John-André Henden, Rolf Anker Ims, Marita Anti Strømeng
Photographic monitoring currently provides the most accurate means for identifying nest predators and eventually their role in bird population declines worldwide. However, previous studies have found that commercially available trail cameras represent an artificial structure that tend to negatively bias predation rates, likely through predator neophobia. Based on an experiment in Arctic tundra, involving 50 artificial nests and 30 cameras in each of 2 breeding seasons, we demonstrated that trail cameras attracted corvids (in particular ravens [Corvus corax]), which caused an extreme and positively biased predation rate that was consistent over a range of experimental and environmental conditions. We call for new technologies that allow for photographic monitoring of bird nests with minimal visual footprints, in the form of smaller cameras and more efficient internal batteries to minimize novel and conspicuous external features detectable by predators. However, even such improved devices need to be assessed with respect to potential effects on nest predation in each case.
{"title":"Trail cameras can greatly inflate nest predation rates","authors":"John-André Henden, Rolf Anker Ims, Marita Anti Strømeng","doi":"10.1002/jwmg.22684","DOIUrl":"https://doi.org/10.1002/jwmg.22684","url":null,"abstract":"<p>Photographic monitoring currently provides the most accurate means for identifying nest predators and eventually their role in bird population declines worldwide. However, previous studies have found that commercially available trail cameras represent an artificial structure that tend to negatively bias predation rates, likely through predator neophobia. Based on an experiment in Arctic tundra, involving 50 artificial nests and 30 cameras in each of 2 breeding seasons, we demonstrated that trail cameras attracted corvids (in particular ravens [<i>Corvus corax</i>]), which caused an extreme and positively biased predation rate that was consistent over a range of experimental and environmental conditions. We call for new technologies that allow for photographic monitoring of bird nests with minimal visual footprints, in the form of smaller cameras and more efficient internal batteries to minimize novel and conspicuous external features detectable by predators. However, even such improved devices need to be assessed with respect to potential effects on nest predation in each case.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22684","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Survival of northern bobwhite (Colinus virginianus) chicks is an important parameter influencing population dynamics. We determined cause-specific mortality and apparent daily survival of bobwhite chicks (n = 170) during 2018 and 2019 at Tall Timbers Research Station, Tallahassee, Florida, USA. We assigned cause-specific mortality to 58 chicks and unknown fates to 45 chicks. Of those with assigned fates, avian predation comprised the majority (n = 21, 36%) followed by snakes (n = 17, 29%), mammals (n = 16, 28%), and research-induced mortality (n = 4, 7%). Corn snakes (Pantherophis guttatus) were the primary snake species (13 of 17 snake predations) responsible for predation followed by northern cottonmouths (Agkistrodon piscivorus; n = 3) and 1 eastern diamondback rattlesnake (Crotalus adamanateus). We determined diel timing of mortalities during 2019. All corn snake predations during 2019 (n = 8) occurred during roosting (2100–0700 hrs), whereas the eastern diamondback mortality was a diurnal event; no cottonmouths depredated chicks during 2019. Nine of 11 mammalian events occurred during roosting. Two avian events occurred during 2019, both during daylight hours. Survival was best predicted by the model including the effects of chick age, hatch timing, year, and their interactions. Daily survival of chicks increased with age and reached an asymptote at approximately 70 days; late hatches (after 15 July) survived better than early hatches (βLateHatch×ChickAge = 0.059, 95% CI =−0.003–0.121) and survival for late hatches was marginally lower in 2019 (βLateHatch×ChickAge×Year19 = −0.058, 95% CI = −0.137–0.022). Management focused on increasing survival during the first 2 months of life and early nesting season may substantially benefit bobwhite population abundance. Additionally, roosting appeared to be a vulnerable period for bobwhite chicks.
