共查询到13条相似文献，搜索用时 0 毫秒
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Abstract: Increases in Yellowstone National Park, USA, bison (Bison bison) numbers and shifts in seasonal distribution have resulted in more frequent movements of bison beyond park boundaries and development of an interagency management plan for the Yellowstone bison population. Implementation of the plan under the adaptive management paradigm requires an understanding of the spatial and temporal structure of the population. We used polythetic agglomerative hierarchical cluster analysis of radiolocations obtained from free-ranging bison to investigate seasonal movements and aggregations. We classified radiolocations into 4 periods: annual, peak rut (15 Jul-15 Sep), extended rut (1 Jun-31 Oct), and winter (1 Nov-31 May). We documented spatial separation of Yellowstone bison into 2 segments, the northern and central herds, during all periods. The estimated year-round exchange rate (4.85-5.83%) of instrumented bison varied with the fusion strategy employed. We did not observe exchange between the 2 segments during the peak rut and it varied during the extended rut (2.15-3.23%). We estimated a winter exchange of 4.85-7.77%. The outcome and effectiveness of management actions directed at Yellowstone bison may be affected by spatial segregation and herd affinity within the population. Reductions based on total population size, but not applied to the entire population, may adversely affect one herd while having little effect on the other. Similarly, management actions targeting a segment of the population may benefit from the spatial segregation exhibited. 相似文献
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Kelly M. Proffitt Justin A. Gude Julee Shamhart Fred King 《The Journal of wildlife management》2012,76(4):847-856
In the Greater Yellowstone Ecosystem, growing concern over increasing rates of brucellosis seroprevalence in wildlife has challenged wildlife managers to develop strategies for minimizing the potential for pathogen exchange within and between wildlife populations. Recent evidence suggests that increases in elk seroprevalence may be associated with increasing elk densities and/or increasing size of elk aggregations. However, the interactions between elk population density, landscape factors, and elk aggregation patterns are not well-understood, making appropriate management responses challenging. Using a unique, long-term elk aggregation dataset collected across a wide range of elk population sizes, we investigated relationships between elk population size, landscape factors, and elk aggregation responses (group size and group density) with goals of clarifying how changes in elk population size may affect elk aggregation patterns. Overall, landscape attributes and weather had a stronger influence on elk aggregation patterns than factors such as elk population size that are within management control. We found little evidence that elk population size affected mean elk group sizes, but we did find evidence that the size and density of the largest elk aggregations increased as elk population size increased. We also found some evidence that group densities increased following the establishment of wolves. However, across the relatively wide range of elk population sizes observed in this study, only modest changes in elk group density were observed, suggesting that dramatic reductions in population sizes would be necessary to produce measureable reductions in elk group density to affect frequency-dependent transmission. Management actions designed to lower disease transmission are likely to negatively affect other objectives related to elk management and conservation. We therefore suggest that a first step in managing disease transmission risk is agreement among stakeholders interested in elk management of all objectives related to elk management, including acknowledgment that disease transmission is undesirable. © 2011 The Wildlife Society. 相似文献
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Elizabeth Hadly Barnosky 《Historical Biology》2013,25(1-4):71-90
Lamar Cave, a late Holocene paleontological site in Yellowstone National Park, USA, has yielded 36 fossil mammal species from 10 stratigraphic units representing about 2000 years. The fossil fauna is similar to the mammals in the park today and affords a unique opportunity to investigate paleocommunity and ecosystem dynamics through time. Remains of an extralimital species in Yellowstone today, Microtus ochrogaster are found only in the oldest cave deposits, dated at 1695 ± 60 yr B.P. Disappearance of this species by about 1550 years ago marks evolution into the ecosystem that has persisted into the present and is recognizable by a fossil mammal assemblage that is virtually identical to the modern one. Relative abundance fluctuations in the mammal populations imply community resilience through the past 2000 years. Trends in relative abundances of small mammals, particularly the inverse relationship between Microtus and Spermophilus are interpreted as evidence of declining grass cover near Lamar Cave between approximately 1500 and 1000 years ago. The initiation of this environmental change may well have stimulated the ecosystem change marked by Microtus ochrogaster extirpation. Support for this hypothesis is found in a pollen record from a nearby lake. 相似文献
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MATTHEW I. PYNE KERRY M. BYRNE KIRSTIN A. HOLFELDER LINDSAY MCMANUS MICHAEL BUHNERKEMPE NATHANIAL BURCH EDDIE CHILDERS SARAH HAMILTON GREG SCHROEDER PAUL F. DOHERTY JR. 《The Journal of wildlife management》2010,74(7):1463-1471
Abstract: The iconic plains bison (Bison bison) have been reintroduced to many places in their former range, but there are few scientific data evaluating the success of these reintroductions or guiding the continued management of these populations. Relying on mark-recapture data, we used a multistate model to estimate bison survival and breeding transition probabilities while controlling for the recapture process. We tested hypotheses in these demographic parameters associated with age, sex, reproductive state, and environmental variables. We also estimated biological process variation in survival and breeding transition probabilities by factoring out sampling variation. The recapture rate of females and calves was high (0.78 ± 0.15 [SE]) and much lower for males (0.41 ± 0.23), especially older males (0.17 ± 0.15). We found that overall bison survival was high (>0.8) and that males (0.80 ± 0.13) survived at lower rates than females (0.94 ± 0.04), but as females aged survival declined (0.89 ± 0.05 for F ≥15 yr old). Lactating and non-lactating females survived at similar rates. We found that females can conceive early (approx. 1.5 yr of age) and had a high probability (approx. 0.8) of breeding in consecutive years, until age 13.5 years, when females that were non-lactating tended to stay in that state. Our results suggest senescence in reproduction and survival for females. We found little support for the effect of climatic covariates on demographic rates, perhaps because the park's current population management goals were predicated from drought-year conditions. This reintroduction has been successful, but continued culling actions will need to be employed and an adaptive management approach is warranted. Our demographic approach can be applied to other heavily managed large-ungulate systems with few or no natural predators. 相似文献
