AUTHORS: Nathan J. Proudman, Illinois Natural History Survey at the University of Illinois Urbana-Champaign; Maximilian L. Allen, Illinois Natural History Survey at the University of Illinois Urbana-Champaign
ABSTRACT: The ability of animals to plasticly adjust their diel activity has important implications for their persistence and the structure of food webs. While many studies have examined diel activity in mammals, few have compared multiple abiotic, biotic, and anthropogenic variables to determine what factors have the strongest effects on sympatric species within a system. Understanding the bounds of variation in behavior is vital to accurately determine the effects of environmental stressors on the diel activity of wildlife. We quantified shifts in diel activity among nine sympatric mammal species using camera traps across Illinois. We found biotic variables to be responsible for the greatest average shifts in diel activity across all mammal species (Δ=16.8%). Domestic cats (Felis catus; Δ=25.7%), red foxes (Vulpes vulpes; Δ=25.2%), bobcats (Lynx rufus; Δ=20.7%), and striped skunks (Mephitis mephitis; Δ=19.3%) exhibited the most behavioral plasticity of our focal species, suggesting contrasting behavioral strategies to the variables we tested. Decreased diurnal activity in more open habitat types by multiple species likely reflects the anthropogenic fear effects in the human-dominated landscape of Illinois, while urban environments may act as spatio-temporal refuges from coyotes (Canis latrans) for subordinate mesocarnivores. Our study shows that a broad range of factors contribute to variation in mammal diel activity, which can in turn affect the predatory and competitive pressures among sympatric species, with the potential for cascading effects across multiple trophic levels. Our study provides a robust baseline for the diel variation in mammal activity, allowing for more accurate assessments of their behavior.
AUTHORS: Ellen M. Audia, Southern Illinois University Carbondale; Katherine M. Buckman, Southern Illinois University Carbondale; Brent S. Pease, Southern Illinois University Carbondale; Clayton K. Nielsen, Southern Illinois University Carbondale; Guillaume Bastille-Rousseau, Southern Illinois University Carbondale
ABSTRACT: Bobcats (Lynx rufus) in the midwestern U.S. experienced dramatic population declines throughout the 1900s due to overharvest and agricultural expansion. Increased protection allowed bobcats to recolonize the agriculturally dominated, fragmented landscape of north-central Illinois, where they are likely using and selecting habitat differently than bobcats in less fragmented landscapes. We evaluated home range size, second order (i.e., home range) habitat selection, and dispersal of 28 bobcats in north-central Illinois during 2022-2024. Mean annual home range size of males was 166.1 ± 99.2 km2 (SD throughout, n = 11) and larger (P = 0.01) than that of females (89.5 ± 119.4 km2, n = 8). Mean annual home range size of juveniles was 273.5 ± 125.3 km2 (n = 4) and larger (P < 0.01) than that of adults (96.6 ± 75.3 km2, n = 15). Home range sizes were similar (P = 0.4) between the kitten-rearing (138.1 ± 155.1 km2, n = 14) and breeding seasons (111.0 ± 102.5 km2, n = 18). Consistent with previous research, bobcats selected for forest cover over other land cover types; locations closer to forest edges, streams, and waterbodies; and locations farther from roads. Mean dispersal distance of 7 juveniles was 65.9 ± 42.4 km and similar to other midwestern populations, with 4 males and 1 female dispersing north, and 2 males dispersing southeast. Home range size differences between sexes, ages, and seasons were generally consistent with other studies; however, home ranges were larger than those of other populations suggesting bobcat space requirements may be greater in this fragmented landscape. The selection of forest cover and locations closer to forest edges and streams indicates that riparian forests along the Illinois river provide important habitat for bobcats and may have helped facilitate their recolonization of this region.
