Urban Ecosystems最新文献

Urbanisation is rapidly transforming and fragmenting natural habitats, disrupting ecosystems and negatively impacting biodiversity. The City of Cape Town (CoCT) is situated in a global biodiversity hotspot, but sustained anthropogenic activities have resulted in the local extirpation of most medium and large mammals. A recent survey of mammals within urban protected areas of CoCT revealed that a few, mostly medium-sized generalist species, persist. It is uncertain which native mammal species, if any, inhabit the unprotected green belts and parks in suburban and urban areas of the city. A total of 37 camera trap sites were established along four transects for a period of four months between 31 January and 31 May 2022. A total of 12 terrestrial mammal species were detected, nine of which were wild native mammals and three domestic species. Most detections were in natural habitat followed by suburban, with urban areas having the lowest detection rate of wildlife. Single season hierarchical multi-species occupancy models revealed that tree cover had a significant positive effect on both community and individual species occupancy. Contrary to our predictions, neither human population density nor the extent of the impervious surface at sites significantly affected occupancy. Cape grysbok (Raphicerus melanotis) were significantly more likely to occur at sites with a higher proportion of impervious surfaces supporting other recent research, which showed this species together with water mongoose (Atilax paludinosus) and Cape porcupine (Hystrix africaeaustralis) are one of only a few native mammals that appear to persist and may even thrive in human-modified landscapes. Our findings underscore the complexity of urban biodiversity conservation and the species-specific responses to environmental factors, emphasising the importance of tree cover in urban wildlife management.

Urbanisation is an ongoing process associated with multiple environmental changes affecting ecosystems worldwide. Temperature and habitat are main drivers of animal communities within cities, but quantifying their relative weights remains a challenge, as urban heat islands (UHI) often co-vary with land-cover. This study aims to disentangle the effects and relevant scale of temperature and habitat on ground-dwelling spider communities. Based on an original sampling design, we collected 20,761 spider individuals belonging to 137 species at 36 sampling sites in the city of Rennes (northwest France). We characterised communities by assessing the number of trapped individuals at each site, as well as calculating several metrics to estimate taxonomic and functional diversities. Temperature metrics were obtained from two sensor networks monitoring UHI (100-m resolution) and near-ground temperature (1-m resolution) independently. Land-cover and isolation were used to describe landscapes, and vegetation structure to describe local habitats. We used generalized linear mixed models to disentangle the effects of temperature from those of habitat at the landscape and local scales, and identified relationships between community descriptors and predictors. We show that temperature-related metrics are important predictors of spider communities, and that the landscape and local scales have independent effects. Near-ground temperature alone explained 24% of the number of trapped individuals, whereas UHI explained 20% of taxonomic diversity. Local vegetation height and cover were significant predictors of functional diversity, and explained 22% and 25% of variance, respectively. We conclude that locally applied planning measures could mitigate the loss of taxonomic diversity induced by the atmospheric UHI and promote the establishment of more diverse communities.

Understanding the diversity of nectar sources in urban honey samples is crucial for effectively managing honey bee (Apis cerana indica Fabricius, 1978.) colonies and promoting pollinator health. This study analysed honey samples from various urban locations in Bangalore to assess pollen diversity, foraging behaviour, and the significance of urban flora in supporting beekeeping practices. A total of 39 pollen types were identified, with 62.50% of samples being unifloral, predominantly from Eucalyptus sp., followed by Casuarina equisetifolia, Areca catechu, Citrus sp., Mallotus philippensis, Cocos nucifera, and Ocimum sp. Multifloral samples (37.50%) highlighted the diverse diet available to urban bees, promoting biodiversity within urban landscapes. Major plant families contributing to pollen content included Myrtaceae, Arecaceae and Fabaceae. Seasonal variation in pollen composition reflected shifts in dominant nectar sources, with the monsoon season characterized by Casuarina equisetifolia, Areca catechu, Citrus sp., Mallotus philippensis, and Cocos nucifera, while winter saw Eucalyptus sp. and Ocimum sp. as predominant sources, and summer featured Pongamia pinnata. Cluster analysis found high similarity in pollen composition in honey samples from Bagalur, Yelahanka and M S Palya but distinct pollen in GKVK, suggesting unique conditions and emphasizing the importance of considering spatial variations in beekeeping practices and conservation strategies. This research underscores the importance of floral diversity in sustaining urban bee populations and provides guidance for urban planning and policy decisions to promote pollinator health and urban sustainability.