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DANIEL R. MACNULTY GLENN E. PLUMB DOUGLAS W. SMITH 《The Journal of wildlife management》2008,72(8):1834-1844
Abstract: Current techniques for remotely monitoring wildlife lack the capability to survey a wide area or to transmit data in real time. We addressed these technology gaps by developing and testing a new video and telemetry system for remotely sampling wildlife abundance, distribution, and behavior across large open areas. The system consisted of 2 pan-tilt-zoom video cameras equipped with 20–200× lens, and an automated telemetry scanner and data logger. All components were charged by wind and solar power and located on a hilltop overlooking an open valley (23 km2) in Yellowstone National Park, USA. A satellite up-link to the internet transmitted data in real time to the University of Minnesota-St. Paul and relayed commands from undergraduate students who controlled the cameras and systematically scanned the area at 2-hour intervals 6 times/day (0800–2000 hr) 7 days/week for about 20 consecutive weeks (Dec-Jun). During each scan, students recorded presence, activity, and location of bison (Bison bison), coyote (Canis latrans), grizzly bear (Ursus arctos), red fox (Vulpes vulpes), and wolf (Canis lupus). The telemetry system continuously scanned frequencies of 100 tagged wolves, including 4 members of the one resident pack. We determined wolf presence in real time by viewing the incoming data stream, or we assessed presence later after off-loading the data logger. Matched pairs of simultaneous observations taken by remote and on-site observers during a 13-day double-sampling period were highly correlated (r = 0.71–0.94), but remote observations were biased toward larger, more visible mammals (e.g., bison) and tended to underestimate their abundance. Nevertheless, the system was deployed longer than was practical for on-site observers and was, therefore, useful for detecting long-term, fine-scale trends such as daily changes in bison numbers as a function of snow depth. (JOURNAL OF WILDLIFE MANAGEMENT 72(8):1834–1844; 2008) 相似文献
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Brian J. Harvey Daniel C. Donato Monica G. Turner 《Global Ecology and Biogeography》2016,25(6):655-669
Aim Climate warming and increased wildfire activity are hypothesized to catalyse biogeographical shifts, reducing the resilience of fire‐prone forests world‐wide. Two key mechanisms underpinning hypotheses are: (1) reduced seed availability in large stand‐replacing burn patches, and (2) reduced seedling establishment/survival after post‐fire drought. We tested for regional evidence consistent with these mechanisms in an extensive fire‐prone forest biome by assessing post‐fire tree seedling establishment, a key indicator of forest resilience. Location Subalpine forests, US Rocky Mountains. Methods We analysed post‐fire tree seedling establishment from 184 field plots where stand‐replacing forest fires were followed by varying post‐fire climate conditions. Generalized linear mixed models tested how establishment rates varied with post‐fire drought severity and distance to seed source (among other relevant factors) for tree species with contrasting post‐fire regeneration adaptations. Results Total post‐fire tree seedling establishment (all species combined) declined sharply with greater post‐fire drought severity and with greater distance to seed sources (i.e. the interior of burn patches). Effects varied among key species groups. For conifers that dominate present‐day subalpine forests (Picea engelmannii, Abies lasiocarpa), post‐fire seedling establishment declined sharply with both factors. One exception was serotinous Pinus contorta, which did not vary with either factor. For montane species expected to move upslope under future climate change (Larix occidentalis, Pseudotsuga menziesii, Populus tremuloides) and upper treeline species (Pinus albicaulis), establishment was unrelated to either factor. Greater post‐fire tree seedling establishment on cooler/wetter aspects suggested local topographic refugia during post‐fire droughts. Main conclusions If future drought and wildfire patterns manifest as expected, post‐fire tree seedling establishment of species that currently characterize subalpine forests could be substantially reduced. Compensatory increases from lower montane and upper treeline species may partially offset these reductions, but our data suggest important near‐ to mid‐term shifts in the composition and structure of high‐elevation forests under continued climate warming and increased wildfire activity. 相似文献
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When group members possess differing information about the environment, they may disagree on the best movement decision. Such conflicts result in group break‐ups, and are therefore a fundamental driver of fusion–fission group dynamics. Yet, a paucity of empirical work hampers our understanding of how adaptive evolution has shaped plasticity in collective behaviours that promote and maintain fusion–fission dynamics. Using movement data from GPS‐collared bison, we found that individuals constantly associated with other animals possessing different spatial knowledge, and both personal and conspecific information influenced an individual's patch choice decisions. During conflict situations, bison used group familiarity coupled with their knowledge of local foraging options and recently sampled resource quality when deciding to follow or leave a group – a tactic that led to energy‐rewarding movements. Natural selection has shaped collective behaviours for coping with social conflicts and resource heterogeneity, which maintain fusion–fission dynamics and play an essential role in animal distribution. 相似文献