The Experts below are selected from a list of 3300 Experts worldwide ranked by ideXlab platform
Paula M Shrewsbury - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics of woodpecker predation on emerald ash borer agrilus planipennis in the northeastern u s a
Agricultural and Forest Entomology, 2016Co-Authors: David E Jennings, Jian J Duan, Leah S Bauer, Jonathan M Schmude, Miles T Wetherington, Paula M ShrewsburyAbstract:Woodpeckers (Picidae) are important natural enemies attacking emerald ash borer (EAB) Agrilus planipennis Fairmaire in North America. There can be considerable variation in predation levels within and between sites, and among different times of year; therefore, understanding what causes these differences is necessary for effectively predicting EAB population dynamics. We examined the temporal dynamics of woodpecker predation on EAB in Michigan and Maryland, as well as how they were affected by season, region, resource availability, tree size and crown condition. In Michigan, we quantified predation in association with EAB developmental stages on different trees over 2 years, whereas, in Maryland, we recorded woodpecker attacks on the same trees for 1 year. Season was a significant predictor of woodpecker predation, with most occurring in winter when late-instar larvae were abundant. Predation also was affected by crown condition and tree size. Additionally, predation levels were similar throughout the year in a region where generations are considered to be less synchronized, representing a more consistent resource for Woodpeckers. The present study highlights the various factors affecting woodpecker predation over time. The results demonstrate the importance of multi-season studies of interactions between invasive species and native natural enemies when aiming to fully understand their dynamics.
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quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer agrilus planipennis
PLOS ONE, 2013Co-Authors: David E Jennings, Jian J Duan, Juli R Gould, John D Vandenberg, Paula M ShrewsburyAbstract:The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as Woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude Woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude Woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which Woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which Woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to Woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude Woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of Woodpeckers.
Kathy Martin - One of the best experts on this subject based on the ideXlab platform.
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Woodpeckers decay and the future of cavity nesting vertebrate communities worldwide
Frontiers in Ecology and the Environment, 2011Co-Authors: Kristina L Cockle, Kathy Martin, Tomasz WesolowskiAbstract:In forests worldwide, tree-cavity supply can limit populations of the 10–40% of bird and mammal species that require cavities for nesting or roosting. Conservation efforts aimed at cavity-using communities have often focused on Woodpeckers because, as cavity excavators, they are presumed to control cavity supply. We show that avian excavators are the primary cavity producers in North America (77% of nesting cavities), but not elsewhere (26% in Eurasia and South America; 0% in Australasia). We studied survivorship of 2805 nest cavities and found similar persistence of cavities created by Woodpeckers and those created by decay in Canada, but low persistence of woodpecker-excavated cavities in Poland and Argentina. Outside of North America, the ephemeral nature of many woodpecker cavities may render most cavity-using vertebrates critically dependent on the slow formation of cavities by damage and decay. The future of most cavity-using communities will therefore be highly dependent on changing forest policies to stem the current loss of old trees.
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Woodpeckers increase in abundance but maintain fecundity in response to an outbreak of mountain pine bark beetles
Forest Ecology and Management, 2011Co-Authors: Amanda B Edworthy, Mark C Drever, Kathy MartinAbstract:Abstract Many temperate woodpecker species are thought to be highly conservative in their fecundity with little response to fluctuations in availability of resources. In a 15-year field study in interior British Columbia, we evaluated responses in abundance and fecundity of six species of resident and migrant Woodpeckers (downy woodpecker [Picoides pubescens], hairy woodpecker [Picoides villosus], American three-toed woodpecker [Picoides dorsalis], pileated woodpecker [Drycopus pileatus], northern flicker [Colaptes auratus], and red-naped sapsucker [Sphyrapicus nuchalis]) to a large-scale outbreak of mountain pine bark beetles that resulted in a strong positive pulse in food supply. Population densities of woodpecker species increased during outbreak years. Despite the year-round multi-annual increase in food resources, and in contrast to the strong increases in fecundity shown by nuthatches and chickadees, annual fecundity (as indicated by clutch size and number of nestlings that fledged) did not change for any woodpecker species over the study. Similarly, we found no changes in fecundity in response to selective forest harvesting despite numerical increases for Woodpeckers at these sites. Our study confirms that these woodpecker species are conservative in their reproductive investment patterns even during strong multi-annual increases in food. Our findings indicate woodpecker populations are regulated numerically through variable survival and/or greater immigration rates, which can result in higher breeding densities temporarily during resource pulses.
