Lawson and B. Slippers},
url = {http://dx.doi.org/10.1007/s10340-014-0558-6},
isbn = {1612-4758},
year = {2015},
date = {2015-03-01},
journal = {Journal of Pest Science},
volume = {88},
pages = {97-106},
abstract = {Thaumastocoris peregrinus is a sap-sucking insect that infests non-native Eucalyptus plantations in Africa, New Zealand, South America and parts of Southern Europe, in addition to street trees in parts of its native range of Australia. In South Africa, pronounced fluctuations in the population densities have been observed. To characterise spatiotemporal variability in T. peregrinus abundance and the factors that might influence it, we monitored adult population densities at six sites in the main eucalypt growing regions of South Africa. At each site, twenty yellow sticky traps were monitored weekly for 30 months, together with climatic data. We also characterised the influence of temperature on growth and survival experimentally and used this to model how temperature may influence population dynamics. T. peregrinus was present throughout the year at all sites, with annual site-specific peaks in abundance. Peaks occurred during autumn (February-April) for the Pretoria site, summer (November-January) for the Zululand site and spring (August-October) for the Tzaneen, Sabie and Piet Retief monitoring sites. Temperature (both experimental and field-collected), humidity and rainfall were mostly weakly, or not at all, associated with population fluctuations. It is clear that a complex interaction of these and other factors (e.g. host quality) influence population fluctuations in an annual, site specific cycle. The results obtained not only provide insights into the biology of T. peregrinus, but will also be important for future planning of monitoring and control programs using semiochemicals, chemical insecticides or biological control agents.},
note = {Cc0pwTimes Cited:1Cited References Count:53},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Thaumastocoris peregrinus is a sap-sucking insect that infests non-native Eucalyptus plantations in Africa, New Zealand, South America and parts of Southern Europe, in addition to street trees in parts of its native range of Australia. In South Africa, pronounced fluctuations in the population densities have been observed. To characterise spatiotemporal variability in T. peregrinus abundance and the factors that might influence it, we monitored adult population densities at six sites in the main eucalypt growing regions of South Africa. At each site, twenty yellow sticky traps were monitored weekly for 30 months, together with climatic data. We also characterised the influence of temperature on growth and survival experimentally and used this to model how temperature may influence population dynamics. T. peregrinus was present throughout the year at all sites, with annual site-specific peaks in abundance. Peaks occurred during autumn (February-April) for the Pretoria site, summer (November-January) for the Zululand site and spring (August-October) for the Tzaneen, Sabie and Piet Retief monitoring sites. Temperature (both experimental and field-collected), humidity and rainfall were mostly weakly, or not at all, associated with population fluctuations. It is clear that a complex interaction of these and other factors (e.g. host quality) influence population fluctuations in an annual, site specific cycle. The results obtained not only provide insights into the biology of T. peregrinus, but will also be important for future planning of monitoring and control programs using semiochemicals, chemical insecticides or biological control agents.
Hurley, Brett P.; Garnas, Jeff; Cooperband, Miriam F.
Assessing trap and lure effectiveness for the monitoring of Sirex noctilio Journal Article
In: Agricultural and Forest Entomology, vol. 17, pp. 64-70, 2015, ISBN: 14619555.
@article{182,
title = {Assessing trap and lure effectiveness for the monitoring of Sirex noctilio},
author = {Brett P. Hurley and Jeff Garnas and Miriam F. Cooperband},
url = {http://dx.doi.org/10.1111/afe.12081},
isbn = {14619555},
year = {2015},
date = {2015-01-01},
journal = {Agricultural and Forest Entomology},
volume = {17},
pages = {64-70},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2014
Garnas, J.; Groden, E.; Drummond, F. A.
Mechanisms of competitive displacement of native ant fauna by invading Myrmica rubra (Hymenoptera: Formicidae) populations Journal Article
In: Environmental Entomology, vol. 43, pp. 1496-506, 2014, ISBN: 1938-2936 (Electronic)0046-225X (Linking), (Garnas, JeffreyGroden, EleanorDrummond, Francis Aeng2014/10/01 06:00Environ Entomol. 2014 Dec;43(6):1496-506. doi: 10.1603/EN14079. Epub 2014 Sep 29.).
@article{180,
title = {Mechanisms of competitive displacement of native ant fauna by invading Myrmica rubra (Hymenoptera: Formicidae) populations},
author = {J. Garnas and E. Groden and F. A. Drummond},
url = {http://dx.doi.org/10.1603/EN14079},
isbn = {1938-2936 (Electronic)0046-225X (Linking)},
year = {2014},
date = {2014-12-01},
journal = {Environmental Entomology},
volume = {43},
pages = {1496-506},
abstract = {Exotic ants have become invasive in many regions around the world, with variable ecological impacts. Postinvasion, native ant communities are often found to be depauperate, though the causes of this apparent lack of coexistence are rarely well known. Myrmica rubra (L.), a Palearctic Myrmecine ant, is currently expanding its range as an invasive in North America. This aggressive ant forms dense, patchy local infestations and appears to aggressively displace native ant fauna. We measured behavioral interactions and rates of recruitment in experimental field assays pitting native foragers against captive colonies of M. rubra at tuna-jelly or aphid baits in uninfested areas of Mt. Desert Island, ME. Behavioral interactions were idiosyncratic with respect to the native opponent, but M. rubra generally showed significantly higher levels of recruitment, aggression, and displacement of native foragers. As with other invasive ant species shown to have broken the "dominance-discovery trade-off," M. rubra was consistently faster to discover baits and disproportionately displaced native foragers, providing a plausible proximate mechanism for native ant exclusion. Finally, we surveyed ant recruitment at baits for 24 h in August 2004 at four sites with varying M. rubra abundance but found little evidence of temporal niche partitioning. Taken together, these results indicate competitive superiority by M. rubra with respect to native ant communities of the northeastern North America and suggest direct aggression and competitive exclusion at food resources can lead to local native displacement.},
note = {Garnas, JeffreyGroden, EleanorDrummond, Francis Aeng2014/10/01 06:00Environ Entomol. 2014 Dec;43(6):1496-506. doi: 10.1603/EN14079. Epub 2014 Sep 29.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Exotic ants have become invasive in many regions around the world, with variable ecological impacts. Postinvasion, native ant communities are often found to be depauperate, though the causes of this apparent lack of coexistence are rarely well known. Myrmica rubra (L.), a Palearctic Myrmecine ant, is currently expanding its range as an invasive in North America. This aggressive ant forms dense, patchy local infestations and appears to aggressively displace native ant fauna. We measured behavioral interactions and rates of recruitment in experimental field assays pitting native foragers against captive colonies of M. rubra at tuna-jelly or aphid baits in uninfested areas of Mt. Desert Island, ME. Behavioral interactions were idiosyncratic with respect to the native opponent, but M. rubra generally showed significantly higher levels of recruitment, aggression, and displacement of native foragers. As with other invasive ant species shown to have broken the "dominance-discovery trade-off," M. rubra was consistently faster to discover baits and disproportionately displaced native foragers, providing a plausible proximate mechanism for native ant exclusion. Finally, we surveyed ant recruitment at baits for 24 h in August 2004 at four sites with varying M. rubra abundance but found little evidence of temporal niche partitioning. Taken together, these results indicate competitive superiority by M. rubra with respect to native ant communities of the northeastern North America and suggest direct aggression and competitive exclusion at food resources can lead to local native displacement.
