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1.
Reintroductions have increasingly become effective at restoring populations of imperiled native wildlife. How animals are reintroduced into unfamiliar environments may have pronounced impacts on behavior, survival, and reproduction. We evaluated the influence of four release methods on survival rates of translocated swift foxes at Bad River Ranches (BRR) in western South Dakota: (1) hard‐release, (2) short‐soft‐release, (3) long‐soft‐release, and (4) captive born. A total of 179 foxes captured in Wyoming during 2002–2007 and in Colorado during 2006–2007 were released into BRR and the surrounding area. In addition, 43 pups born to foxes in the long‐soft‐release category were also released. All release methods incorporated a 14‐ to 21‐day quarantine period. Hard‐release foxes were released directly from a transport kennel, whereas short‐soft‐release foxes were released from soft‐release pens by opening the door and allowing the foxes to leave voluntarily. Long‐soft‐release foxes were held for more than 250 days on‐site in soft‐release pens through the winter and released in the following year in early summer. During 2002–2007, survival of reintroduced foxes differed significantly (p < 0.05) by age (adult vs. juvenile), release year, and release method. The short‐soft‐release method had the highest 60‐day post‐release survival probability compared with the other release methods. We did not detect any differences in mortality hazards between wild‐born and short‐soft‐release foxes. Reintroduction programs based on short‐soft‐releases are useful for restoring or augmenting populations to advance the conservation of the swift fox.  相似文献   

2.
ABSTRACT The distribution and abundance of swift foxes (Vulpes velox) has declined from historic levels. Causes for the decline include habitat loss and fragmentation, incidental poisoning, changing land use practices, trapping, and predation by other carnivores. Coyotes (Canis latrans) overlap the geographical distribution of swift foxes, compete for similar resources, and are a significant source of mortality amongst many swift fox populations. Current swift fox conservation and management plans to bolster declining or recovering fox populations may include coyote population reduction to decrease predation. However, the role of coyote predation in swift fox population dynamics is not well-understood. To better understand the interactions of swift foxes and coyotes, we compared swift fox population demographics (survival rates, dispersal rates, reproduction, density) between areas with and without coyote population reduction. On the Piñon Canyon Maneuver Site, Colorado, USA, we monitored 141 swift foxes for 65,226 radio-days from 15 December 1998 to 14 December 2000 with 18,035 total telemetry locations collected. Juvenile swift fox survival rate was increased and survival was temporarily prolonged in the coyote removal area. Adult fox survival patterns were also altered by coyote removal, but only following late-summer coyote removals and, again, only temporarily. Coyote predation remained the main cause of juvenile and adult fox mortality in both areas. The increase in juvenile fox survival in the coyote removal area resulted in a compensatory increase in the juvenile dispersal rate and an earlier pulse in dispersal movements. Adult fox dispersal rate was more consistent throughout the year in the coyote removal area. Coyote removal did not influence the reproductive parameters of the swift foxes. Even though juvenile survival increased, swift fox density remained similar between the areas due to the compensatory dispersal rate among juvenile foxes. We concluded that the swift fox population in the area was saturated. Although coyote predation appeared additive in the juvenile cohort, it was compensatory with dispersal.  相似文献   

3.
The geography of the Black Hills region of South Dakota and Wyoming may limit connectivity for many species. For species with large energetic demands and large home ranges or species at low densities this can create viability concerns. Carnivores in this region, such as cougars (Puma concolor), have the additive effect of natural and human-induced mortality; this may act to decrease long-term viability. In this study we set out to explore genetic diversity among cougar populations in the Black Hills and surrounding areas. Specifically, our objectives were to first compare genetic variation and effective number of breeders of cougars in the Black Hills during three harvest regimes: pre (2003–2006), moderate (2007–2010), and heavy (2011–2013), to determine if harvest impacted genetic variation. Second, we compared genetic structure of the Black Hills cougar population with cougar populations in neighboring eastern Wyoming and North Dakota. Using 20 microsatellite loci, we conducted genetic analysis on DNA samples from cougars in the Black Hills (n = 675), North Dakota (n = 113), and eastern Wyoming (n = 62) collected from 2001–2013. Here we report that the Black Hills cougar population maintained genetic variation over the three time periods. Our substructure analysis suggests that the maintenance of genetic variation was due to immigration from eastern Wyoming and possibly North Dakota.  相似文献   

