We investigated how a discriminatory housing policy-redlining-has shaped the spatial patterns and configurations of greenspaces throughout 177 cities in the contiguous US. Housing segregation has been a long-term development practice that has sequestered communities of color to areas with elevated environmental and public health risks. Although the lasting environmental, social, and economic impacts of redlining are clear, the impact of redlining on landscapes is still unfolding. In neighborhoods that were historically redlined, we found that (i) less overall greenspace was available, (ii) individual greenspaces were smaller and less connected, and (iii) residents belonged predominantly to communities of color and/or households had lower income. Thus, the legacy of redlining can be seen in the modern spatial patterns of urban greenspaces, and ecosystem services provided by greenspaces have been systematically absent from redlined communities for decades.

Colonization and extinction dynamics are fundamental processes that determine species’ distributions yet nuances of these processes are often overlooked when trying to estimate them. In this study we used dynamic occupancy models to estimate how colonization rates vary when nearby habitat patches are occupied by a species of interest. Our model parameterized colonization as either local (i.e., occurred when a habitat patch was within 2.5 km and was occupied by the species of interest in the previous time step) or long-distance (i.e., occurred when habitat patches within 2.5 km were not occupied by the species of interest in the previous time step). We applied our model to nearly a decade of striped skunk (Mephitis mephitis) camera trap data collected throughout Chicago, Illinois, USA and quantified associations between site-level colonization and persistence rates and proximity to the nearest known stream or river, percentage of developed open space, urbanization, and sampling season (winter, spring, summer, and fall). We found that local colonization was lowest in the fall season and largely controlled by the number of nearby habitat patches occupied by striped skunk. Long-distance colonization was greatest in the fall and positively covaried with developed open space. The probability of skunk persistence was roughly 0.60 adjacent to natural water sources and declined to 0.01 at 14.00 km from natural water sources. Using simulations from our best-fit model we determined that striped skunk occupancy was largely dictated by local colonization and persistence, which collectively accounted for about 80% of the variation in striped skunk occupancy throughout Chicago. Long-distance colonization during the fall season was likely affected by striped skunk offspring dispersing across the landscape. These results demonstrate that by splitting colonization into separate sub-processes, we can more accurately forecast near term changes in species distribution through space and time.

Circadian rhythms are a mechanism by which species adapt to environmental variability and fundamental to understanding species behavior. However, we lack data and a standardized framework to accurately assess and compare temporal activity for species during rapid ecological change. Through a global network representing 38 countries, we leveraged 8.9 million mammalian observations to create a library of 14,587 standardized diel activity estimates for 445 species. We found that less than half the species' estimates were in agreement with diel classifications from the reference literature and that species commonly used more than one diel classification. Species diel activity was highly plastic when exposed to anthropogenic change. Furthermore, body size and distributional extent were strongly associated with whether a species is diurnal or nocturnal. Our findings provide essential knowledge of species behavior in an era of rapid global change and suggest the need for a new, quantitative framework that defines diel activity logically and consistently while capturing species plasticity.

Public participation in research, or community science (CS), has an important role in advancing ecological research, especially data processing. CS contributions to camera trap studies have supported wildlife conservation through the rapid processing of images and videos. However, more studies are needed to quantify the accuracy and efficiency of CS participation. We used a case study from Chicago Wildlife Watch, a Zooniverse project, to explore variability in image classification accuracy and assess efficiency of responsive retirement rules which dictate how many times an image is viewed and annotated. We found that CS participants were highly accurate when classifying empty (96.0 %) and commonly photographed species in our study area (60.14 % across all species). User agreement on species images most impacted classification accuracy, though accuracy was higher for those containing larger species and those annotated by more engaged participants. With respect to efficiency, we found that three consecutive 'empty' classifications from participants led to over 95 % classification accuracy in empty images and if 7 participants agreed on a species present in an image, they were accurate 98 % of the time, on average. These results further support the value of CS in ecological research and the value of applying unique project designs which consider occurrence of regional species and field systems (e.g. camera placement or ecosystem). Given these results, we encourage scientists to continue applying quantitative techniques to custom design projects to effectively use CS participants' time and maximize data accuracy.

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. ### Competing Interest Statement The authors have declared no competing interest.

