E. Dierenfeld, Lena C. Larsson, Aaron C. Pratt, S. Sherrod
We measured fatty acids, minerals, and fat-soluble nutrients in liver tissues from greater prairie-chickens Tympanuchus cupido pinnatus as an ecological dietary surrogate for endangered Attwater’s prairie-chickens T. c. attwateri, and investigated differences associated with captive (non-released captive-raised n = 4), wild (n = 12), and combination (released captive-raised n = 5) diets. In general, we found more variability across all fatty acids in samples from released captive-raised birds compared with either non-released captive-raised or wild birds. Polyunsaturated fatty acids were lowest in captive-raised birds. Regarding minerals, liver sodium values were uniquely lower in released captive-raised birds, and copper and manganese concentrations were lower for both released and non-released captive-raised birds. Of the carotenoids evaluated, β-carotene was lower in livers from captive-raised birds compared with wild prairie-chickens. Zeaxanthin was lowest in livers from birds that were captive-raised but non-released. Differences in hepatic nutrient concentration among the three study groups may be directly correlated with dietary ingredients. Results suggest possible management actions for improved nutrition of prairie-chickens in future release programs such as further refinement of trace mineral and β-carotene content of captive commercial diets, the addition of supplemental feeds in release protocols that include an elevated polyunsaturated fatty acid profile, green plant materials that elevate β-carotene content, provision of trace mineralized salt sources at release sites, and timing releases to coincide with periods of high natural resource availability to better duplicate nutrient diversity.
{"title":"Liver Fatty Acid, Mineral and Fat-Soluble Nutrients in Wild and Captive Greater Prairie-Chickens","authors":"E. Dierenfeld, Lena C. Larsson, Aaron C. Pratt, S. Sherrod","doi":"10.3996/jfwm-22-003","DOIUrl":"https://doi.org/10.3996/jfwm-22-003","url":null,"abstract":"We measured fatty acids, minerals, and fat-soluble nutrients in liver tissues from greater prairie-chickens Tympanuchus cupido pinnatus as an ecological dietary surrogate for endangered Attwater’s prairie-chickens T. c. attwateri, and investigated differences associated with captive (non-released captive-raised n = 4), wild (n = 12), and combination (released captive-raised n = 5) diets. In general, we found more variability across all fatty acids in samples from released captive-raised birds compared with either non-released captive-raised or wild birds. Polyunsaturated fatty acids were lowest in captive-raised birds. Regarding minerals, liver sodium values were uniquely lower in released captive-raised birds, and copper and manganese concentrations were lower for both released and non-released captive-raised birds. Of the carotenoids evaluated, β-carotene was lower in livers from captive-raised birds compared with wild prairie-chickens. Zeaxanthin was lowest in livers from birds that were captive-raised but non-released. Differences in hepatic nutrient concentration among the three study groups may be directly correlated with dietary ingredients. Results suggest possible management actions for improved nutrition of prairie-chickens in future release programs such as further refinement of trace mineral and β-carotene content of captive commercial diets, the addition of supplemental feeds in release protocols that include an elevated polyunsaturated fatty acid profile, green plant materials that elevate β-carotene content, provision of trace mineralized salt sources at release sites, and timing releases to coincide with periods of high natural resource availability to better duplicate nutrient diversity.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42701091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Roads are important drivers of habitat loss, degradation, and fragmentation that affect global biodiversity. Detrimental effects of roads include direct mortality of individual animals, spread of habitat-altering invasive plants, and loss of demographic and genetic connectivity of wildlife populations. Various measures address the negative effects of roads on wildlife. However, most strategies for minimizing or mitigating the effects of roads are focused on the actual roads themselves rather than on the collective travel network across landscapes. We summarized a growing body of literature that has documented the effects of road density on wildlife populations and the benefits associated with lower densities. This literature supports the application of limits on road density as a viable tool for managing cumulative effects. Based on these examples, we recommend road densities, including all linear features used for travel, < 0.6 km/km2 as a general target for travel management in areas where wildlife conservation is a priority. Lower densities may be necessary in particularly sensitive areas, whereas higher densities may be appropriate in areas less important to landscape-level conservation and wildlife connectivity. Public policy and funding also are needed to address challenges of enforcing off-highway vehicle regulations. In applying this general overview to a case study of the Mojave desert tortoise Gopherus agassizii, we found that all management plans across the species’ range lack considerations of road density and that tortoise populations declined within all conservation areas with road densities > 0.75 km/km2. From this we provide several travel-management recommendations specific to Mojave desert tortoise conservation beginning with identifying the entire travel network within management areas. Specific actions for managing or setting limits for road density depend on the site-specific biological or management context, for instance relative to habitat quality or proximity to designated tortoise conservation areas. In addition, increasing law enforcement and public outreach will improve enforcement and compliance of travel regulations, and installing tortoise-exclusion fencing along highways will reduce road-kills and allow tortoise populations to reoccupy depleted areas adjacent to highways. Implementation of these recommendations would improve the prospects of reversing desert tortoise population declines.