AUTHORS: Nadine Pershyn, Southern Illinois University Carbondale; Clay Nielsen, Southern Illinois University Carbondale; Nicole Gorman, Southern Illinois University Carbondale; Abby Weber, Southern Illinois University Carbondale; and Guillaume Bastille-Rousseau, Southern Illinois University Carbondale
ABSTRACT: Gray fox (Urocyon cinereoargenteus) populations have declined throughout the midwestern U.S. without clear causation. Despite this decline, until recently minimal research has been conducted in the region to gain insight into the ecological needs of a vulnerable population. We evaluated gray fox second order habitat selection to determine which habitats are best suited to supporting gray foxes in southern Illinois and similar landscapes throughout the region. Gray foxes were trapped during November-March 2022-2024 using padded foothold traps and fitted with GPS collars programmed to take locations every 2 hr. Using more than 11,000 GPS locations from 10 gray foxes (5 ad F, 4 ad M, 1 ju M), we used a 2nd order resource selection function (RSF) to analyze habitat selection relative to vegetation cover (e.g., forest, grassland, crop, shrub, barren), distance to forest-grassland edges, distance to forest-crop edges, human development, distance to secondary roads, and elevation. We also investigated the impact of relative probability of use (RPU) across the landscape of coyotes (Canis latrans) and bobcats (Lynx rufus), using GPS locations also collected across southern Illinois. Gray foxes selected most strongly for developed areas, grasslands, and forest, and preferred areas closer to forest-grassland edge and farther from forest-crop edges and secondary roads. Our results support previous research that shows interspersed forest and grassland is important gray fox habitat. Gray foxes avoided areas with high coyote RPU but were not impacted by bobcat RPU. Coyotes are intraguild predators of gray foxes, and may contribute to mortality, which could be why gray foxes avoided them. Bobcats have similar habitat requirements and prey as gray foxes, which could explain the lack of response. Our study provides novel insight into habitat selection of a species of concern and sheds light on intraguild carnivore interactions.
AUTHORS: Michael E. Egan, Southern Illinois University; Abigail M. Weber, Southern Illinois University; Nicole T. Gorman, Southern Illinois University; Michael W. Eichholz, Southern Illinois University; Daniel Skinner, Illinois Department of Natural Resources; Peter E. Schlichting, Illinois Department of Natural Resources; and Guillaume Bastille-Rousseau, Southern Illinois University
ABSTRACT: Behavioral responses of prey to predation risk have ecological impacts that can be as great as the direct mortality mediated through behaviors including behavioral state changes and spatial avoidance. Theory suggests that prey choose between these behaviors by pairing responses to risks based on the hunting mode of the prey (hunting mode hypothesis), but prey may ignore hunting mode to prioritize responding to the most lethal predators (lethality hypothesis). Furthermore, prey may respond to the spatial distribution of these risks (risky places hypothesis) or respond only during the periods of highest risk (risky times hypothesis).We test these hypotheses using data from 40 female and 29 male white-tailed deer (Odocoileus virginianus) and two mesopredators (coyotes, Canis latrans and bobcats, Lynx rufus) fitted with GPS collars and human sources of mortality (hunting, roads, human modification).We used hidden Markov models (HMM) to determine whether each covariate impacted the probability of transitioning between behavioral states and step selection functions (SSF) to determine whether deer spatially avoided each covariate. Additionally, we evaluated whether these patterns varied daily and seasonally. Generally, deer changed behavioral state in response to both mesopredators, consistently shifting to slower movement states, but avoided human modification. Spatial responses to human modification varied depending on the time of day. Deer selected for human modification during daylight hours but avoided human modification during the crepuscular and nighttime periods. Space use was most strongly related to more lethal humans, providing support for the lethality hypothesis. Despite prioritizing humans, mesopredators impacted deer behavioral state, suggesting that mesopredators still have important impacts on prey behavior. Finally, temporal patterns of avoidance align with other studies that indicate avoidance of predators is time-dependent while further highlighting the complex push-pull relationship of human modified areas on wildlife.
AUTHORS: Justin J. Remmers, Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign; Sarah Mayhew, Michigan Department of Natural Resources; Kirk Stodola, Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign; Maximilian L. Allen, Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign
ABSTRACT: Furbearer management plans often rely on population models to estimate the abundance and demographic trends of managed species. Fishers (Pekania pennanti), a medium-sized carnivore distributed across Canada and the northern United States, experienced population declines, extirpations, and range contractions in the early 1900s due to habitat loss, predator control, and overharvest by trappers. After being granted legal protections, fisher populations have expanded and recolonized parts of their historic range, enabling some states to allow limited harvest of the species. In particular, Michigan has had limited harvest of fishers in the Upper Peninsula for 30 years; however, the current abundance of fishers is unknown. To address this, we are developing a state-space model using age-at-harvest data to assess the current population status of fishers in Michigan’s Upper Peninsula (93,600 km2). We are investigating the influence of different sex- and age-specific life history traits (i.e., harvest season survival, non-harvest season, mean litter size) to determine how these traits affect the overall population size and where effort should be placed to increase precision of estimates. This work will be useful in predicting population changes and informing future harvest management of fishers. Based on preliminary analysis of current age-at-harvest data, juvenile fishers appear to be more susceptible to harvest and exhibit lower annual survival rates compared to adults. Given that female fishers undergo delayed implantation and will not give birth until their second year, high levels of juvenile and yearling harvest may be more impactful on fisher demographics, especially when compared to other furbearing species.
