Landscape Analysis of Bobcat Habitat in the Northern Lower Peninsula of Michigan

ABSTRACT Controversy over bobcat (Lynx rufus) management in the northern Lower Peninsula of Michigan (NLP), USA, stimulated a need for information on the distribution of Michigan bobcats. From March 2003 to October 2004, we conducted a radiotelemetry and scentstation survey study of bobcats in the NLP. We developed a spatial model to predict bobcat distribution throughout the NLP based on bobcat area requirements, habitat and landscape variables derived from remotely sensed land-cover data, and a multivariate distance statistic. Bobcat 50% minimum convex polygon core areas were comprised of more lowland forest (51%), nonforested wetlands (9%), and streams (3%) than the surrounding NLP. The NLP was comprised primarily of upland forest (44%) and field (32%). Habitat in the northeast and central regions of the NLP was most similar to the habitat composition of bobcat core areas. This model will be useful in aiding Michigan wildlife management agencies with assessing the status and distribution of the NLP bobcat population by identifying areas important to bobcats and supporting the development of regional strategies for carnivore conservation.     

Bobcat Spatial Distribution and Habitat Use Relative to Population Reduction

Abstract Understanding interactions among bobcats (Lynx rufus) may lend insight into less understood life history traits of the bobcat and improve management of the species. Moreover, data from manipulative experiments pertaining to bobcat ecology are largely absent from the scientific literature. Therefore, we investigated bobcat spatial organization and habitat use after an experimental population reduction on an 11,735-ha study site in southwestern Georgia, USA. In response to an approximate 50% population reduction, male bobcats shifted their space use (26.4 ± 1.7% more shift relative to baseline) more (F_1,3 = 138.08, P=0.001) than males where no bobcat removal occurred (28.1 ± 5.5% less shift relative to baseline). Dispersion of radio locations for all female bobcats increased following the population reduction; however, females that were exposed to the removal of a potentially interacting male remained more (F_1,14 = 6.78, P = 0.021) static (increase in dispersion = 7.8 ± 7.3%) than females that were not exposed to removed males (increase in dispersion 41.2 ± 11.1%). Male bobcats likely shifted their central tendency to increase breeding opportunities, whereas the difference in dispersion of female radio locations may be the result of decreased intraspecific competition. Alternatively, reduced dispersion of females following harvest of neighboring males may increase the likelihood that remaining males will interact with females for breeding purposes. Neither habitat use nor habitat selection differed as a function of removal, suggesting that density-dependent habitat selection was not occurring on our study site. Although it is generally accepted that male bobcats use space to increase breeding opportunities, our study suggests that male bobcats may also influence space use of females, but in counterintuitive ways. Because bobcat movements are altered by harvest of neighbors, we suggest that inferring habitat quality for bobcats based on their space use patterns should be avoided unless researchers incorporate knowledge of both short- and long-term population perturbations.     

A Hierarchical Analysis of Habitat Selection by Raccoons in Northern Indiana

Abstract: Although numerous studies have examined habitat use by raccoons (Procyon lotor), information regarding seasonal habitat selection related to resource availability in agricultural landscapes is lacking for this species. Additionally, few studies using radiotelemetry have investigated habitat selection at multiple spatial scales or core-use areas by raccoons. We examined seasonal habitat selection of 55 (31 M, 24 F) adult raccoons at 3 hierarchical orders defined by the movement behavior of this species (second-order home range, second-order core-use area, and third-order home range) in northern Indiana, USA, from May 2003 to June 2005. Using compositional analysis, we assessed whether habitat selection differed from random and ranked habitat types in order of selection during the crop growing period (season 1) and corn maturation period (season 2), which represented substantial shifts in resource availability to raccoons. Habitat rankings differed across hierarchical orders, between seasons within hierarchical orders, and between sexes within seasons; however, seasonal and intersexual patterns of habitat selection were not consistent across hierarchical orders of spatial scale. When nonrandom utilization was detected, both sexes consistently selected forest cover over other available habitats. Seasonal differences in habitat selection were most evident at the core-area scale, where raccoon selection of agricultural lands was highest during the maturation season when corn was available as a direct food source. Habitat use did not differ from availability for either sex in either season at the third-order scale. The selection of forest cover across both seasons and all spatial orders suggested that raccoon distribution and abundance in fragmented landscapes is likely dependent on the availability and distribution of forest cover, or habitats associated with forest (i.e., water), within the landscape. The lack of consistency in habitat selection across hierarchical scales further exemplifies the need to examine multiple biological scales in habitat-selection studies.     