{"title":"Travel Management Planning for Wildlife with a Case Study on the Mojave Desert Tortoise","authors":"Roy C. Averill‐Murray, L. Allison","doi":"10.3996/jfwm-22-030","DOIUrl":"https://doi.org/10.3996/jfwm-22-030","url":null,"abstract":"Roads are important drivers of habitat loss, degradation, and fragmentation that affect global biodiversity. Detrimental effects of roads include direct mortality of individual animals, spread of habitat-altering invasive plants, and loss of demographic and genetic connectivity of wildlife populations. Various measures address the negative effects of roads on wildlife. However, most strategies for minimizing or mitigating the effects of roads are focused on the actual roads themselves rather than on the collective travel network across landscapes. We summarized a growing body of literature that has documented the effects of road density on wildlife populations and the benefits associated with lower densities. This literature supports the application of limits on road density as a viable tool for managing cumulative effects. Based on these examples, we recommend road densities, including all linear features used for travel, < 0.6 km/km2 as a general target for travel management in areas where wildlife conservation is a priority. Lower densities may be necessary in particularly sensitive areas, whereas higher densities may be appropriate in areas less important to landscape-level conservation and wildlife connectivity. Public policy and funding also are needed to address challenges of enforcing off-highway vehicle regulations. In applying this general overview to a case study of the Mojave desert tortoise Gopherus agassizii, we found that all management plans across the species’ range lack considerations of road density and that tortoise populations declined within all conservation areas with road densities > 0.75 km/km2. From this we provide several travel-management recommendations specific to Mojave desert tortoise conservation beginning with identifying the entire travel network within management areas. Specific actions for managing or setting limits for road density depend on the site-specific biological or management context, for instance relative to habitat quality or proximity to designated tortoise conservation areas. In addition, increasing law enforcement and public outreach will improve enforcement and compliance of travel regulations, and installing tortoise-exclusion fencing along highways will reduce road-kills and allow tortoise populations to reoccupy depleted areas adjacent to highways. Implementation of these recommendations would improve the prospects of reversing desert tortoise population declines.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42414031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Wales A. Carter, Thomas J McGreevy, B. Gerber, Amy E. Mayer, Mary E. Sullivan, B. Tefft, T. Husband
Ongoing declines in the imperiled New England cottontail Sylvilagus transitionalis have coincided with the introduction and expansion of the closely related eastern cottontail Sylvilagus floridanus. These paired population trends have led to the inference of competition between the two species. Competition between native and introduced species has often involved overlapping use of food resources, but limited effort has been spent to analyze the diets of New England cottontail and eastern cottontail and to evaluate the potential for resource competition. We used microhistological analysis of fecal pellets to assess the winter diets of both species and we compared diet composition with available plant communities to evaluate their preferences for dietary items across southern New England and southeastern New York. We found no differences in diets between New England cottontail and eastern cottontail, although diets did differ between regions within the study area. Diet preferences also were consistent between the species and largely excluded non-native plant genera. Our results demonstrate that these species are generalist herbivores and that there is high potential for competition for food resources in the winter between them, although the present lack of diet partitioning may indicate the presence of other factors limiting competition. This study highlights the need for careful evaluation of interactions between native and non-native species, a prerequisite for developing conservation plans that appropriately account for interspecific competition.