4.
A serologic survey of swift fox (Vulpes velox) and kit fox (V. macrotis) from the western USA was conducted for 12 infectious diseases. Samples from swift fox were collected between 1987 and 1992 from Colorado (n = 44), Kansas (n = 10), and Wyoming (n = 9). Samples from kit fox were collected in California (n = 86), New Mexico (n = 18), Utah (n = 9), and Arizona (n = 6). Overall antibody prevalence rates were 33 of 110 (30%) for canine parvovirus (CPV), 9 of 72 (13%) for canine distemper virus (CDV), 23 of 117 (20%) for vesicular stomatitis New Jersey, 16 of 117 (14%) for vesicular stomatitis Indiana, six of 117 (5%) for Cache Valley virus, five of 117 (4%) for Jamestown Canyon virus, one of 97 (1%) for rabies virus, one of 117 (1%) for Colorado tick fever virus, and one of 117 (1%) for western equine encephalitis virus. In addition, antibodies were not found to Yersinia pestis, Francisella tularensis, and Borrelia burgdorferi in serum from 25 Colorado swift fox. Adult swift fox from Colorado had serologic evidence of exposure to CPV more often than juveniles. No juvenile swift fox from Colorado had serum antibodies to CDV. There were season-specific differences in serum antibody prevalence for CPV for swift fox from Colorado. No viruses were isolated from ectoparasites or fox from Colorado.  相似文献   

5.
Parental investment varies in mammalian species, with male care of young being more common in social and monogamous species. Monogamy is commonly observed in canid species, with both males and females, and often “helper” individuals, providing some degree of care for the young. Social units of the swift fox (Vulpes velox), a small North American canid species, usually consist of a male–female pair and occasionally helpers. The role of parental investment and behavior in swift fox society is currently poorly understood. We observed swift fox dens during the pup-rearing season in each of 2 years to evaluate attendance and frequency of visits to natal dens by adult males and females. Female foxes remained at dens longer and visited them more frequently than did male foxes. Female attendance and visitation decreased throughout the pup-rearing season as pups became older and more independent. Environmental factors, including climate and its effect on prey, appeared to contribute to differences in fox behavior between the 2 years. We observed only one fox outside of the breeding pair attending a den in each of the 2 years, both of which were males. We concluded that each of these two foxes were living within the social unit of the male–female pair as a trio, but not serving as a helper and contributing to the care of the pups. Our results increased knowledge of the ecology and behavior of the swift fox, a species of conservation concern in the Great Plains of North America.  相似文献   

6.
Gene flow can effectively suppress genetic divergence among widely separated populations in highly mobile species. However, the same may not be true of species that typically disperse over shorter distances. Using mtDNA restriction-site and sequence analyses, we evaluate the extent of divergence among populations of two small relatively sedentary North American canids, the kit and swift foxes (genus Vulpes). We determine the significance of genetic differentiation among populations separated by distance and those separated by discrete topographic barriers. Our results show the among-population component of genetic variation in kit and swift foxes is large and similar to that of small rodents with limited dispersal ability. In addition, we found two distinct groupings of genotypes, separated by the Rocky Mountains, corresponding to the traditional division between kit and swift fox populations. Previous workers have characterized these morphologically similar populations either as separate species or subspecies. Our mtDNA data also suggest that kit and swift fox populations hybridize over a limited geographic area. However, the sequence divergence between kit and swift foxes is similar to that between these taxa and the arctic fox (Alopex lagopus), a morphologically distinct species commonly placed in a separate genus. This result presents a dilemma for species concepts, and we conclude that kit and swift foxes should be recognized as separate species.  相似文献   