Lantschner, M. Victoria; Villacide, José M.; Garnas, Jeffrey R.; Croft, Philip; Carnegie, Angus J.; Liebhold, Andrew M.; Corley, Juan C.
Temperature explains variable spread rates of the invasive woodwasp Sirex noctilio in the Southern Hemisphere Journal Article
In: Biological Invasions, vol. 16, pp. 329-339, 2014, ISBN: 1387-35471573-1464.
@article{181,
title = {Temperature explains variable spread rates of the invasive woodwasp Sirex noctilio in the Southern Hemisphere},
author = {M. Victoria Lantschner and José M. Villacide and Jeffrey R. Garnas and Philip Croft and Angus J. Carnegie and Andrew M. Liebhold and Juan C. Corley},
url = {http://dx.doi.org/10.1007/s10530-013-0521-0},
isbn = {1387-35471573-1464},
year = {2014},
date = {2014-09-01},
journal = {Biological Invasions},
volume = {16},
pages = {329-339},
abstract = {The frequency of introductions of non-indigenous forest insects into new habitats is increasing worldwide, often with profoundly adverse consequences on natural and plantation forest ecosystems. Understanding rates and patterns of spread of invasive forest insects is important for predicting when and where these species will expand their geographical range, with the potential to improve mitigation strategies. The woodwasp Sirex noctilio is a damaging invasive forest insect that kills numerous species of Pinus. Despite encountering highly variable eco-climatic conditions, S. noctilio has arrived and established in exotic pine forest production areas throughout the Southern Hemisphere. In this study, we compiled historical records of S. noctilio invasion to compare spread rates among eight contrasting eco-climatic regions in the Southern Hemisphere and to explore how spread rate is predicted by landscape variation in climate, habitat characteristics and anthropogenic effects. Spread rates for S. noctilio varied considerably among the invaded regions, ranging from 12 to 82 km per year. Among regions, spread rates of S. noctilio increased with increasing mean annual temperature and isothermality. We hypothesize that temperature may directly or indirectly influence S. noctilio population growth and dispersal, thereby influencing spread rates.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The frequency of introductions of non-indigenous forest insects into new habitats is increasing worldwide, often with profoundly adverse consequences on natural and plantation forest ecosystems. Understanding rates and patterns of spread of invasive forest insects is important for predicting when and where these species will expand their geographical range, with the potential to improve mitigation strategies. The woodwasp Sirex noctilio is a damaging invasive forest insect that kills numerous species of Pinus. Despite encountering highly variable eco-climatic conditions, S. noctilio has arrived and established in exotic pine forest production areas throughout the Southern Hemisphere. In this study, we compiled historical records of S. noctilio invasion to compare spread rates among eight contrasting eco-climatic regions in the Southern Hemisphere and to explore how spread rate is predicted by landscape variation in climate, habitat characteristics and anthropogenic effects. Spread rates for S. noctilio varied considerably among the invaded regions, ranging from 12 to 82 km per year. Among regions, spread rates of S. noctilio increased with increasing mean annual temperature and isothermality. We hypothesize that temperature may directly or indirectly influence S. noctilio population growth and dispersal, thereby influencing spread rates.
2013
Kemler, M.; Garnas, J.; Wingfield, M. J.; Gryzenhout, M.; Pillay, K. A.; Slippers, B.
Ion Torrent PGM as tool for fungal community analysis: A case study of endophytes in Eucalyptus grandis reveals high taxonomic diversity Journal Article
In: PLoS OnePlos OnePlos One, vol. 8, pp. e81718 (9 pages), 2013, ISBN: 1932-6203 (Electronic)1932-6203 (Linking), (Kemler, MartinGarnas, JeffWingfield, Michael JGryzenhout, MariekaPillay, Kerry-AnneSlippers, BernardengPLoS One. 2013 Dec 16;8(12):e81718. doi: 10.1371/journal.pone.0081718. eCollection 2013.).