Urbanization has important effects on the distribution and persistence of wildlife communities. Urbanization may alter not just the distributions of individual species, but also co-occurrence patterns and thus the potential for interspecific interactions (e.g., competition, predation) that structure wildlife communities. Little is currently known about how urbanization alters species co-occurrence or how these changes shape urban species assemblages. Using tree squirrels as a model functional group, we quantified how urbanization alters species occurrence and co-occurrence patterns to shape species assemblages, and how these effects vary within and among cities. We constructed a multi-species, multi-season occupancy model to identify relationships between tree squirrel occupancy and co-occurrence and local land and tree canopy cover and examined variation in these relationships within and among nine US cities. Species’ responses to canopy cover were highly variable among, but less variable within cities, suggesting that even common urban wildlife species may respond differently to urban intensity in different landscape contexts. Species co-occurrence was also highly variable among cities and weakly related to canopy cover within a city. These findings provide important evidence that both environmental attributes and species interactions shape urban wildlife communities. Important for management and conservation, they suggest that tree-canopy cover can particularly support forest species co-occurrence and that managing urban forests to provide high canopy cover could contribute to the diversity of urban wildlife communities in forested ecoregions.

While there is increasing recognition that social processes in cities like gentrification have ecological consequences, we lack nuanced understanding of the ways gentrification affects urban biodiversity. We analyzed a large camera trap dataset of mammals (>500 g) to evaluate how gentrification impacts species richness and community composition across 23 US cities. After controlling for the negative effect of impervious cover, gentrified parts of cities had the highest mammal species richness. Change in community composition was associated with gentrification in a few cities, which were mostly located along the West Coast. At the species level, roughly half (11 of 21 mammals) had higher occupancy in gentrified parts of a city, especially when impervious cover was low. Our results indicate that the impacts of gentrification extend to nonhuman animals, which provides further evidence that some aspects of nature in cities, such as wildlife, are chronically inaccessible to marginalized human populations.

Abstract Living in cities creates One Health challenges because urban environments can promote pathogen transmission in wildlife and human-wildlife interactions with commensal species such as rats. In this study, we examined social and ecological processes that lead to an elevated risk of leptospirosis, a fatal rat-associated disease transmitted through Leptospira interrogans bacteria in urine. We examined rat and human factors associated with (1) human exposure to rat urine in the home environment, (2) the presence of rats carrying L. interrogans on the block, and (3) environmental conditions associated with rat infection. We surveyed residents and trapped rats on the same 16 blocks in four neighbourhoods in Chicago. Survey respondents were more likely to observe rat urine in their homes if they had lower incomes. Blocks where rats were carrying L. interrogans had higher rat abundance and respondents with higher incomes, who reported dogs dying from leptospirosis, children playing in yards with rat waste, flooded yards, and gardens with rat burrows. Rats were more likely to be infected with L. interrogans if they were trapped on a block with more accessible garbage and if they were older. Our results highlight that rat presence alone does not determine the risk of close contact with rat-associated pathogens; socio-economics can affect an individual’s ability to exclude animals from living spaces. In addition, improved waste management may help mitigate disease risks for humans, wildlife, and domestic animals. We also discuss opportunities for public education about rat-associated zoonoses and lessons learned about meaningful community engagement in One Health work. Information © The Authors 2024

Anticoagulant rodenticides (ARs) are currently the most common method to control rats in cities, but these compounds also cause morbidity and mortality in non-target wildlife. Little attention has been focused on AR exposure among mesopredators despite their ecological role as scavengers and prey for larger carnivores, thus serving as an important bridge in the biomagnification of rodenticides in food webs. In this study, we sampled liver tissue from raccoons (Procyon lotor; n = 37), skunks (Mephitis mephitis; n = 15), and Virginia opossums (Didelphis virginiana; n = 45) euthanized by pest professionals and brown rats (Rattus norvegicus; n = 101) trapped in alleys in Chicago, USA to evaluate how often these species are exposed to ARs. We tested whether mesopredators had a higher prevalence of ARs and to more AR compounds compared to rats and calculated biomagnification factors (mean concentration in mesopredators/rats) as indicators of biomagnification. Of 93 sampled mesopredators, 100 % were exposed to at least one AR compound, mainly brodifacoum (>= 80 %), and 79 % were exposed to multiple AR compounds. We also documented teal stomach contents consistent with the consumption of rat bait and altricial young tested positive to the same AR as their mother, suggesting mammary transfer. Of the 101 rats, 74 % tested positive to at least one AR compound and 32 % were exposed to multiple AR compounds. All mesopredator species had biomagnification factors exceeding 1.00 for brodifacoum (6.57-29.07) and bromadiolone (1.08-4.31). Our results suggest widespread exposure to ARs among urban mesopredators and biomagnification of ARs in mesopredators compared to rats. Policies that limit AR availability to non-target species, such as restricting the sale and use of ARs to licensed professionals in indoor settings, education on alternatives, and more emphasis on waste management may reduce health risks for urban wildlife and people in cities around the world.

