Influence of urbanization on the occurrence and activity of aerial insectivorous bats

Activity and species-specific responses of insectivorous bats in different urban-forest conditions provides a general perspective on the adaptability and vulnerability of bat species towards urbanization intensity. Here we evaluated species richness and activity patterns of aerial insectivorous bats across an urbanized landscape in the highlands of Chiapas, in Mexico. Acoustic monitoring of echolocation calls was conducted for 27 nights over a period of four months. Species richness and relative activity of insectivorous bats were estimated in a landscape with different conditions of urbanization intensity: urban areas, non-urban and forest areas. We identified a total of 14 bat species and three phonotypes. Bat species richness and relative activity was similar (X² = 0.568, gl = 2, p > 0.05), but species composition differed among conditions. We observed a significant higher occurrence of Bauerus dubiaquercus, Eptesicus brasiliensis and Myotis californicus in forest sites. Urban sites presented higher occurrence of Molossus rufus and phonotype Molossidae 2, while non-urban sites presented a higher occurrence of Eptesicus furinalis and phonotype Molossidae 2. We were able to identify bat species according to their relative activity in relation todifferent landscape conditions. Species of the Molossidae family presented the highest activity in urban sites, which was positively affected by the number of streetlights, while species of the Vespertilionidae presented the highest activity in forest sites, which was positively related totree density. While urbanization tends to diminish native biodiversity and alter faunal communities, our results show a similar richness and relative activity of aerial insectivorous bats along the urban ecosystem. The effect of urbanization intensity becomes more apparent in species-specific bat activity; the response of species towards particular habitat conditions depends on local habitat quality and characteristics (i.e., presence of streetlights, vegetation cover and tree density).     

Analysis of the effect of recreational dog walking on the occupancy probability of the ringtail Bassariscus astutus (Carnivora: Procyonidae) within an urban ecosystem

Despite being highly modified environments, cities are important reservoirs of biodiversity. The ecological reserve situated within southern Mexico City houses several species of mammals, including the ringtail Bassariscus astutus. However, the urban areas surrounding the reserve are subject to various types of uses that could affect the presence of wild species inside and out of the reserve areas. Here, I tested the hypothesis that recreational activities, especially the walking of domestic dogs, can cause the ringtails, smaller sized carnivores, to avoid certain areas. To achieve this, I carried out a survey throughout the reserve and urban landscape, and registered the presence of domestic dogs and ringtails by direct observation or via the detection of feces and latrines during two sampling seasons. I used single species occupancy models to determine the environmental covariates associated with the presence of these carnivores within the reserve and the urban areas around it. In addition, I used two-species occupancy models to estimate the species interaction factor between these species to assess if the presence of domestic dogs has a negative effect over the presence of ringtails. My results reveal that shrub cover in the area affects the occurrence of these species, and that there is no clear evidence that domestic dogs negatively affect the occupancy of ringtails during the studied seasons. These results highlight the capacity of the ringtails to adapt to rapid urbanization, but do not guarantee that recreational activities, especially those involving dogs, have no negative effects on the local distribution of other smaller mammals within this urban reserve.

     

Bats in urban areas of Brazil: roosts,food resources and parasites in disturbed environments

Urbanization is a widespread intense land use that generally results in biodiversity decline. Among the taxa capable to adapt to urban landscapes, bats are particularly ubiquitous. Brazil has one of the world’s largest diversity of bat species and one of the highest urbanization rates of the world. Yet, few studies have synthesized the biology of bats in urban environments, especially in Brazil. To fill this gap, we systematically reviewed the published scientific literature on the bat fauna found in urban areas of Brazil. The knowledge of urban bats is still incipient and heterogeneously spatially distributed, mostly concentrated in the southeastern region of the country. The assembled list of 84 urban species, of which nineteen are new species records for urban areas (including one new family), represents 47% of the bat richness registered in the country. Thirty-one bat species (37%) were captured exclusively inside forest fragments. Moreover, we provide information on the resources used within the urban matrix by summarizing the roosting sites for 38 bat species, as well as 31 plants consumed by at least twelve bat species. Regarding parasitological aspects, we listed eleven zoonotic parasites hosted by 27 bat species and discussed their potential to become a public health threat. Likewise, we considered the different features linked to urbanization, including impacts on immunity, body condition and susceptibility to acquiring parasites, as possible bat conservation issues. Finally, we defined an agenda for bat studies in urban areas of Brazil.     