{"title":"High Similarity in Winter Diet between Imperiled New England Cottontail and Invasive Eastern Cottontail","authors":"Wales A. Carter, Thomas J McGreevy, B. Gerber, Amy E. Mayer, Mary E. Sullivan, B. Tefft, T. Husband","doi":"10.3996/jfwm-22-015","DOIUrl":"https://doi.org/10.3996/jfwm-22-015","url":null,"abstract":"Ongoing declines in the imperiled New England cottontail Sylvilagus transitionalis have coincided with the introduction and expansion of the closely related eastern cottontail Sylvilagus floridanus. These paired population trends have led to the inference of competition between the two species. Competition between native and introduced species has often involved overlapping use of food resources, but limited effort has been spent to analyze the diets of New England cottontail and eastern cottontail and to evaluate the potential for resource competition. We used microhistological analysis of fecal pellets to assess the winter diets of both species and we compared diet composition with available plant communities to evaluate their preferences for dietary items across southern New England and southeastern New York. We found no differences in diets between New England cottontail and eastern cottontail, although diets did differ between regions within the study area. Diet preferences also were consistent between the species and largely excluded non-native plant genera. Our results demonstrate that these species are generalist herbivores and that there is high potential for competition for food resources in the winter between them, although the present lack of diet partitioning may indicate the presence of other factors limiting competition. This study highlights the need for careful evaluation of interactions between native and non-native species, a prerequisite for developing conservation plans that appropriately account for interspecific competition.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49464805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
J. Franson, J. Franson, T. Hollmen, P. Flint, A. Matz
In 2001, we collected whole blood from sea ducks (Steller’s eider Polysticta stelleri, harlequin duck Histrionicus histrionicus, black scoter Melanitta nigra, and long-tailed duck Clangula hyemalis) wintering at Dutch Harbor, Alaska, and from Steller’s eiders molting at Izembek Lagoon on the Alaska Peninsula. Blood samples were analyzed for 19 trace elements, of which 17 were detected in one or more samples. In Steller’s eiders, mean concentrations of six trace elements (As, B, Fe, Hg, Se, Mo) were greater at Dutch Harbor and mean concentrations of four trace elements (Cr, Cu, Mg, Zn) were greater at Izembek Lagoon. Among sea ducks at Dutch Harbor, mean concentrations of five trace elements (Cu, Hg, Se, Zn, V) differed by species. Steller’s eiders had greater concentrations of Cu, Zn, and V in their blood, black scoters had the highest Se, and harlequin ducks had the highest Hg, with a mean concentration slightly above a threshold effect level. One Steller’s eider and one harlequin duck from Dutch Harbor had blood Pb levels above background concentrations. We have no observations to indicate that concentrations of these trace elements were associated with adverse effects.
