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1.
Abstract: Factors influencing patterns of space use by pygmy rabbits (Brachylagus idahoensis) are poorly understood. We studied diurnal space use by adult pygmy rabbits during multiple breeding and nonbreeding seasons at 3 sites in the Lemhi Valley, Idaho, USA, during 2004–2005. Pygmy rabbits used larger areas than predicted by allometric models and documented by some previous investigations. Sex and season strongly influenced space use by rabbits. Males used larger home ranges and core areas, more burrow systems, and more widely dispersed burrow systems than did female rabbits. We also documented significant differences among study sites in many movement parameters, which suggested that local resource distribution also might influence how pygmy rabbits use space. Our results indicated that pygmy rabbits use large areas and exhibit seasonal, sex, and site-specific variation in patterns of movement and space use. Therefore, larger areas of habitat may be needed to conserve pygmy rabbits to accommodate seasonal, regional, and potentially annual variation in resource availability and to maintain linkages among populations. 相似文献
2.
Adams JR Goldberg CS Bosworth WR Rachlow JL Waits LP 《Molecular ecology resources》2011,11(5):808-812
The pygmy rabbit (Brachylagus idahoensis) is a small lagomorph of the western United States that specializes in sagebrush (Artemisia spp.) habitat. Intensive habitat loss and modification have increased the vulnerability of pygmy rabbit populations, but the current geographic distribution and population status remain unclear. To aid in detection and population monitoring, we developed a species identification test that uses mitochondrial DNA species-specific primers to distinguish among six sympatric lagomorph species using DNA isolated from faecal pellets. Applying this test, we successfully identified the species of origin for all pellet samples that produced a positive PCR result (77% of 283 pellets collected). Pellets collected during the winter (December-February) had higher PCR success rate (93%) than pellets collected at other times of the year (72%). This test, using non-invasive genetic sampling of faecal pellets, provides an efficient method for assessing site occupancy and distribution of pygmy rabbits and other lagomorphs across large geographic areas. 相似文献
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We developed 10 polymorphic microsatellite loci for the pygmy rabbit (Brachylagus idahoensis). Nine of the 10 loci amplified reliably and had a low frequency of null alleles. Number of alleles per locus ranged from four to 12, and observed and expected heterozygosities ranged from 0.26 to 0.89 and from 0.63 to 0.88, respectively. These loci will be useful in determining population genetic structure and assessing patterns of gene flow in the pygmy rabbit. 相似文献
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The pygmy rabbit (Brachylagus idahoensis) is a cryptic, burrowing lagomorph of conservation concern for which an efficient method to monitor populations is needed for conservation planning. We developed an index of abundance based on density of active burrow systems at 7 sites (57.2–118.5 ha) in east central Idaho. We conducted censuses of burrow systems and used mark-resight surveys of 80 radio-collared individuals to estimate density of rabbits. At 5 sites, we also used a second method to estimate rabbit numbers based on presence of tracks in snow around burrow systems. We evaluated patterns of burrow use by individuals and examined the relationship between vegetation structure and density of rabbits. Density of active burrow systems varied from 0.19 to 3.46 per ha, and density of rabbits ranged from 0.02 to 0.46 per ha. Number of burrow systems used by individuals increased with density of available burrows, which supported a nonlinear relationship between abundance of burrows and rabbits. Population density increased curvilinearly with density of active burrows accounting for >75% of the variation (r2 = 0.79) in population estimates across sites. We documented a positive relationship between visual obstruction of vegetation and density of rabbits across 6 of the study sites. Our results suggest that density of burrows can serve as an index for monitoring changes in abundance of pygmy rabbits in east central Idaho and that this index also might be useful for monitoring changes in relative abundance over time at other locations. To assess abundance at larger spatial scales or across different regions, the index should be calibrated under regional conditions and site-level covariates should be evaluated. © 2011 The Wildlife Society. 相似文献
6.