{"title":"Cause-specific mortality and survival of northern bobwhite chicks","authors":"Bradley W. Kubečka, Theron M. Terhune","doi":"10.1002/jwmg.22703","DOIUrl":"https://doi.org/10.1002/jwmg.22703","url":null,"abstract":"<p>Survival of northern bobwhite (<i>Colinus virginianus</i>) chicks is an important parameter influencing population dynamics. We determined cause-specific mortality and apparent daily survival of bobwhite chicks (<i>n</i> = 170) during 2018 and 2019 at Tall Timbers Research Station, Tallahassee, Florida, USA. We assigned cause-specific mortality to 58 chicks and unknown fates to 45 chicks. Of those with assigned fates, avian predation comprised the majority (<i>n</i> = 21, 36%) followed by snakes (<i>n</i> = 17, 29%), mammals (<i>n</i> = 16, 28%), and research-induced mortality (<i>n</i> = 4, 7%). Corn snakes (<i>Pantherophis guttatus</i>) were the primary snake species (13 of 17 snake predations) responsible for predation followed by northern cottonmouths (<i>Agkistrodon piscivorus</i>; <i>n</i> = 3) and 1 eastern diamondback rattlesnake (<i>Crotalus adamanateus</i>). We determined diel timing of mortalities during 2019. All corn snake predations during 2019 (<i>n</i> = 8) occurred during roosting (2100–0700 hrs), whereas the eastern diamondback mortality was a diurnal event; no cottonmouths depredated chicks during 2019. Nine of 11 mammalian events occurred during roosting. Two avian events occurred during 2019, both during daylight hours. Survival was best predicted by the model including the effects of chick age, hatch timing, year, and their interactions. Daily survival of chicks increased with age and reached an asymptote at approximately 70 days; late hatches (after 15 July) survived better than early hatches (β<sub>LateHatch×ChickAge</sub> = 0.059, 95% CI =−0.003–0.121) and survival for late hatches was marginally lower in 2019 (β<sub>LateHatch×ChickAge×Year19</sub> = −0.058, 95% CI = −0.137–0.022). Management focused on increasing survival during the first 2 months of life and early nesting season may substantially benefit bobwhite population abundance. Additionally, roosting appeared to be a vulnerable period for bobwhite chicks.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<p>This is the first issue of <i>The Journal of Wildlife Management</i> (<i>JWM</i>) for which I served as Editor-in-Chief (EIC). I am deeply grateful for the trust and support of The Wildlife Society (TWS) and honored to follow in the footsteps of the esteemed EICs that have preceded me.</p><p>Foremost, I want to acknowledge the indelible legacy of our outgoing EIC, Paul Krausman. His collective time as EIC for JWM spanned 11 years (he served another 5 years as EIC for Wildlife Monographs), which contrasts to an average of ~2.5 years for the 31 other JWM EICs (Krausman <span>2022<i>a</i></span>). No other EIC for JWM oversaw such a dramatic scope of change in the publishing arena as Paul. To elaborate on that point, consider that Paul's EIC career began in 1988 with a drive to Texas for the transfer of “boxes upon boxes” of printed manuscripts (Krausman <span>2022<i>a</i></span>) and culminated with navigating how to embrace the benefits and guard against the perils of artificial intelligence in scientific publishing (Krausman <span>2023<i>a</i></span>). Paul deftly guided, protected, and improved our flagship journal through innumerable challenges over his career. I am grateful for his expertise and thoughtful leadership of JWM and his mentorship as he passed the torch to me.</p><p>In reviewing Paul's editorials, key aspects of his legacy as EIC became apparent and invariably underscored his goal of publishing “the best science in the field available to advance wildlife management and conservation” (Krausman <span>2022<i>a</i></span>). Towards that end Paul often offered tips for communicating science effectively (Krausman <span>2016<i>a</i></span>, <span><i>b</i></span>, <span>2017<i>a</i></span>, <span><i>b</i></span>, <span>2018<i>a</i></span>, <span>2020<i>a</i></span>, <span>2024<i>a</i></span>; Krausman and Cox <span>2020</span>), providing specific guidance to graduate students and first-time authors (Krausman <span>2021<i>a</i></span>, <span>2024<i>b</i></span>), establishing a WILD program to improve the quality of English writing and by extension the accessibility of JWM to international authors (Krausman <span>2015<i>a</i></span>), emphasizing ethics in science and publishing (Krausman <span>2016<i>c</i></span>, <span>2021<i>b</i></span>), and providing insights into how to get publications noticed (Krausman <span>2016<i>e</i></span>). As EIC, Paul often sought and was responsive to author concerns (Krausman <span>2017<i>c</i></span>, <span>2022<i>b</i></span>)—summarizing and streamlining author guidelines (Krausman <span>2017<i>d</i></span>, <span><i>e</i></span>, <span>2018<i>b</i></span>), explaining the necessary evils of page charges (Krausman <span>2017<i>f</i></span>) and rejections (Krausman <span>2020<i>b</i></span>), clarifying content differences between JWM and the Wildlife Society Bulletin (Krausman <span>2016<i>d</i></span>), highlighting the benefits of publishing with Wiley (Krausman <span>2017<i>g</i></span>), and b