Effects of urbanization on species richness: A review of plants and animals

Many studies have described the effects of urbanization on species richness. These studies indicate that urbanization can increase or decrease species richness, depending on several variables. Some of these variables include: taxonomic group, spatial scale of analysis, and intensity of urbanization. Recent reviews of birds (the most-studied group) indicate that species richness decreases with increasing urbanization in most cases but produces no change or even increases richness in some studies. Here I expand beyond the bird studies by reviewing 105 studies on the effects of urbanization on the species richness of non-avian species: mammals, reptiles, amphibians, invertebrates and plants. For all groups, species richness tends to be reduced in areas with extreme urbanization (i.e., central urban core areas). However, the effects of moderate levels of urbanization (i.e., suburban areas) vary significantly among groups. Most of the plant studies (about 65%) indicate increasing species richness with moderate urbanization whereas only a minority of invertebrate studies (about 30%) and a very small minority of non-avian vertebrate studies (about 12%) show increasing species richness. Possible explanations for these results are discussed, including the importance of nonnative species importation, spatial heterogeneity, intermediate disturbance and scale as major factors influencing species richness.     

Relationship between urbanization and bat community structure in national parks of the southeastern U.S.

Urbanization and development are predicted to increase considerably in the United States over the next several decades, and this is expected to result in large-scale habitat loss, fragmentation and loss of wildlife species. Thus, natural parks and preserves are becomingly increasingly important in the conservation of regional biodiversity. We used mist-nets and AnabatII acoustic detectors to survey bats in 10 national parks in the southeastern U.S. and examined the relationship between bat community structure and development in the surrounding 5 km. We predicted that species richness would increase with park size and that species richness and evenness would decrease with development. Species richness was not related to development or any other landscape characteristics including park size. In contrast, species evenness declined with increasing development. Percent Developed land in the surrounding 5 km area was the only variable that entered into the stepwise regression model. The decrease in species evenness in the urban parks was due to the dominance of big brown bats (Eptesicus fuscus) in these parks. The percentage of big brown bats in our captures was positively related to percent Developed land in the surrounding area. Our data suggest that urban parks may be important for conserving regional bat biodiversity. However, the low species evenness in these parks suggests that some bat species may be susceptible to the effects of urbanization and may be extirpated over time. Thus, management of urban as well as rural parks should strive to conserve as much bat roosting and foraging habitat as possible.     

Urban areas may serve as habitat and corridors for dry-adapted,heat tolerant species; an example from ants

We collected ants from six urban and one forest land-use types in Raleigh, NC to examine the effects of urbanization on species richness and assemblage composition. Since urban areas are warmer (i.e., heat island effect) we also tested if cities were inhabited by species from warmer/drier environments. Species richness was lower in industrial areas relative to other urban and natural environments. There are two distinct ant assemblages; 1) areas with thick canopy cover, and 2) more disturbed open urban areas. Native ant assemblages in open environments have more southwestern (i.e., warmer/drier) distributions than forest assemblages. High native species richness suggests that urban environments may allow species to persist that are disappearing from natural habitat fragments. The subset of species adapted to warmer/drier environments indicates that urban areas may facilitate the movement of some species. This suggests that urban adapted ants may be particularly successful at tracking future climate change.     

Urbanization is not associated with increased abundance or decreased richness of terrestrial animals - dissecting the literature through meta-analysis

The widely accepted consensus is that urbanization increases abundance but reduces species richness of animals. This assumption is the premise for empirical tests and theoretical explanations. We studied the association of urbanization with abundance and species richness of different animal taxa in 20 and 26 published articles reporting abundances and richness, respectively via meta-analysis. Because some articles had multiple estimates, we analyzed 40 and 58 estimates of abundance and richness, respectively. Contrary to conventional wisdom, the overall abundance of terrestrial animals was not higher in urban areas, but instead actually lower, while we failed to confirm the conventional thinking of lower species richness with urbanization. These findings cannot, however, be generalized across all cities and animal species, as conflicting differences were reported among geographical regions, animal taxa. Our results question the conventional wisdom that urbanization generally increases abundances while reducing species richness, and highlights the variability of urbanization effects on diversity among taxa and geographic regions.     