In urban green space (UGS), diverse acoustic resources are essential for enhancing the public’s well-being, as different sound sources can bring distinct auditory experiences. However, there is a lack of research on the sources-based soundscapes diversity (SSD). In this study, we fill this gap by exploring the characteristics of SSD in different recreational areas of UGSs across three urban gradients in Fuzhou City, China. Additionally, we investigated the relationship between SSD, landscape elements (LEs), and landscape patterns (LPs) at various spatial scales. Our findings identified 53 types of sound sources, predominantly biological sound and anthrophony. The alpha and beta diversity indices effectively characterized SSD in UGSs and captured the differences in three levels of urbanization. Our results showed that urbanization gradients significantly impact soundscape diversity, especially in terms of animal sounds and mechanical sounds. For LEs, we found that trees play a crucial role in enhancing the diversity of animal and recreation sounds, whereas the proportion of buildings negatively correlates with animal sounds. Our analysis between LPs and SSDs revealed a strong correlation between the built environment (mainly roads) and lawn with traffic sound. In contrast, a higher percentage of forest land was associated with more animal sounds and fewer recreational and mechanical sounds. Characterizing urbanization gradients and the factors affecting SSD can be used to guide the development and enhancement of soundscapes in UGS.

In residential landscapes, small neighborhood parks account for a considerable share of urban greenspaces. However, information on their significance for biodiversity conservation is limited. To determine the role of small neighborhood parks as habitat for ground-dwelling arthropods, we evaluated the effects of local and landscape factors on the diversity and traits of carabid beetles, spiders, and ants in small neighborhood parks in Niigata, Japan. Urbanization decreased carabid species richness and abundance, and it altered the species composition of carabids and spiders. The arthropods in urbanized sites were characterized by small-bodied, web-building, highly dispersive spiders, and possibly non-predatory carabids. In contrast, urbanization did not influence any diversity metrics of ants. At the local scale, ground cover, soil moisture, and park border permeability were the major drivers of arthropod diversity. Ground coverage with leaf litter was positively associated with ant occurrence. Soil moisture negatively affected carabid species richness and abundance, whereas it positively affected spider richness. Parks with humid soil conditions favored hunting, low-dispersive spiders. The low permeability of park borders decreased spider richness and altered community structure, which was characterized by highly dispersive, ballooning species. We conclude that small neighborhood parks support numerous species of habitat-generalist arthropods that are adapted to dry and open environments. These parks thus represent an important component of habitat networks in residential landscapes. Managing open environments, protecting litter layers, reducing artificial borders, and retaining other open greenspaces in the surrounding matrix can promote diverse arthropod communities. Such strategies are worth considering during urban planning.

Municipal authorities around the world have come to recognize the importance of making conservation and restoration a priority. Multiple urban restoration programs now foster insects and other pollinators through planting and sowing flowering plants, many of them within residential areas. But residents are not only walking next to pollinators visiting flowering sidewalk grass verges, they are also walking on top of them, nesting in the cracks and interstices of urban pavements.

Combining morphological and molecular monitoring schemes, we conducted a survey of urban pavements at twelve locations across Berlin and found that pavements can foster a surprising number and quantity of soil dwelling insects—in particular wild bees and wasps. Pavements located within 200 m to an insect-friendly flower garden were covered with significantly more nests of wild bees and solitary wasps, and showed higher species richness of these groups, while the degree of sealed surfaces in the surrounding had no effect per se. This underlines the positive impact that insect-friendly gardens can have for pollinators and other insects, even in highly sealed areas. Also, it shows the potential of cobbled pavements as valuable nesting sites in highly sealed urban areas. We provide a list of 55 species of ground-nesting Hymenoptera found in Berlin pavements, including 28 species of wild bees and 22 apoid wasps. In our study, the molecular approach only detected three Hymenoptera species and did not yield comparable results to classical monitoring. Nonetheless, using eDNA methods might be a promising tool for further studying soil nesting insects in the future, and to gain insights into the web of life in urban pavements.