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response of Woodpeckers to changes in forest health and harvest implications for conservation of avian biodiversity
Forest Ecology and Management, 2010Co-Authors: Mark C Drever, Kathy MartinAbstract:Abstract Woodpeckers (family Picidae) merit specific monitoring and management efforts, both as keystone/facilitator species and as indicators of forest condition. Recent studies indicated that species richness of Woodpeckers was correlated with richness of all forest birds, thus suggesting potential exists for management practices that can address needs of Woodpeckers in particular and other forest birds in general. We used data from a long-term study (1995–2008) from forest sites in the interior of British Columbia to evaluate how abundances of seven woodpecker species varied with habitat variables previously identified as associated with forest bird richness. We found that tree species richness had either a neutral or positive effect on the abundance of all woodpecker species, whereas abundances of most woodpecker species tended to be lower in stands with high densities of lodgepole pine. Abundances of most woodpecker species were positively correlated with density of beetle-killed pines. Relative to control sites, higher densities of most woodpecker species were found at harvested sites where most trembling aspen and large Douglas-fir trees had been retained. Therefore, management strategies that favour a mixture of tree species, with particular attention to retention of aspen, should safeguard populations of most woodpecker species. Abundances of individual woodpecker species were weakly but positively inter-correlated before the beetle outbreak, and less so during and post-outbreak. It thus appears that no strong trade-offs exist among woodpecker species. These results, combined with previously identified positive correlations between woodpecker and forest bird richness, indicate Woodpeckers can be managed as a suite for the purpose of managing avian biodiversity as a whole.
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Woodpeckers as reliable indicators of bird richness forest health and harvest
Biological Conservation, 2008Co-Authors: Mark C Drever, Kathy Martin, Kathryn E H Aitken, Andrea R NorrisAbstract:Abstract Woodpeckers (family Picidae) show promise as indicators of avian diversity in forests because their populations can be reliably monitored, and their foraging and nesting activities can positively influence the abundance and richness of other forest birds. A correlation between woodpecker richness and richness of forest birds is known to exist at the landscape scale, but uncertainty remains whether this correlation occurs at the smaller stand-level spatial scales where forest management activities take place. We used data collected under a diverse range of forest types, harvest treatments, and forest health conditions during a long-term study of bird communities in interior British Columbia, Canada, to examine two basic questions: (1) at the level of individual forest stands, is woodpecker richness correlated with bird richness (measured as richness of all other bird species)? and (2) do woodpecker richness and bird richness have similar habitat correlates? Bird richness was positively correlated with woodpecker richness ( β = 0.59, SE = 0.22, 95% CI = [0.14 1.03]). Richness of both Woodpeckers and all other birds were positively correlated with tree species richness and negatively correlated with density of pines, and the effect for forest harvest type was similar for both measures of avian richness (uncut
David E Jennings - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics of woodpecker predation on emerald ash borer agrilus planipennis in the northeastern u s a
Agricultural and Forest Entomology, 2016Co-Authors: David E Jennings, Jian J Duan, Leah S Bauer, Jonathan M Schmude, Miles T Wetherington, Paula M ShrewsburyAbstract:Woodpeckers (Picidae) are important natural enemies attacking emerald ash borer (EAB) Agrilus planipennis Fairmaire in North America. There can be considerable variation in predation levels within and between sites, and among different times of year; therefore, understanding what causes these differences is necessary for effectively predicting EAB population dynamics. We examined the temporal dynamics of woodpecker predation on EAB in Michigan and Maryland, as well as how they were affected by season, region, resource availability, tree size and crown condition. In Michigan, we quantified predation in association with EAB developmental stages on different trees over 2 years, whereas, in Maryland, we recorded woodpecker attacks on the same trees for 1 year. Season was a significant predictor of woodpecker predation, with most occurring in winter when late-instar larvae were abundant. Predation also was affected by crown condition and tree size. Additionally, predation levels were similar throughout the year in a region where generations are considered to be less synchronized, representing a more consistent resource for Woodpeckers. The present study highlights the various factors affecting woodpecker predation over time. The results demonstrate the importance of multi-season studies of interactions between invasive species and native natural enemies when aiming to fully understand their dynamics.