@article{176,
title = {Ion Torrent PGM as tool for fungal community analysis: A case study of endophytes in Eucalyptus grandis reveals high taxonomic diversity},
author = {M. Kemler and J. Garnas and M. J. Wingfield and M. Gryzenhout and K. A. Pillay and B. Slippers},
url = {http://dx.doi.org/10.1371/journal.pone.0081718},
isbn = {1932-6203 (Electronic)1932-6203 (Linking)},
year = {2013},
date = {2013-12-01},
journal = {PLoS OnePlos OnePlos One},
volume = {8},
pages = {e81718 (9 pages)},
publisher = {Public Library of Science},
edition = {2013/12/21},
abstract = {The Kingdom Fungi adds substantially to the diversity of life, but due to their cryptic morphology and lifestyle, tremendous diversity, paucity of formally described specimens, and the difficulty in isolating environmental strains into culture, fungal communities are difficult to characterize. This is especially true for endophytic communities of fungi living in healthy plant tissue. The developments in next generation sequencing technologies are, however, starting to reveal the true extent of fungal diversity. One of the promising new technologies, namely semiconductor sequencing, has thus far not been used in fungal diversity assessments. In this study we sequenced the internal transcribed spacer 1 (ITS1) nuclear encoded ribosomal RNA of the endophytic community of the economically important tree, Eucalyptus grandis, from South Africa using the Ion Torrent Personal Genome Machine (PGM). We determined the impact of various analysis parameters on the interpretation of the results, namely different sequence quality parameter settings, different sequence similarity cutoffs for clustering and filtering of databases for removal of sequences with incomplete taxonomy. Sequence similarity cutoff values only had a marginal effect on the identified family numbers, whereas different sequence quality filters had a large effect (89 vs. 48 families between least and most stringent filters). Database filtering had a small, but statistically significant, effect on the assignment of sequences to reference sequences. The community was dominated by Ascomycota, and particularly by families in the Dothidiomycetes that harbor well-known plant pathogens. The study demonstrates that semiconductor sequencing is an ideal strategy for environmental sequencing of fungal communities. It also highlights some potential pitfalls in subsequent data analyses when using a technology with relatively short read lengths.},
note = {Kemler, MartinGarnas, JeffWingfield, Michael JGryzenhout, MariekaPillay, Kerry-AnneSlippers, BernardengPLoS One. 2013 Dec 16;8(12):e81718. doi: 10.1371/journal.pone.0081718. eCollection 2013.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Kingdom Fungi adds substantially to the diversity of life, but due to their cryptic morphology and lifestyle, tremendous diversity, paucity of formally described specimens, and the difficulty in isolating environmental strains into culture, fungal communities are difficult to characterize. This is especially true for endophytic communities of fungi living in healthy plant tissue. The developments in next generation sequencing technologies are, however, starting to reveal the true extent of fungal diversity. One of the promising new technologies, namely semiconductor sequencing, has thus far not been used in fungal diversity assessments. In this study we sequenced the internal transcribed spacer 1 (ITS1) nuclear encoded ribosomal RNA of the endophytic community of the economically important tree, Eucalyptus grandis, from South Africa using the Ion Torrent Personal Genome Machine (PGM). We determined the impact of various analysis parameters on the interpretation of the results, namely different sequence quality parameter settings, different sequence similarity cutoffs for clustering and filtering of databases for removal of sequences with incomplete taxonomy. Sequence similarity cutoff values only had a marginal effect on the identified family numbers, whereas different sequence quality filters had a large effect (89 vs. 48 families between least and most stringent filters). Database filtering had a small, but statistically significant, effect on the assignment of sequences to reference sequences. The community was dominated by Ascomycota, and particularly by families in the Dothidiomycetes that harbor well-known plant pathogens. The study demonstrates that semiconductor sequencing is an ideal strategy for environmental sequencing of fungal communities. It also highlights some potential pitfalls in subsequent data analyses when using a technology with relatively short read lengths.
Mutitu, Eston K; Garnas, Jeffrey R; Hurley, Brett P; Wingfield, Michael J; Harney, Marlene; Bush, Samantha J; Slippers, Bernard
In: Journal of Economic Entomology, vol. 106, pp. 1979-1985, 2013.
@article{177,
title = {Biology and rearing of Cleruchoides noackae (Hymenoptera: Mymaridae), an egg parasitoid for the biological control of Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)},
author = {Eston K Mutitu and Jeffrey R Garnas and Brett P Hurley and Michael J Wingfield and Marlene Harney and Samantha J Bush and Bernard Slippers},
url = {http://dx.doi.org/10.1603/EC13135},
year = {2013},
date = {2013-10-01},
journal = {Journal of Economic Entomology},
volume = {106},
pages = {1979-1985},
abstract = {Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae) is a solitary egg parasitoid of Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae). The parasitoid was first described in 2009 and its biology and rearing are poorly understood. A key obstacle to the use of C. noackae as a biological control agent has been the ability to consistently rear it under quarantine conditions. This study reports on a series of experiments conducted in quarantine to rear C. noackae and to examine the effects of diet on longevity, per capita reproduction, and progeny sex ratio, as well as to determine development time, and preference and suitability of host eggs of different ages. When supplemented with honey solution, the longevity of C. noackae females increased significantly by 2.4 d and that of males by 1.7 d, relative to the unfed adults. Mean per capita reproduction for the honey-fed wasps was 7.7 offspring per female, with progeny sex ratio slightly skewed toward males. Mean percentage parasitism was 32.2%. C. noackae was capable of parasitizing and completing development from oviposition to adult eclosion within 15.7 d in host eggs between 0 and 5 d old. The ability of C. noackae to parasitize a wide range of host egg ages increases the period of vulnerability of T. peregrinus to attack, increasing its potential efficacy as a biological control agent. The methods and results reported here represent a crucial step in the ongoing efforts to develop this potential biological control system.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae) is a solitary egg parasitoid of Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae). The parasitoid was first described in 2009 and its biology and rearing are poorly understood. A key obstacle to the use of C. noackae as a biological control agent has been the ability to consistently rear it under quarantine conditions. This study reports on a series of experiments conducted in quarantine to rear C. noackae and to examine the effects of diet on longevity, per capita reproduction, and progeny sex ratio, as well as to determine development time, and preference and suitability of host eggs of different ages. When supplemented with honey solution, the longevity of C. noackae females increased significantly by 2.4 d and that of males by 1.7 d, relative to the unfed adults. Mean per capita reproduction for the honey-fed wasps was 7.7 offspring per female, with progeny sex ratio slightly skewed toward males. Mean percentage parasitism was 32.2%. C. noackae was capable of parasitizing and completing development from oviposition to adult eclosion within 15.7 d in host eggs between 0 and 5 d old. The ability of C. noackae to parasitize a wide range of host egg ages increases the period of vulnerability of T. peregrinus to attack, increasing its potential efficacy as a biological control agent. The methods and results reported here represent a crucial step in the ongoing efforts to develop this potential biological control system.
Wooding, A L; Wingfield, M. J.; Hurley, B. P.; Garnas, Jeffrey R; Groot, Peter; Slippers, B
Lack of fidelity revealed in an insect-fungal mutualism after invasion Journal Article
In: Biology Letters, vol. 9, pp. 1-4, 2013.
