The ecology of urban areas and their functions for species diversity

The Role of Greenery in Stress Reduction among City Residents during the COVID-19 Pandemic

Cities, as places of social interactions and human relationships, face new challenges, problems, and threats, which are sources of stress for residents. An additional cause of stress in recent years has been the COVID-19 pandemic; it was urban dwellers who were most exposed to the virus and most affected by it. Chronic stress has led to the serious erosion of physical health and psychophysical well-being among urban dwellers, and so there is a need to seek new solutions in terms of building the resilience of cities and their residents to stress. This study aims to verify the hypothesis that greenery reduced the level of stress among urban dwellers during the pandemic. The verification of this hypothesis was achieved based on a literature analysis and the results of geo-questionnaire studies conducted involving 651 residents of Poznan-among the largest of Polish cities, where the share of green areas in the spatial structure is more than 30%. According to the analysis, the interviewees experienced above-average stress levels that went up during the pandemic, and the source was not so much the virus but the restrictions imposed. Green areas and outdoor activities helped in reducing this stress (being surrounded by and looking at greenery, garden work, or plant cultivation). Residents perceive a post-pandemic city as one that is more green, in which priority is given to unmanaged green areas. It has also been pointed out that a response to the reported need for urban re-construction towards stress resilience may be a biophilic city.

Landscape -scale predictors of persistence of an urban stock dove Columba oenas population

While a few species may thrive in urban areas, urban expansion is a major driver of biodiversity loss. Columbids such as feral Rock Doves (Columba livia domestica) and Common Woodpigeon (Columba palumbus) have adapted extremely well to the urban environment in Europe and beyond, but the Stock Dove (Columba oenas), a bird of farmland and woodland edge in the UK and of national conservation concern, is encountered infrequently in urban areas. Here we explore the multi-scale landscape associations of the little-studied Stock Dove within the urban matrix of Greater Manchester, UK, in order to identify its habitat requirements. We built a pilot model from historical citizen science records to identify potentially occupied sites within the city, and then surveyed these sites for Stock Dove during Spring 2019. We combined the survey results with citizen science records from the same period and described the habitat and landscape characteristics of sites occupied by Stock Dove using four variables at different scales plus twelve unscaled variables. We used a three-stage random forest approach to identify a subset of these variables for interpretation and a subset for prediction for the presence of Stock Dove within these sites. Key variables for predicting Stock Dove presence were their relative abundance in the landscape immediately beyond the core urban area, the greenness (NDVI) of the environment around sites, and the canopy cover of individual trees over 20 m high within sites. Stock Doves tended to be associated with habitats with more surface water during the non-breeding season than the breeding season. Our results highlight the importance of large trees within urban greenspace for this cavity-nesting species, softer boundaries around urban sites for Stock Doves and stock dove presence in nearby areas. While Stock Dove share many traits with species that are successful in the urban environment, they remain relatively poor urban adapters.

Socio-ecological drivers of vertebrate biodiversity and human-animal interfaces across an urban landscape

Urbanization can have profound impacts on the distributional ecology of wildlife and livestock, with implications for biodiversity conservation, ecosystem services and human health. A wealth of studies have assessed biotic responses to urbanization in North America and Europe, but there is little empirical evidence that directly links human activities to urban biodiversity in the tropics. Results from a large-scale field study conducted in Nairobi, Kenya, are used to explore the impact of human activities on the biodiversity of wildlife and livestock with which humans co-exist across the city. The structure of sympatric wildlife, livestock and human populations are characterized using unsupervised machine learning, and statistical modelling is used to relate compositional variation in these communities to socio-ecological drivers occurring across the city. By characterizing landscape-scale drivers acting on these interfaces, we demonstrate that socioeconomics, elevation and subsequent changes in habitat have measurable impacts upon the diversity, density and species assemblage of wildlife, livestock and humans. Restructuring of wildlife and livestock assemblages (both in terms of species diversity and composition) has important implications for the emergence of novel diseases at urban interfaces, and we therefore use our results to generate a set of testable hypotheses that explore the influence of urban change on microbial communities. These results provide novel insight into the impact of urbanization on biodiversity in the tropics. An understanding of associations between urban processes and the structure of human and animal populations is required to link urban development to conservation efforts and risks posed by disease emergence to human health, ultimately informing sustainable urban development policy.

