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Space use overlap of short-tailed weasels based on the utilization distribution overlap index (UDOI) in Corvallis, Oregon, USA, 2012-2013. Dyads were Adult:Adult (n 7, same sex), Adult:Juvenile (n 12, same sex), Juvenile:Juvenile (n 4, same sex), and Female:Male (n 3, opposite sex) combinations of weasels that had home 90% isopleth home ranges that overlapped. Core range and 90% isopleth home ranges shown.
Source publication
Weasels Mustela spp. are specialized, small predators which demonstrate pronounced differences in size and social status according to sex and age, and these differences may manifest in spatial patterns including home range size and habitat selection. In forested North America, favored prey (voles; Microtus spp. and Myodes spp.) of short-tailed weas...
Contexts in source publication
Context 1
... overlap of home ranges was lowest amongst adults of the same sex; intrasexual overlap of core areas was particularly low. In contrast, intersexual spatial overlap was comparatively high but variable. The pattern of spatial overlap among juveniles was highly variable (Fig. ...
Context 2
... cover types (a 0.05, two sample t-test). The difference between cover types with the same number is non-significant. stable (Powell 1979, Debrot andMermod 1983). Adults showed low intrasexual spatial overlap, particularly of high-use core areas within their home ranges. In contrast, intersexual spatial overlap was higher but highly variable (Fig. 4). Most studies have reported little intersexual spatial overlap (Sweden, 10% during the breeding season, Hellst- edt and Henttonen 2006) or did not quantify it (Murphy andDowding 1994, Smith et al. 2007), but observed low intrasexual overlap. We suspect intersexual overlap is often underestimated due to low capture rate of females (King ...
Similar publications
Personality-dependent space use and movement might be crucially influencing ecological interactions, giving way to individual niche specialization. This new approach challenges classical niche theory with potentially great ecological consequences, but so far has only scarce empirical support. Here, we investigated if and how consistent inter-indivi...
Citations
... In forested areas of the western U.S., climate, disease, pests, and forest fire resulted in more recent (post 1970) declines in forest cover, consistent with our findings here (Sleeter et al. 2013;Sohl et al. 2016). While few studies have examined the habitat needs of North American weasels, American ermine have a noted association with forests, though use of grassland, shrubland, and meadows has also been recorded (Lisgo 1999;Linnell et al. 2017;Evans and Mortelliti 2022). We also noted forest cover positively influenced suitability for this species, and regions (e.g., Northeast) that gained forest cover showed corresponding increased suitability while areas that lost forest cover (e.g., Rocky Mountain and Pacific Northwest; Sleeter et al. 2013;Sohl et al. 2016) showed similar declines in the area of predicted suitability. ...
Context
Shifts in climate and land use have dramatically reshaped ecosystems, impacting the distribution and status of wildlife populations. For many species, data gaps limit inference regarding population trends and links to environmental change. This deficiency hinders our ability to enact meaningful conservation measures to protect at risk species.
Objectives
We investigated historical drivers of environmental niche change for three North American weasel species (American ermine, least weasel, and long-tailed weasel) to understand their response to environmental change.
Methods
Using species occurrence records and corresponding environmental data, we developed species-specific environmental niche models for the contiguous United States (1938–2021). We generated annual hindcasted predictions of the species’ environmental niche, assessing changes in distribution, area, and fragmentation in response to environmental change.
Results
We identified a 54% decline in suitable habitat alongside high levels of fragmentation for least weasels and region-specific trends for American ermine and long-tailed weasels; declines in the West and increased suitability in the East. Climate and land use were important predictors of the environmental niche for all species. Changes in habitat amount and distribution reflected widespread land use changes over the past century while declines in southern and low-elevation areas are consistent with impacts from climatic change.
Conclusions
Our models uncovered land use and climatic change as potential historic drivers of population change for North American weasels and provide a basis for management recommendations and targeted survey efforts. We identified potentially at-risk populations and a need for landscape-level planning to support weasel populations amid ongoing environmental changes.
... In forested areas of the western US, climate, disease, pests, and forest re resulted in more recent (post 1970) declines in forest cover, consistent with our ndings here (Sleeter et al. 2013;Sohl et al. 2016). While few studies have examined the habitat needs of North American weasels, American ermine have a noted association with forests, though use of grassland, shrubland, meadows has also been recorded (Lisgo 1999;Linnell et al. 2017; Evans and Mortelliti 2022). We also noted forest cover positively in uenced suitability for this species, and regions (e.g., Northeast) that gained forest cover showed corresponding increased suitability while areas that lost forest cover (e.g., Rocky Mountain and Paci c Northwest; Sleeter et al. 2013, Sohl et al. 2016 showed similar declines in the area of predicted suitability. ...