To thrive in urban environments, birds need to make behavioral adjustments to tolerate the disturbances and threats that are imposed by these environments. Birds constantly need to adjust their assessment of predation risk to maximize their fitness in these environments. Such adjustments can be measured through different reaction distances to an approaching predator, such as flight initiation distance (FID) and distance fled (DF). Using these variables, we compared the perceived risk of predation of 12 bird species in formal (i.e., public parks; FGS) and informal greenspaces (i.e., vacant lots; IGS) in a Latin American city. We also compared these behavioral responses between native and exotic species and explored whether different factors, such as predator abundance, disturbance level (e.g., noise, pedestrians), and other reaction distances (e.g., buffer distance), could help us explain an eventual difference of perceived risk of predation in both habitats. We measured 199 distances in individual birds, of which 104 were obtained in FGS and 95 in IGS. Birds in FGS had significantly shorter FID and DF than birds in IGS, but data variability was higher in IGS than in FGS. This suggests that birds perceive FGS as safer habitats than IGS, and/or that birds in FGS are more tolerant to the presence of humans. Exotic birds were bolder (i.e., shorter FID) than native birds, but native birds had more variable FID and DF than exotic birds, suggesting that native birds could eventually become as successful as exotic birds in colonizing urban environments. The FID was better explained by other reaction distances (i.e., starting and buffer distances) than by the abundance of predators or intensity of disturbance. These findings agree with the “flush early and avoid the rush” hypothesis and with the high availability of resources in both habitats. Our results suggest that IGS can provide refuge to fearful birds and at the same time be a source of bolder behavioral phenotypes allowing bird populations to scale their tolerance to urbanization.

Racist public policies in the US, like redlining, segregated many communities of color to resource poor and impoverished areas, and codified how resources were distributed to communities based on race. Redlining, a historic discriminatory housing policy used to value city neighborhoods by race has codified segregation in cities today. Research has shown how the practice of redlining has shaped the economic and social fabric of modern U.S. cities, but only recently have researchers explored how these discriminatory policies have influenced the ecology in cities. Here, we used camera trap data collected in the Washington, D.C. region to assess if historic redlining impacts medium-sized mammal diversity in present day. We found no significant difference in species richness or community composition among historic neighborhood classifications. We did find that urbanization alone had a significant negative correlation with the persistence of raccoon and occupancy of Virginia opossum, but these variables did not vary significantly between housing classifications for any species. Our study adds to a growing body of knowledge on how historic land use decisions affect biodiversity in cities, allowing managers to better understand where conservation and habitat improvements should be made to reduce nature inequalities.

Online platforms have broadened the opportunities of people to interact with nature through community/citizen science, especially in urban areas. However, there is a lack of comprehensive understanding of the social and environmental factors that influence nature interactions in cities. Here, we aim to identify the social and environmental predictors that impact nature interactions, by combining citizen science data with environmental and demographic data in New York City. We applied generalized linear models to identify which of 12 social and environmental factors influence nature interactions in public parks (n = 355) in the Borough of Queens, New York, New York (USA) in two scenarios, small-medium sized parks only (n = 355) and all parks (n = 359). We used iNaturalist records, including the number of users (Observers), Observations, Observed Biodiversity, and a calculated interaction effect (number of users × observations, Interaction), as metrics of nature interactions. For small-medium parks, all nature interactions were significantly influenced by park area, canopy cover, percent population with blood pressure and asthma conditions, noise, and summer mean temperature. Observers and Interaction were positively associated with median income. Observers, Observations, and Interaction were predicted by percent water cover, impervious cover, distance to public transportation, and ethnic diversity. In the analysis that included all parks, the results were similar with minor differences. This study demonstrates a holistic approach to a very specific type of human-nature interaction newly made available with technological advances, seen through an interdisciplinary lens and will help inform planners, residents, and city government on creating more interactive and socio-environmentally beneficial urban green spaces.

It is now well-recognized that urbanization strongly impacts wildlife communities and populations. However, we typically do not know which feature(s) affect individual species most strongly, and this lack of understanding impedes theory development and effective planning for conservation and management goals. To address this knowledge gap, we evaluated how the abundance of ten mammal species responded to six different features of urbanization quantified at five spatial scales using data from 112 camera traps deployed for two years across a gradient of urbanization in New Hampshire, USA. We fit Bayesian abundance models to measure response to each feature and scale. There was no singular urban feature or spatial scale in the best model for all species. Rather, species responded uniquely to features across scales, and the scale of urban features in the best model also varied. Within a species, the magnitude and direction of response varied across features and scales, with only black bear (Ursus americanus), gray fox (Urocyon cinereoargenteus), and Virginia opossum (Didelphis virginiana) exhibiting a consistently significant unidirectional relationship with a single feature across all scales. Our results emphasize that species respond to specific urban features, thus a failure to include certain features can cause misleading inference about wildlife response to “urbanization”. Therefore, researchers must carefully justify the choice of urban feature and spatial scale at which it is represented for each species of interest. An expanded inclusion of multiple urban features in wildlife research will inform management decisions and help attain conservation goals for species impacted by urbanization.