{"title":"Thank you to our Guardians of Science","authors":"Jacqueline L. Frair","doi":"10.1002/jwmg.22700","DOIUrl":"https://doi.org/10.1002/jwmg.22700","url":null,"abstract":"<p>This is the first issue of <i>The Journal of Wildlife Management</i> (<i>JWM</i>) for which I served as Editor-in-Chief (EIC). I am deeply grateful for the trust and support of The Wildlife Society (TWS) and honored to follow in the footsteps of the esteemed EICs that have preceded me.</p><p>Foremost, I want to acknowledge the indelible legacy of our outgoing EIC, Paul Krausman. His collective time as EIC for JWM spanned 11 years (he served another 5 years as EIC for Wildlife Monographs), which contrasts to an average of ~2.5 years for the 31 other JWM EICs (Krausman <span>2022<i>a</i></span>). No other EIC for JWM oversaw such a dramatic scope of change in the publishing arena as Paul. To elaborate on that point, consider that Paul's EIC career began in 1988 with a drive to Texas for the transfer of “boxes upon boxes” of printed manuscripts (Krausman <span>2022<i>a</i></span>) and culminated with navigating how to embrace the benefits and guard against the perils of artificial intelligence in scientific publishing (Krausman <span>2023<i>a</i></span>). Paul deftly guided, protected, and improved our flagship journal through innumerable challenges over his career. I am grateful for his expertise and thoughtful leadership of JWM and his mentorship as he passed the torch to me.</p><p>In reviewing Paul's editorials, key aspects of his legacy as EIC became apparent and invariably underscored his goal of publishing “the best science in the field available to advance wildlife management and conservation” (Krausman <span>2022<i>a</i></span>). Towards that end Paul often offered tips for communicating science effectively (Krausman <span>2016<i>a</i></span>, <span><i>b</i></span>, <span>2017<i>a</i></span>, <span><i>b</i></span>, <span>2018<i>a</i></span>, <span>2020<i>a</i></span>, <span>2024<i>a</i></span>; Krausman and Cox <span>2020</span>), providing specific guidance to graduate students and first-time authors (Krausman <span>2021<i>a</i></span>, <span>2024<i>b</i></span>), establishing a WILD program to improve the quality of English writing and by extension the accessibility of JWM to international authors (Krausman <span>2015<i>a</i></span>), emphasizing ethics in science and publishing (Krausman <span>2016<i>c</i></span>, <span>2021<i>b</i></span>), and providing insights into how to get publications noticed (Krausman <span>2016<i>e</i></span>). As EIC, Paul often sought and was responsive to author concerns (Krausman <span>2017<i>c</i></span>, <span>2022<i>b</i></span>)—summarizing and streamlining author guidelines (Krausman <span>2017<i>d</i></span>, <span><i>e</i></span>, <span>2018<i>b</i></span>), explaining the necessary evils of page charges (Krausman <span>2017<i>f</i></span>) and rejections (Krausman <span>2020<i>b</i></span>), clarifying content differences between JWM and the Wildlife Society Bulletin (Krausman <span>2016<i>d</i></span>), highlighting the benefits of publishing with Wiley (Krausman <span>2017<i>g</i></span>), and b","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22700","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amy J. Davis, Wesley C. Dixon, Richard B. Chipman, Amy T. Gilbert, Jacob E. Hill, James C. Beasley, Olin E. Rhodes Jr., Guha Dharmarajan
Density estimation for unmarked animals is particularly challenging, yet density estimates are often necessary for effective wildlife management. Raccoons (Procyon lotor) are the primary terrestrial wildlife reservoir for Lyssavirus rabies within the United States. The raccoon rabies variant (RRVV) is actively managed at landscape scales using oral rabies vaccination (ORV) within the eastern United States. To effectively manage RRVV, it is important to know the density of raccoons to appropriately scale the density of ORV baits distributed on the landscape. We compared methods to estimate raccoon densities from camera-trap data versus more intensive capture-mark-recapture (CMR) estimates across 2 land cover types (upland pine and bottomland hardwood) in the southeastern United States during 2019 and 2020. We evaluated the effect of alternative camera configurations and durations of camera trapping on density estimates and used an N-mixture model to estimate raccoon densities, including covariates on abundance and detection. We further compared different methods of scaling camera-based counts, with the maximum number of raccoons seen on any given image within a day best explaining density. Camera-trap density estimates were moderately correlated with CMR estimates (r = 0.56). However, densities from camera-trap data were more reliable when classifying category of density as an index used to inform management (83% correct when compared to CMR estimates), although the densities in our study fell into the 2 lowest density classes only. Using more cameras reduced bias and uncertainty around density estimates; however, if ≤6 camera traps were used at a site, a line transect approach proved less biased than a grid design. Camera trapping should be conducted for at least 3 weeks for more accurate estimates of raccoon population density in our study area (<5% bias). We show that camera-trap data can be used to assign raccoon densities to management-relevant density index bins, but more studies are needed to ensure reliability across a greater range of environmental conditions and raccoon densities.