7.
Translocation is a strategy commonly used to maximize the persistence of threatened species, but it may sometimes lead to undesirable genetic consequences. The northern quoll (Dasyurus hallucatus) is a carnivorous marsupial that is critically endangered in Australia’s Northern Territory due to rapid population declines in areas recently colonized by the exotic cane toad Chaunus [Bufo] marinus. In 2003, 64 quolls were translocated to two offshore islands to establish insurance populations and reduce the species’ risk of extinction. In this study, we assessed genetic diversity at five microsatellite loci in the translocated populations, two endemic islands and three mainland populations. In the short-term (three generations), the translocated populations showed a slight but non-significant reduction in genetic diversity (A = 4.1–4.2; H e = 0.56–0.59) compared to the mainland source populations (A = 5.0–8.4; H e = 0.56–0.71). In comparison, high genetic erosion was observed in the endemic island populations (A = 1.5–2.9; H e = 0.11–0.34). Genetic bottlenecks were detected on both endemic islands and in one mainland population, indicating recent reductions in population size. Our results are consistent with previous studies describing greater losses of genetic diversity on islands compared to mainland populations. Divergence from ancestral allele frequencies in the translocated populations also suggests effects due to founder events. This study, although short-term, highlights the importance of continued monitoring for detecting changes in genetic diversity over time and makes a significant contribution to our understanding of the effects of founder events on island populations.  相似文献   

8.
We investigated diet composition, habitat selection and spatial behaviour of the red fox (Vulpes vulpes) in relation to the availability of wader nests in a coastal polder area in southwest Denmark. The predatory role of the red fox in wet grassland ecosystems has profound implications for conservation status of declining populations of grassland breeding waders. However, few studies have focussed on the foraging ecology and behaviour of the red fox in these landscapes. Faecal analyses revealed that fox diet consisted of birds (43 % of prey remains?/?32 % of biomass), rodents (39 %?/?21 %), sheep (mainly as carrion, 14 %?/?41 %) and lagomorphs (4 %?/?7 %). Charadriiformes (including waders) comprised 3–12 % of prey remains throughout the year. Telemetry data and spotlight counts indicated that foxes did not select areas with high densities of breeding waders, suggesting that foxes did not target wader nests while foraging. Foxes maintained stable home ranges throughout their lives, indicating that the area sustained a permanent fox population all year round. The population densities, estimated from spotlight surveys, were 0.74 visible foxes km?2 (95 % CI; 0.34–1.61) on the preferred breeding habitat for waders and 1.21 km?2 in other open habitats such as cultivated fields. Our results indicate that red fox predation on wader nests is incidental, consistent with the notion that red foxes are generalist predators that opportunistically subsist on many prey groups.  相似文献   

9.
Foxes in the Greater Yellowstone Ecosystem are reported to show high frequencies of blonde and gray coat colors. A survey of park sighting records showed that the frequency of the novel coat colors significantly increases at elevations greater than 2300 m, suggesting some form of elevational isolation. We evaluated the degree of genetic separation between the high-elevation foxes (>2300 m) and contiguous populations of foxes at mid-elevations (1600–2300m). Low-elevation (>1600 m) foxes from North Dakota, >1000 km straight line distance from our populations, were used as a control group. We genotyped 15 high-elevation, 15 mid-elevation, and 10 low-elevation foxes at 10 microsatellite loci each. Heterozygosity was significantly lower in both the high-elevation and mid-elevation populations compared to the low-elevation foxes. The genetic differentiation was significantly greater between the high-elevation and mid-elevation foxes than between the mid-elevation and low-elevation foxes. Similarly, estimates of RST and FST suggest less gene flow occurs between the contiguous high- and mid-elevation fox populations than between the mid- and low-elevation fox populations separated by > 1000 km. The assignment test further supports this hypothesis. Although further work is needed, we suggest that the high-elevation foxes are remnant populations from the Wisconsin glaciation and should be managed as a unique population.  相似文献   