Combining ecological niche modelling and morphology to assess the range‐wide population genetic structure of bobcats (Lynx rufus)

Despite a broad distribution, general habitat requirements, and a large dispersal potential, bobcats (Lynx rufus) exhibit a genetic division that longitudinally transects central North America. We investigated (1) whether the climate of the Last Glacial Maximum (LGM; 21 kya) isolated bobcats into refugia and also whether the current climate influences gene flow between the segregate populations and (2) whether the geographical patterns in cranial morphology reflect population identity. We created ecological niche models (ENMs) to evaluate climatic suitability and to estimate distributions of the disparate populations under both historical (LGM) and contemporary conditions. We used two‐dimensional geometric morphometric methods to evaluate variations in the cranium and mandible. These variations were then regressed across geographical variables to assess morphological differences throughout the range of the bobcat. ENMs projected onto LGM climate provided evidence of refugia during the LGM via increased suitability in the north‐west and south‐east portions of this species' range. Contemporarily, our models suggest that the Great Plains may be restricting bobcat migration and gene flow, effectively maintaining disparate populations. Morphological analyses identified a significant linear trend in shape variation across latitudinal and longitudinal gradients rather than distinct morphological divergence between lineages. Similar shape variations, however, did converge in approximate locations of assumed refugia. The findings of the present study provide a robust assessment of the biogeographical considerations for the population genetic structure of bobcats.     

Using Bobcat Habitat Suitability to Prioritize Habitat Preservation on a Suburbanizing Barrier Island

ABSTRACT Many land-trust organizations attempt to preserve habitat that will benefit specific wildlife species or suites of species. With limited resources available, these organizations need tools to prioritize preservation efforts. One such organization, the Kiawah Island Natural Habitat Conservancy (KINHC), is attempting to preserve wildlife habitat in the face of ever-increasing property values and development pressure on Kiawah Island, South Carolina, USA. We modified an existing bobcat (Lynx rufus) habitat suitability index model, which focuses on suitability of habitats for food, by including components for concealment cover and den habitat. We developed a windows-based computer program that calculates modified habitat suitability index (MHSI) values that can easily be imported into a Geographic Information System for display in map form, allowing for frequent reevaluation of site-specific habitat suitability as land-cover patterns change. We used locations collected from radiocollared bobcats to assess validity of the food and cover components of the MHSI. Bobcats used areas identified as highly suitable for food more than expected during nocturnal time periods (G₅₂ = 640.9, P < 0.001) and areas identified as highly suitable for cover more than expected during diurnal time periods (G₃₇ = 1,194.0, P < 0.001). Our approach for evaluating bobcat habitat suitability will allow KINHC to identify parcels that likely provide the greatest ecological benefit to bobcats and their associated wildlife community. Our approach could be altered to consider habitat requirements of other species, or multiple species, at virtually any location for which fine-scale land-cover data are available.     

Gene flow and pathogen transmission among bobcats (Lynx rufus) in a fragmented urban landscape

Urbanization can result in the fragmentation of once contiguous natural landscapes into a patchy habitat interspersed within a growing urban matrix. Animals living in fragmented landscapes often have reduced movement among habitat patches because of avoidance of intervening human development, which potentially leads to both reduced gene flow and pathogen transmission between patches. Mammalian carnivores with large home ranges, such as bobcats (Lynx rufus), may be particularly sensitive to habitat fragmentation. We performed genetic analyses on bobcats and their directly transmitted viral pathogen, feline immunodeficiency virus (FIV), to investigate the effects of urbanization on bobcat movement. We predicted that urban development, including major freeways, would limit bobcat movement and result in genetically structured host and pathogen populations. We analysed molecular markers from 106 bobcats and 19 FIV isolates from seropositive animals in urban southern California. Our findings indicate that reduced gene flow between two primary habitat patches has resulted in genetically distinct bobcat subpopulations separated by urban development including a major highway. However, the distribution of genetic diversity among FIV isolates determined through phylogenetic analyses indicates that pathogen genotypes are less spatially structured-exhibiting a more even distribution between habitat fragments. We conclude that the types of movement and contact sufficient for disease transmission occur with enough frequency to preclude structuring among the viral population, but that the bobcat population is structured owing to low levels of effective bobcat migration resulting in gene flow. We illustrate the utility in using multiple molecular markers that differentially detect movement and gene flow between subpopulations when assessing connectivity.     