{"title":"Raccoon density estimation from camera traps for raccoon rabies management","authors":"Amy J. Davis, Wesley C. Dixon, Richard B. Chipman, Amy T. Gilbert, Jacob E. Hill, James C. Beasley, Olin E. Rhodes Jr., Guha Dharmarajan","doi":"10.1002/jwmg.22701","DOIUrl":"https://doi.org/10.1002/jwmg.22701","url":null,"abstract":"<p>Density estimation for unmarked animals is particularly challenging, yet density estimates are often necessary for effective wildlife management. Raccoons (<i>Procyon lotor</i>) are the primary terrestrial wildlife reservoir for Lyssavirus rabies within the United States. The raccoon rabies variant (RRVV) is actively managed at landscape scales using oral rabies vaccination (ORV) within the eastern United States. To effectively manage RRVV, it is important to know the density of raccoons to appropriately scale the density of ORV baits distributed on the landscape. We compared methods to estimate raccoon densities from camera-trap data versus more intensive capture-mark-recapture (CMR) estimates across 2 land cover types (upland pine and bottomland hardwood) in the southeastern United States during 2019 and 2020. We evaluated the effect of alternative camera configurations and durations of camera trapping on density estimates and used an N-mixture model to estimate raccoon densities, including covariates on abundance and detection. We further compared different methods of scaling camera-based counts, with the maximum number of raccoons seen on any given image within a day best explaining density. Camera-trap density estimates were moderately correlated with CMR estimates (<i>r</i> = 0.56). However, densities from camera-trap data were more reliable when classifying category of density as an index used to inform management (83% correct when compared to CMR estimates), although the densities in our study fell into the 2 lowest density classes only. Using more cameras reduced bias and uncertainty around density estimates; however, if ≤6 camera traps were used at a site, a line transect approach proved less biased than a grid design. Camera trapping should be conducted for at least 3 weeks for more accurate estimates of raccoon population density in our study area (<5% bias). We show that camera-trap data can be used to assign raccoon densities to management-relevant density index bins, but more studies are needed to ensure reliability across a greater range of environmental conditions and raccoon densities.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22701","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nathan P. Snow, Kelly J. Koriakin, Michael J. Lavelle, Michael P. Glow, Justin W. Fischer, Justin A. Foster, Kim M. Pepin, Kurt C. VerCauteren
Wild pigs are a destructive invasive species throughout many regions of the world and have proven difficult to control or eliminate. Their success as an invasive species is, in part, from their high reproductive potential, which can vary based on available resources, ancestry, and other factors. We opportunistically collected data on demographics (i.e., age and sex), reproduction, and body mass on 2,762 wild pigs throughout various research and operation control activities in Texas, Alabama, Hawai'i, Guam (USA), and Queensland (Australia) during 2016–2024. We evaluated these data for differences among study sites that might lead to a better understanding of wild pig ecology and more effective control of their populations. We found that the age structures of wild pigs varied greatly among sites, with areas with more intense control having younger populations. The timing and frequency of birth pulses also varied by site. Large disparities among populations demonstrated the elasticities of wild pigs in invaded ranges; for example, the Alabama study site had a mostly young population with fast body mass growth rates and 2 discernable birth pulses per year, whereas the Guam study site had an older population with slow body mass growth rates and an indistinguishable birth pulse. We hypothesized that intense population control may increase reproduction rates in younger females through increased body mass growth rates and subsequent reproductive maturity. We recommend that managers identify the seasonal birth pulses of wild pigs in their region, and then intensively focus on removing wild pigs during the 115 days (i.e., gestation period) prior to those birth pulses. This may be counterintuitive to managers that focus on trapping after observing a birth pulse, but it increases the probability of simultaneously removing pregnant females and any associated offspring from previous litters that remained with the pregnant female. We also recommend evaluating regional-specific intensities of removal that might be required for reducing populations with specific emphasis on whether compensatory reproductive behaviors are generated and how to avoid them.