Influence of Urban Landscape on Ants and Spiders Richness and Composition in Forests

As large amounts of natural environments are lost due to urbanization, the role of remnant native vegetation in the preservation of biodiversity has become even more significant. Remnant native forest patches are essential refugia for flora and fauna and are crucial for the maintenance of ecosystem processes in urbanized landscapes. We evaluated the influence of landscape structure on ants and spiders associated with Atlantic Forest remnants in urban landscapes. We sampled 14 forest areas in the Metropolitan Region of Salvador and tested the effect of the landscapes' proportion of forest cover, mean landscape isolation, and mean landscape shape complexity on the taxonomic and functional richness and the community composition of both groups. The species collected were classified into functional groups based on behavioral attributes and environmental preferences. Overall, there were strong adverse effects of forest loss, decreased connectivity, and an increase in edge effects associated with the mean shape complexity of the forest remnants. However, the spiders responded to all three landscape structure characteristics whereas the ants only responded to the landscape mean shape complexity. Our findings indicate that the maintenance of urban forest habitats is essential for the conservation of biodiversity in the Metropolitan Region of Salvador and the preservation of ecological functions performed by species within the forest areas.

Decline in Distribution and Abundance: Urban Hedgehogs under Pressure

Simple Summary

Hedgehogs have been found in higher densities in urban compared to rural areas. Recent dramatic declines in rural hedgehog numbers lead us to pose the question: how are hedgehogs faring in urban areas? In this study, we examined how hedgehog numbers have changed in the city of Zurich, Switzerland, in the last 25 years. We compared data collected through citizen science projects conducted in 1992 and 2016–2018, including: observations of hedgehogs, data from footprint tunnels, and capture-mark recapture studies. We found that hedgehog numbers have declined by 41%, from the former average of more than 30 individuals per km², in the last 25 years. In the same time span, hedgehogs have lost 18% of their former urban distribution. The reasons for this decline are still unknown. Intensification of urban buildup, reduction of green space quality, the use of pesticides, parasites, or diseases, as well as increasing numbers of badgers, which are hedgehog predators, in urban areas are discussed as potential causes. Worryingly, these results suggest that hedgehogs are now under increasing pressure not only in rural but also in urban areas, their former refuges.

Abstract

Increasing urbanization and densification are two of the largest global threats to biodiversity. However, certain species thrive in urban spaces. Hedgehogs Erinaceus europaeus have been found in higher densities in green areas of settlements as compared to rural spaces. With recent studies pointing to dramatically declining hedgehog numbers in rural areas, we pose the question: how do hedgehogs fare in urban spaces, and do these spaces act as refuges? In this study, recent (2016–2018) and past (1992) hedgehog abundance and distribution were compared across the city of Zurich, Switzerland using citizen science methods, including: footprint tunnels, capture-mark recapture, and incidental sightings. Our analyses revealed consistent negative trends: Overall hedgehog distribution decreased by 17.6% ± 4.7%, whereas abundance declined by 40.6% (mean abundance 32 vs. 19 hedgehogs/km², in past and recent time, respectively), with one study plot even showing a 91% decline in this period (78 vs. 7 hedgehogs/km², respectively). We discuss possible causes of this rapid decline: increased urban densification, reduction of insect biomass, and pesticide use, as well as the role of increasing populations of badgers (a hedgehog predator) and parasites or diseases. Our results suggest that hedgehogs are now under increasing pressure not only in rural but also in urban areas, their former refuges.

Research on Ecological Infrastructure from 1990 to 2018: A Bibliometric Analysis

Ecological infrastructure (EI), as the composite system on which the sustainable development of cities depends, has attracted worldwide attention. Considering refined methodologies and broad scope, researchers lacked overall understanding of research patterns and evolutionary processes on EI-related issues. In this study, we applied the bibliometric approach to describe the current situation of EI-related research, and reveal research trends. Based on the Web of Science Core Collection, the bibliometric analysis of EI-related publications from 1990 to 2018 was performed to discuss the history and present research situation of EI, and preview research prospect. The results showed that: (1) the number of EI-related publications has surged astonishingly worldwide over the last three decades; (2) countries in Europe and North America were the first to invest heavily in EI-related research, while China started later but subsequently developed rapidly; (3) the EI-related research focuses were EI-related management, methods for countering extreme meteorological phenomena, providing ecosystem services, and protecting biodiversity; and (4) the EI-related research frontiers included the design of EI, policy research on EI, role of EI in environmental governance, and research on the adaptability of EI.