Habitat modeling used to predict relative abundance of bobcats in Iowa

We combined observations of bobcats (Lynx rufus) from bowhunters with remotely-sensed data to build models that describe habitat and relative abundance of this species in the agricultural landscape of Iowa, USA. We calculated landscape composition and configuration from publicly available land cover, census, road, hydrologic, and elevation data. We used multiple regression models to examine county-level associations between several explanatory variables and relative abundance of bobcats reported by surveyed bowhunters in each county. The most influential explanatory variables in the models were metrics associated with the presence of grassland, including Conservation Reserve, along with configuration of this perennial habitat with forests, although human population density and abundance of eastern cottontails (Sylvilagus floridanus) also correlated with abundance of bobcats. Validation of predictions against 3 years of independent data provided confidence in the models, with 66% of predictions within 1 bobcat/1,000 hunter-hours and 95% within 5 bobcats/1,000 hunter-hours of observed values. Once we accounted for landscape differences, no residual spatial trend was evident, despite relatively recent bobcat recolonization of Iowa. Models suggested that future range expansion of the bobcat population may be possible in some northern Iowa counties where habitat composition is similar to counties in southern Iowa where bobcats are abundant. Results from the county-level model have been useful to the Iowa Department of Natural Resources in evaluating the expansion of this once rare species and for delineating harvest opportunities. © 2011 The Wildlife Society.     

Space Use and Habitat Selection by Bobcats in the Fragmented Landscape of South-Central Iowa

Abstract: Historically, bobcats (Lynx rufus) were found throughout the Corn Belt region, but they nearly disappeared from this area due to habitat loss and unregulated harvest that occurred during the century after European settlement. Reports of bobcat occurrences have been increasing in Iowa, USA, and biologists would like to understand the mechanisms enabling bobcats to recolonize this fragmented agricultural landscape. We determined space use and habitat selection of bobcats by radiocollaring 68 bobcats in south-central Iowa during 2003–2006. We triangulated 12,966 locations and recovered an additional 1,399 3-dimensional locations from Global Positioning System collars. We used a fixed kernel estimator to calculate 95% utilization distributions (UDs) for home ranges and 50% UDs for cores. Annual home range area of males (x̄ = 58.6 km², 95% CI = 49.2–69.9) was nearly 3 times that of females (x̄=19.9 km², 95% CI = 17.0–23.3). Females used smaller home ranges during April-September when they were suspected to have kittens with them (x̄ = 16.8 km², 95% CI = 13.7–20.7), as compared to October-March (x̄ = 24.1 km², 95% CI = 19.0–30.7), whereas home ranges of males did not differ between seasons. Similarly, core area of males (x̄ = 7.7 km², 95% CI = 6.2–9.6) was larger than that of females (x̄ = 2.3 km², 95% CI = 1.9–2.7). Females used significantly smaller cores in April-September (x̄ = 1.8 km², 95% CI = 1.4–2.3) as compared to October-March (x̄ = 2.8 km², 95% CI = 2.2–3.7), whereas males did not. For both sexes, compositional analysis indicated that forest habitat was ranked higher than all other habitat classes at both the landscape and local scale. Standardized habitat selection ratios illustrate that female and male bobcats selected forest habitat about twice as frequently as any other habitat class, including grassland and Conservation Reserve Program land. Predictive models indicated that home range and core area was smaller in landscapes where perennial forest and grassland habitats were less fragmented. Predictive models indicated home ranges were more irregular in shape in landscapes where row crop patches were less aggregated within home ranges. Our results have practical implications for wildlife managers regarding expected bobcat habitat use and distribution as the species becomes more abundant in the agricultural landscape of the Midwest.     