@article{179,
title = {Lack of fidelity revealed in an insect-fungal mutualism after invasion},
author = {A L Wooding and M. J. Wingfield and B. P. Hurley and Jeffrey R Garnas and Peter Groot and B Slippers},
url = {http://dx.doi.org/10.1098/rsbl.2013.0342},
year = {2013},
date = {2013-06-01},
journal = {Biology Letters},
volume = {9},
pages = {1-4},
abstract = {Symbiont fidelity is an important mechanism in the evolution and stability of mutualisms. Strict fidelity has been assumed for the obligate mutualism between Sirex woodwasps and their mutualistic Amylostereum fungi. This assumption has been challenged in North America where the European woodwasp, Sirex noctilio, and its fungal mutualist, Amylostereum areolatum, have recently been introduced. We investigate the specificity of the mutualism between Sirex and Amylostereum species in Canada, where S. noctilio co-infests Pinus with native Sirex nigricornis and its mutualist, Amylostereum chailletii. Using phylogenetic and culture methods, we show that extensive, reciprocal exchange of fungal species and strains is occurring, with 75.3 per cent of S. nigricornis carrying A. areolatum and 3.5 per cent of S. noctilio carrying A. chailletii. These findings show that the apparent specificity of the mutualism between Sirex spp. and their associated Amylostereum spp. is not the result of specific biological mechanisms that maintain symbiont fidelity. Rather, partner switching may be common when shifting geographical distributions driven by ecological or anthropogenic forces bring host and mutualist pairs into sympatry. Such novel associations have potentially profound consequences for fitness and virulence. Symbiont sharing, if it occurs commonly, may represent an important but overlooked mechanism of community change linked to biological invasions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Symbiont fidelity is an important mechanism in the evolution and stability of mutualisms. Strict fidelity has been assumed for the obligate mutualism between Sirex woodwasps and their mutualistic Amylostereum fungi. This assumption has been challenged in North America where the European woodwasp, Sirex noctilio, and its fungal mutualist, Amylostereum areolatum, have recently been introduced. We investigate the specificity of the mutualism between Sirex and Amylostereum species in Canada, where S. noctilio co-infests Pinus with native Sirex nigricornis and its mutualist, Amylostereum chailletii. Using phylogenetic and culture methods, we show that extensive, reciprocal exchange of fungal species and strains is occurring, with 75.3 per cent of S. nigricornis carrying A. areolatum and 3.5 per cent of S. noctilio carrying A. chailletii. These findings show that the apparent specificity of the mutualism between Sirex spp. and their associated Amylostereum spp. is not the result of specific biological mechanisms that maintain symbiont fidelity. Rather, partner switching may be common when shifting geographical distributions driven by ecological or anthropogenic forces bring host and mutualist pairs into sympatry. Such novel associations have potentially profound consequences for fitness and virulence. Symbiont sharing, if it occurs commonly, may represent an important but overlooked mechanism of community change linked to biological invasions.
Garnas, Jeffrey R; Houston, David R; Twery, Mark J; Ayres, M P; Evans, Celia
Inferring controls on the epidemiology of beech bark disease from spatial patterning of disease organisms Journal Article
In: Agricultural and Forest Entomology, vol. 15, pp. 146-156, 2013, (see supplemental material for sharable version).
@article{175,
title = {Inferring controls on the epidemiology of beech bark disease from spatial patterning of disease organisms},
author = {Jeffrey R Garnas and David R Houston and Mark J Twery and M P Ayres and Celia Evans},
url = {http://dx.doi.org/10.1111/j.1461-9563.2012.00595.x},
year = {2013},
date = {2013-02-01},
journal = {Agricultural and Forest Entomology},
volume = {15},
pages = {146-156},
abstract = {1. Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment. 2. The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to population dynamics. 3. Using 84 plots across eastern North America, we studied populations of twoassociated plant parasites, the invasive felted beech scale Cryptococcus fagisuga Lind. and the native Neonectria fungi, which together cause beech bark disease (BBD). 4. We evaluated spatial patterns at the scales of trees within stands, stands within the forest and forests within the landscape to examine four hypothetically important factors in the ecology of the disease: (i) local contagion within stands; (ii) regional contagion, or among patch infection–reinfection dynamics; (iii) variation in host susceptibility linked to genetic and/or environmental heterogeneity; and (iv) climate effects on population growth of BBD organisms.5 Analyses revealed an unexpected lack of spatial aggregation in BBD populations among trees, stands and forests. This implies that propagule pressure is generally sufficiently high throughout the infested region of North America such that neither trees nor stands are spared from the disease by dispersal limitations of the disease agents. Furthermore, variation in tree and stand level susceptibility has minimal impact on BBD dynamics and climate is not a conspicuous driver of abundance within the core range of BBD.},
note = {see supplemental material for sharable version},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1. Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment. 2. The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to population dynamics. 3. Using 84 plots across eastern North America, we studied populations of twoassociated plant parasites, the invasive felted beech scale Cryptococcus fagisuga Lind. and the native Neonectria fungi, which together cause beech bark disease (BBD). 4. We evaluated spatial patterns at the scales of trees within stands, stands within the forest and forests within the landscape to examine four hypothetically important factors in the ecology of the disease: (i) local contagion within stands; (ii) regional contagion, or among patch infection–reinfection dynamics; (iii) variation in host susceptibility linked to genetic and/or environmental heterogeneity; and (iv) climate effects on population growth of BBD organisms.5 Analyses revealed an unexpected lack of spatial aggregation in BBD populations among trees, stands and forests. This implies that propagule pressure is generally sufficiently high throughout the infested region of North America such that neither trees nor stands are spared from the disease by dispersal limitations of the disease agents. Furthermore, variation in tree and stand level susceptibility has minimal impact on BBD dynamics and climate is not a conspicuous driver of abundance within the core range of BBD.
Wingfield, M. J.; Roux, J; Slippers, B; Hurley, B. P.; Garnas, Jeffrey R; Myburg, A A; Wingfield, B. D
Established and new technologies reduce increasing pest and pathogen threats to eucalypt plantations Journal Article
In: Forest Ecology and Management, vol. 301, pp. 35-42, 2013.
@article{178,
title = {Established and new technologies reduce increasing pest and pathogen threats to eucalypt plantations},
author = {M. J. Wingfield and J Roux and B Slippers and B. P. Hurley and Jeffrey R Garnas and A A Myburg and B. D Wingfield},
url = {http://dx.doi.org/10.1016/j.foreco.2012.09.002},
year = {2013},
date = {2013-01-01},
journal = {Forest Ecology and Management},
volume = {301},
pages = {35-42},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Degefu, D T; Hurley, B. P.; Garnas, Jeffrey R; Wingfield, M. J.; Ahumada, R; Slippers, B
Parallel host range expansion in two unrelated cossid moths infesting Eucalyptus nitens on two continents Journal Article
In: Ecological Entomology, vol. 38, pp. 112-116, 2013.