{"title":"Regional variation in demographics, reproduction, and body mass growth rates of wild pigs: Implications for population control","authors":"Nathan P. Snow, Kelly J. Koriakin, Michael J. Lavelle, Michael P. Glow, Justin W. Fischer, Justin A. Foster, Kim M. Pepin, Kurt C. VerCauteren","doi":"10.1002/jwmg.22697","DOIUrl":"https://doi.org/10.1002/jwmg.22697","url":null,"abstract":"<p>Wild pigs are a destructive invasive species throughout many regions of the world and have proven difficult to control or eliminate. Their success as an invasive species is, in part, from their high reproductive potential, which can vary based on available resources, ancestry, and other factors. We opportunistically collected data on demographics (i.e., age and sex), reproduction, and body mass on 2,762 wild pigs throughout various research and operation control activities in Texas, Alabama, Hawai'i, Guam (USA), and Queensland (Australia) during 2016–2024. We evaluated these data for differences among study sites that might lead to a better understanding of wild pig ecology and more effective control of their populations. We found that the age structures of wild pigs varied greatly among sites, with areas with more intense control having younger populations. The timing and frequency of birth pulses also varied by site. Large disparities among populations demonstrated the elasticities of wild pigs in invaded ranges; for example, the Alabama study site had a mostly young population with fast body mass growth rates and 2 discernable birth pulses per year, whereas the Guam study site had an older population with slow body mass growth rates and an indistinguishable birth pulse. We hypothesized that intense population control may increase reproduction rates in younger females through increased body mass growth rates and subsequent reproductive maturity. We recommend that managers identify the seasonal birth pulses of wild pigs in their region, and then intensively focus on removing wild pigs during the 115 days (i.e., gestation period) prior to those birth pulses. This may be counterintuitive to managers that focus on trapping after observing a birth pulse, but it increases the probability of simultaneously removing pregnant females and any associated offspring from previous litters that remained with the pregnant female. We also recommend evaluating regional-specific intensities of removal that might be required for reducing populations with specific emphasis on whether compensatory reproductive behaviors are generated and how to avoid them.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joel Ruprecht, Tavis D. Forrester, Darren A. Clark, Michael J. Wisdom, Joshua B. Smith, Taal Levi
To reverse range-wide population declines, managers of black-tailed and mule deer (Odocoileus hemionus) require information on the vital rates and life stages most influential to population growth to target effective management actions. We extracted black-tailed and mule deer vital rates from a range-wide literature review and used hierarchical models to summarize vital rates, their variability, and how they correlate with one another. We then used matrix models and life-stage simulation analysis to determine the individual vital rates that contributed most to annual population growth rate (i.e., lambda). Annual adult female survival explained the greatest amount of variation (62%) in lambda. Annual juvenile survival explained 44% of the variation in lambda, whereas summer or winter juvenile survival by themselves were far less informative. Winter fawn:doe ratios, a metric often collected by management agencies, explained only 10% of the variation in lambda. Given an adult female survival of 0.84, our simulations estimated a lambda of 1.0 (95% credible interval = 0.88–1.14), indicating equal probability that a population would increase or decrease. Simulations further indicated that given adult survival rates <70%, the population would always decline, but as survival increased lambda increased linearly. In contrast, estimates of lambda plateaued when annual juvenile survival reached approximately 0.5, indicating higher survival rates yielded diminishing returns to population stability. Using simulated values within the observed range of vital rate values across the species' geographical distribution, the mean lambda was 0.975 and in 61% of the simulations, lambda was <1. After 20 years, we estimated that this distribution of lambda values would cause populations to decrease in 92% of instances with a mean decrease of 44%. Our results align with observed declines in mule deer populations throughout their range over recent decades and indicate that these trends will continue until management can improve survival of adult females.
{"title":"Variability and correlations among vital rates and their influence on population growth in mule and black-tailed deer","authors":"Joel Ruprecht, Tavis D. Forrester, Darren A. Clark, Michael J. Wisdom, Joshua B. Smith, Taal Levi","doi":"10.1002/jwmg.22690","DOIUrl":"https://doi.org/10.1002/jwmg.22690","url":null,"abstract":"<p>To reverse range-wide population declines, managers of black-tailed and mule deer (<i>Odocoileus hemionus</i>) require information on the vital rates and life stages most influential to population growth to target effective management actions. We extracted black-tailed and mule deer vital rates from a range-wide literature review and used hierarchical models to summarize vital rates, their variability, and how they correlate with one another. We then used matrix models and life-stage simulation analysis to determine the individual vital rates that contributed most to annual population growth rate (i.e., lambda). Annual adult female survival explained the greatest amount of variation (62%) in lambda. Annual juvenile survival explained 44% of the variation in lambda, whereas summer or winter juvenile survival by themselves were far less informative. Winter fawn:doe ratios, a metric often collected by management agencies, explained only 10% of the variation in lambda. Given an adult female survival of 0.84, our simulations estimated a lambda of 1.0 (95% credible interval = 0.88–1.14), indicating equal probability that a population would increase or decrease. Simulations further indicated that given adult survival rates <70%, the population would always decline, but as survival increased lambda increased linearly. In contrast, estimates of lambda plateaued when annual juvenile survival reached approximately 0.5, indicating higher survival rates yielded diminishing returns to population stability. Using simulated values within the observed range of vital rate values across the species' geographical distribution, the mean lambda was 0.975 and in 61% of the simulations, lambda was <1. After 20 years, we estimated that this distribution of lambda values would cause populations to decrease in 92% of instances with a mean decrease of 44%. Our results align with observed declines in mule deer populations throughout their range over recent decades and indicate that these trends will continue until management can improve survival of adult females.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22690","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonio Del Vallé, Peter W. Guiden, Holly P. Jones
