Kevin L. Monteith, Ryan A. Long, Vernon C. Bleich, James R. Heffelfinger, Paul R. Krausman, R. Terry Bowyer
<p>Hunting remains the cornerstone of the North American model of wildlife conservation and management. Nevertheless, research has indicated the potential for hunting to adversely influence size of horn-like structures of some ungulates. In polygynous ungulates, mating success of males is strongly correlated with body size and size of horn-like structures; consequently, sexual selection has favored the development of large horns and antlers. Horn-like structures are biologically important and are of great cultural interest, both of which highlight the need to identify long-term trends in size of those structures, and understand the underlying mechanisms responsible for such trends. We evaluated trends in horn and antler size of trophy males (individuals exhibiting exceptionally large horns or antlers) recorded from 1900 to 2008 in Records of North American Big Game, which comprised >22,000 records among 25 trophy categories encompassing the geographic extent of species occupying North America. The long-term and broad-scale nature of those data neutralized localized effects of climate and population dynamics, making it possible to detect meaningful changes in size of horn-like structures among trophy males over the past century; however, ages of individual specimens were not available, which prevented us from evaluating age-class specific changes in size. Therefore, we used a weight-of-evidence approach based on differences among trophy categories in life-history characteristics, geographic distribution, morphological attributes, and harvest regimes to discriminate among competing hypotheses for explaining long-term trends in horn and antler size of trophy ungulates, and provide directions for future research. These hypotheses were young male age structure caused by intensive harvest of males (H1), genetic change as a result of selective male harvest (H2), a sociological effect (H3), effects of climate (H4), and habitat alteration (H5). Although the number of entries per decade has increased for most trophy categories, trends in size of horn-like structures were negative and significant for 11 of 17 antlered categories and 3 of 8 horned categories. Mean predicted declines during 1950–2008 were 1.87% and 0.68% for categories of trophy antlers and horns, respectively. Our results were not consistent with a sociological effect (H3), nutritional limitation imposed by climate (H4), or habitat alteration (H5) as potential explanations for long-term trends in size of trophies. In contrast, our results were consistent with a harvest-based explanation. Two of the 3 species that experienced the most conservative harvest regimes in North America (i.e., bighorn sheep [<i>Ovis canadensis</i>] and bison [<i>Bison bison</i>]) did not exhibit a significant, long-term trend in horn size. In addition, horn size of pronghorn (<i>Antilocapra americana</i>), which are capable of attaining peak horn size by 2–3 years of age, increased significantly over the past cen
{"title":"Effects of harvest, culture, and climate on trends in size of horn-like structures in trophy ungulates\u0000 Los Efectos De La Explotación, La Cultura Y El Clima En El Tamaño De Estructuras Corniformes En Los Ungulados Tipo “Trofeo”\u0000 Effets de la récolte, de la culture, et du climat sur les tendances de la taille des ornements chez Les ongulés à trophée†","authors":"Kevin L. Monteith, Ryan A. Long, Vernon C. Bleich, James R. Heffelfinger, Paul R. Krausman, R. Terry Bowyer","doi":"10.1002/wmon.1007","DOIUrl":"https://doi.org/10.1002/wmon.1007","url":null,"abstract":"<p>Hunting remains the cornerstone of the North American model of wildlife conservation and management. Nevertheless, research has indicated the potential for hunting to adversely influence size of horn-like structures of some ungulates. In polygynous ungulates, mating success of males is strongly correlated with body size and size of horn-like structures; consequently, sexual selection has favored the development of large horns and antlers. Horn-like structures are biologically important and are of great cultural interest, both of which highlight the need to identify long-term trends in size of those structures, and understand the underlying mechanisms responsible for such trends. We evaluated trends in horn and antler size of trophy males (individuals exhibiting exceptionally large horns or antlers) recorded from 1900 to 2008 in Records of North American Big Game, which comprised >22,000 records among 25 trophy categories encompassing the geographic extent of species occupying North America. The long-term and broad-scale nature of those data neutralized localized effects of climate and population dynamics, making it possible to detect meaningful changes in size of horn-like structures among trophy males over the past century; however, ages of individual specimens were not available, which prevented us from evaluating age-class specific changes in size. Therefore, we used a weight-of-evidence approach based on differences among trophy categories in life-history characteristics, geographic distribution, morphological attributes, and harvest regimes to discriminate among competing hypotheses for explaining long-term trends in horn and antler size of trophy ungulates, and provide directions for future research. These hypotheses were young male age structure caused by intensive harvest of males (H1), genetic change as a result of selective male harvest (H2), a sociological effect (H3), effects of climate (H4), and habitat alteration (H5). Although the number of entries per decade has increased for most trophy categories, trends in size of horn-like structures were negative and significant for 11 of 17 antlered categories and 3 of 8 horned categories. Mean predicted declines during 1950–2008 were 1.87% and 0.68% for categories of trophy antlers and horns, respectively. Our results were not consistent with a sociological effect (H3), nutritional limitation imposed by climate (H4), or habitat alteration (H5) as potential explanations for long-term trends in size of trophies. In contrast, our results were consistent with a harvest-based explanation. Two of the 3 species that experienced the most conservative harvest regimes in North America (i.e., bighorn sheep [<i>Ovis canadensis</i>] and bison [<i>Bison bison</i>]) did not exhibit a significant, long-term trend in horn size. In addition, horn size of pronghorn (<i>Antilocapra americana</i>), which are capable of attaining peak horn size by 2–3 years of age, increased significantly over the past cen","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"183 1","pages":"1-28"},"PeriodicalIF":4.4,"publicationDate":"2013-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.1007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6082587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heather M. Wilson, Paul L. Flint, Abby N. Powell, J. Barry Grand, Christine L. Moran
<p>Populations of Pacific common eiders (<i>Somateria mollissima v-nigrum</i>) on the Yukon-Kuskokwim Delta (YKD) in western Alaska declined by 50–90% from 1957 to 1992 and then stabilized at reduced numbers from the early 1990s to the present. We investigated the underlying processes affecting their population dynamics by collection and analysis of demographic data from Pacific common eiders at 3 sites on the YKD (1991–2004) for 29 site-years. We examined variation in components of reproduction, tested hypotheses about the influence of specific ecological factors on life-history variables, and investigated their relative contributions to local population dynamics. Reproductive output was low and variable, both within and among individuals, whereas apparent survival of adult females was high and relatively invariant (0.89 ± 0.005). All reproductive parameters varied across study sites and years. Clutch initiation dates ranged from 4 May to 28 June, with peak (modal) initiation occurring on 26 May. Females at an island study site consistently initiated clutches 3–5 days earlier in each year than those on 2 mainland sites. Population variance in nest initiation date was negatively related to the peak, suggesting increased synchrony in years of delayed initiation. On average, total clutch size (laid) ranged from 4.8 to 6.6 eggs, and declined with date of nest initiation. After accounting for partial predation and non-viability of eggs, average clutch size at hatch ranged from 2.0 to 5.8 eggs. Within seasons, daily survival probability (DSP) of nests was lowest during egg-laying and late-initiation dates. Estimated nest survival varied considerably across sites and years (mean = 0.55, range: 0.06–0.92), but process variance in nest survival was relatively low (0.02, CI: 0.01–0.05), indicating that most variance was likely attributed to sampling error. We found evidence that observer effects may have reduced overall nest survival by 0.0–0.36 across site-years. Study sites with lower sample sizes and more frequent visitations appeared to experience greater observer effects. In general, Pacific common eiders exhibited high spatio-temporal variance in reproductive components. Larger clutch sizes and high nest survival at early initiation dates suggested directional selection favoring early nesting. However, stochastic environmental effects may have precluded response to this apparent selection pressure. Our results suggest that females breeding early in the season have the greatest reproductive value, as these birds lay the largest clutches and have the highest probability of successfully hatching. We developed stochastic, stage-based, matrix population models that incorporated observed spatio-temporal (process) variance and co-variation in vital rates, and projected the stable stage distribution (<span></span>) and population growth rate (λ). We used perturbation analyses to examine the relative influence of changes in vital rates on λ and variance deco