Context: Shifts in climate and land use have dramatically reshaped ecosystems, impacting the distribution and status of wildlife populations. For many species, data gaps limit inference regarding population trends and links to environmental change. This deficiency hinders our ability to enact meaningful conservation measures to protect at risk species.
Objectives: We investigated historical drivers of environmental niche change for three North American weasel species (American ermine, least weasel, and long-tailed weasel) to understand their response to environmental change.
Methods: Using species occurrence records and corresponding environmental data, we developed species-specific environmental niche models for the contiguous United States (1938-2021). We generated annual hindcasted predictions of the species’ environmental niche, assessing changes in distribution, area, and fragmentation in response to environmental change.
Results: We identified a 53.96% decline in suitable habitat alongside high levels of fragmentation for least weasels and region-specific trends for American ermine and long-tailed weasels; declines in the West and increased suitability in the East. Climate and land use were important predictors of the environmental niche for all species. Changes in habitat amount and distribution reflected widespread land use changes over the past century while declines in southern and low-elevation areas are consistent with impacts from climatic change.
Conclusions: Our models uncovered land use and climatic change as potential historic drivers of population change for North American weasels and provide a basis for management recommendations and targeted survey efforts. We identified potentially at-risk populations and a need for landscape-level planning to support weasel populations amid ongoing environmental changes.
... Major prey species for small mustelids are the southern red-backed vole (Clethrionomys gapperi) that occupies old forests and disappears for many decades after clearcutting (Martin, 1994;Zwolak, 2009;Linnell et al., 2017b) and Microtus voles that may be common on some clearcuts and other successional stages post-harvest (Simms, 1979;Buskirk and Zielinski, 2003;Wilk and Raphael, 2017). Both C. gapperi and Microtus may undergo dramatic fluctuations in abundance over many years and decades (Krebs, 2013;Sullivan et al., 2017b). ...
... In Europe, Pyšková and coauthors (2018), using camera traps, found weasel species in many natural vegetation types, but they did not investigate areas subject to intensive human disturbance, while other researchers (Łopucki et al. 2019) found that the occupancy probability of least weasels was very low in urban areas. In a recent study in western north America (Linnell et al. 2017a), ermine selected for areas of relatively young forest-however, timber management strategies that intensively replant stands can have reduced understory complexity, resulting in less cover and lower small mammal densities (Ashton and Kelty 2018). Predation may play a confounding role in habitat selection, causing smaller weasels to select areas that are less suitable, but also present lower risk from larger carnivores (Linnell et al. 2017b). ...
... Predation may play a confounding role in habitat selection, causing smaller weasels to select areas that are less suitable, but also present lower risk from larger carnivores (Linnell et al. 2017b). Although it appears highly likely that forest type and timber management affect both long-tailed weasel and ermine populations, very little is known on how these species respond to large-scale intensive timber harvest (but see Linnell et al. 2017a). Our objective was to assess the effects of forest disturbance caused by timber harvest on occupancy patterns of the American ermine and the long-tailed weasel over a large (statewide) scale. ...
... We then generated buffers of varying sizes around each site (300-m, 1-km, 3-km, and 6-km radii) to understand how the spatial scale of disturbance influenced weasel occupancy patterns. Home-range sizes for weasels vary greatly by species, sex, and location (e.g., American ermine females range from 3 to 80 ha, male longtailed weasels from 20 to 200 ha; Hajduk 2008;Linnell et al. 2017a). Because animals respond to habitat features at multiple spatial scales, allowing competition among models at several potentially important scales-such as 300-m radius buffer representing a core home range versus a 6-km buffer representing the entire landscape for a weasel-allows researchers to identify the most influential scale at which disturbance may exert its effects (Mcgarigal et al. 2016). ...
Weasels are small mustelid carnivores that play an important role as predators of small mammals in a wide array of ecosystems. However, their response to land use, such as forest harvest for timber products, is seldom the subject of focused research and management projects. Both the American ermine, also known as the short-tailed weasel (Mustela richardsonii), and the long-tailed weasel (Neogale frenata) are native to Maine, United States, where commercial timber harvesting is widespread. The effects of this forest disturbance on weasels are poorly understood, so to contribute toward filling this knowledge gap, we conducted a 4-year, large-scale field study: specifically, our objective was to assess the effects of forest disturbance caused by timber harvest on occupancy patterns of ermines and long-tailed weasels occupancy patterns in Maine. We collected data from 197 survey sites (three camera traps each) over 4 years and analyzed over 7,000 images of weasels using dynamic false-positive occupancy models. We found that American ermines were widely distributed across the state (naïve occupancy at 54% of sites), while long-tailed weasels were rarer (naïve occupancy at 16% of sites). Both species responded positively to forest disturbance, with higher occupancy probabilities as disturbance increased, especially at the larger scales. American ermines were more likely to occupy stands with a higher percentage of conifer trees, while no such relationship was found for long-tailed weasels. We conclude that current forest harvest practices in Maine are not detrimental to weasel populations, but that the two species warrant continued monitoring.
