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Biology subjects

Murray, M. H.

Publications and source records attributed to Murray, M. H..

4 recordsLinked to original sources

Infection and host-feeding patterns of West Nile virus vectors varies by urban greenspace composition

Greenspaces are integral to the urban environment and affect climate resilience, yet the extent to which they affect mosquito and West Nile virus (WNV) host populations and behavior is not clear. To address this question, we collected mosquitoes along a transect spanning a range of urban development. Mosquitoes were tested for West Nile virus, and the host species that were fed on determined for blood-fed specimens. Bird counts and camera traps were used to assess avian and mammal species availability. Different components that contribute to WNV transmission intensity responded to different landcover variables. Abundance of Culex mosquitoes was most strongly tied to impervious surface, while prevalence of infection was associated with increasing amounts of turf grass. The amount of turf was itself correlated with a measure of avian community reservoir competence. Blood meal analysis suggested the majority of blood meals in the ornithophagic species Cx. pipiens and Cx. restuans came from American robins and northern cardinals, with the latter in particular being overutilized relative to their abundance in sites with higher WNV prevalence. This work furthers our understanding of how the design of urban greenspaces could benefit from consideration of vector-host-virus interactions.

ecology↗

Impacts of urbanization on the health of American Robins (Turdus migratorus) in Chicagoland

Wild animals in urbanized environments face several unique challenges, including increased anthropogenic stressors, decreased natural food availability and quality, and increased pollutant exposure. While some work has shown that individual urbanization stressors can have negative impacts on aspects of wild bird physiology, other studies have demonstrated ambiguous or sometimes positive interactions. As such, the impact of multiple, coincident urban stressors on avian health still needs to be fully understood. Here, we addressed this knowledge gap by holistically measuring multiple physiological markers of American robin (Turdus migratorius) health across a gradient of urbanization throughout Chicagoland. We predicted that birds using highly urbanized habitats would experience higher heavy metal contamination, higher oxidative stress, lower body condition, higher avian malaria burden, and decreased measures of immune response compared to exurban birds in the Chicagoland area. Multiple linear models revealed that robins in more urbanized areas exhibited higher levels of heavy metal contamination and slightly elevated levels of associated physiological impairments compared to their counterparts in exurban sites. Additionally, noise and light pollution were significantly associated with oxidative stress and infection status, respectively, albeit in different directions. Overall, our findings underscore how the complex environmental changes that accompany urbanization can impact the health of urban bird populations.

ecology↗

Mammals adjust diel activity across gradients of urbanization

Time is a fundamental component of ecological processes. How animal behavior changes over time has been explored through well-known ecological theories like niche partitioning and predator-prey dynamics. Yet, changes in animal behavior within the shorter 24-hour light-dark cycle have largely gone unstudied. Understanding if an animal can adjust their temporal activity to mitigate or adapt to environmental change has become a recent topic of discussion and is important for effective wildlife management and conservation. While spatial habitat is a fundamental consideration in wildlife management and conservation, temporal habitat is often ignored. We formulated a temporal resource selection model to quantify the diel behavior of eight mammal species across ten U.S. cities. We found high variability in diel activity patterns within and among species and species-specific correlations between diel activity and human population density, impervious land cover, available greenspace, vegetation cover, and mean daily temperature. We also found that some species may modulate temporal behaviors to manage both natural and anthropogenic risks. Our results highlight the complexity with which temporal activity patterns interact with local environmental characteristics, and suggest that urban mammals may use time along the 24-hour cycle to reduce risk, adapt, and therefore persist in human-dominated ecosystems.

ecology↗

Gut microbiome shifts with urbanization and potentially facilitates a zoonotic pathogen in a wading bird

Microbial communities in the gastrointestinal tract influence many aspects of host health, including metabolism and susceptibility to pathogen colonization. These relationships and the environmental and individual factors that drive them are relatively unexplored for free-living wildlife. We quantified the relationships between urban habitat use, diet, and age with microbiome composition and diversity for 82 American white ibises (Eudocimus albus) captured along an urban gradient in south Florida and tested whether gut microbial diversity was associated with Salmonella enterica prevalence. Shifts in community composition were significantly associated with urban land cover and, to a lesser extent, diets higher in provisioned food. The diversity of genera was negatively associated with community composition associated with urban land cover, positively associated with age class, and negatively associated with Salmonella shedding. Our results suggest that shifts in both habitat use and diet for urban birds significantly alter gut microbial composition and diversity in ways that may influence health and pathogen susceptibility as species adapt to urban habitats.

ecology↗