{"title":"Population ecology of breeding Pacific common eiders on the Yukon-Kuskokwim Delta, Alaska\u0000 Ecología Demográfica de Criar Eiders Común Pacífico en el Delta de Yukón-Kuskokwim, Alaska\u0000 Écologie de la Population Reproductrice des Eiders à Duvet du Pacifique sur le Delta du Yukon-Kuskokwim, Alaska","authors":"Heather M. Wilson, Paul L. Flint, Abby N. Powell, J. Barry Grand, Christine L. Moran","doi":"10.1002/wmon.8","DOIUrl":"https://doi.org/10.1002/wmon.8","url":null,"abstract":"<p>Populations of Pacific common eiders (<i>Somateria mollissima v-nigrum</i>) on the Yukon-Kuskokwim Delta (YKD) in western Alaska declined by 50–90% from 1957 to 1992 and then stabilized at reduced numbers from the early 1990s to the present. We investigated the underlying processes affecting their population dynamics by collection and analysis of demographic data from Pacific common eiders at 3 sites on the YKD (1991–2004) for 29 site-years. We examined variation in components of reproduction, tested hypotheses about the influence of specific ecological factors on life-history variables, and investigated their relative contributions to local population dynamics. Reproductive output was low and variable, both within and among individuals, whereas apparent survival of adult females was high and relatively invariant (0.89 ± 0.005). All reproductive parameters varied across study sites and years. Clutch initiation dates ranged from 4 May to 28 June, with peak (modal) initiation occurring on 26 May. Females at an island study site consistently initiated clutches 3–5 days earlier in each year than those on 2 mainland sites. Population variance in nest initiation date was negatively related to the peak, suggesting increased synchrony in years of delayed initiation. On average, total clutch size (laid) ranged from 4.8 to 6.6 eggs, and declined with date of nest initiation. After accounting for partial predation and non-viability of eggs, average clutch size at hatch ranged from 2.0 to 5.8 eggs. Within seasons, daily survival probability (DSP) of nests was lowest during egg-laying and late-initiation dates. Estimated nest survival varied considerably across sites and years (mean = 0.55, range: 0.06–0.92), but process variance in nest survival was relatively low (0.02, CI: 0.01–0.05), indicating that most variance was likely attributed to sampling error. We found evidence that observer effects may have reduced overall nest survival by 0.0–0.36 across site-years. Study sites with lower sample sizes and more frequent visitations appeared to experience greater observer effects. In general, Pacific common eiders exhibited high spatio-temporal variance in reproductive components. Larger clutch sizes and high nest survival at early initiation dates suggested directional selection favoring early nesting. However, stochastic environmental effects may have precluded response to this apparent selection pressure. Our results suggest that females breeding early in the season have the greatest reproductive value, as these birds lay the largest clutches and have the highest probability of successfully hatching. We developed stochastic, stage-based, matrix population models that incorporated observed spatio-temporal (process) variance and co-variation in vital rates, and projected the stable stage distribution (<span></span>) and population growth rate (λ). We used perturbation analyses to examine the relative influence of changes in vital rates on λ and variance deco","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"182 1","pages":"1-28"},"PeriodicalIF":4.4,"publicationDate":"2012-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5842287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frank T. Van Manen, Matthew F. Mccollister, Jeremy M. Nicholson, Laura M. Thompson, Jason L. Kindall, Mark D. Jones
<p>Among numerous anthropogenic impacts on terrestrial landscapes, expanding transportation networks represent one of the primary challenges to wildlife conservation worldwide. Larger mammals may be particularly vulnerable because of typically low densities, low reproductive rates, and extensive movements. Although numerous studies have been conducted to document impacts of road networks on wildlife, inference has been limited because of experimental design limitations. During the last decade, the North Carolina Department of Transportation (NCDOT) rerouted and upgraded sections of United States Highway 64 between Raleigh and the Outer Banks to a 4-lane, divided highway. A new route was selected for a 24.1-km section in Washington County. The new section of highway included 3 wildlife underpasses with adjacent wildlife fencing to mitigate the effects of the highway on wildlife, particularly American black bears (<i>Ursus americanus</i>). We assessed the short-term impacts of the new highway on spatial ecology, population size, survival, occupancy, and gene flow of black bears. We tested our research hypotheses using a before-after control-impact (BACI) study design. We collected data during 2000–2001 (preconstruction phase) and 2006–2007 (postconstruction phase) in the highway project area and a nearby control area (each approx. 11,000 ha), resulting in 4 groups of data (i.e., pre- or postconstruction study phase, treatment or control area). We captured and radiocollared 57 bears and collected 5,775 hourly locations and 4,998 daily locations. Using mixed-model analysis of variance and logistic regression, we detected no differences in home ranges, movement characteristics, proximity to the highway alignment, or habitat use between the 2 study phases, although minimum detectable effect sizes were large for several tests. However, after completion of the new highway, bears on the treatment area became less inactive in morning, when highway traffic was low, compared with bears on the control area (<i>F</i><sub>1, 43</sub> = 6.05, <i>P</i> = 0.018). We used DNA from hair samples to determine if population size and site occupancy decreased following highway construction. For each study phase, we collected black bear hair from 70 hair snares on each study area during 7 weekly sampling periods and generated genotypes using 10 microsatellite loci. We used the multilocus genotypes to obtain capture histories for 226 different bears and used capture-mark-recapture models to estimate population size. Model-averaged estimates of population size decreased on the treatment area from 87.7 bears before construction to 31.6 bears after construction (64% reduction) and on the control area from 163.6 bears to 108.2 bears (34% reduction). Permutation procedures indicated this reduction was proportionally greater for the treatment area (<i>P</i> = 0.086). We also applied a spatially explicit capture-recapture technique to test our research hypothesis. The model with
