Elizabeth W. Lehrer

Prevalence of antibodies to Toxoplasma gondii in woodchucks across an urban-rural gradient.

Increasing urbanization has important consequences for wildlife, including the potential for higher prevalence of diseases within “urban adapter” species exposed to spillover from domestic animals. We investigated whether prevalence of antibodies to Toxoplasma gondii in woodchucks (Marmota monax) was related to urbanization in a Midwestern landscape. We collected serum samples from adult woodchucks captured across an urban–rural gradient in Illinois, USA in May–November 2007. We used an indirect fluorescent antibody test (IFAT) on the serum samples to detect T. gondii antibodies. Five of 35 (14.3%) sera from woodchucks had detectable T. gondii antibodies. Prevalence was related positively to urbanization. All positive samples were from individuals inhabiting areas in which urban land cover exceeded 70%. Urban woodchucks are likely exposed to high levels of T. gondii oocysts in the environment due to habitat overlap with the definitive hosts for the parasite, domestic and feral cats, which reach high densities in urban areas.

Mammal diversity and metacommunity dynamics in urban green spaces: implications for urban wildlife conservation

As urban growth expands and natural environments fragment, it is essential to understand the ecological roles fulfilled by urban green spaces. To evaluate how urban green spaces function as wildlife habitat, we estimated mammal diversity and metacommunity dynamics in city parks, cemeteries, golf courses, and natural areas throughout the greater Chicago, Illinois, USA region. We found similar α-diversity (with the exception of city parks), but remarkably dissimilar communities in different urban green spaces. Additionally, the type of urban green space greatly influenced species colonization and persistence rates. For example, coyotes (Canis latrans) had the highest, but white-tailed deer (Odocoileus virginianus) the lowest probability of persistence in golf courses compared to other green space types. Further, most species had a difficult time colonizing city parks even when sites were seemingly available. Our results indicate that urban green spaces contribute different, but collectively important, habitats for maintaining and conserving biodiversity in cities.

Habitat Dynamics of the Virginia Opossum in a Highly Urban Landscape

Abstract As urban habitats vary in composition and structure along the urban to rural gradient, different degrees of urbanization likely result in a diversity of landscape responses from wildlife. We investigated this relationship with the Virginia opossum (Didelphis virginiana), an urban adapted species that is both common and understudied in highly metropolitan landscapes. We investigated which landscape factors affect opossum occupancy, colonization, extinction, and detection by using a large system of motion-triggered camera traps in the Chicago metropolitan area over 10 seasons from spring 2010 to summer 2012. Opossum patch occupancy rates were highest near natural water sources regardless of urbanization, whereas occupancy rates in patches ≥1000 m from natural water sources decreased with increasing urbanization. Our results suggest opossums have relaxed habitat needs at intermediate levels of disturbance, as the ability to locate anthropogenic water sources may allow them to occupy previously uninhabitable patches.

Invasive European Buckthorn (Rhamnus cathartica L.) Association with Mammalian Species Distribution in Natural Areas of the Chicagoland Region, USA

ABSTRACT: Common buckthorn (Rhamnus cathartica L.) is an invasive Eurasian shrub that has successfully invaded many of the woodlands of the northeastern United States. While the ecology and invasive properties of this species are well documented, little research has focused on buckthorns effects on wildlife species. In this study, we surveyed 35 forest preserves and natural areas in the Chicago metropolitan region for the presence of buckthorn. Motion-triggered infrared cameras were used to detect mammal species in sites with and without buckthorn. Cameras were active for an average of four weeks for seven seasons during 2010 and 2011. White-tailed deer (Odocoileus virginianus Zimm.) were more likely to be present in sites without buckthorn, while coyotes (Canis latrans Say) and Virginia opossums (Didelphis virginiana Kerr) were more likely to be present in sites invaded with buckthorn. While there was no overall significant difference in raccoon (Procyon lotor L.) presence between the two site types, raccoons were more likely to be present in invaded sites during the spring season, a trend that was also observed for other mesocarnivores. Our results strongly suggest that the presence of invasive buckthorn impacts habitat use and the presence of wildlife species.

