Urban Noise and Surrounding City Morphology Influence Green Space Occupancy by Native Birds in a Mediterranean-type South American Metropolis

Urban green spaces provide natural habitat for birds in urban landscapes, yet the effects of noise and surrounding urban morphology on bird community structure and distribution are not well understood in Latin America, the second most urbanized region in the world. Santiago of Chile is the single city belonging to the Mediterranean ecosystem in South America and is subject to extensive urbanization as seen throughout Latin America. We examined the role of 65 urban green spaces (6 large: PAR and 59 small: SGS) in harboring native birds during winter 2019, analyzing the quality of green areas in terms of vegetation (i.e. NDVI, native vegetation, and tree cover), exotic bird species, noise levels, and surrounding urban matrix (i.e. building height and cover). Significantly higher noise levels were detected in SGS, along with significantly greater exotic bird (n=4) richness and abundance than PAR, which possessed significantly greater native bird (n=25) richness and abundance. Native birds were more abundant than exotic birds in green spaces with average noise levels < 52 dB and average NDVI > 0.5. Occupancy models indicate that green space occupancy by 50% of modeled native bird species was influenced by maximum noise levels, playing a larger role than vegetation (30%) and the urban matrix (0%). We stress the importance of developing networks of large green spaces in rapidly urbanizing regions, with abundant tree cover, surrounded by smaller urban morphology, and regulating noise levels to ensure the conservation of native bird communities in cities, particularly those that are threatened.

Wildlife is imperiled in peri-urban landscapes: threats to arboreal mammals

Urbanization and deforestation impose severe challenges to wildlife, particularly for forest-living vertebrates. Understanding how the peri-urban matrix impacts their survival is critical for designing strategies to promote their conservation. We investigated the threats faced by brown howler monkeys (Alouatta guariba clamitans) in peri-urban regions of Rio Grande do Sul (RS) and Santa Catarina (SC) states, southern Brazil, by compiling conflicts reported over more than two decades. We assessed the major conflicts, their distribution among age-sex classes, and the predictors of conflict-related mortality using GLMMs. After 20+ years of monitoring, we compiled 540 conflicts (RS=248 and SC=292). Electrocution in power lines was the most frequent cause of death or injury (37%), followed by dog attack (34%), run over (17%), and human mistreatment (12%). The occurrence of lethal injuries ranged from 5% to 69% depending on the type of conflict and state. The overall post-conflict mortality was 56%. Adult males and females were the major victims in both states. The minimal adequate GLMM explained 83% of the variation in conflict-related mortality. State, conflict type, and age-sex class were the main predictors of mortality. Overall, mortality was lower in SC and after human mistreatment, and higher among adult females than in the other classes. We found that the survival of brown howlers in the forest-urban interface is constrained by both the urban infrastructure and the growing interactions with humans and domestic and stray dogs. We propose the placement of aerial bridges, road signs and speed bumps in areas of frequent animal crossing, the sterilization of stray dogs, and the sensitization of local inhabitants on the importance of respecting and protecting wildlife to reduce their conflicts with humans and domestic animals in the forest-urban interface.

Bioindicator snake shows genomic signatures of natural and anthropogenic barriers to gene flow

Urbanisation alters landscapes, introduces wildlife to novel stressors, and fragments habitats into remnant ‘islands’. Within these islands, isolated wildlife populations can experience genetic drift and subsequently suffer from inbreeding depression and reduced adaptive potential. The Western tiger snake (Notechis scutatus occidentalis) is a predator of wetlands in the Swan Coastal Plain, a unique bioregion that has suffered substantial degradation through the development of the city of Perth, Western Australia. Within the urban matrix, tiger snakes now only persist in a handful of wetlands where they are known to bioaccumulate a suite of contaminants, and have recently been suggested as a relevant bioindicator of ecosystem health. Here, we used genome-wide single nucleotide polymorphism (SNP) data to explore the contemporary population genomics of seven tiger snake populations across the urban matrix. Specifically, we used population genomic structure and diversity, effective population sizes (Ne), and heterozygosity-fitness correlations to assess fitness of each population with respect to urbanisation. We found that population genomic structure was strongest across the northern and southern sides of a major river system, with the northern cluster of populations exhibiting lower heterozygosities than the southern cluster, likely due to a lack of historical gene flow. We also observed an increasing signal of inbreeding and genetic drift with increasing geographic isolation due to urbanisation. Effective population sizes (Ne) at most sites were small (< 100), with Ne appearing to reflect the area of available habitat rather than the degree of adjacent urbanisation. This suggests that ecosystem management and restoration may be the best method to buffer the further loss of genetic diversity in urban wetlands. If tiger snake populations continue to decline in urban areas, our results provide a baseline measure of genomic diversity, as well as highlighting which ‘islands’ of habitat are most in need of management and protection.