{"title":"Short-Term Impacts of a 4-Lane Highway on American Black Bears in Eastern North Carolina\u0000 Impactos a Corto Plazo De Una Carretera De Cuatro vias Sobre Osos Negros Americanos en la Region Este De Carolina Del Norte\u0000 Impacts à Court-Terme D'une Route à 2 × 2 Voies Sur Les ours Noirs Américains Dans L'Est De La Caroline Du Nord","authors":"Frank T. Van Manen, Matthew F. Mccollister, Jeremy M. Nicholson, Laura M. Thompson, Jason L. Kindall, Mark D. Jones","doi":"10.1002/wmon.7","DOIUrl":"https://doi.org/10.1002/wmon.7","url":null,"abstract":"<p>Among numerous anthropogenic impacts on terrestrial landscapes, expanding transportation networks represent one of the primary challenges to wildlife conservation worldwide. Larger mammals may be particularly vulnerable because of typically low densities, low reproductive rates, and extensive movements. Although numerous studies have been conducted to document impacts of road networks on wildlife, inference has been limited because of experimental design limitations. During the last decade, the North Carolina Department of Transportation (NCDOT) rerouted and upgraded sections of United States Highway 64 between Raleigh and the Outer Banks to a 4-lane, divided highway. A new route was selected for a 24.1-km section in Washington County. The new section of highway included 3 wildlife underpasses with adjacent wildlife fencing to mitigate the effects of the highway on wildlife, particularly American black bears (<i>Ursus americanus</i>). We assessed the short-term impacts of the new highway on spatial ecology, population size, survival, occupancy, and gene flow of black bears. We tested our research hypotheses using a before-after control-impact (BACI) study design. We collected data during 2000–2001 (preconstruction phase) and 2006–2007 (postconstruction phase) in the highway project area and a nearby control area (each approx. 11,000 ha), resulting in 4 groups of data (i.e., pre- or postconstruction study phase, treatment or control area). We captured and radiocollared 57 bears and collected 5,775 hourly locations and 4,998 daily locations. Using mixed-model analysis of variance and logistic regression, we detected no differences in home ranges, movement characteristics, proximity to the highway alignment, or habitat use between the 2 study phases, although minimum detectable effect sizes were large for several tests. However, after completion of the new highway, bears on the treatment area became less inactive in morning, when highway traffic was low, compared with bears on the control area (<i>F</i><sub>1, 43</sub> = 6.05, <i>P</i> = 0.018). We used DNA from hair samples to determine if population size and site occupancy decreased following highway construction. For each study phase, we collected black bear hair from 70 hair snares on each study area during 7 weekly sampling periods and generated genotypes using 10 microsatellite loci. We used the multilocus genotypes to obtain capture histories for 226 different bears and used capture-mark-recapture models to estimate population size. Model-averaged estimates of population size decreased on the treatment area from 87.7 bears before construction to 31.6 bears after construction (64% reduction) and on the control area from 163.6 bears to 108.2 bears (34% reduction). Permutation procedures indicated this reduction was proportionally greater for the treatment area (<i>P</i> = 0.086). We also applied a spatially explicit capture-recapture technique to test our research hypothesis. The model with ","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"181 1","pages":"1-35"},"PeriodicalIF":4.4,"publicationDate":"2012-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5697602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael F. Proctor, David Paetkau, Bruce N. Mclellan, Gordon B. Stenhouse, Katherine C. Kendall, Richard D. Mace, Wayne F. Kasworm, Christopher Servheen, Cori L. Lausen, Michael L. Gibeau, Wayne L. Wakkinen, Mark A. Haroldson, Garth Mowat, Clayton D. Apps, Lana M. Ciarniello, Robert M. R. Barclay, Mark S. Boyce, Charles C. Schwartz, Curtis Strobeck
<p>Population fragmentation compromises population viability, reduces a species ability to respond to climate change, and ultimately may reduce biodiversity. We studied the current state and potential causes of fragmentation in grizzly bears over approximately 1,000,000 km<sup>2</sup> of western Canada, the northern United States (US), and southeast Alaska. We compiled much of our data from projects undertaken with a variety of research objectives including population estimation and trend, landscape fragmentation, habitat selection, vital rates, and response to human development. Our primary analytical techniques stemmed from genetic analysis of 3,134 bears, supplemented with radiotelemetry data from 792 bears. We used 15 locus microsatellite data coupled with measures of genetic distance, isolation-by-distance (IBD) analysis, analysis of covariance (ANCOVA), linear multiple regression, multi-factorial correspondence analysis (to identify population divisions or fractures with no a priori assumption of group membership), and population-assignment methods to detect individual migrants between immediately adjacent areas. These data corroborated observations of inter-area movements from our telemetry database. In northern areas, we found a spatial genetic pattern of IBD, although there was evidence of natural fragmentation from the rugged heavily glaciated coast mountains of British Columbia (BC) and the Yukon. These results contrasted with the spatial pattern of fragmentation in more southern parts of their distribution. Near the Canada–US border area, we found extensive fragmentation that corresponded to settled mountain valleys and major highways. Genetic distances across developed valleys were elevated relative to those across undeveloped valleys in central and northern BC. In disturbed areas, most inter-area movements detected were made by male bears, with few female migrants identified. North–south movements within mountain ranges (Mts) and across BC Highway 3 were more common than east–west movements across settled mountain valleys separating Mts. Our results suggest that relatively distinct subpopulations exist in this region, including the Cabinet, Selkirk South, and the decades-isolated Yellowstone populations. Current movement rates do not appear sufficient to consider the subpopulations we identify along the Canada–US border as 1 inter-breeding unit. Although we detected enough male movement to mediate gene flow, the current low rate of female movement detected among areas is insufficient to provide a demographic rescue effect between areas in the immediate future (0–15 yr). In Alberta, we found fragmentation corresponded to major east–west highways (Highways 3, 11, 16, and 43) and most inter-area movements were made by males. Gene flow and movement rates between Alberta and BC were highest across the Continental Divide south of Highway 1 and north of Highway 16. In the central region between Highways 1 and 11, we found evidence of natur
{"title":"Population fragmentation and inter-ecosystem movements of grizzly bears in western Canada and the northern United States\u0000 Fragmentación de Poblaciones y Movimientos Entre Ecosistemas de Osos Grizzli en el Oeste de Canadá y el Norte de Estados Unidos","authors":"Michael F. Proctor, David Paetkau, Bruce N. Mclellan, Gordon B. Stenhouse, Katherine C. Kendall, Richard D. Mace, Wayne F. Kasworm, Christopher Servheen, Cori L. Lausen, Michael L. Gibeau, Wayne L. Wakkinen, Mark A. Haroldson, Garth Mowat, Clayton D. Apps, Lana M. Ciarniello, Robert M. R. Barclay, Mark S. Boyce, Charles C. Schwartz, Curtis Strobeck","doi":"10.1002/wmon.6","DOIUrl":"https://doi.org/10.1002/wmon.6","url":null,"abstract":"<p>Population fragmentation compromises population viability, reduces a species ability to respond to climate change, and ultimately may reduce biodiversity. We studied the current state and potential causes of fragmentation in grizzly bears over approximately 1,000,000 km<sup>2</sup> of western Canada, the northern United States (US), and southeast Alaska. We compiled much of our data from projects undertaken with a variety of research objectives including population estimation and trend, landscape fragmentation, habitat selection, vital rates, and response to human development. Our primary analytical techniques stemmed from genetic analysis of 3,134 bears, supplemented with radiotelemetry data from 792 bears. We used 15 locus microsatellite data coupled with measures of genetic distance, isolation-by-distance (IBD) analysis, analysis of covariance (ANCOVA), linear multiple regression, multi-factorial correspondence analysis (to identify population divisions or fractures with no a priori assumption of group membership), and population-assignment methods to detect individual migrants between immediately adjacent areas. These data corroborated observations of inter-area movements from our telemetry database. In northern areas, we found a spatial genetic pattern of IBD, although there was evidence of natural fragmentation from the rugged heavily glaciated coast mountains of British Columbia (BC) and the Yukon. These results contrasted with the spatial pattern of fragmentation in more southern parts of their distribution. Near the Canada–US border area, we found extensive fragmentation that corresponded to settled mountain valleys and major highways. Genetic distances across developed valleys were elevated relative to those across undeveloped valleys in central and northern BC. In disturbed areas, most inter-area movements detected were made by male bears, with few female migrants identified. North–south movements within mountain ranges (Mts) and across