Estimation of the Allergenic Potential of Urban Trees and Urban Parks: Towards the Healthy Design of Urban Green Spaces of the Future

The impact of allergens emitted by urban green spaces on health is one of the main disservices of ecosystems. The objective of this work is to establish the potential allergenic value of some tree species in urban environments, so that the allergenicity of green spaces can be estimated through application of the Index of Urban Green Zones Allergenicity (IUGZA). Multiple types of green spaces in Mediterranean cities were selected for the estimation of IUGZ. The results show that some of the ornamental species native to the Mediterranean are among the main causative agents of allergy in the population; in particular, Oleaceae, Cupressaceae, Fagaceae, and Platanus hispanica. Variables of the strongest impact on IUGZA were the bioclimatic characteristics of the territory and design aspects, such as the density of trees and the number of species. We concluded that the methodology to assess the allergenicity associated with urban trees and urban areas presented in this work opens new perspectives in the design and planning of urban green spaces, pointing out the need to consider the potential allergenicity of a species when selecting plant material to be used in cities. Only then can urban green areas be inclusive spaces, in terms of public health.

Big Data-Based Evaluation of Urban Parks: A Chinese Case Study

Urban parks play a key role in urban sustainable development. This paper proposes a method for the evaluation of public parks from the perspective of accessibility and quality. The method includes the data extraction of urban park locations and the delineation of urban built-up areas. The processing of urban park data not only involves the extraction from digital maps, but also the classification of urban parks using a semi-automated model in ArcGIS. The urban area is identified using the Point of Interest (POI) data in digital maps, taking economic and human activities into consideration. The service area and its overlapped time is included in the evaluation indicators. With a clear definition of park and urban built-up area, the evaluation result of urban parks is of great comparability. Taking China as an example, the quality of urban parks in 273 prefecture-level cities has been evaluated. The results show that the average service coverage of urban parks in Chinese cities is 64.8%, and that there are significant disparities between cities with different population sizes and locations. The results suggest the necessity to improve public parks in small-and-medium sized cities and inland areas to strengthen the coordination of urbanization and regional development.

Using Parasitic Load to Measure the Effect of Anthropogenic Disturbance on Vervet Monkeys

Vervet monkeys, Chlorocebus pygerythrus, thrive in urban areas of KwaZulu-Natal, South Africa, and present a suitable model to assess parasitic load as a measure of anthropogenic disturbance, such as urbanization. We collected vervet monkey faecal samples from four study sites representing a gradient of land use and urbanization. We assessed faecal parasites using the faecal flotation method calculating eggs per gram and parasite richness. Overall, the more urban vervet monkey populations had a significantly higher parasite richness and abundance. Our study shows the applicability of using parasite load to measure the effect of urbanization on wildlife.

Human–wildlife interactions in urban areas: a review of conflicts, benefits and opportunities

Wildlife has existed in urban areas since records began. However, the discipline of urban ecology is relatively new and one that is undergoing rapid growth. All wildlife in urban areas will interact with humans to some degree. With rates of urbanisation increasing globally, there is a pressing need to understand the type and nature of human–wildlife interactions within urban environments, to help manage, mitigate or even promote these interactions. Much research attention has focussed on the core topic of human–wildlife conflict. This inherent bias in the literature is probably driven by the ease with which it can be quantified and assessed. Human–wildlife conflicts in terms of disease transmission, physical attack and property damage are important topics to understand. Equally, the benefits of human–wildlife interactions are becoming increasingly recognised, despite being harder to quantify and generalise. Wildlife may contribute to the provision of ecosystem services in urban areas, and some recent work has shown how interactions with wildlife can provide a range of benefits to health and wellbeing. More research is needed to improve understanding in this area, requiring wildlife biologists to work with other disciplines including economics, public health, sociology, ethics, psychology and planning. There will always be a need to control wildlife populations in certain urban situations to reduce human–wildlife conflict. However, in an increasingly urbanised and resource-constrained world, we need to learn how to manage the risks from wildlife in new ways, and to understand how to maximise the diverse benefits that living with wildlife can bring.

A global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers

Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common being Columba livia and Poa annua. The density of bird and plant species (the number of species per km(2)) has declined substantially: only 8% of native bird and 25% of native plant species are currently present compared with estimates of non-urban density of species. The current density of species in cities and the loss in density of species was best explained by anthropogenic features (landcover, city age) rather than by non-anthropogenic factors (geography, climate, topography). As urbanization continues to expand, efforts directed towards the conservation of intact vegetation within urban landscapes could support higher concentrations of both bird and plant species. Despite declines in the density of species, cities still retain endemic native species, thus providing opportunities for regional and global biodiversity conservation, restoration and education.