10.
The silver fox (Vulpes vulpes) offers a novel model for studying the genetics of social behavior and animal domestication. Selection of foxes, separately, for tame and for aggressive behavior has yielded two strains with markedly different, genetically determined, behavioral phenotypes. Tame strain foxes are eager to establish human contact while foxes from the aggressive strain are aggressive and difficult to handle. These strains have been maintained as separate outbred lines for over 40 generations but their genetic structure has not been previously investigated. We applied a genotyping-by-sequencing (GBS) approach to provide insights into the genetic composition of these fox populations. Sequence analysis of EcoT22I genomic libraries of tame and aggressive foxes identified 48,294 high quality SNPs. Population structure analysis revealed genetic divergence between the two strains and more diversity in the aggressive strain than in the tame one. Significant differences in allele frequency between the strains were identified for 68 SNPs. Three of these SNPs were located on fox chromosome 14 within an interval of a previously identified behavioral QTL, further supporting the importance of this region for behavior. The GBS SNP data confirmed that significant genetic diversity has been preserved in both fox populations despite many years of selective breeding. Analysis of SNP allele frequencies in the two populations identified several regions of genetic divergence between the tame and aggressive foxes, some of which may represent targets of selection for behavior. The GBS protocol used in this study significantly expanded genomic resources for the fox, and can be adapted for SNP discovery and genotyping in other canid species.  相似文献   

11.
Abstract: Survival and cause-specific mortality of pronghorns (Antilocapra americana) have been well-documented in several western states and Canadian provinces. However, no information has been collected in western South Dakota, USA, where mixed-grass prairie habitats characterize rangelands. The objectives of our study were to determine survival and cause-specific mortality of adult (>18 months) and yearling (6-18 months) pronghorns and to determine monthly and summer (Jun-Aug) survival for neonatal (<1 month of age) pronghorns in South Dakota. We radiocollared 93 adult female and 142 neonatal pronghorns on 3 areas in western South Dakota. We used bed sites from initial neonate captures to collect microhabitat information throughout Harding and Fall River counties. We measured vegetation understory and overstory height, shrub canopy, and distance to nearest concealment cover to the nearest centimeter inside 1-m2 quadrats by collecting measurements at 15 random points within a 30-m radius of the bed site. We documented that coyote (Canis latrans) predation was the primary cause of mortality for neonates in western South Dakota and that microhabitat characteristics at neonate bed sites differed between northwestern and southwestern South Dakota. More intensive aerial predator control may increase neonate survival in Fall River County. Management of rangelands by state and federal employees throughout western South Dakota and Wind Cave National Park that maximizes height of overstory and understory vegetation would provide neonates with adequate concealment cover for protection from predators, thereby increasing 4-week and 12-week postcapture survival. Our study provides South Dakota game managers with region-specific, annual and seasonal survival rates that were previously only estimated, thus improving the accuracy of simulated pronghorn population model output. Hunting was the primary cause of mortality (26%) for adult females in Harding and Fall River counties, thereby confirming the continued use of annual harvest by South Dakota game managers as the primary management tool for maintaining pronghorn populations within statewide population management goals.  相似文献   

12.
The status of many carnivore species is a growing concern for wildlife agencies, conservation organizations, and the general public. Historically, kit foxes (Vulpes macrotis) were classified as abundant and distributed in the desert and semi-arid regions of southwestern North America, but is now considered rare throughout its range. Survey methods have been evaluated for kit foxes, but often in populations where abundance is high and there is little consensus on which technique is best to monitor abundance. We conducted a 2-year study to evaluate four survey methods (scat deposition surveys, scent station surveys, spotlight survey, and trapping) for detecting kit foxes and measuring fox abundance. We determined the probability of detection for each method, and examined the correlation between the relative abundance as estimated by each survey method and the known minimum kit fox abundance as determined by radio-collared animals. All surveys were conducted on 15 5-km transects during the 3 biological seasons of the kit fox. Scat deposition surveys had both the highest detection probabilities (p = 0.88) and were most closely related to minimum known fox abundance (r2 = 0.50, P = 0.001). The next best method for kit fox detection was the scent station survey (p = 0.73), which had the second highest correlation to fox abundance (r2 = 0.46, P<0.001). For detecting kit foxes in a low density population we suggest using scat deposition transects during the breeding season. Scat deposition surveys have low costs, resilience to weather, low labor requirements, and pose no risk to the study animals. The breeding season was ideal for monitoring kit fox population size, as detections consisted of the resident population and had the highest detection probabilities. Using appropriate monitoring techniques will be critical for future conservation actions for this rare desert carnivore.  相似文献   

