Suburban landscapes can alter spatial patterns by white-tailed deer (Odocoileus virginianus) and increase animal contact with vectors, pathogens, and humans. Close-contact relationships at a ...landscape level can have broad implications for disease epidemiology. From 1995-1999, we captured and radio-collared 41 deer in two suburban forest preserves in Chicago, Illinois. We collected blood to determine if animals were seronegative or seropositive for Jamestown Canyon virus and tracked deer movements within suburban habitats. We developed utilization distributions at the population-level and evaluated resource selection for seronegative and seropositive deer. We used maximum likelihood estimation for model selection via Akaike information criterion and then restricted maximum likelihood estimation to attain unbiased estimates of the parameters in the top-ranking models. The top-ranking model describing the resource selection of seronegative deer received almost the full weight of evidence (Akaike information criterion ωi = 0.93), and included the proportion of wetlands, precipitation in year t, and an interaction of the proportion of wetlands and precipitation in year t. The top-ranking model describing resource selection of seropositive deer received the full weight of evidence (Akaike information criterion ωi = 1.00). The model included distance to nearest populated place, distance to nearest river, length of road in each grid cell, precipitation in year t, and an interaction of the length of road in each grid cell and precipitation in year t. These results are valuable for mapping the spatial configuration of hotspots for Jamestown Canyon virus and could be used to educate local residents and recreationalists to reduce human exposure.
Advancements in statistical ecology offer the opportunity to gain further inferences from existing data with minimal financial cost. Spatial capture-recapture (SCR) models extend traditional ...capture-recapture models to incorporate spatial position of capture and enable direct estimation of animal densities across a region of interest. The additional inferences provided are both ecologically interesting and valuable for decision making, which has resulted in traditional capture-recapture data being repurposed using SCR. Yet, many capture-recapture studies were not designed for SCR and the limitations of repurposing data from such studies are rarely assessed in practice. We used simulation to evaluate the robustness of SCR for retrospectively estimating large mammal densities over a variety of scenarios using repurposed capture-recapture data collected by an asymmetrical sampling grid and covering a broad spatial extent in a heterogenous landscape. We found performance of SCR models fit using repurposed data simulated from the existing grid was not robust, but instead bias and precision of density estimates varied considerably among simulations scenarios. For example, while the smallest relatives bias of density estimates was 3%, it ranged by 14 orders of magnitude among scenarios and was most strongly influenced by detection parameters. Our results caution against the casual repurposing of non-spatial capture-recapture data using SCR and demonstrate the importance of using simulation to assessing model performance during retrospective applications.
Climate change and habitat loss are recognized as important drivers of shifts in wildlife species' geographic distributions. While often considered independently, there is considerable overlap ...between these drivers, and understanding how they contribute to range shifts can predict future species assemblages and inform effective management. Our objective was to evaluate the impacts of habitat, climatic, and anthropogenic effects on the distributions of climate‐sensitive vertebrates along a southern range boundary in Northern Michigan, USA. We combined multiple sources of occurrence data, including harvest and citizen‐science data, then used hierarchical Bayesian spatial models to determine habitat and climatic associations for four climate‐sensitive vertebrate species (American marten Martes americana, snowshoe hare Lepus americanus, ruffed grouse Bonasa umbellus and moose Alces alces). We used total basal area of at‐risk forest types to represent habitat, and temperature and winter habitat indices to represent climate. Marten associated with upland spruce‐fir and lowland riparian forest types, hares with lowland conifer and aspen‐birch, grouse with lowland riparian hardwoods, and moose with upland spruce‐fir. Species differed in climatic drivers with hares positively associated with cooler annual temperatures, moose with cooler summer temperatures and grouse with colder winter temperatures. Contrary to expectations, temperature variables outperformed winter habitat indices. Model performance varied greatly among species, as did predicted distributions along the southern edge of the Northwoods region. As multiple species were associated with lowland riparian and upland spruce‐fir habitats, these results provide potential for efficient prioritization of habitat management. Both direct and indirect effects from climate change are likely to impact the distribution of climate‐sensitive species in the future and the use of multiple data types and sources in the modelling of species distributions can result in more accurate predictions resulting in improved management at policy‐relevant scales.
Climate and habitat are important drivers of species' distributions. We used a variety of data sources to fit Bayesian hierarchical models and determine associations between habitat, climatic and anthropogenic conditions for four climate‐sensitive species' in Northern Michigan and predict contemporary distributions. Species were associated with multiple climate‐sensitive habitat classes, while temperature itself was a stronger predictor than more mechanistic variables of snow cover.