Space use of woodchucks across an urbanization gradient within an agricultural landscape

Abstract Rapidly increasing urbanization creates novel environmental conditions for mammals even in already human-dominated, agricultural landscapes. Previous research on the behavioral responses of mammals to urbanization has focused on carnivores. Herbivores may respond to similar factors as carnivores, but herbivores also could respond to landscape alterations that generate variation in predation risk. We examined movements of 35 radiomarked, adult woodchucks (Marmota monax) located across an urbanization gradient within an agricultural landscape in central Illinois from 2007 to 2008. As predicted, home-range size was related negatively to urbanization. Home-range size of woodchucks in urban areas was ∼10% of that of rural woodchucks. Urbanization had stronger effects on home-range sizes of males compared to females. Woodchucks are multiple central-place foragers, and their use of burrows within home ranges also was influenced by urbanization, with number of burrows per individual decreasing with urbanization. Because number of burrows was not scaled proportionally to home-range size, however, distances between burrows decreased in urban areas, and predation risk during interburrow movements should be reduced for urban woodchucks. Our results demonstrate the ability of woodchucks to exhibit substantial behavioral plasticity in response to urbanization and provide insights into how space use by multiple central-place foragers relates to predation risk.

Need for multiscale planning for conservation of urban bats.

For over a century there have been continual efforts to incorporate nature into urban planning. These efforts (i.e., urban reconciliation) aim to manage and create habitats that support biodiversity within cities. Given that species select habitat at different spatial scales, understanding the scale at which urban species respond to their environment is critical to the success of urban reconciliation efforts. We assessed species-habitat relationships for common bat species at 50-m, 500-m, and 1 km spatial scales in the Chicago (U.S.A.) metropolitan area and predicted bat activity across the greater Chicago region. Habitat characteristics across all measured scales were important predictors of silver-haired bat (Lasionycteris noctivagans) and eastern red bat (Lasiurus borealis) activity, and big brown bat (Eptesicus fuscus) activity was significantly lower at urban sites relative to rural sites. Open vegetation had a negative effect on silver-haired bat activity at the 50-m scale but a positive effect at the 500-m scale, indicating potential shifts in the relative importance of some habitat characteristics at different scales. These results demonstrate that localized effects may be constrained by broader spatial patterns. Our findings highlight the importance of considering scale in urban reconciliation efforts and our landscape predictions provide information that can help prioritize urban conservation work.

Happily ever after? Fates of translocated nuisance woodchucks in the Chicago metropolitan area

Human-wildlife conflict is increasing as urbanization expands and wildlife species adjust to living near people. Translocation is often used to manage human-wildlife conflict because it is considered to be humane, yet fates of translocated animals are largely unknown. As an urban adapter, woodchucks (Marmota monax) are a common source of human-wildlife conflict due to their burrowing, foraging, and scent-marking behavior. We examined survival and movements of 27 nuisance woodchucks captured by a nuisance wildlife operator in the Chicago metropolitan area, radiomarked with internal transmitters, and translocated to exurban release sites mimicking typical practices. We also captured and radiomarked 16 resident woodchucks from the release landscape for comparison. Translocated woodchucks moved farther than residents immediately post release with no evidence of homing and most left the release site. Annual survival did not differ between translocated and resident woodchucks. However, survival was extremely low (0.18) compared to previous estimates for woodchucks, primarily due to high predation by coyotes (Canis latrans). Translocation should be used only when other nonlethal methods are ineffective (e.g., exclusion, removing food sources, selecting unpalatable plants for gardens). When necessary, the practice of translocation could be improved by reducing predation risk for translocated animals, either by selecting release sites with low predation risk, or by using soft-release methods, such as acclimation enclosures or artificial burrows.