Grazing from megaherbivores such as bison (Bison bison) and periodic fire are 2 important disturbance regimes in grassland ecosystems. In restored tallgrass prairies where these processes were previously removed, prescribed fire application and bison reintroduction are tools used by managers to recreate habitat heterogeneity formed by these disturbances. Tallgrass prairie bird communities may be indirectly affected by these disturbances, as bison and prescribed fire alter the structure of critical breeding habitat for grassland birds. The objectives of this research were to determine the effects of bison and prescribed fire on grassland breeding birds in 2 tallgrass prairie preserves in the Midwest region of the United States. We surveyed bird communities, vegetation structure, and bison activity at an Illinois preserve (n = 20 sites) and an Indiana preserve (n = 27 sites) in 2020 and 2021 and compiled a history of restoration activities (e.g., prescribed fire, planting year) at these sites. Grazing and fire disturbances affected grassland bird diversity and abundances, whereas we found little to no evidence that restoration planting age and spatiotemporal factors affected grassland bird populations. Disturbance effects often corresponded to species-specific responses to changes in vegetation structure. Grassland-obligate bird diversity was lower in recently burned and ungrazed management units, in comparison to unburned-ungrazed and unburned-grazed sites. Henslow's sparrow (Centronyx henslowii), a species known to be sensitive to recent prescribed fire, exhibited increased abundance with time since fire, an increase that was further amplified with bison presence. These results highlight the importance of applying varying levels of grazing and fire disturbance to provide variable vegetation structure to accommodate the habitat preferences of a diversity of grassland bird species. Moreover, our results indicate that bison may play a role in mediating the differing effects of variable prescribed fire frequencies on grassland bird species of concern.
{"title":"Grassland bird responses to bison and prescribed fire in restored tallgrass prairies","authors":"Antonio Del Vallé, Peter W. Guiden, Holly P. Jones","doi":"10.1002/jwmg.22699","DOIUrl":"https://doi.org/10.1002/jwmg.22699","url":null,"abstract":"<p>Grazing from megaherbivores such as bison (<i>Bison bison</i>) and periodic fire are 2 important disturbance regimes in grassland ecosystems. In restored tallgrass prairies where these processes were previously removed, prescribed fire application and bison reintroduction are tools used by managers to recreate habitat heterogeneity formed by these disturbances. Tallgrass prairie bird communities may be indirectly affected by these disturbances, as bison and prescribed fire alter the structure of critical breeding habitat for grassland birds. The objectives of this research were to determine the effects of bison and prescribed fire on grassland breeding birds in 2 tallgrass prairie preserves in the Midwest region of the United States. We surveyed bird communities, vegetation structure, and bison activity at an Illinois preserve (<i>n</i> = 20 sites) and an Indiana preserve (<i>n</i> = 27 sites) in 2020 and 2021 and compiled a history of restoration activities (e.g., prescribed fire, planting year) at these sites. Grazing and fire disturbances affected grassland bird diversity and abundances, whereas we found little to no evidence that restoration planting age and spatiotemporal factors affected grassland bird populations. Disturbance effects often corresponded to species-specific responses to changes in vegetation structure. Grassland-obligate bird diversity was lower in recently burned and ungrazed management units, in comparison to unburned-ungrazed and unburned-grazed sites. Henslow's sparrow (<i>Centronyx henslowii</i>), a species known to be sensitive to recent prescribed fire, exhibited increased abundance with time since fire, an increase that was further amplified with bison presence. These results highlight the importance of applying varying levels of grazing and fire disturbance to provide variable vegetation structure to accommodate the habitat preferences of a diversity of grassland bird species. Moreover, our results indicate that bison may play a role in mediating the differing effects of variable prescribed fire frequencies on grassland bird species of concern.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonathan Tichon, Elyasaf Freiman, Orr Spiegel, Erez Baruchi, Aviam Atar, Roi Lapid, Roni King, Shirli Bar-David, David Saltz
The behavioral characteristics of species may result in certain populations being inherently more susceptible to fragmentation. For example, species exhibiting spatial sexual segregation or those constrained to elongated and narrow habitats. We studied the fragmentation threats, spatial dynamics, resource utilization, and movement ecology of a particularly vulnerable species that is both sexually segregated and constrained to elongated and narrow habitat—the north Judean Desert population of Nubian ibex (Capra nubiana). From 2016‒2020 we tracked 48 marked ibex (27 male, 21 female), of which 38 (20 male, 18 female) also had global position system (GPS) collars. Using GPS-collar and camera-trap data in zones delineated around perennial water sources (PWSs), we calculated ibex drinking frequencies and individual utilization distributions by season and sex, focusing on their overall (95% isopleth) and core (50% isopleth) home ranges. We quantified joint space use between sexes using a utilization distribution overlap index (UDOI) and ibex daily movements and space use via movement indices. Female groups formed philopatric activity centers that were anchored around PWSs year-round and arranged in a metapopulation-like structure, with no female movement detected between them. Conversely, movement of adult males changed seasonally, with the cores of male groups anchored around PWSs only during the dry season, and long-range movement between female activity centers during the rut. Female groups also spent more time at steeper terrain and higher elevations compared with male groups. Outside the rut, groups of males and groups of females exhibited minimal joint space use (i.e., average dry season UDOI was 0.06). These patterns indicate high sensitivity of this population to intersexual fragmentation by obstacles (physical or virtual). Management strategies to mitigate fragmentation threats for such populations should be sex-specific and landscape-oriented.