... al. (2018) found weasel species in many natural habitat types using camera traps in central Europe. In a recent study in western North America (Linnell et al. 2017a), short-tailed weasels selected for areas of relatively young forest-however, timber management strategies that intensively replant stands can have reduced understory complexity, resulting in less cover and lower small mammal densities (Ashton and Kelty 2018). Predation may play a confounding role in habitat selection (Linnell et al. 2017b). ...
... Predation may play a confounding role in habitat selection (Linnell et al. 2017b). Although it appears highly likely that forest type and timber management affect both long-tailed and short-tailed weasel populations, very little is known on how these species respond to large-scale intensive timber harvest (but see Linnell et al. 2017a). Our objective was to assess the effects of forest disturbance caused by timber harvest on short-tailed and long-tailed weasels' occupancy patterns over a large (state-wide) scale. ...
... This variation in size is an important component in the co-existence of otherwise similar species, as dramatic differences in body size allow individuals of both species to have their own competitive advantages (Aldous and Manweiler 1942, Proulx and Drescher 1993, King and Powell 2007. Weasels are considered habitat generalists, but research in North America suggests that younger forest stands are preferred by short-tailed weasel (Gehring 2000, Hajduk 2008, Linnell et al. 2017a). Short-tailed weasels are circumboreal and found in most of northern North America, distributed across Canada excepting the arctic and into the northern United States excepting the prairie bioregions (e.g. ...
Understanding trends in the abundance and distribution of carnivores is important at global, regional and local scales due to their ecological role, their aesthetic and economic value, and the numerous threats to their populations. Carnivores in Maine range from the American black bear (Ursus americanus), to numerous native mesocarnivore species, such as American marten (Martes americana), fisher (Pekania pennanti), coyote (Canis latrans), red fox (Vulpes vulpes), bobcat (Lynx rufus), Canada lynx (Lynx canadensis) and to two small weasel species (Mustela erminea and Neogale frenata). Though smaller than their apex carnivore cousins, Mesocarnivores are essential components of ecosystems and have complex impacts on prey species and intraguild dynamics. However, these species can vary in how they respond to human disturbances, from direct declines due to unregulated harvest and habitat loss, and their ability to adapt to land-use change. Maine is a working landscape which provides habitat for diverse wildlife species coincident with extensive forest harvest industries, as well as tourism and recreation. The intensity, timing, and configuration of harvest activities all interact to modify the landscape, with cascading impacts on the distribution of many animals. Forest management practices have changed through time (Maine Forest Service 2003) with potentially unpredictable outcomes (e.g. Simons 2009). However, the extent to which carnivore species adapt to land use change is a key knowledge gap that needs to be addressed to ensure proper management and conservation going forward. I investigated these patterns by designing a natural experiment across the forested landscape of Maine, and by collecting detection data on multiple species at camera trapping survey stations deployed along a gradient of forest disturbance. My dissertation aims to collect broad-scale, relevant information for carnivore management and conservation, and assess the efficacy of motion-triggered trail cameras for long-term monitoring. My work is divided into four sections, reflected by the four chapters included in the dissertation. My first goal was to determine the optimal number and configuration of camera-trap transects, to balance between reasonable effort expended and high-quality data collection. I used multi-method occupancy analyses to compare between one, two or three camera units spaced either 100 m or 150 m apart. We found that a design with three cameras spaced 100 m apart increased detection probabilities up to five-fold over a single camera trap, and thus used this configuration for the duration of the following research. Once the survey unit was selected, I established a large-scale, multi-year camera trapping regimen across the northern two-thirds of Maine. Survey sites were selected in compliance with a natural experimental design, replicating across all combinations of a) forest disturbance intensity, b) latitude, and c) fur trapping harvest reports for key furbearing species. In the second chapter I present this study design in more detail, and use the resulting data to investigate the interspecies dynamics of marten and fisher, two species of interest to the state of Maine that co-exist in several geographic areas and partition habitat in distinct ways. Both species are sensitive to habitat change resulting from timber harvest, which was a more important factor in occupancy patterns than intraguild dynamics. In chapter three, I took advantage of the large data set I collected to provide a landscape scale understanding of long-tailed and short-tailed weasel distribution patterns in the face of habitat change. Both of these species are poorly studied, and may be in decline in North American. My results indicate that short-tailed weasel are widespread in Maine and do not appear limited by forest harvest practices, while long-tailed weasel are rarer and more apt to be present in southern Maine. Finally in chapter four I ran models incorporating multiple states for species occupancy, beyond mere present or absent, to understand the dynamics of black bears and of black bear reproduction across managed forests in Maine. I found that generally disturbance at a small scale was positively associated with both occupancy and probability of reproduction, while the availability of hardwood trees (an important food source for bears) was also positively linked to the probability of female bears being with cubs. In addition to meeting our stake holder needs for informed management guidelines, I hope that many of my findings will be directly relevant to the broader research community—as camera trapping equipment becomes more affordable, it will become feasible to both monitor and rigorously study wildlife populations in remote locations and under many scenarios of human land-use.