Amber Jimenez Jennifer Schmalz Masako N. Wright Michele M. Skopec 《The Journal of wildlife management》2020,84(7):1306-1314
The pygmy rabbit (Brachylagus idahoensis) is endemic to the sagebrush steppe landscapes in the western United States. Pygmy rabbits have adapted to this region by depending on big sagebrush (Artemisia tridentata) as a source of nutrition and concealment from predators. Being a central place forager, and a dietary specialist makes pygmy rabbits an ideal subject to study foraging tradeoffs. Our objectives were to determine if pygmy rabbit foraging patterns are influenced by the nutrient content of individual sagebrush, or the size and location of individual sagebrush. We first developed a near infrared spectroscopy assay that can be conducted in the field, with whole plant foliage, to determine individual sagebrush crude protein (CP) and acid detergent fiber (ADF) contents. We then measured the size, location, protein, and fiber contents of >1,500 foraged and non-foraged sagebrush plants surrounding pygmy rabbit burrows in 2 field sites in northern Utah, USA. We found significant site differences in sagebrush CP levels and significant season differences in sagebrush ADF levels; sagebrush closer to central burrows were higher in protein and lower in fiber. Pygmy rabbits preferred to forage on taller sagebrush plants that were closer to the central burrow but only marginally higher in CP (0.2%) and lower in ADF (1%). Sagebrush plants with a >50% chance of being foraged, were <5.6 m from the burrow, >0.67 m tall, >10.4% CP, and <34.95% ADF. The selection of closer, larger, and more nutrient-dense sagebrush may be influenced by pygmy rabbits' need for concealment from predators or a way to minimize foraging effort. © 2020 The Wildlife Society. 相似文献
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Abstract: Degradation of sagebrush habitat and a lack of information on current status motivated a petition to list the pygmy rabbit (Brachylagus idahoensis) as threatened or endangered under the Endangered Species Act. The petition brought on renewed interest in obtaining data on pygmy rabbits; however, pygmy rabbits are notoriously difficult to capture, especially in summer. We tested box-trap, net, noose-pole, and fabric-fence methods to capture pygmy rabbits in 4 areas of northern Nevada and eastern California, USA. We captured 25 different pygmy rabbits in 30 captures from April 2005 to July 2006. The combination of camouflaged box traps baited with canned green beans was 35% more successful and required less effort per captured rabbit than any other method. Noose-pole methods also were successful. These techniques provide an efficient method of capturing pygmy rabbits in summer when many remote field sites are most accessible. 相似文献
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Tammy L. Wilson Frank P. Howe Thomas C. Edwards Jr. 《The Journal of wildlife management》2011,75(2):393-398
The effects of widespread sagebrush removal treatments on pygmy rabbits (Brachylagus idahoensis) are not well understood. Due to reliance on sagebrush, pygmy rabbits are among the species for which these treatments may be detrimental. Our objectives were to evaluate the effects of experimental sagebrush treatment on 8 radio-collared pygmy rabbits between and within home range habitat selection using Monte Carlo simulation from null models. Pygmy rabbits were not extirpated from plots containing habitat treatments, and we found no evidence that treatments affected home range placement. The mean treatment distance of observed home range centers did not differ from repeated trials of random points. However, we found evidence of within home range selection against treatments from 2 of 8 rabbits located close to the treatments. The mean treatment distance of all observed locations for these 2 rabbits was greater than expected based on a null model. We also used snow tracking to show that pygmy rabbits entered treatments in 4 out of 21 trials, which was less often than expected by chance (G2 = 8.662, P = 0.003). Conservatively, sagebrush removal treatments should not be conducted on active or recently active pygmy rabbit burrows. Elsewhere near known pygmy rabbit sites, treated patches should be small and connected by untreated corridors to prevent potentially limiting movement of rabbits among the untreated habitat. © 2011 The Wildlife Society. 相似文献
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Jena A. Moon David A. Haukos Warren C. Conway 《The Journal of wildlife management》2017,81(3):461-469
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Stephanie M. DeMay Penny A. Becker Chad A. Eidson Janet L. Rachlow Timothy R. Johnson Lisette P. Waits 《Molecular ecology resources》2013,13(4):654-662
Noninvasive genetic sampling of faecal pellets can be a valuable method for monitoring rare and cryptic wildlife populations, like the pygmy rabbit (Brachylagus idahoensis). To investigate this method's efficiency for pygmy rabbit monitoring, we evaluated the effect of sample age on DNA degradation in faecal pellets under summer field conditions. We placed 275 samples from known individuals in natural field conditions for 1–60 days and assessed DNA quality by amplifying a 294‐base‐pair (bp) mitochondrial DNA (mtDNA) locus and five nuclear DNA (nDNA) microsatellite loci (111–221 bp). DNA degradation was influenced by sample age, DNA type, locus length and rabbit sex. Both mtDNA and nDNA exhibited high PCR success rates (94.4%) in samples <1 day old. Success rates for microsatellite loci declined rapidly from 80.0% to 42.7% between days 5 and 7, likely due to increased environmental temperature. Success rates for mtDNA amplification remained higher than nDNA over time, with moderate success (66.7%) at 21 days. Allelic dropout rates were relatively high (17.6% at <1 day) and increased to 100% at 60 days. False allele rates ranged from 0 to 30.0% and increased gradually over time. We recommend collecting samples as fresh as possible for individual identification during summer field conditions. Our study suggests that this method can be useful for future monitoring efforts, including occupancy surveys, individual identification, population estimation, parentage analysis and monitoring of genetic diversity both of a re‐introduced population in central Washington and across their range. 相似文献