Interspecific interactions between wild felids vary across scales and levels of urbanization

Ongoing global landscape change resulting from urbanization is increasingly linked to changes in species distributions and community interactions. However, relatively little is known about how urbanization influences competitive interactions among mammalian carnivores, particularly related to wild felids. We evaluated interspecific interactions between medium‐ and large‐sized carnivores across a gradient of urbanization and multiple scales. Specifically, we investigated spatial and temporal interactions of bobcats and pumas by evaluating circadian activity patterns, broad‐scale seasonal interactions, and fine‐scale daily interactions in wildland–urban interface (WUI), exurban residential development, and wildland habitats. Across levels of urbanization, interspecific interactions were evaluated using two‐species and single‐species occupancy models with data from motion‐activated cameras. As predicted, urbanization increased the opportunity for interspecific interactions between wild felids. Although pumas did not exclude bobcats from areas at broad spatial or temporal scales, bobcats responded behaviorally to the presence of pumas at finer scales, but patterns varied across levels of urbanization. In wildland habitat, bobcats avoided using areas for short temporal periods after a puma visited an area. In contrast, bobcats did not appear to avoid areas that pumas recently visited in landscapes influenced by urbanization (exurban development and WUI habitat). In addition, overlap in circadian activity patterns between bobcats and pumas increased in exurban development compared to wildland habitat. Across study areas, bobcats used sites less frequently as the number of puma photographs increased at a site. Overall, bobcats appear to shape their behavior at fine spatial and temporal scales to reduce encounters with pumas, but residential development can potentially alter these strategies and increase interaction opportunities. We explore three hypotheses to explain our results of how urbanization affected interspecific interactions that consider activity patterns, landscape configuration, and animal scent marking. Altered competitive interactions between animals in urbanized landscapes could potentially increase aggressive encounters and the frequency of disease transmission.     

Prey-mediated avoidance of an intraguild predator by its intraguild prey

Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally. For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG predators to coexist.     

Habitat selection and spatiotemporal interactions of a reintroduced mesocarnivore

Habitat quality and quantity are key factors in evaluating the potential for success of a wildlife translocation. However, because of the difficulty or cost of evaluating these factors, habitat assessments may not include valuable information on important habitat attributes including the abundance and distribution of prey, predators, and competitors. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, and they are a species of conservation concern in their western range. We examined the relative importance of landscape features and species interactions in determining habitat use of a reintroduced population of fishers in the southern Cascade Mountains, Washington, USA. We used detections of prey and predators at 134 remote camera stations, remotely sensed forest structure data, and telemetry locations of fishers in a resource selection function to assess the relative importance of prey, predators, and forest structure in fisher habitat selection. Fishers selected habitats based on forest conditions and activity levels of snowshoe hares (Lepus americanus), whereas bobcat (Lynx rufus) and coyote (Canis latrans) activity levels did not directly affect habitat selection. The probability of fisher use increased in older stands, close to recently disturbed stands, and in areas with intermediate levels of hare activity. Bobcat and hare activity levels were positively correlated, and fishers avoided areas with the greatest hare activity, suggesting that fishers may experience a food-safety tradeoff in the study area. Temporal activity patterns in photo detections indicate that fishers may mediate this danger by avoiding bobcats temporally. Our findings suggest that fishers in Washington prefer habitat mosaics of old and recently disturbed stands where they have greater access to resting structures and hares. Management that maintains mosaics of young and old forest across large landscapes is likely to support fisher recovery. Future reintroduction efforts would benefit from an assessment of prey and predator abundance in proposed reintroduction areas before project initiation. © 2019 The Wildlife Society.     

Transient persistence of bobcat (Lynx rufus) occurrence throughout a human-dominated landscape

Human developments have detrimental effects on wildlife populations globally with carnivores being particularly sensitive. The bobcat (Lynx rufus) is often considered an adaptable mesocarnivore that occurs throughout varied landcover types within its wide distribution and may be less susceptible to the negative effects of development. Our objectives were to investigate the landscape occupancy dynamics of bobcats in a highly developed and densely populated region of the northeastern United States to evaluate the sensitivity of bobcat occurrence to natural and anthropogenic landscape features. We established a large-scale camera trapping survey throughout Rhode Island, USA, sampling from 2018 to 2020. Using dynamic occupancy models, we found initial site occupancy was positively influenced by the amount of forested wetland habitat, while increasing road density and shrub cover negatively influenced the probability of site colonization. Surprisingly, we found no hypothesized variables to influence site-level extirpation probability, or any seasonal effects on dynamic parameters. Lastly, we found that forest cover and road density negatively influenced the probability of detection. The probability of occupancy was high, >0.8, throughout much of the study area (49%), but we also found relatively high site transients, with the probability a site would change occurrence status from season to season at ≈0.27 in the majority of the study area (70%). Our results show that although bobcats can persist in human-dominated landscapes, they require contiguous natural areas to do so. Future expansion of road infrastructure may reduce habitat connectivity and increase road mortalities, thus jeopardizing the population.     