13.
《Mammalian Biology》2014,79(1):77-80
The red fox (Vulpes vulpes) is a highly adaptable omnivorous mammal distributed across all continents on the northern hemisphere. Although the red fox is present throughout Europe, where it plays an important ecological and socio-economic role not only as a game species but also as a rabies reservoir, few studies have examined its population-level mitochondrial DNA variability. In this study, 27 mitochondrial DNA control region haplotypes were identified in 229 red fox samples taken from four regions in Croatia. Haplotype diversity of Croatian red foxes (0.901) was found to be among the highest of all European red fox populations studied to date. Genetic differentiation among regions was quite low, and statistically significant estimates of differentiation were obtained only when comparing the population from the peninsular region of Istria with the three continental populations. It seems that landscape barriers like rivers and small mountains do not restrict gene flow among foxes in the continental part of Croatia, while the combination of a narrow land bridge and altitudes exceeding 1000 m limit fox migration between Istria and the rest of the continent. Better understanding of small-scale population structure will require analysis of highly variable nuclear markers like microsatellites.  相似文献   

14.
The swift fox Vulpes velox Say, 1823, a small canid native to shortgrass prairie ecosystems of North America, has been the subject of enhanced conservation and research interest because of restricted distribution and low densities. Previous studies have described distributions of the species in the southern Great Plains, but data on density are required to evaluate indices of relative abundance and monitor population trends. We examined regressions of swift fox density (estimated by mark-recapture) on timed-track surveys, scat surveys, and catch-per-unit effort indices. Seventy-nine swift foxes (42 male, 37 female) were captured 151 times during 10 240 trapnights between May 2003 and December 2004 in the Panhandle of Oklahoma, USA. Density estimates, based on mark-recapture data from autumn 2004, were 0.08–0.44 foxes/km2. Survey indices explained 51 to 76% of the variation in estimates of fox density. Our study indicates that surveys of time-to-track encounters and scat deposition rates show promise in monitoring trends in population abundance over large areas.  相似文献   

15.
American Dippers (Cinclus mexicanus) were once known to occur in streams throughout the Black Hills of South Dakota and Wyoming, but now dippers number about 50–75 individuals and reside almost exclusively in a single stream. The recent decline of the American Dipper in the Black Hills of South Dakota is thought to be due to local stream degradation. As a result of the decline of C. mexicanus in the Black Hills of South Dakota and Wyoming, the Black Hills population of American Dippers is a candidate for designation as a distinct population segement (DPS) and might warrant protection and special management. One criterion for DPS designation is genetic uniqueness. Here we present the results of a genetic assessment of the Black Hills population of C. mexicanus. Data presented here indicate that the dipper population in the Black Hills is genetically distinct from other sampled populations. Further population sampling will be needed to understand the genetic population structure of C. mexicanus throughout its range. Furthermore, the recent decline in the Black Hills dipper population should be a warning that other populations (and other species) may be experiencing similar declines and that such montane habitats are worthy of special management.  相似文献   

16.
Invasive predators are globally significant drivers of threatened fauna population decline and extinction, and the early detection of new incursions is critical to the chances of successful predator eradication and fauna conservation. Here, we provide evidence of the recent invasion of European red foxes (Vulpes vulpes) on to two large and internationally significant islands off the southeast coast of Queensland, Australia – Fraser Island (K'gari) and South Stradbroke Island. From camera trap footage collected on Fraser Island since 2009, foxes have now been observed on seven different occasions between 2012 and 2016. Two scats collected on South Stradbroke Island in 2013 and 2014 tested positive for fox DNA (and negative for Canis spp. DNA), with fox presence confirmed by subsequent camera trap footage in 2016. These data confirm the recent incursion of foxes on to these islands and suggest that small populations now exist there. Fraser Island and South Stradbroke Island represent key RAMSAR wetland areas of refuge for populations of multiple threatened fauna that have never been previously been exposed to foxes. Fox impacts on these fauna can only be expected to increase without management intervention to eradicate them before they become widespread.  相似文献   