Determining species specific nightly bat activity in sites with varying urban intensity

Time of peak bat activity during the night differs among bat species due to temperature, prey availability, habitat availability, and/or interactions between species. Habitat availability is altered in urban areas, which may affect insect prey availability and interspecies interactions. Our objectives were to use mobile acoustic monitoring to determine when bat species were active in a single night in urban and nonurban sites and if nightly bat activity patterns differed in urban versus nonurban sites. Bat echolocation call sequences were recorded using Anabat acoustic detectors while driving transects through the night at five sites (three “urban” and two “nonurban”) located in the Piedmont region of north-central North Carolina from May through August 2016. Transects were driven three times per night starting 45 min, 180 min, and 300 min after sunset. Recorded echolocation call sequences were analyzed manually using AnalookW and automatically using Bat Call Identification and Echoclass software. Total bat activity was not different between urban and nonurban sites. However, total bat activity was lower later in the night in urban sites, but stayed the same in nonurban sites. Species specifically, there were more Eptesicus fuscus, Lasionycteris noctivagans, and Tadarida brasiliensis call sequences and fewer Lasiurus borealis, Nycticeius humeralis, and Perimyotis subflavus call sequences in urban sites than nonurban sites. There were also fewer E. fuscus, L. noctivagans, and N. humeralis call sequences later in the night in both urban and nonurban sites. Only Lasiurus borealis activity in urban sites later in the night reduced and L. borealis activity in nonurban sites remained at the same. These results suggest that bats in urban areas partition time differently, which is important to consider for urban conservation efforts and planning.     

Effects of urban structure on plant species richness in a large European city

Urban areas have developed under anthropogenic impact and hence feature strongly altered environmental conditions that influence today’s plant species distribution. Generally, urban areas are rich in plant species, but on smaller scales richness can vary considerably. Our study aim is to identify areas of high species richness and to assess richness distribution patterns in the city of Hamburg by analyzing a floristic mapping dataset on the scale of 1 km². Differences in plant species richness were analyzed between three urbanization zones. With multiple regression analyses, we tested effects of urban structure, habitat, and environmental conditions on the distribution of species richness measures. Total species richness per 1 km² was 274?±?60 on average and differed only slightly between the urbanization zones. It increased with habitat diversity and decreased with Ellenberg indicator values (EIV) for nutrients (multiple R²?=?0.31). Proportion of non-native species increased with mean annual temperature and decreased with EIVs for moisture (multiple R²?=?0.72), while proportion of endangered species increased with EIVs for moisture and decreased with EIVs for nutrients (multiple R²?=?0.66). Proportion of thermophilic species (multiple R²?=?0.58) could be explained by mean annual temperature. The emerging patterns probably differ from those in other cities due to the central port harboring a particular flora. Besides the expected high proportions of non-native species, high proportions of endangered species were also found in this area. Our results contribute to identifying drivers of biodiversity in cities and can thus be used to develop measures for the conservation of urban biodiversity.     

Influence of habitat type and distance from source area on bird taxonomic and functional diversity in a Neotropical megacity

The Neotropical region has been subjected to massive urbanization, which poses high risks for some global biodiversity hotspots and losses of ecosystem functions and services. In this study, we investigate how distance from large patches of native forests (source areas) and vegetation (green)/and infrastructure (gray) characteristics affect bird species richness and functional diversity in São Paulo megacity, southeastern Brazil. We analyzed the effects of source areas and green/gray characteristics on species richness and functional diversity (richness, evenness, and divergence) indices. We detected 231 bird species, and our data confirmed our predictions: (1) bird species richness in urbanized habitats was found to be (~?50–85%) lower than in source habitats; (2) species richness and trait composition significantly decreased as the distance from the source area increased, while functional richness was not affected by this metric; and (3) shrub and herbaceous covers and maximum height of trees were positively correlated with species richness and unique functional traits regarding habitat, diet, foraging and nesting strata and dispersal ability of birds in the forest-urban matrix. The number of buildings was negatively correlated with bird species richness and functional richness. Maximum height of buildings caused dramatic declines in functional evenness. Functional divergence was notably lower in sites with high shrub cover. Our study stresses the complexity of vegetation embedded in large Neotropical urban settlements and the need to maintain large protected areas surrounding megacities to mitigate the impacts of urbanization on birds.