Nation-wide indicators of ecological integrity in Mexico: The status of mammalian apex-predators and their habitat

Ecological indicators that evaluate the status and trends of mammalian apex predators are necessary for monitoring the ecological integrity of landscapes. Several nation-wide spatial indicators that describe the status of apex predators after habitat transformation have been developed for México. These spatial indicators show the condition of the remnant natural landscape for maintaining the complexity of predator-prey interactions and habitat selection and use. The indicators were obtained using the concept of ecological integrity, that characterize the landscape based upon manifest and latent variables of naturalness, stability and self-organization, according with the measures of spatial distribution of species and natural habitat. When the current status is evaluated for individual species of apex predators, all species showed less than 50% of their distribution areas with a high degree of ecological integrity. Neotropical predators (such as jaguars and ocelots) are more threatened by the transformation of natural habitat, than their counterparts in Nearctic regions (e.g., bears, cougars, bobcats, and coyotes), which showed nonetheless, a high amount of their distribution areas with a high proportion of degraded habitat. The indicators allowed evaluating the status of still extant top predators in the landscape and their habitat condition within major ecoregions in the country.     

Bobcat Hair Cortisol Correlates with Land Use and Climate

Bobcats (Lynx rufus) have been increasing in abundance in the northeast United States despite a corresponding trend of increased anthropogenic land uses. Inhabiting areas of high human land use can affect stress levels, and hence cortisol titers, for wildlife species by increasing frequency of human interaction and altering habitats. In turn, increased cortisol levels can have negative effects at the individual and population level including decreased immune function, slowed growth and tissue repair, reduced reproductive capacity, and nutritional deficiencies. We quantified cortisol in bobcats across New Hampshire and Vermont, USA, using hair samples, then explored associations between hair cortisol and various organismal, land use, land cover, and climatic variables at 2 different spatial scales. Hair cortisol differed by season and bobcat mass. On average, cortisol levels were higher in fall than in spring, and larger bobcats had lower cortisol levels. Anthropogenic land uses—especially residential and agricultural uses—were the most important predictors of hair cortisol at the town scale ( area = 93 km²). At a larger scale (Wildlife Management Units; area = 1,256 km²), temperature and precipitation were better predictors of hair cortisol, suggesting that extreme weather may have significant effects on bobcat population dynamics. Our results highlight the importance of landscape composition and local conditions in the sustainable management of furbearer populations. © 2021 The Wildlife Society.     

Competition and intraguild predation among three sympatric carnivores

We examined the relative roles of dominance in agonistic interactions and energetic constraints related to body size in determining local abundances of coyotes (Canis latrans, 8-20 kg), gray foxes (Urocyon cinereoargenteus, 3-5 kg) and bobcats (Felis rufus, 5-15 kg) at three study sites (hereafter referred to as NP, CP, and SP) in the Santa Monica Mountains of California. We hypothesized that the largest and behaviorally dominant species, the coyote, would exploit a wider range of resources (i.e., a higher number of habitat and/or food types) and, consequently, would occur in higher density than the other two carnivores. We evaluated our hypotheses by quantifying their diets, food overlap, habitat-specific abundances, as well as their overall relative abundance at the three study sites. We identified behavioral dominance of coyotes over foxes and bobcats in Santa Monica because 7 of 12 recorded gray fox deaths and 2 of 5 recorded bobcat deaths were due to coyote predation, and no coyotes died as a result of their interactions with bobcats or foxes. Coyotes and bobcats were present in a variety of habitats types (8 out of 9), including both open and brushy habitats, whereas gray foxes were chiefly restricted to brushy habitats. There was a negative relationship between the abundances of coyotes and gray foxes (P=0.020) across habitats, suggesting that foxes avoided habitats of high coyote predation risk. Coyote abundance was low in NP, high in CP, and intermediate in SP. Bobcat abundance changed little across study sites, and gray foxes were very abundant in NP, absent in CP, and scarce in SP; this suggests a negative relationship between coyote and fox abundances across study sites, as well. Bobcats were solely carnivorous, relying on small mammals (lagomorphs and rodents) throughout the year and at all three sites. Coyotes and gray foxes also relied on small mammals year-round at all sites, though they also ate significant amounts of fruit. Though there were strong overall interspecific differences in food habits of carnivores (P<0.0001), average seasonal food overlaps were high due to the importance of small mammals in all carnivore diets [bobcat-gray fox: 0.79ǂ.09 (SD), n=4; bobcat-coyote: 0.69ǂ.16, n=6; coyote-gray fox: 0.52ǂ.05, n=4]. As hypothesized, coyotes used more food types and more habitat types than did bobcats and gray foxes and, overall, coyotes were the most abundant of the three species and ranged more widely than did gray foxes. We propose that coyotes limit the number and distribution of gray foxes in Santa Monica Mountains, and that those two carnivores exemplified a case in which the relationship between their body size and local abundance is governed by competitive dominance of the largest species rather than by energetic equivalences. However, in the case of the intermediate-sized bobcat no such a pattern emerged, likely due to rarity or inconsistency of agonistic interactions and/or behavioral avoidance of encounters by subordinate species.     