BC Highway 3 were more common than east–west movements across settled mountain valleys separating Mts. Our results suggest that relatively distinct subpopulations exist in this region, including the Cabinet, Selkirk South, and the decades-isolated Yellowstone populations. Current movement rates do not appear sufficient to consider the subpopulations we identify along the Canada–US border as 1 inter-breeding unit. Although we detected enough male movement to mediate gene flow, the current low rate of female movement detected among areas is insufficient to provide a demographic rescue effect between areas in the immediate future (0–15 yr). In Alberta, we found fragmentation corresponded to major east–west highways (Highways 3, 11, 16, and 43) and most inter-area movements were made by males. Gene flow and movement rates between Alberta and BC were highest across the Continental Divide south of Highway 1 and north of Highway 16. In the central region between Highways 1 and 11, we found evidence of natur","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"180 1","pages":"1-46"},"PeriodicalIF":4.4,"publicationDate":"2011-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5946619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ray T. Alisauskas, Robert F. Rockwell, Kevin W. Dufour, Evan G. Cooch, Guthrie Zimmerman, Kiel L. Drake, James O. Leafloor, Timothy J. Moser, Eric T. Reed
<p>We assessed the effectiveness of an extensive and unprecedented wildlife reduction effort directed at a wide-ranging migratory population of geese. Population reduction efforts that targeted several populations of light geese (greater snow geese [<i>Chen caerulescens atlantica</i>], lesser snow geese [<i>C. c. caerulescens</i>], and Ross's geese [<i>C. rossii</i>]) began in 1999 in central and eastern North America. Such efforts were motivated by a broad consensus that abundance of these geese was causing serious ecological damage to terrestrial and salt marsh ecosystems in central and eastern parts of the Canadian Arctic and subarctic regions along Hudson Bay. Starting in February 1999, special conservation measures (or, in the U.S., a conservation order) were added to the respective federal regulations that permitted hunters to take snow geese (in parts of Canada and the U.S.) and Ross's geese (in parts of the U.S.) during specified harvest periods outside of the hunting season. These measures were accompanied by increase or removal of daily kill and possession limits and by permissions to use previously prohibited equipment for hunting these species in certain regions of the continent. The intent was to reduce adult survival through increased hunting mortality, which was judged to be the most cost-effective approach to reversing population growth. Our principal goal was to assess the effectiveness of reduction efforts directed at the midcontinent population of lesser snow geese, which was thought to be the most serious threat to arctic and subarctic ecosystems of the 3 light goose populations. Our multiple objectives included the estimation and detection of change in the response measures of total annual harvest, harvest rate, survival rate, and abundance, using the 1998 hunting period (defined as 1 Aug 1998 to 31 Jul 1999) as a point of reference. We used information about hunter recoveries of leg-banded snow geese and estimates of regular-season harvest to estimate 1) conservation-order harvest and total annual harvest, 2) geographic and temporal distribution of recoveries by age class, 3) survival and recovery probability, and 4) abundance of snow geese each August using Lincoln's (<span>1930</span>) method. We also modeled population growth to infer the form of population response to management efforts. Toward that end, we also proposed a method of estimating conservation-order harvest and tested for differences in band-reporting rate between Canada and the United States. Overall, the balance of evidence favored the conclusion that the midcontinent population has continued to grow during the conservation order, although perhaps at a reduced rate. We suggest that annual rate of population growth <span></span>, derived from estimates of annual population size in August, likely provides the most reliable inference about change in the midcontinent population. There was a decline in annual survival probability between these 2 periods from ab
{"title":"Harvest, survival, and abundance of midcontinent lesser snow geese relative to population reduction efforts†Récolte, Survie et Abondance de la Petite Oie des Neiges du Milieu du Continent en Relation avec les Efforts de Réduction de la Population","authors":"Ray T. Alisauskas, Robert F. Rockwell, Kevin W. Dufour, Evan G. Cooch, Guthrie Zimmerman, Kiel L. Drake, James O. Leafloor, Timothy J. Moser, Eric T. Reed","doi":"10.1002/wmon.5","DOIUrl":"https://doi.org/10.1002/wmon.5","url":null,"abstract":"<p>We assessed the effectiveness of an extensive and unprecedented wildlife reduction effort directed at a wide-ranging migratory population of geese. Population reduction efforts that targeted several populations of light geese (greater snow geese [<i>Chen caerulescens atlantica</i>], lesser snow geese [<i>C. c. caerulescens</i>], and Ross's geese [<i>C. rossii</i>]) began in 1999 in central and eastern North America. Such efforts were motivated by a broad consensus that abundance of these geese was causing serious ecological damage to terrestrial and salt marsh ecosystems in central and eastern parts of the Canadian Arctic and subarctic regions along Hudson Bay. Starting in February 1999, special conservation measures (or, in the U.S., a conservation order) were added to the respective federal regulations that permitted hunters to take snow geese (in parts of Canada and the U.S.) and Ross's geese (in parts of the U.S.) during specified harvest periods outside of the hunting season. These measures were accompanied by increase or removal of daily kill and possession limits and by permissions to use previously prohibited equipment for hunting these species in certain regions of the continent. The intent was to reduce adult survival through increased hunting mortality, which was judged to be the most cost-effective approach to reversing population growth. Our principal goal was to assess the effectiveness of reduction efforts directed at the midcontinent population of lesser snow geese, which was thought to be the most serious threat to arctic and subarctic ecosystems of the 3 light goose populations. Our multiple objectives included the estimation and detection of change in the response measures of total annual harvest, harvest rate, survival rate, and abundance, using the 1998 hunting period (defined as 1 Aug 1998 to 31 Jul 1999) as a point of reference. We used information about hunter recoveries of leg-banded snow geese and estimates of regular-season harvest to estimate 1) conservation-order harvest and total annual harvest, 2) geographic and temporal distribution of recoveries by age class, 3) survival and recovery probability, and 4) abundance of snow geese each August using Lincoln's (<span>1930</span>) method. We also modeled population growth to infer the form of population response to management efforts. Toward that end, we also proposed a method of estimating conservation-order harvest and tested for differences in band-reporting rate between Canada and the United States. Overall, the balance of evidence favored the conclusion that the midcontinent population has continued to grow during the conservation order, although perhaps at a reduced rate. We suggest that annual rate of population growth <span></span>, derived from estimates of annual population size in August, likely provides the most reliable inference about change in the midcontinent population. There was a decline in annual survival probability between these 2 periods from ab","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"179 1","pages":"1-42"},"PeriodicalIF":4.4,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5958907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mark A. Hurley, James W. Unsworth, Peter Zager, Mark Hebblewhite, Edward O. Garton, Debra M. Montgomery, John R. Skalski, Craig L. Maycock