     

Habitat type,food resources,noise and light pollution explain the species composition,abundance and stability of a winter bird assemblage in an urban environment

At present, urban areas cover almost 3% of the Earth’s terrestrial area, and this proportion is constantly increasing. Although urbanization leads to a decline in biodiversity, at the same time it creates extensive habitats that are exploited by an assemblage of organisms, including birds. The species composition and density of birds nesting in towns and cities are determined by the types of buildings, the structure and maturity of urban greenery, and habitat diversity. In contrast, the habitat traits shaping the community of birds wintering in urban areas are not known. The aim of this work was to assess the influence of habitat structure, food resources and the urban effects (pollution, noise, artificial light) on an assemblage of birds overwintering in an urban area. It was carried out in 2014 and 2015 in the city of Kraków (southern Poland), on 56 randomly chosen sample plots, in which the composition, density and interseasonal similarity of bird assemblage were assessed with line transect method. A total of 64 bird species (mean = 17.7 ± 4.9 SD species/plot) was recorded. The mean density was 89.6 ind./km ±63.3 SD. The most numerous species were Great Tit Parus major, Magpie Pica pica, Blackbird Turdus merula, Blue Tit Cyanistes caeruleus, Rook Corvus frugilegus, Fieldfare Turdus pilaris and House Sparrow Passer domesticus. Noise adversely affected species numbers and density, but artificial light acted positively on the density of birds and their interseasonal stability. The species richness and density of birds were also determined by the number of food sources available (e.g. bird-feeders). In addition, the greater the proportion of open areas, the fewer species were recorded. In contrast, the more urban greenery there was, the greater the density of the entire bird assemblage. Urban infrastructure (buildings, roads, refuse tips) had a positive effect on the interseasonal stabilization of the species composition of wintering birds. The results of this work indicate that the urban effect, i.e. noise and light pollution, apart from purely habitat factors, provide a good explanation for the species richness, density and stability of bird assemblage wintering in urban areas.     

Composition,distribution and habitat effects of vascular plants on the vertical surfaces of an ancient city wall

The vertical surfaces of walls accommodate diverse plants in urban areas. Characterizing species composition and distribution of plants growing in these habitats is of great significance towards a better understanding and management of urban ecosystems. Here we focused on the City Wall of Nanjing (CWN), one of the biggest and best reserved ancient masonry city walls in the world. Through detailed field survey, we investigated species composition, richness and cover of the vascular plants on the CWN, and examined their relationships with a set of local habitat factors including aspect, position, height of the wall and ground vegetation status, using canonical correspondence analysis and multiple regression models. In total we found 67 plant species on the CWN. They are mostly widespread ruderal plants, with a conspicuously high proportion of vine species. Surprisingly, we found that the investigated habitat factors generally have weak correlations (R ² < 10 %) with species composition, species richness and plant cover. The relationships remain weak when specified in different species groups in terms of life forms and seed dispersal traits. However, these species groups appear to have distinct responses to particular micro-habitat conditions such as light and intensity of human activities. Our results provide useful implications for protecting the walls and enhancing ecosystem services of their associated vegetation.

     

Bat boxes in urban non-native forests: a popular practice that should be reconsidered

Impact mitigation practices are currently one of the hottest topics in conservation and regarded as priorities worldwide. Forest bat populations are known to provide important ecosystem services such as pest control and bat boxes have become one of the most popular management options for counteracting the loss of roosts. However, bat boxes tend to be employed in non-native forests near highly humanized areas where human disturbance is higher. The aim of this study was to evaluate how the surrounding landscape composition affects bat box occupancy in urban non-native forests along the Mediterranean corridor in the Northeastern Iberian Peninsula. Two hundred wooden bat boxes were monitored in young non-native forests in the period 2004–2012. The influence of land cover on occupancy rate of bat boxes was analysed at the landscape level in a 5 km buffer around bat-box stations. In total, 1659 inspections were carried out, in which a 15 % occupancy rate was detected. Bat boxes hosted three different species (Pipistrellus pygmaeus, Pipistrellus kuhlii and Nyctalus leisleri). More than 70 % of the occupancy can be explained by habitat and spatial composition. The presence of urban areas around bat boxes tends to have a negative impact on bat occupation rates; by contrast, forest coverage has a positive effect, especially for the tree-dwelling bats. These patterns could be associated with the large number of available roosts in buildings, microhabitat or phylopatry. Thus, to increase success, we suggest that landscape composition should be considered when using bat boxes for conservation.     

Renaissance of a rural artifact in a city with a million people: biodiversity responses to an agro-forestry restoration in a large urban traditional fruit orchard

The rural landscapes surrounding large cities are rapidly becoming incorporated into the urban environment. The most conspicuous changes involve green spaces, such as former agro-forestry systems like fruit orchards. In this paper, we assess the influence on biodiversity of restoring a large urban traditional fruit orchard as reflected by six selected taxa: plants, lichens, butterflies, beetles, orthopteroids and birds. The study was performed in Prague, which is the capital city of the Czech Republic and has more than a million inhabitants. We studied the effect of orchard renewal in 45 patches (15 for birds and 30 for other taxa). The majority of taxa responded positively to the restoration. The restoration had a significant positive effect on the species richness of lichens, butterflies and beetles. All taxa showed significantly altered species compositions, and the number of red-listed species increased. Orchards have a high potential for multi-functional use. Orchards are productive agro-forestry systems and host numerous possible human activities. Therefore, orchard restoration also has a social aspect. Moreover, our research in this artificial ecosystem revealed that its restoration increased the biodiversity and conservation potential of the associated areas.