{"title":"Species behavioral characteristics lead to unique fragmentation threats: The Nubian ibex as a case study","authors":"Jonathan Tichon, Elyasaf Freiman, Orr Spiegel, Erez Baruchi, Aviam Atar, Roi Lapid, Roni King, Shirli Bar-David, David Saltz","doi":"10.1002/jwmg.22698","DOIUrl":"https://doi.org/10.1002/jwmg.22698","url":null,"abstract":"<p>The behavioral characteristics of species may result in certain populations being inherently more susceptible to fragmentation. For example, species exhibiting spatial sexual segregation or those constrained to elongated and narrow habitats. We studied the fragmentation threats, spatial dynamics, resource utilization, and movement ecology of a particularly vulnerable species that is both sexually segregated and constrained to elongated and narrow habitat—the north Judean Desert population of Nubian ibex (<i>Capra nubiana</i>). From 2016‒2020 we tracked 48 marked ibex (27 male, 21 female), of which 38 (20 male, 18 female) also had global position system (GPS) collars. Using GPS-collar and camera-trap data in zones delineated around perennial water sources (PWSs), we calculated ibex drinking frequencies and individual utilization distributions by season and sex, focusing on their overall (95% isopleth) and core (50% isopleth) home ranges. We quantified joint space use between sexes using a utilization distribution overlap index (UDOI) and ibex daily movements and space use via movement indices. Female groups formed philopatric activity centers that were anchored around PWSs year-round and arranged in a metapopulation-like structure, with no female movement detected between them. Conversely, movement of adult males changed seasonally, with the cores of male groups anchored around PWSs only during the dry season, and long-range movement between female activity centers during the rut. Female groups also spent more time at steeper terrain and higher elevations compared with male groups. Outside the rut, groups of males and groups of females exhibited minimal joint space use (i.e., average dry season UDOI was 0.06). These patterns indicate high sensitivity of this population to intersexual fragmentation by obstacles (physical or virtual). Management strategies to mitigate fragmentation threats for such populations should be sex-specific and landscape-oriented.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22698","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeff A. Alvarez, Jesse H. Schmieg, Jeffery T. Wilcox
Foothill yellow-legged frogs (Rana boylii) are a declining species, and methodologies for assessing population occupancy have been associated with only diurnal work on the species. Diurnal visual encounter surveys are typically used to determine presence within suitable habitat; however, studies of ecologically similar species indicate a potential advantage of nocturnal surveys. At 5 sites in 4 counties in California, USA, we compared diurnal and nocturnal surveys (n = 53 paired surveys) for foothill yellow-legged frogs, conducted 2016-2023, to determine the value of each survey period. Generally, occupancy probabilities increased 1–22 times, detection probabilities 1–69 times, and estimated abundances 3–12 times during nocturnal versus diurnal surveys. Associated standard errors were also lower in nocturnal versus diurnal surveys. However, we noted 2 locations where diurnal surveys yielded higher detection probability or higher estimates densities compared to nocturnal surveys. We suggest that both diurnal and nocturnal surveys be required when assessing occupancy of foothill yellow-legged frogs.