17.
We used variation in a portion of the mitochondrial DNA control region to examine phylogeography of Tamiasciurus hudsonicus, a boreal-adapted small mammal in the central Rocky Mountain region. AMOVA revealed that 65.66% of genetic diversity was attributable to variation within populations, 16.93% to variation among populations on different mountain ranges, and 17.41% to variation among populations within mountain ranges. Nested clade analysis revealed two major clades that likely diverged in allopatry during the Pleistocene: a southern clade from southern Colorado and a northern clade comprising northern Colorado, Wyoming, eastern Utah, and eastern Idaho. Historically restricted gene flow as a result of geographic barriers was indicated between populations on opposite sides of the Green River and Wyoming Basin and among populations in eastern Wyoming. In some instances genetic structure indicated isolation by distance.  相似文献   

18.
The genetic diversity of 116 barley accessions, representing five Chinese eco-geographic populations, was studied using simple sequence repeat (SSR) markers. The 21 SSR loci revealed 128 alleles with an average of 6.1 alleles per locus. The highest values of proportion of polymorphic loci (P) and gene diversity index (He) were obtained in the Northern (P = 1.00; He = 0.60) and the Yangtze River reaches and Southern populations (P = 1.00; He = 0.59). The lowest values were in the populations of the Yellow River reaches (P = 0.86; He = 0.44). The highest average number of alleles per locus (4.52) and number of unique alleles (7) were found in the Qinghai–Tibet plateau population. Cluster analysis revealed that together with the row type, strong eco-geographic variables influenced the classification. Associations of SSR and eco-geographic values were established for 11 SSR loci. Four to six markers were found to discriminate among geographic groups, which may serve as tools for diagnosis of the eco-geographic populations and provide evidence for the adaptive nature of SSR markers.  相似文献   

19.
In Scandinavia, an increased red fox Vulpes vulpes density during the last decades has been suggested to be caused by direct and indirect human influences on food availability. Recently, attention has been focused on the role of increasing scavenging opportunities due to intensified hunting of ungulates and the reestablishment of large carnivores. In our study, we investigated seasonal and annual variations in diet composition of red fox in Varaldskogen, SE Norway, an area with cyclic voles and a high density of moose Alces alces. Analyses of scats revealed significant differences among seasons in the occurrence of ungulates—mainly moose—and ungulates were the dominating food category during winter (44.9 % of all remains). Snow tracking of red fox (71 km) in winter confirmed the importance of ungulate carcasses, i.e. one case of scavenging per 3 km. The proportions of voles were high during all seasons (11.2–28.8 %); in spite of variation in available abundances, no significant seasonal or annual differences were detected. Other food categories with seasonal variation were birds, berries/seeds and amphibians/reptiles, all more common in snow-free seasons. Our study underlines the importance of ungulate remains during periods when the abundance and diversity of alternative food sources is low. Increased and stabilized populations of red foxes—mediated through remains from hunting and wolf kills from high moose populations—might have an important effect on the population dynamics of small game. Hence, we recommend that this relationship be given attention in future studies.  相似文献   

20.
The golden jackal and red fox are among the wildlife species protected by Israeli law as enforced by the Israel Nature and Parks Authority. In 1964, as a part of a management program to control rabies in Israel, a poison eradication campaign was launched to exterminate golden jackals, considered to be the main reservoir of the disease. The program resulted in the near-complete extermination of jackals in Israel, while foxes were only mildly affected. Jackals have since regained their original numbers and have recolonized southern Israel. We here examined the population structure of the golden jackal and red fox in Israel, 48 years after the poison eradication campaign. DNA from 88 golden jackals and 89 red foxes representing five different geographic regions was extracted and amplified at 13 microsatellite loci in order to characterize the populations on a genetic level. High genetic diversity was found among the jackal and fox populations. A possible migration route through the Jordan Rift Valley was suggested for both species by the genetic similarity of populations in northern and southern Israel. However, in both species, the animals from the center of Israel were distinctive from those north or south, indicating the relative isolation of central populations, likely due to fragmentation or a high abundance of food resources. Genetic profiles obtained for the golden jackal and the red fox in Israel may aid in their conservation management and in the study of zoonotic diseases.  相似文献   

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