@article{174,
title = {Parallel host range expansion in two unrelated cossid moths infesting Eucalyptus nitens on two continents},
author = {D T Degefu and B. P. Hurley and Jeffrey R Garnas and M. J. Wingfield and R Ahumada and B Slippers},
url = {http://dx.doi.org/10.1111/j.1365-2311.2012.01396.x},
year = {2013},
date = {2013-01-01},
journal = {Ecological Entomology},
volume = {38},
pages = {112-116},
abstract = {1. Two cossid moths, Coryphodema tristis Drury and Chilecomadia valdiviana Philippi, have recently become pests on Eucalyptus nitens H. Deane & Maiden in South Africa and Chile, respectively. Both C. tristis and C. valdiviana have large host ranges and high levels of similarity in their host distributions. Their infestations of E. nitens are the first records of these moths on Myrtaceae. 2. The contemporaneous adoption of E. nitens as a novel host, despite widespread availability of native and introduced Myrtaceae, suggests a non-random pattern of invasion. Phylogenetic relatedness among the two species linked to cryptic invasion of one or both moths at some time in the recent past provides a possible explanation for this pattern. 3. To test this hypothesis, variation in mtDNA sequences for the COI gene of C. tristis and C. valdiviana were analyzed. The COI mtDNA sequence data showed that C. tristis and C. valdiviana are highly divergent genetically, indicating that both are native on their respective continents with independent evolutionary trajectories. 4. The parallel host range expansions to E. nitens on different continents appear to be unrelated events, likely driven by characteristics of the biology and/or ecology of the host.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1. Two cossid moths, Coryphodema tristis Drury and Chilecomadia valdiviana Philippi, have recently become pests on Eucalyptus nitens H. Deane & Maiden in South Africa and Chile, respectively. Both C. tristis and C. valdiviana have large host ranges and high levels of similarity in their host distributions. Their infestations of E. nitens are the first records of these moths on Myrtaceae. 2. The contemporaneous adoption of E. nitens as a novel host, despite widespread availability of native and introduced Myrtaceae, suggests a non-random pattern of invasion. Phylogenetic relatedness among the two species linked to cryptic invasion of one or both moths at some time in the recent past provides a possible explanation for this pattern. 3. To test this hypothesis, variation in mtDNA sequences for the COI gene of C. tristis and C. valdiviana were analyzed. The COI mtDNA sequence data showed that C. tristis and C. valdiviana are highly divergent genetically, indicating that both are native on their respective continents with independent evolutionary trajectories. 4. The parallel host range expansions to E. nitens on different continents appear to be unrelated events, likely driven by characteristics of the biology and/or ecology of the host.
2012
Garnas, Jeffrey R; Hurley, Brett P; Slippers, Bernard; Wingfield, Michael J
Biological control of forest plantation pests in an interconnected world requires greater international focus Journal Article
In: International Journal of Pest Management, vol. 58, pp. 211-223, 2012.
@article{172,
title = {Biological control of forest plantation pests in an interconnected world requires greater international focus},
author = {Jeffrey R Garnas and Brett P Hurley and Bernard Slippers and Michael J Wingfield},
url = {http://dx.doi.org/10.1080/09670874.2012.698764},
year = {2012},
date = {2012-09-01},
journal = {International Journal of Pest Management},
volume = {58},
pages = {211-223},
abstract = {The worldwide homogenization of genetic resources used in plantation forestry (primarily Pinus, Eucalypus, Populus and Acacia spp.) together with accelerating rates of human-aided dispersal of exotic pests, is resulting in plantation pests becoming broadly distributed extremely quickly, sometimes reaching a global distribution within a decade. This unprecedented rate of establishment and spread means that the risk associated with new and emerging pests is shared globally. Biological control represents a major component of the strategy to mitigate such risk, but the current efforts and scope for developing such controls are woefully inadequate for dealing with the increasing rates of pest spread. Given the global nature of the problem, biological control would benefit enormously from an international, collaborative focus. Though inherent difficulties and potential pitfalls exist, opportunities for cost-sharing, growth and maintenance of resources and capacity, and more comprehensive research programmes are critical to the long-term success of biological control. Governments and industries will need to increase their strategic investment in structures specifically designed to promote such focus if they are to successfully protect their forest resources.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The worldwide homogenization of genetic resources used in plantation forestry (primarily Pinus, Eucalypus, Populus and Acacia spp.) together with accelerating rates of human-aided dispersal of exotic pests, is resulting in plantation pests becoming broadly distributed extremely quickly, sometimes reaching a global distribution within a decade. This unprecedented rate of establishment and spread means that the risk associated with new and emerging pests is shared globally. Biological control represents a major component of the strategy to mitigate such risk, but the current efforts and scope for developing such controls are woefully inadequate for dealing with the increasing rates of pest spread. Given the global nature of the problem, biological control would benefit enormously from an international, collaborative focus. Though inherent difficulties and potential pitfalls exist, opportunities for cost-sharing, growth and maintenance of resources and capacity, and more comprehensive research programmes are critical to the long-term success of biological control. Governments and industries will need to increase their strategic investment in structures specifically designed to promote such focus if they are to successfully protect their forest resources.
McPhee, Katherine; Garnas, Jeffrey R; Drummond, Frank; Groden, Eleanor
Homopterans and an invasive red ant, Myrmica rubra (L.), in Maine Journal Article
In: Environmental Entomology, vol. 41, pp. 59-71, 2012.