{"title":"Diurnal versus nocturnal surveys for foothill yellow-legged frogs","authors":"Jeff A. Alvarez, Jesse H. Schmieg, Jeffery T. Wilcox","doi":"10.1002/jwmg.22695","DOIUrl":"https://doi.org/10.1002/jwmg.22695","url":null,"abstract":"<p>Foothill yellow-legged frogs (<i>Rana boylii</i>) are a declining species, and methodologies for assessing population occupancy have been associated with only diurnal work on the species. Diurnal visual encounter surveys are typically used to determine presence within suitable habitat; however, studies of ecologically similar species indicate a potential advantage of nocturnal surveys. At 5 sites in 4 counties in California, USA, we compared diurnal and nocturnal surveys (<i>n</i> = 53 paired surveys) for foothill yellow-legged frogs, conducted 2016-2023, to determine the value of each survey period. Generally, occupancy probabilities increased 1–22 times, detection probabilities 1–69 times, and estimated abundances 3–12 times during nocturnal versus diurnal surveys. Associated standard errors were also lower in nocturnal versus diurnal surveys. However, we noted 2 locations where diurnal surveys yielded higher detection probability or higher estimates densities compared to nocturnal surveys. We suggest that both diurnal and nocturnal surveys be required when assessing occupancy of foothill yellow-legged frogs.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dale G. Miquelle, Anna S. Mukhacheva, Eugenia V. Bragina, Scott J. Waller, Yuri K. Petrunenko, Sergei V. Naidenko, Jose. A. Hernandez-Blanco, Vyacheslav A. Kastrikin, Alexander N. Rybin, Nikolai N. Rybin, Ivan V. Seryodkin, Ekaterina Yu. Blidchenko, Anna A. Yachmennikova, Maria D. Chistopolova, Svetlana V. Soutyrina, Viatcheslav V. Rozhnov
Empty but suitable habitat exists for many of the world's terrestrial large carnivores, yet reintroductions are often considered difficult. In the Russian Far East, orphaned Amur tiger (Panthera tigris altaica) cubs were brought into captivity but prepared for re-release into the wild. We addressed 2 questions after reintroduction: 1) were individuals raised in captivity capable of killing prey at a rate sufficient to survive, and 2) did individuals avoid use of domestic animals as a primary source of food? We collected data on hunting behavior of 6 orphaned tigers re-released into their indigenous range, and compared kill composition, kill rate, and consumption rate to individuals studied within the existing range (Sikhote-Alin) of Amur tigers. Prey composition of rehabilitated tigers varied from that of the Sikhote-Alin tigers, but composition of major food groups was nearly identical. Kill rate of rehabilitated tigers was higher and prey size was smaller than that of Sikhote-Alin tigers, but consumption rates were nearly identical. One young male tiger depredated domestic animals, but other individuals only rarely preyed on dogs or cattle they encountered in forests. We documented high survival, reproduction, and recruitment of re-released individuals. These results indicate that tigers held in captivity during the majority of their early lives can survive in the wild, so long as exposure to humans is kept to a minimum and individuals learn to hunt wild prey before release. Results provide a potential framework for reintroductions of tigers and other large felids across the globe.
{"title":"Rehabilitating tigers for range expansion: lessons from the Russian Far East","authors":"Dale G. Miquelle, Anna S. Mukhacheva, Eugenia V. Bragina, Scott J. Waller, Yuri K. Petrunenko, Sergei V. Naidenko, Jose. A. Hernandez-Blanco, Vyacheslav A. Kastrikin, Alexander N. Rybin, Nikolai N. Rybin, Ivan V. Seryodkin, Ekaterina Yu. Blidchenko, Anna A. Yachmennikova, Maria D. Chistopolova, Svetlana V. Soutyrina, Viatcheslav V. Rozhnov","doi":"10.1002/jwmg.22691","DOIUrl":"https://doi.org/10.1002/jwmg.22691","url":null,"abstract":"<p>Empty but suitable habitat exists for many of the world's terrestrial large carnivores, yet reintroductions are often considered difficult. In the Russian Far East, orphaned Amur tiger (<i>Panthera tigris altaica</i>) cubs were brought into captivity but prepared for re-release into the wild. We addressed 2 questions after reintroduction: 1) were individuals raised in captivity capable of killing prey at a rate sufficient to survive, and 2) did individuals avoid use of domestic animals as a primary source of food? We collected data on hunting behavior of 6 orphaned tigers re-released into their indigenous range, and compared kill composition, kill rate, and consumption rate to individuals studied within the existing range (Sikhote-Alin) of Amur tigers. Prey composition of rehabilitated tigers varied from that of the Sikhote-Alin tigers, but composition of major food groups was nearly identical. Kill rate of rehabilitated tigers was higher and prey size was smaller than that of Sikhote-Alin tigers, but consumption rates were nearly identical. One young male tiger depredated domestic animals, but other individuals only rarely preyed on dogs or cattle they encountered in forests. We documented high survival, reproduction, and recruitment of re-released individuals. These results indicate that tigers held in captivity during the majority of their early lives can survive in the wild, so long as exposure to humans is kept to a minimum and individuals learn to hunt wild prey before release. Results provide a potential framework for reintroductions of tigers and other large felids across the globe.</p>","PeriodicalId":17504,"journal":{"name":"Journal of Wildlife Management","volume":"89 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jwmg.22691","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}