<p>Manipulating predator populations is often posed as a solution to depressed ungulate populations. However, predator–prey dynamics are complex and the effect on prey populations is often an interaction of predator life history, climate, prey density, and habitat quality. The effect of predator removal on ungulate and, more specifically, mule deer (<i>Odocoileus hemionus</i>) populations has not been adequately investigated at a management scale. We tested the efficacy of removing coyotes (<i>Canis latrans</i>) and mountain lions (<i>Puma concolor</i>) for increasing survival and population growth rate of mule deer in southeastern Idaho, USA, during 1997–2003. We assigned 8 game management units (GMUs) to treatments under a 2 × 2 factorial design (treatments of coyote removal and lion removal) with 2 replicates of each treatment or reference area combination. We used methods typically available to wildlife managers to achieve predator removals and a combination of extensive and intensive monitoring in these 8 GMUs to test the hypothesis that predator removal increased vital rates and population growth rate of mule deer. We determined effects of predator removal on survival and causes of mortality in 2 intensive study sites, one with coyote and mountain lion removal and one without. We also considered the effects of other variables on survival including lagomorph abundance and climatic conditions. In these 2 intensive study areas, we monitored with radiotelemetry 250 neonates, 284 6-month-old fawns, and 521 adult females. At the extensive scale, we monitored mule deer population trend and December fawn ratios with helicopter surveys. Coyote removal decreased neonate mortality only when deer were apparently needed as alternate prey, thus removal was more effective when lagomorph populations were reduced. The best mortality model of mule deer captured at 6 months of age included summer precipitation, winter precipitation, fawn mass, and mountain lion removal. Over-winter mortality of adult female mule deer decreased with removal of mountain lions. Precipitation variables were included in most competing mortality models for all age classes of mule deer. Mountain lion removal increased fawn ratios and our models predicted fawn ratios would increase 6% at average removal rates (3.53/1,000 km<sup>2</sup>) and 27% at maximum removal rates (14.18/1,000 km<sup>2</sup>). Across our extensive set of 8 GMUs, coyote removal had no effect on December fawn ratios. We also detected no strong effect of coyote or mountain lion removal alone on mule deer population trend; the best population-growth-rate model included previous year's mountain lion removal and winter severity, yet explained only 27% of the variance in population growth rate. Winter severity in the current and previous winter was the most important influence on mule deer population growth. The lack of response in fawn ratio or mule deer abundance to coyote reduction at this extensive (landscape) scal
{"title":"Demographic response of mule deer to experimental reduction of coyotes and mountain lions in southeastern Idaho\u0000 Respuesta Demografica del Ciervo Mula a la Reducción Experimental de Coyotes y Pumas en el Sureste de Idaho","authors":"Mark A. Hurley, James W. Unsworth, Peter Zager, Mark Hebblewhite, Edward O. Garton, Debra M. Montgomery, John R. Skalski, Craig L. Maycock","doi":"10.1002/wmon.4","DOIUrl":"https://doi.org/10.1002/wmon.4","url":null,"abstract":"<p>Manipulating predator populations is often posed as a solution to depressed ungulate populations. However, predator–prey dynamics are complex and the effect on prey populations is often an interaction of predator life history, climate, prey density, and habitat quality. The effect of predator removal on ungulate and, more specifically, mule deer (<i>Odocoileus hemionus</i>) populations has not been adequately investigated at a management scale. We tested the efficacy of removing coyotes (<i>Canis latrans</i>) and mountain lions (<i>Puma concolor</i>) for increasing survival and population growth rate of mule deer in southeastern Idaho, USA, during 1997–2003. We assigned 8 game management units (GMUs) to treatments under a 2 × 2 factorial design (treatments of coyote removal and lion removal) with 2 replicates of each treatment or reference area combination. We used methods typically available to wildlife managers to achieve predator removals and a combination of extensive and intensive monitoring in these 8 GMUs to test the hypothesis that predator removal increased vital rates and population growth rate of mule deer. We determined effects of predator removal on survival and causes of mortality in 2 intensive study sites, one with coyote and mountain lion removal and one without. We also considered the effects of other variables on survival including lagomorph abundance and climatic conditions. In these 2 intensive study areas, we monitored with radiotelemetry 250 neonates, 284 6-month-old fawns, and 521 adult females. At the extensive scale, we monitored mule deer population trend and December fawn ratios with helicopter surveys. Coyote removal decreased neonate mortality only when deer were apparently needed as alternate prey, thus removal was more effective when lagomorph populations were reduced. The best mortality model of mule deer captured at 6 months of age included summer precipitation, winter precipitation, fawn mass, and mountain lion removal. Over-winter mortality of adult female mule deer decreased with removal of mountain lions. Precipitation variables were included in most competing mortality models for all age classes of mule deer. Mountain lion removal increased fawn ratios and our models predicted fawn ratios would increase 6% at average removal rates (3.53/1,000 km<sup>2</sup>) and 27% at maximum removal rates (14.18/1,000 km<sup>2</sup>). Across our extensive set of 8 GMUs, coyote removal had no effect on December fawn ratios. We also detected no strong effect of coyote or mountain lion removal alone on mule deer population trend; the best population-growth-rate model included previous year's mountain lion removal and winter severity, yet explained only 27% of the variance in population growth rate. Winter severity in the current and previous winter was the most important influence on mule deer population growth. The lack of response in fawn ratio or mule deer abundance to coyote reduction at this extensive (landscape) scal","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"178 1","pages":"1-33"},"PeriodicalIF":4.4,"publicationDate":"2011-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6082335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David K. Delaney, Larry L. Pater, Lawrence D. Carlile, Eric W. Spadgenske, Timothy A. Beaty, Robert H. Melton
<p>Military lands are a valuable resource in recovery of threatened, endangered, and at-risk species worldwide and have the highest density of threatened and endangered species of all major land management agencies in the United States. Many red-cockaded woodpeckers (<i>Picoides borealis</i>) that reside on federal lands occur on 15 military installations in the southeastern United States. This close association has increased concern over potential conflicts between conservation requirements of endangered species and the military's mission of combat readiness. Our objectives were to 1) determine if military training operations affect behavior, reproductive success, and productivity of red-cockaded woodpeckers; 2) develop a frequency-weighting function to assess woodpecker hearing sensitivity; 3) identify factors that affect woodpecker responses to military training operations; 4) develop distance and dose-response thresholds for quantifying woodpecker responses to noise levels and stimulus distances; 5) characterize military training operations through quantification of sound levels, source identification, distance from active woodpecker nests, frequency spectra, duration, and frequency of occurrence; and 6) document baseline woodpecker nesting behavior. We conducted our study on the Fort Stewart Military Installation located in southeast Georgia, USA.</p><p>Downy woodpeckers, as surrogates for red-cockaded woodpeckers, had their best hearing sensitivity within the peak range of the power spectrum of both downy and red-cockaded woodpecker vocalizations, which is at a higher frequency than that of a typical passerine. Overall, woodpeckers had a reduced auditory sensitivity relative to human hearing sensitivity and other species of small birds, especially in the frequency range >4 kHz. Woodpeckers were most sensitive in the 1.5- to 4.0-kHz range. Sensitivity appeared to drop off quickly at frequencies <1.0 kHz and >4.0 kHz. Overall, we did not find that the woodpecker-frequency-weighting function we developed provided a better predictor of woodpecker flush response compared with A-weighting. More research is needed to better understand the relationship between frequency-weighting functions and woodpecker response behavior.</p><p>Potential breeding groups of woodpeckers across the population increased from 158 in 1997 to 181 in 2000, wheras nesting groups increased from 141 in 1998 to 170 in 2000, for overall increases of 14.6% and 20.6%, respectively, over the 3 years of this project. Fledging success rates for individual nests within the overall population remained consistent from 1998 to 2000, averaging 84.4%. Mean clutch sizes for woodpecker groups for 1998 to 2000 ranged from 2.75 to 3.01 eggs/nest, brood size ranged from 2.01 to 2.22 nestlings/nest, whereas the average number of young fledged ranged from 1.57 to 1.76 young/occupied nest. We observed no difference in reproductive success or productivity between experimental and control