{"title":"Trace Elements in Blood of Sea Ducks from Dutch Harbor and Izembek Lagoon, Alaska","authors":"J. Franson, J. Franson, T. Hollmen, P. Flint, A. Matz","doi":"10.3996/jfwm-21-065","DOIUrl":"https://doi.org/10.3996/jfwm-21-065","url":null,"abstract":"In 2001, we collected whole blood from sea ducks (Steller’s eider Polysticta stelleri, harlequin duck Histrionicus histrionicus, black scoter Melanitta nigra, and long-tailed duck Clangula hyemalis) wintering at Dutch Harbor, Alaska, and from Steller’s eiders molting at Izembek Lagoon on the Alaska Peninsula. Blood samples were analyzed for 19 trace elements, of which 17 were detected in one or more samples. In Steller’s eiders, mean concentrations of six trace elements (As, B, Fe, Hg, Se, Mo) were greater at Dutch Harbor and mean concentrations of four trace elements (Cr, Cu, Mg, Zn) were greater at Izembek Lagoon. Among sea ducks at Dutch Harbor, mean concentrations of five trace elements (Cu, Hg, Se, Zn, V) differed by species. Steller’s eiders had greater concentrations of Cu, Zn, and V in their blood, black scoters had the highest Se, and harlequin ducks had the highest Hg, with a mean concentration slightly above a threshold effect level. One Steller’s eider and one harlequin duck from Dutch Harbor had blood Pb levels above background concentrations. We have no observations to indicate that concentrations of these trace elements were associated with adverse effects.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48684884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Skylar L. Wolf, Scott Tolentino, Robert C. Shields
We used bomb calorimetry to quantify the energy density of three fish species endemic to Bear Lake, Utah-Idaho that were collected in 2020 – 2021. We collected Bear Lake Whitefish Prosopium abyssicola , Bonneville Whitefish P. spilonotus , and Bonneville Cisco P. gemmifer . We found that mean (± standard deviation) wet weight energy densities were 6,312 (± 760) joules per gram for Bear Lake Whitefish, 5,301 (± 778) joules per gram for Bonneville Whitefish, and 4,743 (± 443) joules per gram for Bonneville Cisco. We built linear mixed models and found relationships between energy density and dry matter ratio (i.e., ratio of dried weight to wet weight of a fish) for all three species, suggesting that the energy density of future samples collected in Bear Lake could potentially be determined from comparisons between the dried and wet weight of fishes belonging to these species. Our results will be useful for future bioenergetics modeling with these three Bear Lake endemic species, and potentially with others species in related genera that share similar feeding, behavior, and life history traits.
我们使用炸弹量热法量化了2020 - 2021年收集的犹他州-爱达荷州熊湖特有的三种鱼类的能量密度。我们采集了熊湖白鱼Prosopium abyssicola、Bonneville Whitefish P. spilonotus和Bonneville Cisco P. gemmifer。我们发现熊湖白鱼的平均(±标准差)湿重能量密度为6312(±760)焦耳/克，博纳维尔白鱼为5301(±778)焦耳/克，博纳维尔思科为4743(±443)焦耳/克。我们建立了线性混合模型，并发现了所有三种鱼类的能量密度与干物质比(即鱼的干重与湿重之比)之间的关系，这表明未来在熊湖收集的样本的能量密度可能会通过比较属于这些物种的鱼的干重和湿重来确定。我们的研究结果将有助于未来对这三种熊湖特有物种的生物能量学建模，以及对具有相似摄食、行为和生活史特征的其他相关属物种的生物能量学建模。
{"title":"Energy Density of Three Prosopium Fish Species Endemic to Bear Lake, Utah-Idaho","authors":"Skylar L. Wolf, Scott Tolentino, Robert C. Shields","doi":"10.3996/jfwm-22-020","DOIUrl":"https://doi.org/10.3996/jfwm-22-020","url":null,"abstract":"We used bomb calorimetry to quantify the energy density of three fish species endemic to Bear Lake, Utah-Idaho that were collected in 2020 – 2021. We collected Bear Lake Whitefish Prosopium abyssicola , Bonneville Whitefish P. spilonotus , and Bonneville Cisco P. gemmifer . We found that mean (± standard deviation) wet weight energy densities were 6,312 (± 760) joules per gram for Bear Lake Whitefish, 5,301 (± 778) joules per gram for Bonneville Whitefish, and 4,743 (± 443) joules per gram for Bonneville Cisco. We built linear mixed models and found relationships between energy density and dry matter ratio (i.e., ratio of dried weight to wet weight of a fish) for all three species, suggesting that the energy density of future samples collected in Bear Lake could potentially be determined from comparisons between the dried and wet weight of fishes belonging to these species. Our results will be useful for future bioenergetics modeling with these three Bear Lake endemic species, and potentially with others species in related genera that share similar feeding, behavior, and life history traits.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47954971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Dams impede the upstream migration of juvenile American eel Anguilla rostrata, limiting their access to freshwater habitat and potentially contributing to population declines across their range. The implementation of fishways at large hydropower dams help restore access to upstream habitat, and represents a long-term dataset of American eel captures. We analyzed the relationships between eel captures and select environmental variables (river discharge, water temperature, and lunar illumination) at four hydropower projects on east coast rivers with a comparable decade of data and sampling techniques; Roanoke Rapids Dam on the Roanoke River in North Carolina, Conowingo Dam, on the Susquehanna River in Maryland, Holyoke Dam, on the Connecticut River in Massachusetts, and the Moses-Saunders Dam on St. Lawrence River in New York and Canada. The number of eels captured varied among projects, from year to year, and seasonally. American Eel are opportunistic in their upstream movements, with peak movement events associated with high flows, increased water temperature, and low lunar illumination. Our results suggest that systems altered by hydropower dams offer unique challenges to American eel migrants, and that a multitude of factors play a role in the timing of upstream movements.