     

Are invasive House Sparrows a nuisance for native avifauna when scarce?

Biological invasions are the second most important cause of species extinction. Aided by processes such as transportation and urbanization, exotic species can establish and spread to new locations, causing changes in the function and structure of ecosystems. The House Sparrow is a widespread and highly abundant landbird associated to human presence. Previous studies performed in urban landscapes have suggested that this species could be acting, in synergy with urbanization, as a potential threat to native urban avian assemblages. In this study we assessed the relationship between House Sparrow density and native bird species richness in a region where the sparrows are scarce and sparsely distributed. We surveyed bird assemblages in and around four small-sized human settlements, considering three conditions in relation to House Sparrow presence: urban invaded, urban non-invaded, and non-urban non-invaded. To assess the potential detrimental role of House Sparrows on native bird species richness, we measured, additionally to sparrow densities, 20 predictor variables that describe vegetation structure and complexity, as well as urban infrastructure and human activities across four seasons of 1 year. Our results show that maximum shrub height was positively related to bird species richness, built cover was negatively associated with it, and House Sparrow invaded sites were related to a significant decrease of bird species richness, with increasing richness loss when more sparrows were present. Thus, we here provide evidence that urban areas can act in synergy with the presence of House Sparrows (even in low densities) in the urban-related species richness decline pattern.

     

Butterflies in the city: a review of urban diurnal Lepidoptera

Human migration to urban centers has resulted in diverse environmental disturbances that affect biodiversity. Although urbanization has been highlighted as one of the main drivers of biodiversity endangerment, this topic is still poorly studied in many countries. In order to establish the status quo of the ecology of butterflies in urban centers, we gathered publications focused on urban butterflies (Lepidoptera). We compiled a total of 173 studies from 37 countries and more than 110 urban areas, including published papers and theses (1956–2015). Most papers (69 %) addressed ecological topics, 14 % were focused on biological conservation, and 17 % corresponded to species lists. In summary, most studies revealed a negative impact of urbanization intensity on butterfly diversity (richness and abundance). In fact, we found studies reporting local extinctions due to urbanization, highlighting the causes related to them. The study of charismatic urban wildlife groups, such as butterflies, is a promising field, as there are still important gaps in our comprehension of the ecological patterns and processes that occur in urban areas. Undoubtedly, understanding the response of butterflies to urbanization will aid in the development of urban biodiversity management, planning, and conservation strategies worldwide, which together with knowledge of other wildlife groups and socioeconomic variables, will lead us to more sustainable, livable, and biodiverse cities.     

Effects of artificial night lighting on endangered ocelots (Leopardus paradalis) and nocturnal prey along the United States-Mexico border: A literature review and hypotheses of potential impacts

Artificial night lighting is one of the least studied outcomes of urbanization. While the effects of night lighting on mammals and their habitats seem obvious, they remain difficult to quantify. By reviewing laboratory and field studies conducted on mammals since 1943, this paper summarizes the most salient effects of artificial night lighting on activity patterns and behavior. These studies assist us in generating hypotheses regarding the effects of lights, erected across the militarized U.S.-Mexico border, on the endangered Ocelot and its nocturnal prey. We predict that activity patterns for Ocelots and their nocturnal prey would be altered under artificial night lighting conditions. Specifically, evening activity levels would either be reduced or redirected towards areas with dense vegetation. In addition, Ocelot foraging success would likely be altered as a result of turning night into day. Recommendations are made for Ocelot recovery and future research on surrogate species.     