... We also found long-tailed weasels moved at faster rates in agricultural fields compared to forests or corridors (Gehring and Swihart, 2004). Linnell et al. (2017a) found short-tailed weasels (Mustela erminea) more commonly used early successional stage habitat in a forest landscape and core area home range size was inversely related to the amount of that habitat type, whereas we found mature forest patches with available coarse woody debris were important for weasel core area selection. Results of this study and our related studies (Gehring andSwihart, 2003, 2004) suggest the use of this intensive row-crop agricultural landscape likely was constrained by both the physical features of the landscape and ecological attributes of weasels (e.g., avoidance of agricultural fields because of increased predation risk from coyotes and predatory birds). ...
... Łopucki et al. (2019) found prey abundance may be too low in some habitat patches, rendering them unsuitable for least weasels. Others have suggested that long-tailed weasels prefer habitat characterized by more abundant small mammals and birds (Polderboer et al., 1941;Hajduk, 2008) and greater prey diversity (Gamble, 1981;Linnell et al., 2017a). Our results lend support to this suggestion (Fig. 1). ...
... For M. erminea, home range sizes, prey and habitat selection, and perhaps predator avoidance varies by sex. Females tend to have smaller home ranges, prefer voles, and inhabit areas with high vole abundance (Hellstedt and Henttonen 2006), whereas males tend to be more general in both habitat and prey selection (Lisgo 1999, Edwards and Forbes 2003, Linnell et al. 2017. ...
Predators may limit populations of small carnivores indirectly through exploitative competition for resources, and directly through interference competition, including predation. We evaluated direct effects of predation by large predators on small, specialist carnivores by estimating annual survival and cause-specific mortality. We used known fate models to estimate annual survival of 23 radio-collared short-Tailed weasels (Mustela erminea) in western Oregon in 2012-2013. Further, we reviewed published and unpublished studies of radio-Tracked weasels (Mustela spp.) in North America, to identify main predators of weasels and survival. If the study did not report survival but did report number of days tracked and causespecific mortalities, we extrapolated an annual survival index, based on daily survival rates (Mayfield index), to facilitate comparisons between studies. Estimated mean ± SD annual survival of short-Tailed weasels in our study was 0.26 ± 0.08, and did not vary by season or sex of the weasel. Most (80%) predation mortalities, however, occurred in winter, and were attributed to predatory birds, suspected to be barred owls (Strix varia). For seven North American studies, including ours, we estimated the average annual survival index for M. erminea and Mustela frenata to be 0.37 ± 0.28. Across studies, most mortality was attributed to predation. Predators killed weasels > 2x more frequently in winter when most mortality (86%) was attributed to predatory birds. Mammalian predators, in contrast, killed weasels most frequently in summer (75%). Our results support the hypothesis that predation may play an important role limiting weasel populations in North America.
Aboveground pipelines (AGP) associated with in-situ oil sands may restrict mammal movement, potentially increasing extinction probability and decreasing reproductive success. Our 12-year study used winter track count techniques to assess the response of winter-active mammals to AGP in northern Alberta, Canada. The primary questions were: which species were most prone to movement obstruction by AGP, facilities or natural factor(s)?; and which factor exerted the strongest influence on crossing likelihood?
A total of 2,068 trails of 12 different species were observed. All species crossed more than half of the time. Focal species crossed on average 80% of the time. Crossing likelihood of white-tailed deer (Odocoileus virginianus), ermine (Mustela erminea), coyote (Canis latrans), lynx (Lynx canadensis), and fisher (Martes pennanti) were significantly influenced by predictors including pipeline height, pipeline corridor width, infrastructure age, vegetation type, and proximity to infrastructure. Deer and lynx crossing likelihood was positively affected by pipe height. Deer, coyote, and ermine crossing likelihood was positively affected by age of pipe. Fisher and deer crossing likelihood was negatively affected by pipeline corridor widths. Our investigations show that most species cross AGP with high crossing frequencies of pipe heights, ranging from 130 cm to 160 cm.
These findings are important for impact mitigation because of the scarcity of published studies of wildlife movement responses to AGP, our inclusion of small and mid-sized carnivores, and our investigation of multiple factors. We highlight mitigation and design improvements, effects of pipeline corridor widths, and challenges posed by coupling infrastructure with pipelines, serving to reduce movement barriers and fragmentation.