@article{173,
title = {Homopterans and an invasive red ant, Myrmica rubra (L.), in Maine},
author = {Katherine McPhee and Jeffrey R Garnas and Frank Drummond and Eleanor Groden},
url = {http://dx.doi.org/10.1603/EN11046},
year = {2012},
date = {2012-04-01},
journal = {Environmental Entomology},
volume = {41},
pages = {59-71},
abstract = {Myrmica rubra (L.), is an invasive ant that is spreading across eastern North America. It is presently found in over 40 communities in Maine and areas in Vermont, New Hampshire, Massachusetts, New York, and several provinces in the Canadian Maritimes and Ontario. In addition to disrupting native ant faunas, invasive ants also have been shown to influence homopteran abundance and species composition. We conducted surveys of Homoptera in infested and noninfested sites and conducted manipulative experiments to quantify the effects of M. rubra on homopteran abundance and composition in the summers of 2003, 2006, and 2007 on Mount Desert Island, ME. In 2003, Homoptera family-level richness was higher in infested sites compared with noninfested sites with two out of three sampling methods. Homopteran abundance in infested compared with noninfested sites depended upon the site. The sites with the highest population of M. rubra were associated with significant differences in Homoptera population abundance. In 2006 and 2007, two out of three host plants sampled had significantly higher abundances of the aphids, Aphis spiraephila Patch and Prociphilus tessellatus Fitch. An ant exclusion field experiment on the native plant, meadowsweet (Spiraea alba Du Roi), resulted in higher abundances of A. spiraephila with M. rubra tending compared with native ant tending. A predator exclusion field experiment was conducted on meadowsweet using adult ladybeetles, Hippodamia convergens Guérin-Méneville, larval green lacewings, Chyrsoperla carnea Stephens, and no predators. Predator impacts on aphid populations were reduced in the presence of M. rubra with C. carnea and moderately reduced with H. convergens.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Myrmica rubra (L.), is an invasive ant that is spreading across eastern North America. It is presently found in over 40 communities in Maine and areas in Vermont, New Hampshire, Massachusetts, New York, and several provinces in the Canadian Maritimes and Ontario. In addition to disrupting native ant faunas, invasive ants also have been shown to influence homopteran abundance and species composition. We conducted surveys of Homoptera in infested and noninfested sites and conducted manipulative experiments to quantify the effects of M. rubra on homopteran abundance and composition in the summers of 2003, 2006, and 2007 on Mount Desert Island, ME. In 2003, Homoptera family-level richness was higher in infested sites compared with noninfested sites with two out of three sampling methods. Homopteran abundance in infested compared with noninfested sites depended upon the site. The sites with the highest population of M. rubra were associated with significant differences in Homoptera population abundance. In 2006 and 2007, two out of three host plants sampled had significantly higher abundances of the aphids, Aphis spiraephila Patch and Prociphilus tessellatus Fitch. An ant exclusion field experiment on the native plant, meadowsweet (Spiraea alba Du Roi), resulted in higher abundances of A. spiraephila with M. rubra tending compared with native ant tending. A predator exclusion field experiment was conducted on meadowsweet using adult ladybeetles, Hippodamia convergens Guérin-Méneville, larval green lacewings, Chyrsoperla carnea Stephens, and no predators. Predator impacts on aphid populations were reduced in the presence of M. rubra with C. carnea and moderately reduced with H. convergens.
Garnas, Jeffrey R; Houston, David R; Ayres, M P; Evans, Celia
Disease ontogeny overshadows effects of climate and species interactions on population dynamics in a nonnative forest disease complex Journal Article
In: Ecography, vol. 35, pp. 412-421, 2012, (a).
@article{171,
title = {Disease ontogeny overshadows effects of climate and species interactions on population dynamics in a nonnative forest disease complex},
author = {Jeffrey R Garnas and David R Houston and M P Ayres and Celia Evans},
url = {http://dx.doi.org/10.1111/j.1600-0587.2011.06938.x},
year = {2012},
date = {2012-01-01},
journal = {Ecography},
volume = {35},
pages = {412-421},
publisher = {Wiley Online Library},
abstract = {Biotic threats to trees often arise from interactions among two or more species, frequently insects and fungi, that function together to defeat host defenses, secure resources and colonize new hosts. Feedbacks among plant enemies can have large effects on host population and disease dynamics, either by promoting stabilizing negative feedbacks or contributing to positive feedbacks that can destabilize populations and permit outbreaks. Feedbacks can be rapid and direct (e.g. within trees or among years) or can arise from slowly developing changes in host resource quantity or quality at the scale of for- est stands or landscapes. Climate may also influence system dynamics by altering feedbacks within or among species or through density independent effects. We evaluated major drivers of population dynamics of beech bark disease (BBD), an important forest disease in eastern deciduous forests of North America, using data from 28 study sites in the eastern United States monitored for up to 14 yr between 1979 and 1992. Both primary causal agents of BBD – the introduced felted beech scale Cryptococcus fagisuga and native fungi Neonectria spp. – showed strong simple density dependence in all study populations. Surprisingly, densities of scale insects and fungi had little or no effects on population growth rates of the other, despite their habit of living in close physical relationships. For both insects and fungi, ecologically important features of the density dependent functions (slope, carrying capacity and density independent variance) were variable across sites. Climatic effects on density-dependent functions (and scatter around them) were evident but generally weak and variable. The most striking predictor of patterns in density dependence was duration since establishment of BBD in the region. Apparently BBD alters forests over decades in ways that strengthen self-regulation among causal agents without eliminating or even dramatically reducing host populations.},
note = {a},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Biotic threats to trees often arise from interactions among two or more species, frequently insects and fungi, that function together to defeat host defenses, secure resources and colonize new hosts. Feedbacks among plant enemies can have large effects on host population and disease dynamics, either by promoting stabilizing negative feedbacks or contributing to positive feedbacks that can destabilize populations and permit outbreaks. Feedbacks can be rapid and direct (e.g. within trees or among years) or can arise from slowly developing changes in host resource quantity or quality at the scale of for- est stands or landscapes. Climate may also influence system dynamics by altering feedbacks within or among species or through density independent effects. We evaluated major drivers of population dynamics of beech bark disease (BBD), an important forest disease in eastern deciduous forests of North America, using data from 28 study sites in the eastern United States monitored for up to 14 yr between 1979 and 1992. Both primary causal agents of BBD – the introduced felted beech scale Cryptococcus fagisuga and native fungi Neonectria spp. – showed strong simple density dependence in all study populations. Surprisingly, densities of scale insects and fungi had little or no effects on population growth rates of the other, despite their habit of living in close physical relationships. For both insects and fungi, ecologically important features of the density dependent functions (slope, carrying capacity and density independent variance) were variable across sites. Climatic effects on density-dependent functions (and scatter around them) were evident but generally weak and variable. The most striking predictor of patterns in density dependence was duration since establishment of BBD in the region. Apparently BBD alters forests over decades in ways that strengthen self-regulation among causal agents without eliminating or even dramatically reducing host populations.
2011
Garnas, Jeffrey R.; Ayres, Matthew P.; Liebhold, Andrew M.; Evans, Celia
Subcontinental impacts of an invasive tree disease on forest structure and dynamics Journal Article
In: Journal of Ecology, vol. 99, pp. 532-541, 2011, ISBN: 00220477.