{"title":"Generalizing Trends in Upstream American Eel Movements at Four East Coast Hydropower Projects","authors":"K. Mack, Twyla Cheatwood","doi":"10.3996/jfwm-21-066","DOIUrl":"https://doi.org/10.3996/jfwm-21-066","url":null,"abstract":"Dams impede the upstream migration of juvenile American eel Anguilla rostrata, limiting their access to freshwater habitat and potentially contributing to population declines across their range. The implementation of fishways at large hydropower dams help restore access to upstream habitat, and represents a long-term dataset of American eel captures. We analyzed the relationships between eel captures and select environmental variables (river discharge, water temperature, and lunar illumination) at four hydropower projects on east coast rivers with a comparable decade of data and sampling techniques; Roanoke Rapids Dam on the Roanoke River in North Carolina, Conowingo Dam, on the Susquehanna River in Maryland, Holyoke Dam, on the Connecticut River in Massachusetts, and the Moses-Saunders Dam on St. Lawrence River in New York and Canada. The number of eels captured varied among projects, from year to year, and seasonally. American Eel are opportunistic in their upstream movements, with peak movement events associated with high flows, increased water temperature, and low lunar illumination. Our results suggest that systems altered by hydropower dams offer unique challenges to American eel migrants, and that a multitude of factors play a role in the timing of upstream movements.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42814979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Lauren M. McGarvey, Jason E. Ilgen, C. S. Guy, J. McLellan, M. Webb
Skipped spawning occurs in many annual spawning fish species and should be evaluated to effectively manage their populations. We assessed plasma sex steroid concentrations, gonad size measured by ultrasonography, and ovarian follicle diameter as metrics to non-lethally identify mass ovarian follicular atresia (i.e., skipped spawning) in Burbot Lota lota. We maintained wild fish in captivity and exposed them to increasing water temperatures during a three-week period prior to the spawning season to induce mass ovarian follicular atresia. We collected ovarian follicles, blood plasma, and gonadal sonograms from fish weekly between January 28, 2018 to March 25, 2018. We histologically analyzed ovarian follicles to confirm stage of maturity. We measured plasma sex steroid concentrations, testosterone (T) and estradiol-17β (E2), by radioimmunoassay. We measured gonad diameter and circumference by ultrasonography and ovarian follicle diameter by image analysis. Mean plasma T concentration decreased from 8.94 ng/ml during late vitellogenesis to 1.83 ng/ml during atresia, suggesting that plasma T concentrations may be used to identify mass ovarian follicular atresia. We do not recommend using plasma E2 concentrations to identify mass ovarian follicular atresia because concentrations rapidly decreased during the completion of vitellogenesis and the initiation of atresia in Burbot; therefore, plasma E2 may not accurately identify mass ovarian follicular atresia. Mean gonad diameter measured by ultrasonography decreased from 4.05 cm during late vitellogenesis to 3.65 cm during atresia. Mean diameter of ovarian follicles decreased during the last week of the study suggesting that ovarian follicle diameter may be used to identify advanced mass ovarian follicular atresia. The non-lethal tools assessed in this paper (plasma sex steroid concentrations, ultrasonography, and ovarian follicle diameter) will enable fisheries biologists to determine the occurrence and frequency of mass ovarian follicular atresia among Burbot in Lake Roosevelt and may be applied to other Burbot populations.