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Allyson K. Jackson Joshua P. Froneberger Daniel A. Cristol 《The Journal of wildlife management》2011,75(5):1082-1093
Golf courses ostensibly offer green space in urbanized areas, but it is unclear how suitable these human-modified habitats are for wildlife populations. Golf courses are home to a variety of wildlife, but in particular they have been the focus of research on avian responses to urbanization. Although numerous reproductive and diversity studies have been conducted on birds of golf courses, no research exists on postfledging survival in this created landscape. In 2008 and 2009, we estimated survival of eastern bluebird (Sialia sialis) fledglings using radio telemetry on golf course and other developed sites in Williamsburg, Virginia. We used nest survival models in Program MARK set in an information theoretic framework to assess whether the golf course habitat predicted mortality along with other previously studied variables, such as fledgling age, year, site, body condition, fledging date, and transmitter weight. We found no evidence that inhabiting a golf course increased mortality during the fledgling period, but we did find support for both fledgling age and fledging date as predictors of survival. Mortality decreased for older fledglings and those that fledged later in the season. Cause-specific postfledging survival rates did not differ among sites. Fledgling bluebirds did, however, move into habitat that was significantly more forested and less grassy than their natal habitat. For managers of wildlife on golf courses and other urbanized sites, our study is the first to show that placing nest boxes in manicured habitat may attract birds to areas without suitable habitat for fledglings. © 2011 The Wildlife Society. 相似文献
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JOHN R. SQUIRES JEFFREY P. COPELAND TODD J. ULIZIO MICHAEL K. SCHWARTZ LEONARD F. RUGGIERO 《The Journal of wildlife management》2007,71(7):2213-2220
ABSTRACT We instrumented 36 wolverines (Gulo gulo) on 2 study areas in western Montana and one study area on the Idaho-Montana (USA) border: 14 (9 M, 5 F) on the Pioneer study area, 19 (11 M, 8 F) on the Glacier study area, and 3 (2 M, 1 F) on the Clearwater study area. During 2002–2005, harvest from licensed trapping accounted for 9 (6 M, 3 F) of 14 mortalities, including individuals from all 3 study areas. Based on Akaike's Information Criterion adjusted for small sample sizes (AICc) rankings of 8 a priori models, a trapping model and a trapping-by-sex interaction model were equally supported (ΔAICc < 2) in explaining wolverine survival. Estimated annual survival was 0.80 when we did not consider harvest, whereas additive mortality from harvest reduced annual survival to 0.57. Glacier National Park in the Glacier study area provided some refuge as evidenced by an annual survival rate of 0.77 compared to 0.51 for the Pioneer Mountain study area. We incorporated these survival rates into a simple Lefkovitch stage-based model to examine rates of population change. The finite rate of population change (Λ) for the Glacier study area was 1.1, indicating a stable to slightly increasing population, whereas Λ for the Pioneer study area was 0.7, indicating a 30% annual population decrease during our study. Changes in Λ for both study areas were most sensitive to adult survival. In 2004, we used a Lincoln Index to estimate that 12.8 ± 2.9 (95% CI) wolverines resided in the 4 mountain ranges comprising the Pioneer study area, suggesting that small, island ranges in western Montana supported few individuals. Our results suggest that if wolverines are harvested, they should be managed within individual mountain ranges or small groupings of mountain ranges to limit mortality to within biologically defined limits in recognition of the increased vulnerabilities owing to low fecundity and low population numbers in small mountain ranges. We found that refugia, such as Glacier National Park, were important by reducing trap mortality and providing immigrants to the surrounding population, but even large parks were inadequate to provide complete protection to wolverines from trapping as they ranged outside park borders. 相似文献
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FALINE M. DRUMMOND Kevin A. Parker Tim G. Lovegrove Doug P. Armstrong 《The Journal of wildlife management》2019,83(8):1744-1752
Detailed data on juvenile survival are rare in the literature. Although many studies estimate recruitment, if you cannot distinguish between permanent dispersal and mortality, the management implications for a population may be unclear. We estimated juvenile survival in a reintroduced North Island robin (Petroica longipes) population in a protected sanctuary surrounded by an unprotected landscape where the species is extirpated. The population has had marginal population growth due to poor recruitment so we modeled 3 types of data (resighting of fledglings, radio-telemetry of independent juveniles, resighting of adults) in an integrated framework to determine the life stages where high mortality was occurring, and to distinguish mortality from dispersal. Approximately 16% of birds that fledged (n = 109) were present at the start of the next breeding season, consistent with recruitment rates from previous years. Low survival in the first 6 weeks after fledging was the primary cause of poor recruitment. Only 50% survived to independence (4 weeks after fledging), and 18% survived to the end of the radio-tracking period (14 weeks), after which juvenile survival matched adult survival. No dispersal from the sanctuary occurred during the radio-tracking period. Juveniles moved between adjacent forest fragments within the sanctuary, but did not leave the sanctuary. This information, which demonstrates the importance of distinguishing between natal mortality and dispersal, is important for ongoing management of the site and selection of future reintroduction sites for this species. © 2019 The Wildlife Society. 相似文献
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Hundreds of thousands of juvenile yellow tang, Zebrasoma flavescens, are caught each year in the state of Hawai’i (USA) for the live aquarium trade. As part of an extensive adaptive management
strategy built around a network of protected areas, an emphasis was placed on understanding this important species’ life history.