AUTHORS: Tadao Kishimoto, Southern Illinois University; Michael Egan, Southern Illinois University; Michael Eichholz, Southern Illinois University; Peter Schlichting, Illinois Department of Natural Resources; Daniel Skinner, Illinois Department of Natural Resources; Guillaume Bastille-Rousseau, Southern Illinois University
ABSTRACT: Human activity can impact wildlife behavior by altering habitat conditions, increasing stress or predation risk, and disrupting natural patterns of movement, foraging, and reproduction. We investigated the impact of non-consumptive recreational activities, specifically mountain biking, on white-tailed deer (Odocoileus virginianus) space-use in an exurban forest setting in southern Illinois. Using GPS collar data from 37 individual deer collected before and after trail installation, we assessed whether newly introduced mountain bike trails altered key movement metrics: home range size, core area size, and speed. Home range and core area sizes were estimated using autocorrelated kernel density estimation (AKDE), and scale-insensitive speed estimates were calculated using a continuous-time speed and distance (CTSD) method. Home range size, core area size, and speed estimates were fit to linear mixed-effects models with sex as a covariate and individuals as random intercepts. We found no significant change in home range or core area size following trail installation. We found significant changes in speed for both males and females after trail installation, however, changes were independent of their overlap status with the trails, suggesting the changes were not due to trail installation. These findings contrast with existing literature suggesting human disturbance typically affects wildlife movement. The low frequency of recreational activity and partial habituation to humans may explain the lack of significant behavioral change. This study demonstrates the value of long-term monitoring and underscores the need for further research in areas with heavier recreational use to inform management practices that mitigate the impact of outdoor recreation on wildlife populations.
AUTHORS: Max R. Larreur, Southern Illinois University; Clayton K. Nielsen, Southern Illinois University; Damon B. Lesmeister, USDA Forest Service, Oregon State University; Guillaume Bastille-Rousseau, Southern Illinois University
ABSTRACT: Broad ecological changes can alter species' temporal activity, thereby impacting interspecific interactions. Temporal niche separation promotes coexistence, causing species to adjust activity patterns to avoid direct competition. Although studying carnivore species offers a unique perspective into the stability of their temporal activity and niche, few analyses have been conducted over long-term periods in areas experiencing conspecific population changes. We quantified species-specific and pairwise temporal activity patterns, using kernel density analysis overlap, for 6 native (i.e., bobcat, coyote, gray fox, red fox, striped skunk, and raccoon) and 2 non-native (i.e., domestic dog and cat) carnivore species along with their diel niche between decades. We used camera trap data collected January – April 2008 – 2010 (n = 1,118 camera locations) and January – April 2022 – 2024 (n = 1,325 camera locations) across 16,058-km2 of southern Illinois to identify potential changes in temporal overlap or niche separation between decades. Species-specific activity overlap was high (range = 0.81 - 0.95) between decades, however, activity patterns of striped skunk, raccoon, and domestic dogs were different. Both past and contemporary pairwise comparisons had 6 activity patterns indicating potential avoidance between larger-bodied and smaller-bodied guild members, and 7 activity patterns indicating potential avoidance between native and non-native carnivore species. However, 7 novel pairwise activity patterns have experienced significant changes from the past, 3 between natives and 4 between natives and non-natives. The diel niche of bobcat, gray fox, red fox, and striped skunk indicated minor changes in their diel activity potentially in response to larger-bodied coyote and domestic dog spatial presence throughout the study area. Larger-bodied carnivore species may be altering activity patterns of smaller-bodied members, thereby decreasing competition and negative interspecific interactions. Our results emphasize the importance of considering alterations to activity overlap and potential niche separation amongst carnivores with high resource overlap and propensity for interspecific interactions.