How small cities affect the biodiversity of ground-dwelling mammals and the relevance of this knowledge in planning urban land expansion in terms of urban wildlife

Fundamental principles regarding urban biodiversity are based on studies conducted in large cities. However we cannot know whether the same phenomena occur in smaller cities or how small cities affect biodiversity. Small cities are an inherent element of urbanization and in the future, most global urban growth is expected to take place in small and medium-sized cities. Understanding the effects of small cities on biodiversity will be an important aspect in planning urban land expansion. Our study examined the effects of a small city on communities of small ground-dwelling mammals on 41 sites arranged in a four step gradient of urbanization. In 6700 trap-days, we caught 2333 individuals comprising 15 species. In the downtown area the same phenomena as those described for large cities were observed: a reduction in species richness and diversity, a decline in the abundance of urban sensitive species and an increase in synurbic species. However, in contrast to large city studies, green areas outside the downtown area did not differ from rural sites in small mammal population parameters. This phenomenon of relatively unchanged fauna outside the downtown area shows that small cities have the potential to maintain a high level of diversity of small ground-dwelling mammals if appropriate planning of further building expansion is implemented. More studies of small cities are needed to better assess their impact on biodiversity. This knowledge can then be applied in better planning for urban wildlife. Generalizations based solely on large city studies are inadequate and may lead to incomplete or inappropriate conservation strategies for small cities.     

Perimeter-area ratio effects of urbanization intensity on forest characteristics,landscape patterns and their associations in Harbin City,Northeast China

To maximize the ecological services of urban forests, a better understanding of the effects of urbanization on urban forest characteristics, landscape metrics, and their associations is needed for landscape-related regulations in space-limited green infrastructure of metropolitan regions. In this study, Harbin, a typical fast-growing provincial-capital city in Northeast China, is used as a case study. Based on remote sensing images, field surveys, and correlation and variation partitioning analyses, we conclude that landscape characteristics and forest attributes have large variations among different urbanization intensity (UI) regions. Forest patch density (PD), landscape shape index, woody plants species richness, and the Shannon–Wiener index (H′) increased linearly, while stem section area and tree height decreased linearly with the increasing of UIs. UI had a greater influence on tree size and forest community attributes than the forest landscape pattern. Accordingly, any landscape regulation on forest attributes should be implemented according to UIs. In addition, Euclidean nearest neighbor distance(ENN-MN), mean perimeter-area ratio (PARA-MN), fractal dimension index(FRAC-MN), and PD could probably indicate forest attributes the most, e.g., the increase of PARA-MN may be accompanied with taller trees in low and heavy UI regions, but lower woody plants species evenness in low and medium UI regions. More diversified woody plants species, and afforested areas should be advocated in a low UI region, while in a heavy UI region, the conservation of large trees should be implemented. Our results highlight that the implementation of urban forest management should vary according to different urbanization regions to maximize ecological services.

     

Distribution of neotropical migratory bird species across an urbanizing landscape

Urbanization leads to long-term modification of landscapes by habitat loss, fragmentation, and the creation of new habitats. Species’ distributions respond to these modifications of habitat availability, but the combination of parameters and scale at which habitat alteration most strongly influences species distributions is poorly understood. We evaluated responses of neotropical migratory birds, a group known to be sensitive to habitat modification, across a gradient of urbanization in the southeastern United States. Thirteen Breeding Bird Survey routes, each with 40 to 50 point counts, were used to quantify species richness across the gradient of urbanization extending from downtown areas of Columbus, GA to natural woodlands. Buffers of 100, 200, and 1000 m radii were constructed from remote images around each counting point to quantify land-use with the goal of evaluating land-use parameters and scales that best described spatial variation in migrant bird species richness. Within each buffer we quantified the proportion of each cover type and within the 1000 m buffers we included several configuration parameters. We used an information-theoretic approach to separate models whose predictor variables were land-use parameters. Because measures of landscape configuration were all correlated with urban cover, these variables were entered separately. In 2002, the best model was composed of large-scale urban cover (negative effect) and mid-scale mixed hardwoods (negative and positive effect) and transitional cover (negative and positive effect) as well as the interaction between the latter two terms (positive effect). In 2003, the best model was composed of weighted edge density (negative effect), mid-scale mixed hardwood cover (negative and positive effect) and large scale transitional cover (positive effect) and the interaction between mixed hardwoods and weighted edge density (positive effect). Our results indicate that large scale habitat attributes influence the local species richness of migrant birds more than smaller scales. These results also indicate that urbanization, through increased urban cover or increasing edge contrast, has strong negative effects on species richness. Our findings support the contention that the conservation value of small woodlots in urban settings may be minimal and suggest that conservation of migratory birds will be best achieved by giving higher priority to sites where urban cover is still low and by preserving large areas of “green space” in urbanizing landscapes. The negative influence of urban cover combined with relatively minor effects of non-urban habitats on distributions of neotropical migratory birds indicates that continued urbanization of landscapes is a serious concern for conservation efforts.