Multiple capture-mark-recapture techniques and a model selection approach to data analysis in Program MARK were used to estimate
the effects of individual age and conspecific density on natural per-capita daily survival probabilities of yellow tang recruits
(recently settled individuals, 30–50 mm total length) and the effects of body size and site on natural per-capita monthly
survival probabilities for juveniles (58–127 mm total length). The models of recruit survival that included additive effects
of density and age were best supported by the data and indicated an increase of survival with age and decrease of survival
with increased conspecific density. At 1 day post-settlement, the model averaged daily per-capita survival probability ranged
from 0.963 (95% CI: 0.932–0.981) at a low density of 0.1 recruits m−2 to 0.848 (95% CI: 0.752–0.911) at a high density of 1.3 recruits m−2. The best supported model of juvenile survival had no effect of fish length or site, with a constant monthly per-capita survival
of 0.939 (95% CI: 0.925–0.950). Only about 1% of recruits may survive to adulthood when protected from fishing. These results
can be used to better analyze and interpret data from protected area monitoring surveys and refine management practices. Continued
long-term monitoring, combined with targeted life history studies and demographic modeling, is needed to further investigate
the population level effects of fishing yellow tang juveniles. 相似文献
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R. DOUGLAS HOLT L. WES BURGER JR. STEPHEN J. DINSMORE MARK D. SMITH SCOTT J. SZUKAITIS K. DAVID GODWIN 《The Journal of wildlife management》2009,73(6):989-995
ABSTRACT Radiotelemetry is used extensively in zoographic studies of wildlife species, including northern bobwhite (Colinus virginianus). These studies assume that radiomarking does not affect survival of marked individuals. However, most researchers implicitly acknowledge that capture, handling, and radiomarking may have short-term deleterious effects on individuals and, therefore, include in analyses only animals that survive an adjustment period of arbitrary length (often 7 days) following capture and marking. Length of adjustment period is rarely empirically based and may potentially bias survival estimates. We outline an analytical approach to determine an appropriate adjustment period and illustrate this approach by examining effects of time-since-marking on survival of 410 northern bobwhite captured during winter from 1997 to 2001, in Mississippi, USA. We modeled daily survival rates using time-since-marking as a covariate in the nest-survival model of Program MARK. Although survival varied among and within years, we found no evidence to suggest that standard adjustment periods of 7–14 days were appropriate for our sample. If adjustment periods are used in radiotelemetry studies, those that are empirically based may be more appropriate than arbitrarily set periods. 相似文献
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Ecology of juvenile grouse during the transition to adulthood 总被引：1，自引：0，他引：1
17.
