Urban Ecosystems最新文献

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.

Large old trees (LOTs) are important ecological assets that contribute significantly to biodiversity, ecosystem functioning and local culture. This study analyzed the abundance, species composition, spatial and altitudinal distribution patterns, and conservation needs of LOTs in Baisha County, tropical southern China. We conducted a comprehensive field survey of 301 LOTs and recorded their biological characteristics, geographical locations, and environmental conditions. Species importance values were calculated, and the spatial distribution was analyzed using GIS techniques. Redundancy analysis (RDA) examined the relationships between LOT diversity and environmental factors. The results indicated a complex and diverse stock dominated by species from the Moraceae family, particularly of the genus Ficus. The structural analysis displayed a skewed age distribution, with a higher frequency of younger trees and a decline in older classes. Spatial analysis showed that LOTs are concentrated in the northwestern and central areas and are favored by microclimatic conditions, soil types, and historical land-use practices. The abundance and species richness of LOTs were greater at intermediate elevations. Redundancy analysis highlighted the intricate relationships between LOT diversity, abundance, and socioeconomic factors. This study provided crucial insights into the ecology and conservation requirements for LOTs in Baisha. The findings underscored the importance of targeted conservation efforts, particularly for older trees and mid-elevation habitats. We recommended integrating ecological research, long-term monitoring, traditional ecological knowledge, and community involvement in formulating conservation strategies to preserve these ecologically and culturally significant trees for future generations.

Urban areas with low tree cover in Brazil are found mainly in the Amazon, highlighting the disparities in access to benefits of urban greening. The goal of this study was to analyze how urban afforestation is associated with sociodemographic factors to understand the distribution of trees (and their benefits) among different social segments in the city of Macapá, in the extreme Northeastern Amazon. We conducted a floristic inventory in 217 blocks belonging to 32 neighborhoods, and classified species according to origin (exotic or native) and fruit use (fruit-bearing or non-fruit-bearing). Additionally, we selected 12 variables to represent sociodemographic gradients among neighborhoods. We reduced the dimensionality of floristic and sociodemographic data using ordination techniques, and used their first axes to represent gradients of species composition and sociodemographic factors. The effect of sociodemographic gradients on tree abundance, species richness and composition was tested using generalized linear models. The results indicate that most urban trees are exotic, non-fruit-bearing, and of medium size (10–30 cm in diameter). Older neighborhoods with higher human population age and income showed higher tree abundance and higher species richness. The species composition was related to the gradient of human population density, proportion of old people, income, and household occupancy. Large non-fruit trees were more frequent in neighborhoods with low population density. Exotic trees were more frequent in older neighborhoods with older people and high income, and large fruit trees showed higher abundance in neighborhoods with low household occupancy rates. Ensuring that low-income neighborhoods and historically marginalized communities have equal access to green spaces and adequate tree coverage is a key element to promote environmental justice and to develop healthier and more sustainable cities.

This study analyzed urban forests in cities of the state of Minas Gerais, Brazil, aiming to explore the floristic composition, determine whether native or exotic species predominate, and investigate whether the biome of origin influences species composition. A survey of floristic studies in urban areas conducted in 2002–2023, utilized four databases: Google Scholar, Scopus, Scielo, and Web of Science. The search used the following descriptors: "qualitative analysis", "urban afforestation", "urban forest", "urban green spaces", and "Minas Gerais". Species were classified by origin, i.e., native or exotic, and in relation to their biome (Atlantic Forest, Cerrado, and Caatinga). A total of 407 species were identified, with 56% classified as exotic. The floristic profile of the urban forest was characterized by high richness of Fabaceae and significant representation of species such as Cenostigma pluviosum, Moquilea tomentosa, Terminalia catappa, Ficus benjamina, and Murraya paniculata. A Wilcoxon test revealed a significantly higher number of exotic species than natives. Based on the results of non-metric multidimensional scaling, along with cluster analysis, it was confirmed that the species composition of the urban forest is not related to the biome of origin or associated with the mesoregions of Minas Gerais, demonstrating biotic homogenization. In conclusion, the notable number of exotic species highlights a lack of planning by municipal authorities in developing a Green Infrastructure System. We recommend that species selection for the urban forest composition consider ecological, economic, and sociocultural criteria, consider the biome of local ecosystems, and prioritize the native indigenous species.