{"title":"Response of red-cockaded woodpeckers to military training operations\u0000 Respuesta del pájaro carpintero de cresta roja a las operaciones del entrenamiento militar","authors":"David K. Delaney, Larry L. Pater, Lawrence D. Carlile, Eric W. Spadgenske, Timothy A. Beaty, Robert H. Melton","doi":"10.1002/wmon.3","DOIUrl":"https://doi.org/10.1002/wmon.3","url":null,"abstract":"<p>Military lands are a valuable resource in recovery of threatened, endangered, and at-risk species worldwide and have the highest density of threatened and endangered species of all major land management agencies in the United States. Many red-cockaded woodpeckers (<i>Picoides borealis</i>) that reside on federal lands occur on 15 military installations in the southeastern United States. This close association has increased concern over potential conflicts between conservation requirements of endangered species and the military's mission of combat readiness. Our objectives were to 1) determine if military training operations affect behavior, reproductive success, and productivity of red-cockaded woodpeckers; 2) develop a frequency-weighting function to assess woodpecker hearing sensitivity; 3) identify factors that affect woodpecker responses to military training operations; 4) develop distance and dose-response thresholds for quantifying woodpecker responses to noise levels and stimulus distances; 5) characterize military training operations through quantification of sound levels, source identification, distance from active woodpecker nests, frequency spectra, duration, and frequency of occurrence; and 6) document baseline woodpecker nesting behavior. We conducted our study on the Fort Stewart Military Installation located in southeast Georgia, USA.</p><p>Downy woodpeckers, as surrogates for red-cockaded woodpeckers, had their best hearing sensitivity within the peak range of the power spectrum of both downy and red-cockaded woodpecker vocalizations, which is at a higher frequency than that of a typical passerine. Overall, woodpeckers had a reduced auditory sensitivity relative to human hearing sensitivity and other species of small birds, especially in the frequency range >4 kHz. Woodpeckers were most sensitive in the 1.5- to 4.0-kHz range. Sensitivity appeared to drop off quickly at frequencies <1.0 kHz and >4.0 kHz. Overall, we did not find that the woodpecker-frequency-weighting function we developed provided a better predictor of woodpecker flush response compared with A-weighting. More research is needed to better understand the relationship between frequency-weighting functions and woodpecker response behavior.</p><p>Potential breeding groups of woodpeckers across the population increased from 158 in 1997 to 181 in 2000, wheras nesting groups increased from 141 in 1998 to 170 in 2000, for overall increases of 14.6% and 20.6%, respectively, over the 3 years of this project. Fledging success rates for individual nests within the overall population remained consistent from 1998 to 2000, averaging 84.4%. Mean clutch sizes for woodpecker groups for 1998 to 2000 ranged from 2.75 to 3.01 eggs/nest, brood size ranged from 2.01 to 2.22 nestlings/nest, whereas the average number of young fledged ranged from 1.57 to 1.76 young/occupied nest. We observed no difference in reproductive success or productivity between experimental and control","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"177 1","pages":"1-38"},"PeriodicalIF":4.4,"publicationDate":"2011-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5711509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<p>Invasions by nonnative plants have changed the structure of many terrestrial ecosystems and altered important ecological processes such as fire, the dominant driver in grassland ecosystems. Reestablishing fire has been proposed as a mechanism to restore dominance of native plants in grasslands invaded by nonnative plants, yet fire may function differently in these altered systems, potentially affecting animals in novel ways. To assess whether invasions by nonnative plants alter the effects of fire on animals, we performed a manipulative experiment in semi-desert grasslands of southeastern Arizona that have been invaded by a perennial, nonnative grass from Africa, Lehmann lovegrass (<i>Eragrostis lehmanniana</i>). We applied fire to 36 of 54 1-ha plots established along an invasion gradient where dominance of <i>E. lehmanniana</i> ranged from 0% to 91% of total live plant biomass. Over the 5-year period from 2000 to 2004, we used mark-recapture methods to assess how population and community attributes of small mammals varied along the gradient of nonnative grass and in response to fire. We quantified changes in presence of 17 species, abundance of 9 species, total abundance of all species combined, species richness, and species composition. Based on 11,226 individual mammals from 24 species, we found that effects of nonnative-grass dominance varied with habitat preferences of each species, resulting in composition of the small-mammal community changing predictably along the invasion gradient. As dominance of nonnative grass increased, presence and abundance of granivorous heteromyids and insectivores (e.g., <i>Chaetodipus</i>, <i>Perognathus</i>, <i>Onychomys</i>; pocket mice and grasshopper mice) decreased, whereas presence and abundance of omnivorous and herbivorous murids (e.g., <i>Reithrodontomys</i>, <i>Sigmodon</i>; harvest mice and cotton rats) increased. Species richness of the small-mammal community averaged 8.4 species per plot and was highest at intermediate levels of nonnative-grass dominance where vegetation heterogeneity was greatest. Abundance of all small mammals combined averaged 26.9 individuals per plot and did not vary appreciably with nonnative-grass dominance. During the 4- to 8-week period immediately after fire, abundance of 6 of the 9 most common species changed, with 5 species decreasing and 1 species increasing on burned plots relative to unburned plots. During this same time period, species richness of small mammals decreased by an average of 3 species (38%) and total abundance of all species combined decreased by an average of 16 individuals (61%) on burned plots relative to unburned plots. Effects of fire on vegetation biomass, on presence of 9 of 17 mammalian species, and on abundance of 4 of 9 mammalian species remained evident ≥2 years after fire. Effects of fire on most small-mammal species varied with the degree of nonnative-grass dominance, suggesting that fire functioned differently in areas invaded by nonna
{"title":"Interactive effects of fire and nonnative plants on small mammals in Grasslands\u0000 Efectos Interactivos del Fuego y Plantas No Nativas Sobre Pequeños Mamíferos en Pastizales","authors":"Andrea R. Litt, Robert J. Steidl","doi":"10.1002/wmon.2","DOIUrl":"https://doi.org/10.1002/wmon.2","url":null,"abstract":"<p>Invasions by nonnative plants have changed the structure of many terrestrial ecosystems and altered important ecological processes such as fire, the dominant driver in grassland ecosystems. Reestablishing fire has been proposed as a mechanism to restore dominance of native plants in grasslands invaded by nonnative plants, yet fire may function differently in these altered systems, potentially affecting animals in novel ways. To assess whether invasions by nonnative plants alter the effects of fire on animals, we performed a manipulative experiment in semi-desert grasslands of southeastern Arizona that have been invaded by a perennial, nonnative grass from Africa, Lehmann lovegrass (<i>Eragrostis lehmanniana</i>). We applied fire to 36 of 54 1-ha plots established along an invasion gradient where dominance of <i>E. lehmanniana</i> ranged from 0% to 91% of total live plant biomass. Over the 5-year period from 2000 to 2004, we used mark-recapture methods to assess how population and community attributes of small mammals varied along the gradient of nonnative grass and in response to fire. We quantified changes in presence of 17 species, abundance of 9 species, total abundance of all species combined, species richness, and species composition. Based on 11,226 individual mammals from 24 species, we found that effects of nonnative-grass dominance varied with habitat preferences of each species, resulting in composition of the small-mammal community changing predictably along the invasion gradient. As dominance of nonnative grass increased, presence and abundance of granivorous heteromyids and insectivores (e.g., <i>Chaetodipus</i>, <i>Perognathus</i>, <i>Onychomys</i>; pocket mice and grasshopper mice) decreased, whereas