{"title":"Non-lethal Tools to Identify Mass Ovarian Follicular Atresia in Burbot Lota lota","authors":"Lauren M. McGarvey, Jason E. Ilgen, C. S. Guy, J. McLellan, M. Webb","doi":"10.3996/jfwm-22-018","DOIUrl":"https://doi.org/10.3996/jfwm-22-018","url":null,"abstract":"Skipped spawning occurs in many annual spawning fish species and should be evaluated to effectively manage their populations. We assessed plasma sex steroid concentrations, gonad size measured by ultrasonography, and ovarian follicle diameter as metrics to non-lethally identify mass ovarian follicular atresia (i.e., skipped spawning) in Burbot Lota lota. We maintained wild fish in captivity and exposed them to increasing water temperatures during a three-week period prior to the spawning season to induce mass ovarian follicular atresia. We collected ovarian follicles, blood plasma, and gonadal sonograms from fish weekly between January 28, 2018 to March 25, 2018. We histologically analyzed ovarian follicles to confirm stage of maturity. We measured plasma sex steroid concentrations, testosterone (T) and estradiol-17β (E2), by radioimmunoassay. We measured gonad diameter and circumference by ultrasonography and ovarian follicle diameter by image analysis. Mean plasma T concentration decreased from 8.94 ng/ml during late vitellogenesis to 1.83 ng/ml during atresia, suggesting that plasma T concentrations may be used to identify mass ovarian follicular atresia. We do not recommend using plasma E2 concentrations to identify mass ovarian follicular atresia because concentrations rapidly decreased during the completion of vitellogenesis and the initiation of atresia in Burbot; therefore, plasma E2 may not accurately identify mass ovarian follicular atresia. Mean gonad diameter measured by ultrasonography decreased from 4.05 cm during late vitellogenesis to 3.65 cm during atresia. Mean diameter of ovarian follicles decreased during the last week of the study suggesting that ovarian follicle diameter may be used to identify advanced mass ovarian follicular atresia. The non-lethal tools assessed in this paper (plasma sex steroid concentrations, ultrasonography, and ovarian follicle diameter) will enable fisheries biologists to determine the occurrence and frequency of mass ovarian follicular atresia among Burbot in Lake Roosevelt and may be applied to other Burbot populations.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45907595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Richard D. Sample, Rylee D. Tomey, Zackary J. Delisle, Alexis R. Trumbower, Phoebe J. Habeck, J. Brooke, M. Jenkins
Fecal-pellet surveys provide density estimates of pellet groups, which offer a quick and reliable index of population densities for white-tailed deer Odocoileus virginianus and other wildlife species. Comparisons of differing fecal-pellet survey methodologies have previously shown that they vary in the precision. However, these comparisons have been made outside of the United States in regions with lower white-tailed deer densities. In this study, we compared pellet-group density estimates and precisions from line-transects, quadrat sampling, and strip-transects. At each site, three observers surveyed simultaneously with each being responsible for one method. Like other studies, we found that each method produced similar estimates of pellet-group density, but quadrat sampling produced the most precise estimates. Furthermore, all three methods suggested that the central region of Indiana had both the highest pellet-group density and the highest precision. Thus, suggesting that pellet groups may be more homogenously distributed in areas with higher white-tailed deer densities, which may increase the precision of all methods. Our results suggest that quadrat sampling may be the most effective method for estimating pellet-group densities within woodlots of the Midwest United States, and that precision may increase in areas with higher white-tailed deer densities. This study not only improves deer management within the Midwest United States but provides guidelines for other studies to potentially advance the conservation and management of other species.