Urbanization profoundly alters natural landscapes, leading to changes in species assemblages and ecological interactions. Despite increasing interest in understanding the effects of urbanization on species interactions, there is still a gap in knowledge regarding the structure of plant-herbivore networks in urban environments. Previous studies have indicated that anthropogenic impacts can alter the topology of plant-herbivore networks, making them more generalized in disturbed environments. Here, we investigate the topology of a plant-herbivore network in urban fragments of neotropical savanna in Brazil. As specialist species (i.e., those with few interactions) tend to be more sensitive to urbanization than generalist species (i.e., those with many interactions), we hypothesized that the urban savanna network would exhibit low specialization and modularity but high nestedness. We also tested if different attributes of insects (abundance, feeding guild, developmental stage, and taxon) and plants (abundance, height, and coverage) affect the diversity of their interactions at the species level. Contrary to our expectations, the network exhibited higher specialization and modularity than expected by null models, indicating urban environments may foster levels of specialization comparable to observed in previous studies for wild savannas. Regarding the species-level descriptors, we found that different characteristics of insect and plant species affect the diversity and specialization of their interactions. Our results showed that adult insects have higher degree and centrality in shaping the network, possibly attributed to their increased mobility and capacity to link various segments of the network. Similarly, chewing insects and thrips (Thysanoptera), known for their generalist interactions with plants, had higher number of interactions and were central within the network. Furthermore, larger plant species had a higher degree and greater betweenness centrality, while plant species with greater cover had lower specialization compared to herbs. This indicates that plant species with greater structural complexity accumulate more generalized interactions. Our results also show that more abundant species, both insects and plants, had a higher number of interactions and greater centrality in the network. Our study provides insights into the structure of plant-herbivore networks in urban savanna fragments, contributing to our understanding of species interactions in urban environments and their response to anthropogenic pressures.

Rats are a problem in cities worldwide, particularly in low-income neighborhoods. Urbanization works (e.g. construction, excavations, demolition, etc.) in these neighborhoods must be a priority to improve the quality of life of their residents. The disturbances generated by these works can destroy the habitats of rodents, forcing them to seek new shelters in nearby areas, such as homes and human structures, taking advantage of rubble and construction materials that offer ideal conditions for their survival. However, limited research has focused on how infrastructural works affect the dispersion of rodents to surrounding areas. The current study aimed to evaluate the effectiveness of a rodent control program implemented during infrastructural works and its effect on the spatiotemporal dynamics of rodent population in a low-income neighborhood in Buenos Aires, Argentina. For three months, multiple infrastructural works were carried out in the neighborhood. Rodent control measures and estimation of rodent activity were carried out jointly by installing chemical box stations and contact glue traps throughout the neighborhood. We carried out a generalized additive mixed model to assess spatiotemporal changes and identify factors influencing rodent activity during the infrastructural intervention. Our results revealed that the proximity to construction works affected rodent activity, with higher infestations closer to work sites. However, after the initial 30-day period, rodent activity increased with distance. Also, remote sites located more than 150 m away exhibited a constant level of rodent activity throughout the entire study period. The findings suggest that rodent control strategies should prioritize control interventions within a 150-meter radius for at least the first month following the commencement of construction works. This ecological knowledge contributes to form a robust framework for evidence-based rat management in urban environments and provides valuable insights for urban planners, pest control professionals, and public health authorities.

Seed dispersal has been an indispensable ecosystem process mediated by biotic and abiotic vectors. Animal-mediated seed dispersal, such as endozoochory, has supported plants to sustain and establish in new locations. However, increasing urbanisation make feces deposition sites as a detrimental factor for the successful seed establishment. In this regard, this study explores the deposition of feces across the eight natural urban forest fragments with varying urbanisation rates in Tokyo-Yokohama, one of the largest urban agglomerations in the world. Paved roads within the forest fragments were surveyed for feces deposition and the urbanisation rate was estimated for all the studied sites. We found 1381 feces deposited on the paved roads, with the highest in ‘Sagamihara Chuo green space’ (n = 673) and the second highest in ‘Yokohama National University’ forest area (n = 488). This study revealed a strong influence of urbanisation on feces deposition in the forest fragments. Birds were the prominent group of animals that deposited feces on paved roads. This is the first study systematically showing the influence of urbanisation on transforming the seed dispersal service by animals into potential low services due to seed wastage in feces deposited on paved roads. Urban forest management needs to consider the impact of urbanisation on not just species diversity, but the interactions and services provided by species.