Wildlife abundance and movement are strongly impacted by landscape heterogeneity, especially in cities which are among the world's most heterogeneous landscapes. Nonetheless, current global land cover maps, which are used as a basis for large-scale spatial ecological modeling, represent urban areas as a single, homogeneous, class. This often requires urban ecologists to rely on geographic resources from local governments, which are not comparable between cities and are not available in underserved countries, limiting the spatial scale at which urban conservation issues can be tackled. The recent expansion of community-based geographic databases, for example, OpenStreetMap (OSM), represents an opportunity for ecologists to generate large-scale maps geared toward their specific research needs. However, computational differences in language and format, and the high diversity of information within, limit the access to these data. We provide a framework, using R, to extract geographic features from the OSM database, classify, and integrate them into global land cover maps. The framework includes an exhaustive list of OSM features describing urban and peri-urban landscapes and is validated by quantifying the completeness of the OSM features characterized, and the accuracy of its final output in 34 cities in North America. We portray its application as the basis for generating landscape variables for ecological analysis by using the OSM-enhanced map to generate an urbanization index, and subsequently analyze the spatial occupancy of six mammals throughout Chicago, Illinois, USA. The OSM features characterized had high completeness values for impervious land cover classes (50%-100%). The final output, the OSM-enhance map, provided an 89% accurate representation of the landscape at 30m resolution. The OSM-derived urbanization index outperformed other global spatial data layers in the spatial occupancy analysis and concurred with previously seen local response trends, whereby lagomorphs and squirrels responded positively to urbanization, while skunks, raccoons, opossums, and deer responded negatively. This study provides a roadmap for ecologists to leverage the fine resolution of open-source geographic databases and apply it to spatial modeling by generating research-specific landscape variables. As our occupancy results show, using context-specific maps can improve modeling outputs and reduce uncertainty, especially when trying to understand anthropogenic impacts on wildlife populations.

Rats are an understudied stressor for people in urban environments around the world but the effects may not be distributed equally among residents. In this study, we examined associations between residential rat sightings and mental health in Chicago, where rat complaints are the highest of any American city. We examined how this relationship varied by frequency of rat sightings, race, ethnicity, income, home ownership, and gender and explored potential psychosocial pathways (e.g. feelings about the home) between rat sightings and mental distress. We conducted a randomized household survey along an income gradient in 2021 and asked about depressive symptoms in the past week (i.e. Center for Epidemiologic Studies Depression scale), frequency of rat sightings in/around the home, perceptions of rats, neighborhood conditions, and socio-demographic characteristics. We used logistic regression to assess relationships among these variables for our entire sample and for specific demographics using stratified models. Respondents (n = 589; 409 complete cases) who saw rats in/around the home daily/almost daily had 5.5 times higher odds of reporting high depressive symptoms relative to respondents who saw rats less frequently after accounting for socio-demographics and neighborhood conditions. This relationship was significant for men and respondents with lower incomes or race or ethnicity other than white. Our results show that rat infestations should be considered a threat to mental health among urban residents. Increased mental health support for residents living in rat-infested housing may improve public health in cities.

Abstract Urban environments are uniquely variable within and across regions, differing along a complex set of biophysical axes. This work describes the primary sources of this variation including biological, geophysical, cultural, economic, and policy differences within and between cities. In addition, it explains why these variances are important to the distribution and abundance of urban biodiversity. The emergence of multicity networks and datasets—including the National Science Foundation’s Urban LTER projects (Baltimore Ecosystem Study, Central Arizona-Phoenix, and Minneapolis-St. Paul), the Urban Biodiversity Research Coordination Network (UrBioNet), the Urban Wildlife Information Network (UWIN), WildCam, and others—is integral to urban biodiversity science, predicting future scenarios for unsampled neighborhoods or cities, and conservation. Multicity networks facilitate long-term sampling and allow inferences across vast spatial scales, including capturing variation between regions, cities, and sites; different types of urban development; different degrees of urban intensity; different socioeconomic factors; different policies and cultural norms; and varying attitudes toward biodiversity. Such information facilitates a broad array of urban conservation issues, informing when and how conservation strategies should be implemented for a given city. Finally, this work reviews some of the major findings from urban research networks and concludes with recommendations to improve on multicity data collection in the future. This includes the need for more data from outside of North America, more data on rarely sampled taxa such as herpetofauna and fish, more collaboration between networks, and networks that span across disciplines.