{"title":"Comparing Methods of Estimating Fecal Pellet-Group Density in Woodlots of the Midwest United States","authors":"Richard D. Sample, Rylee D. Tomey, Zackary J. Delisle, Alexis R. Trumbower, Phoebe J. Habeck, J. Brooke, M. Jenkins","doi":"10.3996/jfwm-21-098","DOIUrl":"https://doi.org/10.3996/jfwm-21-098","url":null,"abstract":"Fecal-pellet surveys provide density estimates of pellet groups, which offer a quick and reliable index of population densities for white-tailed deer Odocoileus virginianus and other wildlife species. Comparisons of differing fecal-pellet survey methodologies have previously shown that they vary in the precision. However, these comparisons have been made outside of the United States in regions with lower white-tailed deer densities. In this study, we compared pellet-group density estimates and precisions from line-transects, quadrat sampling, and strip-transects. At each site, three observers surveyed simultaneously with each being responsible for one method. Like other studies, we found that each method produced similar estimates of pellet-group density, but quadrat sampling produced the most precise estimates. Furthermore, all three methods suggested that the central region of Indiana had both the highest pellet-group density and the highest precision. Thus, suggesting that pellet groups may be more homogenously distributed in areas with higher white-tailed deer densities, which may increase the precision of all methods. Our results suggest that quadrat sampling may be the most effective method for estimating pellet-group densities within woodlots of the Midwest United States, and that precision may increase in areas with higher white-tailed deer densities. This study not only improves deer management within the Midwest United States but provides guidelines for other studies to potentially advance the conservation and management of other species.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70143604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
With continued losses, the need for grassland restoration increases, and other contemporary threats, such as climate change, may require new techniques for restorations to be successful and resilient. The conservation community has promoted the use of locally sourced seed for grassland restorations, but it is unclear how widespread the practice has become. Furthermore, rethinking how seed is sourced for grassland restorations is one potential strategy to facilitate climate change adaptation. We surveyed practitioners (anyone conducting grassland restorations) across the U.S. and Canada in 2017 regarding organizational, state/local government, or individual policies for using locally sourced seed in grassland restorations, how local was defined, and whether climate change was considered in these policies and decisions. We received 494 responses from 40 U.S. states and 5 Canadian provinces. Policies and individual decisions supporting locally sourced seed were common, with only 3.6% reporting no consideration of local seed sources in restorations. However, the definition of local varied widely with relatively large geographic areas, such as ecoregions, considered as a local source. Some practitioners considered climate change, but it was not the greatest concern when making seed-sourcing decisions. When they did consider climate change, their most reported strategy was expanding seed zones used for their seed mix. Although there was a heavy upper Midwest bias in the survey responses, the number and geographic scope of responses provides a snapshot of seed sourcing strategies used by practitioners. Our results suggest practitioners are concerned about maintaining adaptation, given the focus on local seed sources, and outreach could be useful to help practitioners incorporate climate adaptation strategies into seed sourcing practices.
{"title":"Locally Sourced Seed is a Commonly Used but Widely Defined Practice for Grassland Restoration","authors":"M. Ahlering, Casey Binggeli","doi":"10.3996/jfwm-21-079","DOIUrl":"https://doi.org/10.3996/jfwm-21-079","url":null,"abstract":"With continued losses, the need for grassland restoration increases, and other contemporary threats, such as climate change, may require new techniques for restorations to be successful and resilient. The conservation community has promoted the use of locally sourced seed for grassland restorations, but it is unclear how widespread the practice has become. Furthermore, rethinking how seed is sourced for grassland restorations is one potential strategy to facilitate climate change adaptation. We surveyed practitioners (anyone conducting grassland restorations) across the U.S. and Canada in 2017 regarding organizational, state/local government, or individual policies for using locally sourced seed in grassland restorations, how local was defined, and whether climate change was considered in these policies and decisions. We received 494 responses from 40 U.S. states and 5 Canadian provinces. Policies and individual decisions supporting locally sourced seed were common, with only 3.6% reporting no consideration of local seed sources in restorations. However, the definition of local varied widely with relatively large geographic areas, such as ecoregions, considered as a local source. Some practitioners considered climate change, but it was not the greatest concern when making seed-sourcing decisions. When they did consider climate change, their most reported strategy was expanding seed zones used for their seed mix. Although there was a heavy upper Midwest bias in the survey responses, the number and geographic scope of responses provides a snapshot of seed sourcing strategies used by practitioners. Our results suggest practitioners are concerned about maintaining adaptation, given the focus on local seed sources, and outreach could be useful to help practitioners incorporate climate adaptation strategies into seed sourcing practices.