AUTHORS: Katherine M. Buckman, Ellen M. Audia, Brent S. Pease, Guillaume Bastille-Rousseau, and Clayton K. Nielsen
Southern Illinois University Carbondale
ABSTRACT: Bobcats (Lynx rufus) are a focal species for carnivore management and research. Although bobcat survival has been studied extensively throughout much of their North-American range, it can be difficult to identify the broader conclusions of such studies based on study-specific factors, such as sample size, harvest status, and study length. We conducted a meta-analysis to estimate mean bobcat survival across the U.S. to document trends, identify knowledge gaps, and inform future study designs. We identified 18 studies across 15 U.S. states conducted during 1985–2023 that reported a single estimate of annual bobcat survival (i.e., effect size) and a corresponding variance (i.e., weight). We assigned an “exploitation level” to each study based on whether the study area and/or adjacent lands were open to bobcat harvest (i.e., zero = no harvest permitted within or outside the study area; indirect = no harvest permitted within the study area but permitted outside the study area; direct = harvest permitted within and outside the study area). Bobcat survival estimates ranged from 0.19–0.93, with a mean annual survival of 0.75 (95% CI = 0.69–0.81). Heterogeneity in reported survival rates was not significantly different across years (Q = 3.29, P = 0.06), however survival rates appeared to increase slightly between 1985–2000 and reported estimates after 2001 were >0.68 (n = 9 studies). The mean number of days monitoring individual survival (range = 188–870 days, n = 12 studies), and the relative exploitation level accounted for 99.98% of heterogeneity in survival rates across studies (Q = 27.13, P
AUTHORS: Samantha Dennis, Stephen Blake, Saint Louis University; Stella Uiterwaal, Elizabeth Carlen, Washington University; Zachary Reyes, Saint Louis University, Sabrina Hardy, Purdue University
ABSTRACT: Urban expansion in the Midwest poses significant challenges to wildlife habitats vital to supporting biodiversity. As cities grow, green spaces within urban environments can become important habitat refugia for numerous species. Urban parks often provide mosaics of semi-natural habitats in a matrix of high human use areas within which some native wildlife species may persist. In the midwestern US, the conservation value of urban parks for small mammal communities is poorly understood. We studied the abundance and diversity of small rodent populations in iconic Forest Park, St. Louis, in which habitat restoration has been underway for a decade. We hypothesized that small mammal abundance and diversity would be correlated with restoration effort. Over three months in summer 2024, we used live trapping methods to capture rodents and survey tree and understory vegetation across the restoration gradient of the park. We identified captured mammals to species and sex, collected morphometric data and collected hair and scat samples to characterize diets through stable isotope analysis. We completed 1,646 traps nights capturing 94 individuals. Rodent diversity was extremely low; ninety of the individuals captured were Peromyscus spp. (Deer mice), two Sciurus carolinensis (Eastern gray squirrel), one Tamias striatus (Eastern chipmunk), and 1 Didelphis virginiana (Virginia opossum). Our results showed that older restoration sections with the highest plant density and diversity supported a greater abundance of rodents than younger restoration sections with correspondingly lower plant density and diversity. While restoration duration was correlated with the abundance of small native rodents, it had no effect on rodent diversity. We speculate this may be due to dispersal limitation through the cityscape. Effective restoration management is essential to ensure that the wildlife inhabiting these areas is not only surviving but thriving, providing insights for enhancing biodiversity a long-term sustainability in urban green spaces.
AUTHORS: Stephen Blake, Department of Biology, Saint Louis University, Max Planck Institute of Animal Behavior, WildCare Institute, Saint Louis Zoo.
Sharon L. Deem, Institute for Conservation Medicine, Saint Louis Zoo.
Jamie Palmer, Institute for Conservation Medicine, Saint Louis Zoo.
Jeff Meshach, World Bird Sanctuary.
Stanton Braude, Department of Biology, Washington University in St. Louis.
Amy Witt, Forest Park Forever.
August Wise, Saint Louis University.
Anthony I. Dell, National Great Rivers Research and Education Center.
Stella F. Uiterwaal, Living Earth Collaborative, Washington University in St. Louis, Department of Biology, Saint Louis University, Institute for Conservation Medicine, Saint Louis Zoo, National Great Rivers Research and Education Center.
ABSTRACT: Catastrophic native ecosystem degradation is usually a consequence of urban expansion. However, urban areas can support some elements of native biodiversity with benefits for conservation and human health. Understanding the ecology of urban biodiversity is increasingly important in a rapidly urbanizing world. Species responses to urbanization vary enormously from rapid local extinction to population expansion, with responses often strongly correlated with life history traits. Among animals, “urban adapters” often have r selected traits, such as small body size, high fecundity, and generalist niches. Long lived, large-bodied organisms with low fecundity tend to experience population declines and high local extinction probability under urbanization. Mobility can govern animals’ ability to exploit high-quality habitats and disperse out of poor-quality habitats. City parks are often mosaics of intense human use and semi-natural areas. They can function as urban biodiversity hotspots, which provides opportunities to understand the movement ecology of animals within urban communities. Over the last three years, we have fitted GPS and radio tracking tags to individuals from 15 species of animals in Forest Park, St. Louis. Additionally, we have acquired human mobility data from anonymous smart phone tracking within the park. We mapped habitat characteristics including vegetation and human footprint metrics across the city. We characterized animal movement strategies and habitat use using net squared displacement and resource selection functions. Forest Park wildlife displays all major movement strategies including residence, dispersal, nomadism and migration. Species’ responses to the human footprint varied dramatically from strongly negative, mostly among low mobility terrestrial omnivores, to strongly positive among highly mobile terrestrial and avian predators. Mortality was high among these species. This first quantitative window into the movement ecology of an urban animal community provokes myriad research and management questions and implications, demanding more extensive applied research to influence urban planning policy.