We studied flexibility of life history tactics, in terms of habitat-dependent survival and reproduction, in a pulsed resource consumer, the edible dormouse (Glis glis). We compared capture–mark–recapture data from three subpopulations of dormice: one in a homogeneous beech forest (Forest), and two in patches of woodland (Grove/Hedge), with more constant but less energy-rich food availability (e.g., fleshy fruits), over a period of 5 years. The general seasonal pattern of hibernation and reproduction was similar in all three subpopulations. Juveniles were born in only 3 out of 5 years at all study sites, which was paralleled by the occurrence of strong seed production in beech. Reproductive output (number of juveniles/female) was lower at the two sites with low seed tree abundance (Grove: 1.3; Hedge: 2.0) than in the Forest (4.4). Yearly survival probability of adults was significantly lower in the Forest (0.57, CI = 0.42–0.70) than in the areas Grove and Hedge (0.83, CI = 0.70–0.91). Despite their shortened lifespan, estimated lifetime reproductive success of females in the Forest was higher (6.2 young) than in the areas Grove/Hedge (4.8 young). Together, these data indicate that, in more constant habitats (Grove/Hedge), lower reproductive investment was associated with increased longevity. However, dormice apparently maximise lifetime reproductive success by a ‘sit tight’ strategy that synchronises reproduction with energy rich seed pulses in deciduous forests. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. 相似文献
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Abstract: We selected 2 adjacent populations of mule deer (Odocoileus hemionus hemionus) in the Bridger Mountains, Montana, USA, to measure effects on survival rates and causes of mortality of 2 hunting regulations designed to enhance representation of mature males. We compared male survival between the West Slope and South 16 Mile populations considering both hunting and nonhunting sources of mortality with respect to age (fawn, yearling, and mature), month (Jun-May), and year (1990-1995). Harvest rates of mature males were greater than for yearlings, demonstrating hunter preferences. We found no differences in yearling monthly survival rates between October and November or between areas or years. In contrast, we found survival of mature males differed between October and November and across years and study areas. During these months, survival rates of mature males averaged 0.602 on the West Slope under the 2-point regulation and 0.762 on South 16 Mile under the outfitted hunt. Monthly survival during summer also differed by age class, but not area, with estimates of 0.963 for yearling males, and corresponding mature male survival estimates of 0.991, demonstrating greater yearling summer mortality. Winter survival rates of yearlings and matures were similar for both areas with a monthly estimate of 0.986. We found differences in spring monthly survival estimates for the 2 areas, mainly for matures. Yearling male monthly survival estimates were 0.959 and 0.958 for the 2 areas, whereas corresponding mature male estimates during spring were 0.991 and 0.936 on the West Slope and South 16 Mile, respectively. Fawn survival rates varied from 0.101 to 0.770 among years and between areas overwinter. Cumulative effects of nonhunting mortality among all age classes reduced the effectiveness of 2 hunting regulations designed to enhance survival of males to age classes ≥4 years associated with maximum antler development despite accomplishing reductions in harvest rates. Low and variable fawn survival and relatively high nonhunting-related losses of yearling and mature males might be typical of many populations in the Northern Rocky Mountains. Deer managers should avoid populations coexisting with a diversity of large predators in environments with strong year effects when considering opportunities for implementing harvest regulations to improve representation of mature males. 相似文献
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Red squirrels (Tamiasciurus hudsonicus) defend food-based territoriesyear round, and juveniles must acquire a territory before winterto survive. We experimentally removed territory owners duringthe time that juveniles were becoming independent to examinethe effect of local vacancies on dispersal patterns. Juvenilesattempted to take over removal territories most frequently.However, females with offspring still on the natal territoryactually took over twice as many territories as juveniles. Thesefemales did not appear to move because of low reproductive potentialor to increase territory quality. Instead, moving to a removalterritory allowed more of their offspring to remain on the natalterritory, which appeared to increase juvenile survival. 相似文献
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Capsule Changes in return date coincided with marked changes in population size that probably resulted in fluctuating competition for nest-sites. Aims To document the changes in return dates over a 44-year period and to identify the factors associated with these changes. Methods We compared changes in return date at Shetland colonies with those for the Isle of May, southeast Scotland, and with the available information on population size, the abundance of some fish species eaten by Common Guillemots and large-scale changes in the oceanography and climate of the eastern Atlantic as reflected by the winter index of the North Atlantic Oscillation (NAO). Results Common Guillemots normally return to colonies in Shetland in late winter. However, during the 1960s return dates became gradually earlier with birds present from early October. Autumn return remained the norm for about ten years after which return dates gradually reverted back to late winter. In contrast, Common Guillemots on the Isle of May, 400 km south of Shetland, showed no marked shift, returning in October each year. There was a strong negative correlation between date of return of Shetland birds and population size, whereas on the Isle of May birds came back earlier when there was a large positive winter NAO index. There was no convincing evidence that changes in wintering areas or fish abundance influenced when birds returned to the colonies, although the fish data may not have been collected on the correct spatial scale. Conclusion Competition for high quality nest-sites is the most likely reason for Common Guillemots returning to the colonies during the autumn and winter. 相似文献