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47579397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
J. B. Davis, Melanie R. Boudreau, Kira C. Monroe, R. Kaminski
American black ducks Anas rubripes are declining in traditionally important wintering areas in the south-central Mississippi flyway. Understanding resource exploitation by black ducks and morphologically similar and co-existing mallards A. platyrhynchos during winter may provide insight into competitive interactions which could exacerbate these declines. We radiomarked female black ducks and mallards at the Tennessee National Wildlife Refuge, Tennessee USA, during winter 2011–2012. We hypothesized that resource partitioning may occur to avoid or lessen interspecific competition between the two species and examined this in the context of home range overlap, resource selection and proportional resource use, niche breadth, and inter- and intraspecific resource overlap. Black duck and mallard home ranges were similar in area, with black duck individual home ranges ranging from 15 to 77 km2 and mallards from 21 to 72 km2 in size; 93% of the total area used by each species overlapped. Black ducks selected emergent wetlands 1.2x more than mallards, and mallards selected cultivated lands 2x more than black ducks. However, there were only minor differences between species in their proportional use of landcover types, and there were no temporal differences in resource selection at the diurnal or seasonal scale. Additionally, while black ducks and mallards had moderate and small niche breadths (niche breadth = 0.47 and 0.34, respectively), the two species had a substantial degree of inter- and intraspecific resource overlap. Our results indicate that these species do not competitively exclude each other spatiotemporally. Further research is needed to understand fine-scale interactions between these species and other factors which may be impacting black duck declines in the south-central Mississippi flyway, such as effects occurring in the breeding grounds or the potential influences of climate on northern shifts in duck distribution.
{"title":"Resource Use Overlap by Sympatric Wintering American Black Ducks and Mallards in Tennessee","authors":"J. B. Davis, Melanie R. Boudreau, Kira C. Monroe, R. Kaminski","doi":"10.3996/jfwm-21-039","DOIUrl":"https://doi.org/10.3996/jfwm-21-039","url":null,"abstract":"American black ducks Anas rubripes are declining in traditionally important wintering areas in the south-central Mississippi flyway. Understanding resource exploitation by black ducks and morphologically similar and co-existing mallards A. platyrhynchos during winter may provide insight into competitive interactions which could exacerbate these declines. We radiomarked female black ducks and mallards at the Tennessee National Wildlife Refuge, Tennessee USA, during winter 2011–2012. We hypothesized that resource partitioning may occur to avoid or lessen interspecific competition between the two species and examined this in the context of home range overlap, resource selection and proportional resource use, niche breadth, and inter- and intraspecific resource overlap. Black duck and mallard home ranges were similar in area, with black duck individual home ranges ranging from 15 to 77 km2 and mallards from 21 to 72 km2 in size; 93% of the total area used by each species overlapped. Black ducks selected emergent wetlands 1.2x more than mallards, and mallards selected cultivated lands 2x more than black ducks. However, there were only minor differences between species in their proportional use of landcover types, and there were no temporal differences in resource selection at the diurnal or seasonal scale. Additionally, while black ducks and mallards had moderate and small niche breadths (niche breadth = 0.47 and 0.34, respectively), the two species had a substantial degree of inter- and intraspecific resource overlap. Our results indicate that these species do not competitively exclude each other spatiotemporally. Further research is needed to understand fine-scale interactions between these species and other factors which may be impacting black duck declines in the south-central Mississippi flyway, such as effects occurring in the breeding grounds or the potential influences of climate on northern shifts in duck distribution.","PeriodicalId":49036,"journal":{"name":"Journal of Fish and Wildlife Management","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48292797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
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