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quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer agrilus planipennis
PLOS ONE, 2013Co-Authors: David E Jennings, Jian J Duan, Juli R Gould, John D Vandenberg, Paula M ShrewsburyAbstract:The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as Woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude Woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude Woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which Woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which Woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to Woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude Woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of Woodpeckers.
Eliot T Miller - One of the best experts on this subject based on the ideXlab platform.
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the hairy downy game revisited an empirical test of the interspecific social dominance mimicry hypothesis
Animal Behaviour, 2018Co-Authors: Gavin M Leighton, Alexander C Lees, Eliot T MillerAbstract:© 2018 The Association for the Study of Animal Behaviour. Understanding the emergence and persistence of convergent phenotypes is the subject of considerable debate. Species may converge on nearly identical phenotypes for a variety of reasons, including occupying similar environments, exhibiting similar foraging ecologies, and for signalling reasons such as mimicry. Interspecific social dominance mimicry (ISDM) is a hypothesis that states that socially subordinate species evolve a phenotype mimicking a dominant species so as to accrue resources and avoid aggression. A recently proposed test case for this phenomenon asserts that downy Woodpeckers, Picoides pubescens, evolved mimetic plumage to avoid attacks from hairy Woodpeckers, Picoides villosus. We examined this claim with a large behavioural data set collected by citizen scientists. We employed phylogenetic methods and simulations to test whether downy Woodpeckers avoid aggression, and whether downy Woodpeckers are more dominant than expected based on body mass. Contrary to the expectations of ISDM, we found that downy Woodpeckers were markedly more often the target of hairy woodpecker attacks than expected based on their relative abundances. Our empirical data thus offers no support for the strict ISDM hypothesis as an explanation for downy–hairy woodpecker plumage convergence. However, downy Woodpeckers are slightly more dominant than expected based on their body mass, albeit not significantly so. Our data therefore lend weight to previous suggestions that the benefits of mimicry potentially accrue from third-party species mistaking the mimic for the model, rather than the model mistaking the mimic for another model.
Jian J Duan - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics of woodpecker predation on emerald ash borer agrilus planipennis in the northeastern u s a
Agricultural and Forest Entomology, 2016Co-Authors: David E Jennings, Jian J Duan, Leah S Bauer, Jonathan M Schmude, Miles T Wetherington, Paula M ShrewsburyAbstract:Woodpeckers (Picidae) are important natural enemies attacking emerald ash borer (EAB) Agrilus planipennis Fairmaire in North America. There can be considerable variation in predation levels within and between sites, and among different times of year; therefore, understanding what causes these differences is necessary for effectively predicting EAB population dynamics. We examined the temporal dynamics of woodpecker predation on EAB in Michigan and Maryland, as well as how they were affected by season, region, resource availability, tree size and crown condition. In Michigan, we quantified predation in association with EAB developmental stages on different trees over 2 years, whereas, in Maryland, we recorded woodpecker attacks on the same trees for 1 year. Season was a significant predictor of woodpecker predation, with most occurring in winter when late-instar larvae were abundant. Predation also was affected by crown condition and tree size. Additionally, predation levels were similar throughout the year in a region where generations are considered to be less synchronized, representing a more consistent resource for Woodpeckers. The present study highlights the various factors affecting woodpecker predation over time. The results demonstrate the importance of multi-season studies of interactions between invasive species and native natural enemies when aiming to fully understand their dynamics.
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quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer agrilus planipennis
PLOS ONE, 2013Co-Authors: David E Jennings, Jian J Duan, Juli R Gould, John D Vandenberg, Paula M ShrewsburyAbstract:The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as Woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude Woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude Woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which Woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which Woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to Woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude Woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of Woodpeckers.