Noisy Urbanization: Green Space Occupancy By Native Birds in a Mediterranean-Type South American City

Urban green spaces provide natural habitat for birds in city landscapes, yet the effects of noise and surrounding urban morphology on bird community structure and distribution are not well understood in Latin America, the second most urbanized region in the world. Santiago, Chile, located in the epicenter of the single portion of Mediterranean ecosystem in South America, is subject to extensive urbanization seen throughout Latin America. We examined the role of 65 urban green spaces (6 large: PAR and 59 small: SGS) in harboring native birds during winter 2019, analyzing the quality of green areas in terms of vegetation (i.e. NDVI, native vegetation, and tree cover), exotic bird species, noise levels, and surrounding urban matrix (i.e. building height and cover). Significantly higher noise levels were detected in SGS, along with significantly greater exotic bird (n=4) richness and abundance than PAR, which possessed significantly greater native bird (n=25) richness and abundance. Native birds were more abundant than exotic birds in green spaces with average noise levels < 52 dB and average NDVI > 0.5. Occupancy models indicate that green space occupancy by 50% of modeled native bird species was influenced by maximum noise levels, playing a larger role than vegetation (30%) and the urban matrix (0%). We stress the importance of developing networks of large green spaces in rapidly urbanizing regions, with abundant tree cover, surrounded by smaller urban morphology, and regulating noise levels to ensure the preservation of native bird communities in cities, particularly those of greater conservation value.

Impact of Urbanization to an Island and the Continent: Species Turnover and Nestedness in Neotropical Bird Assemblages

Islands are well-known as particular and vulnerable ecosystems with evolutionary histories, environmental characteristics, and original communities different from those of continents. On the contrary, urban environments are recent, artificial, and structurally similar among distant regions. To assess the relative importance of regional and local processes on urban biota, we chose two urban environments, i.e., one on the mainland and another on an island in the same ecoregion. We asked whether the urbanization process affects the avian biodiversity of the ISLAND in the same way as in the continent. We defined an urban gradient with three levels of building density, namely, patches of native vegetation (remnant woodlands in the urban matrix), medium density urbanized areas that maintain vegetation along the streets and gardens, and residential areas with less vegetation cover and higher building density. In each geographical locality, we selected three sites (replicates) for each level of the urban gradient and did bird surveys. We found two times as many species in the urban landscape of the continent (69) as on the island (35), with the analogous richness decrease along the gradient in both regions. Species similarity was higher between urbanized sites of both regions compared with the similarity between woodlands and urbanized sites, showing that urban matrix filters similar species of each pool regionally. Individual species responded to urban structure in different ways. We found 32% of bird species were urban exploiters, 48% urban tolerant, and 20% urban avoiders in both regions. However, some species showed different frequencies of occurrence on the island and the continent. Species turnover contributed more than richness differences to species dissimilarity along the urban gradient on the continent. Contrarily, the nestedness component (i.e., species being a strict subset of the species at a richer site) was higher on the island. We concluded that the negative impact of highly urbanized areas on birds was stronger on the island than on the continent. Our results may help to assess the implications of beta-diversity loss, especially on islands.

Effects of Urban Matrix on Plant Diversity of Urban Remnant Mountains in Karst Area: A Case Study of Guiyang, Guizhou Province, China.