In North America, wild pigs (Sus scrofa; feral pigs, feral swine, wild boars) are a widespread exotic species capable of creating large-scale biotic and abiotic landscape perturbations. ...Quantification of wild pig environmental effects has been particularly problematic in northern climates, where they occur only recently as localized populations at low densities. Between 2016 and 2017, we assessed short-term (within ∼2 yrs of disturbance) effects of a low-density wild pig population on forest features in the central Lower Peninsula of Michigan, USA. We identified 16 8-ha sites using global positioning system locations from 7 radio-collared wild pigs for sampling. Within each site, we conducted fine-scale assessments at 81 plots and quantified potential disturbance by wild pigs. We defined disturbance as exposure of overturned soil, often resulting from rooting behavior by wild pigs. We quantified ground cover of plants within paired 1-m² frames at each plot, determined effects to tree regeneration using point-centered quarter sampling, and collected soil cores from each plot. We observed less percent ground cover of native herbaceous plants and lower species diversity, particularly for plants with a coefficient of conservatism ≥5, in plots disturbed by wild pigs. We did not observe an increase in colonization of exotic plants following disturbance, though the observed prevalence of exotic plants was low. Wild pigs did not select for tree species when rooting, and we did not detect any differences in regeneration of light- and heavy-seeded tree species between disturbed or undisturbed plots. Magnesium and ammonium content in soils were lower in disturbed plots, suggesting soil disturbance accelerated leaching of macronutrients, potentially altering nitrogen transformation. Our study suggested that disturbances by wild pigs, even at low densities, alters short-term native herbaceous plant diversity and soil chemistry. Thus, small-scale exclusion of wild pigs from vulnerable and rare plant communities may be warranted.
Invasive feral swine can damage ecosystems, disrupt plant and animal populations, and transmit diseases. Monitoring of feral swine populations requires expensive and labor-intensive techniques such ...as aerial surveys, field surveys for sign, trail cameras, and verifying landowner reports. Environmental DNA (eDNA) provides an alternative method for locating feral swine. To aid in detection of this harmful invasive species, a novel assay was developed incorporating molecular methods. From August 2017 to April 2018, water samples and stream data were collected along 400 m transects in two different stream types where swine DNA was artificially introduced to investigate potential factors affecting detection. A generalized linear model (family binomial) was used to characterize environmental conditions affecting swine DNA detection; detection was the dependent variable and stream measurements included stream type, distance downstream, water temperature, velocity, turbidity, discharge, and pH as independent variables. Parameters from the generalized linear model were deemed significant if 95% confidence intervals did not overlap 0. Detection probability for swine DNA negatively related to water temperature (
= - 0.21, 95% CI -0.35 to -0.09), with the highest detection probability (0.80) at 0 °C and lowest detection probability (0.05) at 17.9 °C water temperature. Results indicate that sampling for swine eDNA in free-flowing stream systems should occur at lower water temperatures to maximize detection probability. This study provides a foundation for further development of field and sampling techniques for utilizing eDNA as a viable alternative to monitoring a terrestrial invasive species in northern regions of the United States.
Animal movement models can be used to understand species behavior and assist with implementation of management activities. We explored behavioral states of an invasive wild pig (Sus scrofa) ...population that recently colonized central Michigan, USA, 2014–2018. To quantify environmental factors related to wild pig movement ecology and spatio‐temporal landscape use, we predicted wild pig behavioral states relative to land cover type, landscape structure (i.e., edge and patch cohesion), and weather conditions. We used global positioning system (GPS)‐collars and monitored 8 wild pigs from 2014–2018. We fit local convex hulls and calculated movement metrics revealing 3 wild pig behavioral states (resting, exploratory, and relocating) and constructed a 3‐level model to predict behavioral state probabilities relative to biotic and abiotic conditions. Probabilities of exploratory and resting behaviors were higher nearer to riparian and open herbaceous cover types (oftentimes emergent marsh), indicating that these cover types provided security cover during activity and bedding. Hard mast cover types had a strong positive association with relocating behaviors. More cohesive patches of agriculture and shrub cover types were associated with higher probabilities of exploratory behaviors, while resting was more likely in continuous patches of agriculture (mostly mid‐summer corn). The probability of exploratory behaviors increased exponentially with warming ambient temperature. Our results may be used by managers to develop control strategies conducive to landscape and environmental conditions where the likelihood of encountering wild pigs is highest or targeting wild pigs when in a behavioral state most vulnerable to a particular removal technique.
We found associations between wild pig resting and exploratory behaviors with agriculture and riparian cover types. Wild pigs were more active with increasing ambient temperature and used hard mast cover types when relocating. Our results may be used by managers to develop control strategies conducive to the landscape and environmental conditions where likelihood of encountering wild pigs is highest or target wild pigs when most vulnerable to a particular removal technique.