Competitive interactions between felid species may limit the southern distribution of bobcats Lynx rufus

Bobcats are opportunistic felids occurring in a diverse range of habitats and with a widespread distribution from southern Canada to southern Mexico. To explore why the bobcat's distribution stops at the Isthmus of Tehuantepec, we modelled the ecological niches, projected as potential distributions, of the felid community (bobcat Lynx rufus, puma Puma concolor, jaguar Panthera onca, margay Leopardus wiedii, jaguarundi Herpailurus yagouaroundi, and ocelot Leopardus pardalis) in southern Mexico, using occurrence data, environmental maps, the computer algorithm GARP, and a GIS platform. The resulting geographical projection of the ecological niche of bobcats extends south of the Isthmus of Tehuantepec, suggesting that ecological conditions exist for the establishment of populations. The overlap of the modelled distribution of the bobcat was large with that of the puma (97%), but low with that of the ocelot (44%), margay (46%), jaguar (49%), and jaguarundi (52%), the latter three having relatively similar size and feeding habits to bobcats. Moreover, an independent analysis computing a geographic co‐occurrence index showed a similar trend of geographic avoidance (values 0.15), while all felids, except bobcats, showed a geographic co‐occurrence in southern Mexico (values ranging from ?1.91 to 4.71). The Isthmus of Tehuantepec, a lowland region with subtropical habitat, is unlikely to serve as a geographic and ecological barrier to bobcats. As mammal inventories have been conducted for over a century in this region with no records of bobcats, it is unlikely that bobcats are present but have just not been seen. Fossil records also provide no support for the presence of bobcats in that region in the past. Thus, competitive interactions with other felid species appear important in limiting the southern distribution of bobcats, preventing dispersal to a suitable but geographically reduced area south of the Isthmus of Tehuantepec.     

Effects of Prey Presence and Scale on Bobcat Resource Selection during Winter

Factors relevant to resource selection in carnivores may vary across spatial and temporal scales, both in magnitude and rank. Understanding relationships among carnivore occupancy, prey presence, and habitat characteristics, as well as their interactions across multiple scales, is necessary to improve our understanding of resource selection and predict population changes. We used a multi-scale dynamic hierarchical co-occurrence model with camera data to study bobcat and snowshoe hare occupancy in the Upper Peninsula of Michigan during winter 2012–2013. Bobcat presence was influenced at the local scale by snowshoe hare presence, and by road density at the local and larger scale when hare were absent. Hare distribution was related primarily to vegetation cover types, and detectability varied in space and time. Bobcat occupancy dynamics were influenced by different factors depending on the spatial scale considered and the resource availability context. Moreover, considering observed co-occurrence, we suggest that bobcat presence had a greater effect on hare occupancy than hare presence on bobcat occupancy. Our results highlight the importance of studying carnivore distributions in the context of predator-prey relationships and its interactions with environmental covariates at multiple spatial scales. Our approach can be applied to other carnivore species to provide insights beneficial for management and conservation.     