@article{170,
title = {Subcontinental impacts of an invasive tree disease on forest structure and dynamics},
author = {Jeffrey R. Garnas and Matthew P. Ayres and Andrew M. Liebhold and Celia Evans},
url = {http://dx.doi.org/10.1111/j.1365-2745.2010.01791.x},
isbn = {00220477},
year = {2011},
date = {2011-01-01},
journal = {Journal of Ecology},
volume = {99},
pages = {532-541},
abstract = {1. Introduced pests and pathogens are a major source of disturbance to ecosystems world-wide. The famous examples have produced dramatic reductions in host abundance, including virtual extirpation, but most introductions have more subtle impacts that are hard to quantify but are potentially at least as important due to the pathogens’ effects on host reproduction, competitive ability and stress tolerance. A general outcome could be reduced host abundance with concomitant increases in the abundance of competitors.
2. Beech bark disease (BBD) is a widespread, fatal affliction of American beech (Fagus grandifolia), currently present in c. 50% of beech’s distribution in eastern North America. Despite high adult mortality, beech remains a dominant component of the forest community.
3. Employing spatially extensive data from the national Forest Inventory and Analysis program of the United States Forest Service, we show that forests have changed dramatically in the presence of BBD. Within the 2.3 million km2 range of beech, size-specific mortality was 65% higher in the longest-infected regions, and large beech (>90 cm diameter at breast height) have declined from c. 79 individuals km-2 to being virtually absent. Small stem beech density was dramatically higher (>350%) such that infested forests contain a roughly equivalent cross-sectional (basal) area of beech as before BBD.
4. There was no evidence for compensation by sugar maple or other co-occurring tree species via increased recruitment or adult survivorship at the landscape scale. Overall, community composition remained roughly unchanged as a result of BBD.
5. Surprisingly, trajectory of stand dynamics (shifts in stem density and mean tree size reflecting normal stand maturation (self-thinning) or retrogression (more abundant, smaller trees over time)) did not differ between affected and unaffected regions. Variance in stand dynamics was greater in afflicted forests, however, indicating that predictability of forest structure has been diminished by BBD.
6. Synthesis. Forests of eastern North America have shifted to increased density and dramatically smaller stature – without notable change in tree species composition – following the invasion of a novel forest disease. Our results reinforce the conclusion that introduced diseases alter fundamental properties of ecosystems, but indicate that the spectrum of potential effects is broader than generally appreciated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1. Introduced pests and pathogens are a major source of disturbance to ecosystems world-wide. The famous examples have produced dramatic reductions in host abundance, including virtual extirpation, but most introductions have more subtle impacts that are hard to quantify but are potentially at least as important due to the pathogens’ effects on host reproduction, competitive ability and stress tolerance. A general outcome could be reduced host abundance with concomitant increases in the abundance of competitors.
2. Beech bark disease (BBD) is a widespread, fatal affliction of American beech (Fagus grandifolia), currently present in c. 50% of beech’s distribution in eastern North America. Despite high adult mortality, beech remains a dominant component of the forest community.
3. Employing spatially extensive data from the national Forest Inventory and Analysis program of the United States Forest Service, we show that forests have changed dramatically in the presence of BBD. Within the 2.3 million km2 range of beech, size-specific mortality was 65% higher in the longest-infected regions, and large beech (>90 cm diameter at breast height) have declined from c. 79 individuals km-2 to being virtually absent. Small stem beech density was dramatically higher (>350%) such that infested forests contain a roughly equivalent cross-sectional (basal) area of beech as before BBD.
4. There was no evidence for compensation by sugar maple or other co-occurring tree species via increased recruitment or adult survivorship at the landscape scale. Overall, community composition remained roughly unchanged as a result of BBD.
5. Surprisingly, trajectory of stand dynamics (shifts in stem density and mean tree size reflecting normal stand maturation (self-thinning) or retrogression (more abundant, smaller trees over time)) did not differ between affected and unaffected regions. Variance in stand dynamics was greater in afflicted forests, however, indicating that predictability of forest structure has been diminished by BBD.
6. Synthesis. Forests of eastern North America have shifted to increased density and dramatically smaller stature – without notable change in tree species composition – following the invasion of a novel forest disease. Our results reinforce the conclusion that introduced diseases alter fundamental properties of ecosystems, but indicate that the spectrum of potential effects is broader than generally appreciated.
2. Beech bark disease (BBD) is a widespread, fatal affliction of American beech (Fagus grandifolia), currently present in c. 50% of beech’s distribution in eastern North America. Despite high adult mortality, beech remains a dominant component of the forest community.
3. Employing spatially extensive data from the national Forest Inventory and Analysis program of the United States Forest Service, we show that forests have changed dramatically in the presence of BBD. Within the 2.3 million km2 range of beech, size-specific mortality was 65% higher in the longest-infected regions, and large beech (>90 cm diameter at breast height) have declined from c. 79 individuals km-2 to being virtually absent. Small stem beech density was dramatically higher (>350%) such that infested forests contain a roughly equivalent cross-sectional (basal) area of beech as before BBD.
4. There was no evidence for compensation by sugar maple or other co-occurring tree species via increased recruitment or adult survivorship at the landscape scale. Overall, community composition remained roughly unchanged as a result of BBD.
5. Surprisingly, trajectory of stand dynamics (shifts in stem density and mean tree size reflecting normal stand maturation (self-thinning) or retrogression (more abundant, smaller trees over time)) did not differ between affected and unaffected regions. Variance in stand dynamics was greater in afflicted forests, however, indicating that predictability of forest structure has been diminished by BBD.
6. Synthesis. Forests of eastern North America have shifted to increased density and dramatically smaller stature – without notable change in tree species composition – following the invasion of a novel forest disease. Our results reinforce the conclusion that introduced diseases alter fundamental properties of ecosystems, but indicate that the spectrum of potential effects is broader than generally appreciated.
2009
Dukes, Jeffrey S; Pontius, Jennifer; Orwig, David; Garnas, Jeffrey R; Rodgers, Vikki L; Brazee, Nicholas; Cooke, Barry; Theoharides, Kathleen A; Stange, Erik E; Harrington, Robin; Ehrenfeld, Joan; Gurevitch, Jessica; Lerdau, Manuel; Stinson, Kristina; Wick, Robert; Ayres, M P
In: Canadian Journal of Forest Resources, vol. 39, pp. 231-248, 2009.