EDITORIAL article Front. Ecol. Evol., 15 September 2023Sec. Population, Community, and Ecosystem Dynamics Volume 11 - 2023 | https://doi.org/10.3389/fevo.2023.1282679

Mesopredators including coyotes (Canis latrans) and red foxes (Vulpes vulpes) often co-occur in urban environments, but how niche partitioning facilitates their coexistence remains unclear. Highly urbanized areas can be spatial refuges for smaller mesopredators (i.e., spatial human shield effect), however these species also may coexist through temporal niche partitioning. We used camera traps (n = 110 sites) across an urbanization gradient in Chicago to examine coyote-fox interactions from 2011 to 2018. We analyzed spatial partitioning through multi-season occupancy models and structural equation modeling (SEM), and quantified temporal overlap between canids and with humans. Coyotes most often occurred in natural areas, and urbanization reduced their colonization rates and increased their extinction rates. Initial occupancy for red foxes was negatively impacted by urbanization, but their extinction rates depended on a surprising interaction between coyotes and humans. When coyotes were rare, fox extinction was related positively to human activity; but when coyotes were more common, fox extinction was related negatively to human activity. This outcome may reflect a human shield effect at a within-site scale. The SEM further supported the negative impact of urbanization on both canids, and lack of an effect of coyotes on the distribution of foxes. Diel activity of coyotes and red foxes indicated temporal niche partitioning intensified at more urbanized sites. Our results suggest the spatial human shield effect is not operating across sites in Chicago. Instead, coyotes and red foxes may share green spaces, especially in highly urbanized areas, where species coexistence is promoted by temporal niche partitioning.

Transitioning from the normal course of science–collecting data, writing papers, getting grants–to generating real-world impacts from research is a massive challenge for many wildlife ecologists. As founder of a large research collaboration that works to improve human-wildlife coexistence in cities, the Urban Wildlife Information Network, I work at many different scales to ensure that the data we collect have real implications for urban wildlife management and conservation. Chiefly this takes the form of collaborations with planners, architects, community members and others in an “ecology with cities” context. In this essay, I provide personal observations about the current state of collaborations towards wildlife-friendly urban design, and reflections on my efforts to engage with policy makers and the community on behalf of urban wildlife. I have found the most success with a collaborative, listening-based approach, though progress has required a great deal of time and trust-building. Creating an impact requires us to stretch outside of our disciplinary silos and methodological comfort zones, but can yield tangible rewards such as protections for local species that more than justify the associated challenges.

Human-driven environmental changes shape ecological communities from local to global scales. Within cities, landscape-scale patterns and processes and species characteristics generally drive local-scale wildlife diversity. However, cities differ in their structure, species pools, geographies and histories, calling into question the extent to which these drivers of wildlife diversity are predictive at continental scales. In partnership with the Urban Wildlife Information Network, we used occurrence data from 725 sites located across 20 North American cities and a multi-city, multi-species occupancy modelling approach to evaluate the effects of ecoregional characteristics and mammal species traits on the urbanization-diversity relationship. Among 37 native terrestrial mammal species, regional environmental characteristics and species traits influenced within-city effects of urbanization on species occupancy and community composition. Species occupancy and diversity were most negatively related to urbanization in the warmer, less vegetated cities. Additionally, larger-bodied species were most negatively impacted by urbanization across North America. Our results suggest that shifting climate conditions could worsen the effects of urbanization on native wildlife communities, such that conservation strategies should seek to mitigate the combined effects of a warming and urbanizing world.

In 1898, Herbert and Alice Walter started a 5-year survey of birds in Lincoln Park—the largest park in Chicago, Illinois—and summarized their data in an urban birding field guide, Wild Birds in City Parks. Twenty-nine years later, William Dreuth compared the relative frequency of species in the Walters’ study to that in his own 5-year Lincoln Park survey. Between 2012 and 2015, we replicated these surveys to investigate a century of bird diversity and community composition change in urban Chicago. While species richness did not change, community composition did. We found that (1) species with a greater diet breadth and (2) species that increased in statewide occupancy were more likely to increase in frequency over time. We conclude that factors at multiple scales brought temporal changes to Chicago’s bird community. Overall, this survey highlights the slow and subtle ways in which species may respond to a century of urban intensification.

Reduced human activity to mitigate the spread of the COVID-19 pandemic was accompanied by reports of unusual wildlife sightings in highly developed areas. Such experiences with urban nature may have helped residents cope with the stress of the pandemic and increased public interest in urban wildlife; however, this may depend on the species residents encountered. In this study, we surveyed Chicago, Illinois, USA residents during a stay-at-home order to understand if residents in more affluent or greener neighborhoods saw more wildlife species. We also evaluated whether encounters with pest and non-pest species were associated with residents’ values about wildlife. Of 593 responses included in our analyses, respondents in higher-income and greener neighborhoods were more likely to perceive increased wildlife sightings and respondents in higher-income areas reported observing a higher number common birds and mammals. Support for seeing wildlife in residential areas was associated with seeing passerine birds and not seeing rats during the stay-at-home order. Our results suggest that perceived increases in wildlife sightings were common during a stay-at-home order, especially for affluent residents, and that residents’ perceptions depended on the species encountered. Understanding how changes in human behavior modifies human-wildlife interactions can help mitigate human-wildlife conflict and foster positive engagement with local wildlife.