Bobcat occupancy,tree islands,and invasive Burmese pythons in an Everglades conservation area

Bobcats (Lynx rufus) are terrestrial mammals that also inhabit tree islands (i.e., topographically elevated patches of forested land) embedded in the subtropical Everglades wetlands, which serve as a dry refuge habitat during the wet season in this region of Florida, USA. The Comprehensive Everglades Restoration Plan seeks to restore Everglades water flow to pre-drainage conditions, but little is known about how water levels or other landscape-level factors may influence mammalian occurrence, such as bobcats, on the tree islands in this ecosystem. We used game camera records and occupancy modeling to test for effects of static habitat variables and dynamic hydrologic variables. We hypothesized that deep water levels would limit the accessibility of tree islands to bobcats; therefore, we predicted that bobcat occupancy would decline with higher water levels. We also tested for the effect of an expanding invasive snake (i.e., Burmese python [Python molarus bivittatus]) using output from a model constructed to predict density and spread of Burmese pythons across southern Florida. We hypothesized that increases in Burmese pythons on the landscape would influence the food resources of bobcats, resulting in reduced bobcat occupancy at higher predicted densities of pythons. We built detection histories using 1,855 bobcat images from game cameras set on 87 tree islands in an Everglades conservation area from 2005–2019. Bobcat occupancy was significantly diminished when predicted Burmese python densities exceeded approximately 3 Burmese pythons/km². Bobcat occupancy probability also increased with tree-island density around the focal tree island. Although water depth and hydroperiod surrounding tree islands appeared in our top 3 candidate models, the hydrologic variables had weak effects on bobcat occupancy. Our results suggest that while hydrologic dynamics may play a role, the invasive Burmese python has stronger influences on bobcat occupancy of tree islands in this Everglades conservation area.     

Human activity reduces niche partitioning among three widespread mesocarnivores

Anthropogenic disturbances can constrain the realized niche space of wildlife by inducing avoidance behaviors and altering community dynamics. Human activity might contribute to reduced partitioning of niche space by carnivores that consume similar resources, both by promoting tolerant species while also altering behavior of species (e.g. activity patterns). We investigated the influence of anthropogenic disturbance on habitat and dietary niche breadth and overlap among competing carnivores, and explored if altered resource partitioning could be explained by human‐induced activity shifts. To describe the diets of coyotes, bobcat, and gray foxes, we designed a citizen science program to collect carnivore scat samples in low‐ (‘wildland’) and high‐ (‘interface’) human‐use open space preserves, and obtained diet estimates using a DNA metabarcoding approach. Habitat use was determined at scat locations. We found that coyotes expanded habitat and dietary niche breadth in interface preserves, whereas bobcats and foxes narrowed both niche breadth measures. High human use was related to increased dietary niche overlap among all mesocarnivore pairs, increased coyote habitat overlap with bobcats and foxes, and a small reduction in habitat overlap between bobcats and foxes. The strongest increase in diet overlap was among coyotes and foxes, which was smaller in magnitude than their habitat overlap increase. Finally, coyote scats were more likely to contain nocturnal prey in interface preserves, whereas foxes appeared to reduce consumption of nocturnal prey. Our results suggest that dominant and generalist mesocarnivores may encroach on the niche space of subordinate mesocarnivores in areas with high human activity, and that patterns in resource use may be related to human‐induced activity shifts.     

Habitat selection and movement ecology of eastern Hermann’s tortoises in a rural Romanian landscape

Understanding wildlife movements and habitat selection are critical to drafting conservation and management plans. We studied a population of eastern Hermann’s tortoise (Testudo hermanni boettgeri) in a traditionally managed rural landscape in Romania, near the northern edge of the species geographic distribution. We used telemetry to radio-track 24 individuals between 2005 and 2008 and performed a Euclidian distance-based habitat selection analysis to investigate habitats preferred by tortoises at both landscapes (second-order order selection) and individual (third-order selection) home range scales. The home range size for tortoises in our study area was 3.79?±?0.62 ha and did not differ by gender or season (pre- and post-nesting seasons). Their movement ecology was characterized by short-distance movements (daily mean?=?31.18?±?1.59 m), apparently unaffected by habitat type. In contrast to other studies, movements of males and females were of similar magnitude. At the landscape (population home range) scale, grasslands and shrubs were preferred, but tortoises also showed affinity to forest edges. At the individual home range scale, tortoises selected grassland and shrub habitats, avoided forests, and used forest edges randomly. Creeks were avoided at both spatial scales. Our results suggest that tortoise home ranges contain well-defined associations of habitats despite a higher selection for grasslands. As such, avoiding land conversion to other uses and maintaining habitat heterogeneity through traditional practices (e.g., manual mowing of grasslands, livestock grazing) are critical for the persistence of tortoise populations.