Seasonal Use of Latrines by Bobcats HILTS, DYLAN J.; GEHRING, THOMAS M.; NIELSEN, CLAYTON K. ...
The Journal of wildlife management,
11/2020, Volume:
84, Issue:
8
Journal Article
Peer reviewed
Latrines serve as important communication networks among felids for transmitting information relative to social dominance, reproductive status, and defense of hunting areas. During January ...2011–August 2012, we monitored 10 bobcat (Lynx rufus) latrines in the northern Lower Peninsula (NLP) of Michigan, USA, using motion-sensitive cameras to estimate bobcat visitation and scat deposition rates among 3 biological seasons (mating, kitten-rearing, non-mating). Bobcat visitation rates differed among the 3 seasons. We found equal number of visits during the mating and kitten-rearing seasons, and lower visitation rates during the non-mating season. Scat deposition rates differed among the 3 seasons. We found a net gain of scats deposited during the mating and non-mating seasons, whereas there was a net loss of scats during the kitten-rearing season. An artificial latrine protocol we developed yielded visitation at 4 of 12 artificial latrine sites. Monitoring natural and artificial latrines during the mating and kitten-rearing seasons could provide valuable data for managing bobcat populations.
Understanding the factors that affect dispersal is a fundamental question in ecology and conservation biology, particularly as populations are faced with increasing anthropogenic impacts. Here we ...collected georeferenced genetic samples (n = 2,540) from three generations of black bears (Ursus americanus) harvested in a large (47,739 km2), geographically isolated population and used parentage analysis to identify mother-offspring dyads (n = 337). We quantified the effects of sex, age, habitat type and suitability, and local harvest density at the natal and settlement sites on the probability of natal dispersal, and on dispersal distances. Dispersal was male-biased (76% of males dispersed) but a small proportion (21%) of females also dispersed, and female dispersal distances (mean ± SE = 48.9±7.7 km) were comparable to male dispersal distances (59.0±3.2 km). Dispersal probabilities and dispersal distances were greatest for bears in areas with high habitat suitability and low harvest density. The inverse relationship between dispersal and harvest density in black bears suggests that 1) intensive harvest promotes restricted dispersal, or 2) high black bear population density decreases the propensity to disperse. Multigenerational genetic data collected over large landscape scales can be a powerful means of characterizing dispersal patterns and causal associations with demographic and landscape features in wild populations of elusive and wide-ranging species.
Despite the widespread use of noninvasive hair-sampling for American black bear (Ursus americanus) population monitoring, there is no explicit analysis of black bear behavior at hair snare sites. ...During 2016, we deployed hair snares and camera traps at 40 sites across the northern Lower Peninsula of Michigan, USA, and collected 560 video recordings of black bear activity. Our objectives were to develop an ethogram of bear behaviors at snare sites and quantify their occurrence. We found that bears allocated their time consistently when they were physically inside or outside of the snare, but they divided their time among multiple behaviors when crossing the wire. The inconsistencies in wire crossing revealed unexpected behaviors with important implications for study design. Our findings explicitly describe how black bears interact with hair snares, provide recommendations for addressing the influence of behavior on sampling efficiency, and establish a foundation for further study of animal behavior at hair snares.
Harvest data (e.g., number of animals harvested, trapper effort) are an important source of information for state wildlife agencies to manage harvested furbearers. These data provide evidence to ...support adapting harvest regulations when necessary. Setting appropriate harvest regulations for fishers (Martes pennanti) and American martens (Martes americana) is critical, as these species often exist at low densities, are sensitive to timber-management practices and trapper-harvest, and experience some level of interspecific predation and competition in sympatric populations. We estimated effects of management (e.g., number of fishers or martens harvested per trapper per season harvest limit, season length) and extrinsic (e.g., weather, pelt prices) factors on regulated harvests of fishers and martens in the Upper Peninsula of Michigan during 1996–2007. We used generalized linear mixed models in an information-theoretic approach (quasi-likelihood adjusted Akaike Information Criterion QAIC) to discern which factors most strongly influenced fisher and marten harvests. For harvest of fishers, the 3 QAIC-best models included harvest limit, season length, and number of trappers, suggesting that regulatory changes within the ranges tested may be implemented to influence harvest. The QAIC-best model (harvest limit) contained 26% of the weight of evidence, and using an independent subset of data, showed no difference between model predictions and harvest data. In contrast, harvest of martens was not strongly influenced by any factors we tested. Possible reasons for a lack of measurable effects while modeling harvest of martens include a low harvest limit (i.e., 1 marten) or incidental harvest of martens by fisher or bobcat (Lynx rufus) trappers. Knowledge of influences on harvest will lead to informed decision-making when managers are setting harvest regulations, particularly for low-density furbearers.
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