presence and abundance of omnivorous and herbivorous murids (e.g., <i>Reithrodontomys</i>, <i>Sigmodon</i>; harvest mice and cotton rats) increased. Species richness of the small-mammal community averaged 8.4 species per plot and was highest at intermediate levels of nonnative-grass dominance where vegetation heterogeneity was greatest. Abundance of all small mammals combined averaged 26.9 individuals per plot and did not vary appreciably with nonnative-grass dominance. During the 4- to 8-week period immediately after fire, abundance of 6 of the 9 most common species changed, with 5 species decreasing and 1 species increasing on burned plots relative to unburned plots. During this same time period, species richness of small mammals decreased by an average of 3 species (38%) and total abundance of all species combined decreased by an average of 16 individuals (61%) on burned plots relative to unburned plots. Effects of fire on vegetation biomass, on presence of 9 of 17 mammalian species, and on abundance of 4 of 9 mammalian species remained evident ≥2 years after fire. Effects of fire on most small-mammal species varied with the degree of nonnative-grass dominance, suggesting that fire functioned differently in areas invaded by nonna","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"176 1","pages":"1-31"},"PeriodicalIF":4.4,"publicationDate":"2011-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5810499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gary L. Krapu, David A. Brandt, Kenneth L. Jones, Douglas H. Johnson
<p>The Mid-continent Population (MCP) of sandhill cranes (<i>Grus canadensis</i>) is widely hunted in North America and is separated into the Gulf Coast Subpopulation and Western Subpopulation for management purposes. Effective harvest management of the MCP requires detailed knowledge of breeding distribution of subspecies and subpopulations, chronology of their use of fall staging areas and wintering grounds, and exposure to and harvest from hunting. To address these information needs, we tagged 153 sandhill cranes with Platform Transmitting Terminals (PTTs) during 22 February–12 April 1998–2003 in the Central and North Platte River valleys of south-central Nebraska. We monitored PTT-tagged sandhill cranes, hereafter tagged cranes, from their arrival to departure from breeding grounds, during their fall migration, and throughout winter using the Argos satellite tracking system. The tracking effort yielded 74,041 useable locations over 49,350 tag days; median duration of tracking of individual cranes was 352 days and 73 cranes were tracked >12 months. Genetic sequencing of mitochondrial DNA (mtDNA) from blood samples taken from each of our random sample of tagged cranes indicated 64% were <i>G. c. canadensis</i> and 34% were <i>Grus canadensis tabida</i>. Tagged cranes during the breeding season settled in northern temperate, subarctic, and arctic North America (U.S. [23%, <i>n</i> = 35], Canada [57%, <i>n</i> = 87]) and arctic regions of northeast Asia (Russia [20%, <i>n</i> = 31]). Distribution of tagged cranes by breeding affiliation was as follows: Western Alaska–Siberia (WA–S, 42 ± 4% [SE]), northern Canada–Nunavut (NC–N, 21 ± 4%), west-central Canada–Alaska (WC–A, 23 ± 4%) and East-central Canada–Minnesota (EC–M, 14 ± 3%). All tagged cranes returned to the same breeding affiliation used during the previous year with a median distance of 1.60 km (range: 0.08–7.7 km, <i>n</i> = 53) separating sites used in year 1 and year 2. Fall staging occurred primarily in central and western Saskatchewan (69%), North Dakota (16%), southwestern Manitoba (10%), and northwestern Minnesota (3%). Space-use sharing indices showed that except for NC–N and WC–A birds, probability of finding a crane from one breeding affiliation within the home range of another breeding affiliation was low during fall staging. Tagged cranes from WC–A and EC–M breeding affiliations, on average, spent 25 and 20 days, respectively, longer on fall staging areas in the northern plains than did WA–S and NC–N birds. Cranes in the NC–N, WA–S, and WC–A affiliations spent 99%, 74%, and 64%, respectively, of winter in western Texas in Hunting Zone A; EC–M cranes spent 83% of winter along the Texas Gulf Coast in Hunting Zone C. Tagged cranes that settled within the breeding range of the Gulf Coast Subpopulation spent 28% and 42% of fall staging and winter within the range of the Western Subpopulation, indicating sufficient exchange of birds to potentially limit effectiveness of MCP harvest
{"title":"Geographic distribution of the mid-continent population of sandhill cranes and related management applications\u0000 Distribución Geográfica de la Población Centro-Continental de la Grulla Canadiense y Aplicación de Gestiones Relacionadas","authors":"Gary L. Krapu, David A. Brandt, Kenneth L. Jones, Douglas H. Johnson","doi":"10.1002/wmon.1","DOIUrl":"https://doi.org/10.1002/wmon.1","url":null,"abstract":"<p>The Mid-continent Population (MCP) of sandhill cranes (<i>Grus canadensis</i>) is widely hunted in North America and is separated into the Gulf Coast Subpopulation and Western Subpopulation for management purposes. Effective harvest management of the MCP requires detailed knowledge of breeding distribution of subspecies and subpopulations, chronology of their use of fall staging areas and wintering grounds, and exposure to and harvest from hunting. To address these information needs, we tagged 153 sandhill cranes with Platform Transmitting Terminals (PTTs) during 22 February–12 April 1998–2003 in the Central and North Platte River valleys of south-central Nebraska. We monitored PTT-tagged sandhill cranes, hereafter tagged cranes, from their arrival to departure from breeding grounds, during their fall migration, and throughout winter using the Argos satellite tracking system. The tracking effort yielded 74,041 useable locations over 49,350 tag days; median duration of tracking of individual cranes was 352 days and 73 cranes were tracked >12 months. Genetic sequencing of mitochondrial DNA (mtDNA) from blood samples taken from each of our random sample of tagged cranes indicated 64% were <i>G. c. canadensis</i> and 34% were <i>Grus canadensis tabida</i>. Tagged cranes during the breeding season settled in northern temperate, subarctic, and arctic North America (U.S. [23%, <i>n</i> = 35], Canada [57%, <i>n</i> = 87]) and arctic regions of northeast Asia (Russia [20%, <i>n</i> = 31]). Distribution of tagged cranes by breeding affiliation was as follows: Western Alaska–Siberia (WA–S, 42 ± 4% [SE]), northern Canada–Nunavut (NC–N, 21 ± 4%), west-central Canada–Alaska (WC–A, 23 ± 4%) and East-central Canada–Minnesota (EC–M, 14 ± 3%). All tagged cranes returned to the same breeding affiliation used during the previous year with a median distance of 1.60 km (range: 0.08–7.7 km, <i>n</i> = 53) separating sites used in year 1 and year 2. Fall staging occurred primarily in central and western Saskatchewan (69%), North Dakota (16%), southwestern Manitoba (10%), and northwestern Minnesota (3%). Space-use sharing indices showed that except for NC–N and WC–A birds, probability of finding a crane from one breeding affiliation within the home range of another breeding affiliation was low during fall staging. Tagged cranes from WC–A and EC–M breeding affiliations, on average, spent 25 and 20 days, respectively, longer on fall staging areas in the northern plains than did WA–S and NC–N birds. Cranes in the NC–N, WA–S, and WC–A affiliations spent 99%, 74%, and 64%, respectively, of winter in western Texas in Hunting Zone A; EC–M cranes spent 83% of winter along the Texas Gulf Coast in Hunting Zone C. Tagged cranes that settled within the breeding range of the Gulf Coast Subpopulation spent 28% and 42% of fall staging and winter within the range of the Western Subpopulation, indicating sufficient exchange of birds to potentially limit effectiveness of MCP harvest","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"175 1","pages":"1-38"},"PeriodicalIF":4.4,"publicationDate":"2011-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wmon.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5736633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-13DOI: 10.2193/0084-0173(2006)161[1:TSAEIO]2.0.CO;2
CHARLES C. SCHWARTZ, MARK A. HAROLDSON, GARY C. WHITE, RICHARD B. HARRIS, STEVE CHERRY, KIM A. KEATING, DAVE MOODY, CHRISTOPHER SERVHEEN