@article{169,
title = {Responses of insect pests, pathogens, and invasive plant species to climate change in the forests of northeastern North America: What can we predict?},
author = {Jeffrey S Dukes and Jennifer Pontius and David Orwig and Jeffrey R Garnas and Vikki L Rodgers and Nicholas Brazee and Barry Cooke and Kathleen A Theoharides and Erik E Stange and Robin Harrington and Joan Ehrenfeld and Jessica Gurevitch and Manuel Lerdau and Kristina Stinson and Robert Wick and M P Ayres},
url = {http://dx.doi.org/10.1139/X08-171},
year = {2009},
date = {2009-01-01},
journal = {Canadian Journal of Forest Resources},
volume = {39},
pages = {231-248},
abstract = {Climate models project that by 2100, the northeastern US and eastern Canada will warm by approximately 3–5 textdegreeC, with increased winter precipitation. These changes will affect trees directly and also indirectly through effects on textquotedblleftnuisancetextquotedblright species, such as insect pests, pathogens, and invasive plants. We review how basic ecological principles can be used to predict nuisance species’ responses to climate change and how this is likely to impact northeastern forests. We then examine in detail the potential responses of two pest species (hemlock woolly adelgid (Adelges tsugae Annand) and forest tent caterpillar (Malacosoma disstria Hubner)), two pathogens (armillaria root rot (Armillaria spp.) and beech bark disease (Cryptococcus fagisuga Lind. + Neonectria spp.)), and two invasive plant species (glossy buckthorn (Frangula alnus Mill.) and oriental bittersweet (Celastrus orbiculatus Thunb.)). Several of these species are likely to have stronger or more widespread effects on forest composition and structure under the projected climate. However, uncertainty pervades our predictions because we lack adequate data on the species and because some species depend on complex, incompletely understood, unstable relationships. While targeted research will increase our confidence in making predictions, some uncertainty will always persist. Therefore, we encourage policies that allow for this uncertainty by considering a wide range of possible scenarios.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Climate models project that by 2100, the northeastern US and eastern Canada will warm by approximately 3–5 textdegreeC, with increased winter precipitation. These changes will affect trees directly and also indirectly through effects on textquotedblleftnuisancetextquotedblright species, such as insect pests, pathogens, and invasive plants. We review how basic ecological principles can be used to predict nuisance species’ responses to climate change and how this is likely to impact northeastern forests. We then examine in detail the potential responses of two pest species (hemlock woolly adelgid (Adelges tsugae Annand) and forest tent caterpillar (Malacosoma disstria Hubner)), two pathogens (armillaria root rot (Armillaria spp.) and beech bark disease (Cryptococcus fagisuga Lind. + Neonectria spp.)), and two invasive plant species (glossy buckthorn (Frangula alnus Mill.) and oriental bittersweet (Celastrus orbiculatus Thunb.)). Several of these species are likely to have stronger or more widespread effects on forest composition and structure under the projected climate. However, uncertainty pervades our predictions because we lack adequate data on the species and because some species depend on complex, incompletely understood, unstable relationships. While targeted research will increase our confidence in making predictions, some uncertainty will always persist. Therefore, we encourage policies that allow for this uncertainty by considering a wide range of possible scenarios.
2007
Garnas, J. R.; Drummond, F. A.; Groden, E.
Intercolony aggression within and among local populations of the invasive ant, Myrmica rubra (Hymenoptera: Formicidae), in coastal Maine Journal Article
In: Environmental Entomology, vol. 36, pp. 105-13, 2007, ISBN: 0046-225X (Print)0046-225X (Linking), (Garnas, Jeffrey RDrummond, Francis AGroden, EleanorengEnviron Entomol. 2007 Feb;36(1):105-13.).
@article{168,
title = {Intercolony aggression within and among local populations of the invasive ant, Myrmica rubra (Hymenoptera: Formicidae), in coastal Maine},
author = {J. R. Garnas and F. A. Drummond and E. Groden},
url = {www.ncbi.nlm.nih.gov/pubmed/17349123},
isbn = {0046-225X (Print)0046-225X (Linking)},
year = {2007},
date = {2007-02-01},
journal = {Environmental Entomology},
volume = {36},
pages = {105-13},
edition = {2007/03/14},
abstract = {Myrmica rubra L. was introduced into New England in the early 20th century, and at present, has a patchy distribution in parts of northeastern North America, including records from 31 communities in Maine. M. rubra is highly polygynous, and colonies reproduce vegetatively, forming dense local populations where conditions are favorable. Using mobile nests and baited arenas in a series of field aggression bioassays, we tested patterns of internest tolerance within and among local populations on Mt. Desert Island, ME. We found that foragers originating from fragments of the same colony or from neighboring nests retained a high level of intraspecific tolerance over several months, whereas significant intercolony aggression among workers was present between colonies within the same local patch separated by approximately 10 m. Within populations, aggression score values were found to increase linearly with internest distance within a site. Aggression was highest between colonies from spatially different populations on the island and was higher still when nests were assayed against colonies at an off-island site 70 km away in Castine, ME. These data strongly suggest a multicolonial organization within and among local populations of M. rubra in parts of its introduced range. These findings contradict the loss of intraspecific aggression and unicolonial social structure over large geographic areas that have previously been observed in other invasive ant species, particularly Linepithema humile Mayr.},
note = {Garnas, Jeffrey RDrummond, Francis AGroden, EleanorengEnviron Entomol. 2007 Feb;36(1):105-13.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Myrmica rubra L. was introduced into New England in the early 20th century, and at present, has a patchy distribution in parts of northeastern North America, including records from 31 communities in Maine. M. rubra is highly polygynous, and colonies reproduce vegetatively, forming dense local populations where conditions are favorable. Using mobile nests and baited arenas in a series of field aggression bioassays, we tested patterns of internest tolerance within and among local populations on Mt. Desert Island, ME. We found that foragers originating from fragments of the same colony or from neighboring nests retained a high level of intraspecific tolerance over several months, whereas significant intercolony aggression among workers was present between colonies within the same local patch separated by approximately 10 m. Within populations, aggression score values were found to increase linearly with internest distance within a site. Aggression was highest between colonies from spatially different populations on the island and was higher still when nests were assayed against colonies at an off-island site 70 km away in Castine, ME. These data strongly suggest a multicolonial organization within and among local populations of M. rubra in parts of its introduced range. These findings contradict the loss of intraspecific aggression and unicolonial social structure over large geographic areas that have previously been observed in other invasive ant species, particularly Linepithema humile Mayr.