With the rapid development of urbanization, large numbers of cone-shaped or tower-shaped isolated peaks and peak forest were surrounded by a human-dominated urban matrix in the process of urban expansion in Karst areas,forming urban remnant hills (URHs), which are important resources of indigenous plant diversity from the urban environment in these areas.Although the studies on urban plant diversity have been extensive, studies on the plant diversity of the remnant habitats, especially those based on URHs,is very weak.In this study, a total of 143 sample plots were set up on 15 hills based on the combination of slope direction and elevation.Alpha diversity was calculated at four levels, i.e.,tree,shrub,herb and whole plant.Four urban matrix characteristic indices,namely,percent total impervious surface area (PTIA),land use,vegetation coverage (VC) and fragmentation indices (FIs),were measured for each hill.Twenty scales, ranging from 100 m to 2000 m and with increasing steps of 100 m,were used as spatial scales.Pearson correlation analysis and linear regression model were used to study the relationship between URHs plant diversity indices and urban matrix indices.The results showed the following:(1)There was a significant positive correlation between the overall plant diversity of URHs of different sizes and PTIA in the surrounding urban matrix within 1600 m.The overall plant diversity of URHs of different scales was significantly correlated with single or multiple Land-use types.There was no significant correlation between VC,FI and URHs overall plant diversity.(2)There was a significant linear relationship between plant diversity at all levels of different scales URHs and the four urban matrix indices.In addition to the small URHs herbaceous diversity,plant diversity at all levels of URHs was jointly affected by double or multiple factors at the 1800 m spatial scale. plant diversity of URHs of different scales in hilly Karst cities are extremely complex under the combined action of multiple factors and multiple scales.

Supporting Bees in Cities: How Bees Are Influenced by Local and Landscape Features

Urbanization is a major anthropogenic driver of decline for ecologically and economically important taxa including bees. Despite their generally negative impact on pollinators, cities can display a surprising degree of biodiversity compared to other landscapes. The pollinating communities found within these environments, however, tend to be filtered by interacting local and landscape features that comprise the urban matrix. Landscape and local features exert variable influence on pollinators within and across taxa, which ultimately affects community composition in such a way that contributes to functional trait homogenization and reduced phylogenetic diversity. Although previous results are not easily generalizable, bees and pollinators displaying functional trait characteristics such as polylectic diet, cavity-nesting behavior, and later emergence appear most abundant across different examined cities. To preserve particularly vulnerable species, most notably specialists that have become underrepresented within city communities, green spaces like parks and urban gardens have been examined as potential refuges. Such spaces are scattered across the urban matrix and vary in pollinator resource availability. Therefore, ensuring such spaces are optimized for pollinators is imperative. This review examines how urban features affect pollinators in addition to ways these green spaces can be manipulated to promote greater pollinator abundance and diversity.

Thinking outside the park: recommendations for camera trapping mammal communities in the urban matrix

Urbanization is increasing globally, fragmenting habitats and prompting human–wildlife conflict. Urban wildlife research is concurrently expanding, but sampling methods are often biased towards large and intact habitats in public green spaces, neglecting the far more abundant, but degraded, habitats in the urban matrix. Here, we introduce the Five P’s of Urban Ecology—Partnerships, Planning, Placements, Public participation and Processing—as a path to overcoming the logistical barriers often associated with camera-trapping in the urban matrix. Though the Five P’s can be applied to a variety of urban sampling methods, we showcase the camera-trapping efforts of the DC Cat Count project in Washington, DC, as a case study. We compared occupancy models for eight urban mammal species using broad categorizations of land cover and local land use to determine drivers of mammal occurrence within the urban matrix as compared with urban habitat patches. Many native species maintained a strong association with large, semi-natural green spaces, but occupancy was not limited to these locations, and in some cases, the use of private yards and the built environment were not notably different. Furthermore, some species exhibited higher occupancy probabilities in developed areas over green spaces. Though seemingly intuitive, we offer advice on how to greatly reduce habitat-biased sampling methods in urban wildlife research and illustrate the importance of doing so to ensure accurate results that support the formation of effective urban planning and policy.