<div> <section> <h3> ABSTRACT</h3> <p>During the past 2 decades, the grizzly bear (<i>Ursus arctos</i>) population in the Greater Yellowstone Ecosystem (GYE) has increased in numbers and expanded in range. Understanding temporal, environmental, and spatial variables responsible for this change is useful in evaluating what likely influenced grizzly bear demographics in the GYE and where future management efforts might benefit conservation and management. We used recent data from radio-marked bears to estimate reproduction (1983–2002) and survival (1983–2001); these we combined into models to evaluate demographic vigor (lambda [λ]). We explored the influence of an array of individual, temporal, and spatial covariates on demographic vigor.</p> <p>We identified an important relationship between λ and where a bear resides within the GYE. This potential for a source-sink dynamic in the GYE, coupled with concerns for managing sustainable mortality, reshaped our thinking about how management agencies might approach long-term conservation of the species. Consequently, we assessed the current spatial dynamic of the GYE grizzly bear population. Throughout, we followed the information-theoretic approach. We developed suites of a priori models that included individual, temporal, and spatial covariates that potentially affected reproduction and survival. We selected our best approximating models using Akaike's information criterion (AIC) adjusted for small sample sizes and overdispersion (AIC<sub>c</sub> or QAIC<sub>c</sub>, respectively).</p> <p>We provide recent estimates for reproductive parameters of grizzly bears based on 108 adult (>3 years old) females observed for 329 bear-years. We documented production of 104 litters with cub counts for 102 litters. Mean age of females producing their first litter was 5.81 years and ranged from 4 to 7 years. Proportion of nulliparous females that produced cubs at age 4–7 years was 9.8, 29.4, 56.4, and 100%, respectively. Mean (±SE) litter size (<i>n</i> = 102) was 2.0 λ 0.1. The proportion of litters of 1, 2, and 3 cubs was 0.18, 0.61, and 0.22, respectively. Mean yearling litter size (<i>n</i> = 57) was 2.0 ± 0.1. The proportion of litters containing 1, 2, 3, and 4 yearlings was 0.26, 0.51, 0.21, and 0.02, respectively. The proportion of radio-marked females accompanied by cubs varied among years from 0.05 to 0.60; the mean was 0.316 ± 0.03. Reproductive rate was estimated as 0.318 female cubs/female/year. We evaluated the probability of producing a litter of 0–3 cubs relative to a suite of individual and temporal covariates using multinomial logistic regression. Our best models indicated that reproductive output, measured as cubs per litter, was most strongly influenced by indices of population size and whitebark pine (<i>Pinus albicaulis</i>) cone production. Our data suggest a possible density
在过去的20年里，大黄石生态系统(GYE)的灰熊(Ursus arctos)种群数量增加，范围扩大。了解造成这种变化的时间、环境和空间变量有助于评估可能影响GYE中灰熊人口统计的因素，以及未来的管理工作可能有利于保护和管理的地方。我们使用无线电标记熊的最新数据来估计繁殖(1983-2002)和生存(1983-2001);我们将这些组合成模型来评估人口活力(lambda [λ])。我们探讨了一系列个体、时间和空间协变量对人口活力的影响。我们确定了λ和熊在GYE中的位置之间的重要关系。GYE中这种源库动态的潜力，加上对可持续死亡率管理的关注，重塑了我们对管理机构如何处理物种长期保护的思考。因此，我们评估了当前GYE灰熊种群的空间动态。自始至终，我们都遵循信息论的方法。我们开发了一套先验模型，其中包括可能影响生殖和生存的个体、时间和空间协变量。我们使用Akaike信息准则(AIC)(分别为AICc或QAICc)对小样本量和过度分散进行调整)选择了我们的最佳近似模型。我们根据对108只成年(>3岁)灰熊329熊年的观察，提供了最近对灰熊生殖参数的估计。我们记录了104窝产仔和102窝幼崽的数量。母鼠平均产仔年龄5.81岁，4 ~ 7岁不等。4 ~ 7岁无生育母熊产仔比例分别为9.8、29.4%、56.4和100%。平均(±SE)凋落物数(n = 102)为2.0 λ 0.1。1窝、2窝和3窝的比例分别为0.18、0.61和0.22。平均年产仔数(n = 57)为2.0±0.1。1岁、2岁、3岁和4岁的窝鼠比例分别为0.26、0.51、0.21和0.02。带放射性标记的母熊带幼崽的比例在0.05 ~ 0.60之间变化;平均值为0.316±0.03。繁殖率估计为0.318只雌崽/母崽/年。我们使用多项逻辑回归评估了相对于一组个体和时间协变量产生0-3只幼崽的概率。我们的最佳模型表明，种群规模和白皮松(Pinus albicaulis)球果产量指数对繁殖产量(以每窝幼崽为单位)的影响最大。我们的数据表明，尽管围产期死亡率可以解释相关性，但生殖产量可能存在密度依赖性反应。我们利用无线电遥测技术分析了49只母熊的幼崽和幼崽的存活率，这些母熊共65窝，含137只幼仔。我们记录了42例死亡:32只幼崽，5只一岁的幼崽，5只可能在幼崽或一岁时死亡。使用Program MARK编码的巢生存估计器，我们的最佳模型表明幼崽和一岁幼崽的生存受GYE居住的影响最大。生活在黄石国家公园(YNP)以外，但在美国鱼类和野生动物管理局(USFWS)灰熊恢复区内(RZ)的幼崽和一岁熊的存活率最高。生活在YNP内的幼崽和一岁幼崽存活率较低，而生活在RZ外的幼崽存活率最低。存活率与种群指数呈负相关，表明密度依赖性。存活率随着白皮松种子产量的增加、冬季严酷程度的提高、产仔数的增加和雌(母)龄的增加而提高。我们测试了性别选择性杀婴的理论，但结果是模棱两可的。我们研究了影响亚成年和成年灰熊生存的因素，使用了对323只标记了无线电的灰熊进行了5,989个月的监测。遥测记录转换为每月的相遇历史，并使用程序MARK中已知的命运数据类型估计生存率。根据捕获和监测的情况，熊被分为研究样本和冲突样本(由于与人类发生冲突而被困的熊)，两种样本的数据都有助于生存估计。经过审查的(C)数据集包括69只记录在案的死亡，但审查了22只命运不明的熊。第二个假设死亡(AD)数据集将这22只熊视为死亡。大多数已知死亡(85.5%)是人为造成的，分别有26例和43例来自研究样本和冲突样本。使用C和AD数据集的研究样本雌熊的平均年生存率S′CF为S′CF = 0.950 (95% CI = 0.898-0)。 976)， S ' ADF = 0.922 (95% CI = 0.857-0.995)。研究样本母熊的过程标准差(SD)估计为SDC = 0.013, SDAD = 0.034。我们的最佳模型表明，研究样本熊的存活率高于冲突样本熊，雌性熊的存活率高于雄性熊，秋季存活率最低，白皮松果产量好的年份存活率增加。与经常出现在YNP、RZ或两者内的个体相比，每年出现在RZ外的比例较高的熊的存活率较低。在我们的模型中，冬季严重度、有蹄类生物量和种群规模的指数，加上个体协变量，包括依赖性幼崽的存在、与人类的先前冲突和年龄等级，都不是重要的生存预测因子。我们通过研究记录了一种增加的生存趋势，近年来，这种趋势被更频繁地位于RZ之外的熊的低生存所抵消。这一结果表明，1983年开始的降低雌性死亡率的努力是成功的，在区域外采取的类似措施将改善GYE灰熊种群持续增长和扩大的前景。为了估计种群的可持续死亡率，我们使用基于个体的随机模拟程序和无线电标记熊的人口统计数据，在独立雌性(2岁)的存活率范围内产生了GYE灰熊种群的轨迹。我们纳入了每年(过程)生存率的变化，这是在消除抽样变化后从数据中估计的。我们用平均λ和λ <的概率来总结轨迹;1，都是在10年的时间内，并通过改变我们的初始假设来反映不确定性来检验结果的敏感性。由于雌性存活的过程变异较低，λ仅比完全确定性模型下的预期值略有随机下降。平均幼崽和一岁幼崽存活率的不确定性是相当大的，但由于λ对这些参数相对不敏感，结合这种不确定性也只会略微降低结果轨迹。独立雌性生存的不确定性对种群下降概率的影响要大得多，尽管对预期λ的影响很小。根据我们目前对GYE灰熊种群动态的理解，λ与雄性存活率无关;男性死亡率的变化只对丰度产生短期影响，对性别比产生长期影响。独立雌熊的适当死亡率目标取决于种群数量下降的风险(即λ <1)管理者和公众都愿意接受。在1983-2002年的条件下，为了使种群下降的几率≤5%，独立雌性的年死亡率必须≤10%。只有在相对较短的时间范围内进行预测才有用，因为它们完全基于1983-2002年的平均情况，而且样本量小，管理人员很难知道真实的死亡率。为了进一步探索地理结构对女性生存的影响，我们建立了一系列确定性模型，利用我们最好的模型来估计繁殖和生存。我们计算了λ的确定性估计，包括我们的居住协变量加上白皮松果产量和冬季严重性的变化。在YNP和RZ内，λ≥1，但RZ外λ≤1。这种源库动态需要对种群管理、死亡率阈值和消除生态系统边缘的人为食物进行新的讨论。为了加强未来的管理，我们提出了应根据我们的研究结果考虑的食品和人口监测指南。resume Durante las dos últimas dsamaccadas, la población del oso pardo (Ursus arctos)，该文件在números通过扩展的地理修改。在大黄石生态系统(GYE)中，通过对大黄石生态系统(el ecosistema mayor de Yellowstone) (GYE)，通过对大黄石生态系统(el ecosistema mayor de Yellowstone) (el ecosistema mayor de Yellowstone) (GYE)，通过对大黄石生态系统(el ecosistema mayor de Yellowstone) (GYE)的研究，通过对大黄石生态系统(el ecosistema
{"title":"Temporal, Spatial, and Environmental Influences on the Demographics of Grizzly Bears in the Greater Yellowstone Ecosystem","authors":"CHARLES C. SCHWARTZ, MARK A. HAROLDSON, GARY C. WHITE, RICHARD B. HARRIS, STEVE CHERRY, KIM A. KEATING, DAVE MOODY, CHRISTOPHER SERVHEEN","doi":"10.2193/0084-0173(2006)161[1:TSAEIO]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2006)161[1:TSAEIO]2.0.CO;2","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>During the past 2 decades, the grizzly bear (<i>Ursus arctos</i>) population in the Greater Yellowstone Ecosystem (GYE) has increased in numbers and expanded in range. Understanding temporal, environmental, and spatial variables responsible for this change is useful in evaluating what likely influenced grizzly bear demographics in the GYE and where future management efforts might benefit conservation and management. We used recent data from radio-marked bears to estimate reproduction (1983–2002) and survival (1983–2001); these we combined into models to evaluate demographic vigor (lambda [λ]). We explored the influence of an array of individual, temporal, and spatial covariates on demographic vigor.</p>\u0000 \u0000 <p>We identified an important relationship between λ and where a bear resides within the GYE. This potential for a source-sink dynamic in the GYE, coupled with concerns for managing sustainable mortality, reshaped our thinking about how management agencies might approach long-term conservation of the species. Consequently, we assessed the current spatial dynamic of the GYE grizzly bear population. Throughout, we followed the information-theoretic approach. We developed suites of a priori models that included individual, temporal, and spatial covariates that potentially affected reproduction and survival. We selected our best approximating models using Akaike's information criterion (AIC) adjusted for small sample sizes and overdispersion (AIC<sub>c</sub> or QAIC<sub>c</sub>, respectively).</p>\u0000 \u0000 <p>We provide recent estimates for reproductive parameters of grizzly bears based on 108 adult (>3 years old) females observed for 329 bear-years. We documented production of 104 litters with cub counts for 102 litters. Mean age of females producing their first litter was 5.81 years and ranged from 4 to 7 years. Proportion of nulliparous females that produced cubs at age 4–7 years was 9.8, 29.4, 56.4, and 100%, respectively. Mean (±SE) litter size (<i>n</i> = 102) was 2.0 λ 0.1. The proportion of litters of 1, 2, and 3 cubs was 0.18, 0.61, and 0.22, respectively. Mean yearling litter size (<i>n</i> = 57) was 2.0 ± 0.1. The proportion of litters containing 1, 2, 3, and 4 yearlings was 0.26, 0.51, 0.21, and 0.02, respectively. The proportion of radio-marked females accompanied by cubs varied among years from 0.05 to 0.60; the mean was 0.316 ± 0.03. Reproductive rate was estimated as 0.318 female cubs/female/year. We evaluated the probability of producing a litter of 0–3 cubs relative to a suite of individual and temporal covariates using multinomial logistic regression. Our best models indicated that reproductive output, measured as cubs per litter, was most strongly influenced by indices of population size and whitebark pine (<i>Pinus albicaulis</i>) cone production. Our data suggest a possible density","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"161 1","pages":"1-8"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2006)161[1:TSAEIO]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：