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Occupancy-frequency distribution of birds in land-sharing and -sparing urban landscapes in Europe
Urban birds' tolerance towards humans was largely unaffected by COVID-19 shutdown-induced variation in human presence
AbstractThe coronavirus disease 2019 (COVID-19) pandemic and respective shutdowns dramatically altered human activities, potentially changing human pressures on urban-dwelling animals. Here, we use such COVID-19-induced variation in human presence to evaluate, across multiple temporal scales, how urban birds from five countries changed their tolerance towards humans, measured as escape distance. We collected 6369 escape responses for 147 species and found that human numbers in parks at a given hour, day, week or year (before and during shutdowns) had a little effect on birds’ escape distances. All effects centered around zero, except for the actual human numbers during escape trial (hourly scale) that correlated negatively, albeit weakly, with escape distance. The results were similar across countries and most species. Our results highlight the resilience of birds to changes in human numbers on multiple temporal scales, the complexities of linking animal fear responses to human behavior, and the challenge of quantifying both simultaneously in situ.
Disentangling the drivers of urban bird diversity in the non‐breeding season: A general synthesis
AbstractCurrent knowledge about the impacts of urbanisation on bird assemblages is based on evidence from studies partly or wholly undertaken in the breeding season. In comparison, the non‐breeding season remains little studied, despite the fact that winter conditions at higher latitudes are changing more rapidly than other seasons. During the non‐breeding season, cities may attract or retain bird species because they offer milder conditions or better feeding opportunities than surrounding habitats. However, the range of climatic, ecological and anthropogenic mechanisms shaping different facets of urban bird diversity in the non‐breeding season are poorly understood. We explored these mechanisms using structural equation modelling to assess how urbanisation affects the taxonomic, phylogenetic and functional diversity of avian assemblages sampled worldwide in the non‐breeding season. We found that minimum temperature, elevation, urban area and city age played a critical role in determining taxonomic diversity while a range of factors—including productivity, precipitation, elevation, distance to coasts and rivers, socio‐economic (as a proxy of human facilitation) and road density—each contributed to patterns of phylogenetic and functional diversity. The structure and function of urban bird assemblages appear to be predominantly shaped by temperature, productivity and city age, with effects of these factors differing across seasons. Our results underline the importance of considering multiple hypotheses, including seasonal effects, when evaluating the impacts of urbanisation on biodiversity.
Spatial Overlap and Habitat Selection of Corvid Species in European Cities
Understanding habitat and spatial overlap in sympatric species of urban areas would aid in predicting species and community modifications in response to global change. Habitat overlap has been widely investigated for specialist species but neglected for generalists living in urban settings. Many corvid species are generalists and are adapted to urban areas. This work aimed to determine the urban habitat requirements and spatial overlap of five corvid species in sixteen European cities during the breeding season. All five studied corvid species had high overlap in their habitat selection while still having particular tendencies. We found three species, the Carrion/Hooded Crow, Rook, and Eurasian Magpie, selected open habitats. The Western Jackdaw avoided areas with bare soil cover, and the Eurasian Jay chose more forested areas. The species with similar habitat selection also had congruent spatial distributions. Our results indicate that although the corvids had some tendencies regarding habitat selection, as generalists, they still tolerated a wide range of urban habitats, which resulted in high overlap in their habitat niches and spatial distributions.
EVI and NDVI as proxies for multifaceted avian diversity in urban areas
AbstractMost ecological studies use remote sensing to analyze broad‐scale biodiversity patterns, focusing mainly on taxonomic diversity in natural landscapes. One of the most important effects of high levels of urbanization is species loss (i.e., biotic homogenization). Therefore, cost‐effective and more efficient methods to monitor biological communities' distribution are essential. This study explores whether the Enhanced Vegetation Index (EVI) and the Normalized Difference Vegetation Index (NDVI) can predict multifaceted avian diversity, urban tolerance, and specialization in urban landscapes. We sampled bird communities among 15 European cities and extracted Landsat 30‐meter resolution EVI and NDVI values of the pixels within a 50‐m buffer of bird sample points using Google Earth Engine (32‐day Landsat 8 Collection Tier 1). Mixed models were used to find the best associations of EVI and NDVI, predicting multiple avian diversity facets: Taxonomic diversity, functional diversity, phylogenetic diversity, specialization levels, and urban tolerance. A total of 113 bird species across 15 cities from 10 different European countries were detected. EVI mean was the best predictor for foraging substrate specialization. NDVI mean was the best predictor for most avian diversity facets: taxonomic diversity, functional richness and evenness, phylogenetic diversity, phylogenetic species variability, community evolutionary distinctiveness, urban tolerance, diet foraging behavior, and habitat richness specialists. Finally, EVI and NDVI standard deviation were not the best predictors for any avian diversity facets studied. Our findings expand previous knowledge about EVI and NDVI as surrogates of avian diversity at a continental scale. Considering the European Commission's proposal for a Nature Restoration Law calling for expanding green urban space areas by 2050, we propose NDVI as a proxy of multiple facets of avian diversity to efficiently monitor bird community responses to land use changes in the cities.
Gender differences in birding specialization from 25 countries: effects are large in skill/knowledge and minimal in commitment
Abstract This study investigates gender differences in birding specialization, a leisure activity characterized by three dimensions: skill/knowledge, behavior, and psychological commitment. We used data from a worldwide survey during December 19th 2020 and April 16th 2021 from 25 countries and psychometrically validated instruments. A total of 4006 people (2737 men, 1269 women; mean age 50.13 years, SD = 16.5) participated in the study. Meta-analytical tools were used to analyze the results. Men reported higher levels of skill/knowledge (effect size d = 0.75), behavior ( d = 0.43), and psychological commitment ( d = 0.18) than women. Gender-related differences in skill/knowledge correlated with gender equality indices, indicating that differences between men and women are large in more gender-equal societies. Gender-related behavioral differences reflect societal constraints on women’s leisure due to care responsibilities, while men’s higher skills could be related to competitive tendencies in birding. The results align with the “gender-equality paradox,” suggesting greater gender differences in contexts of higher societal equality. Recommendations for future research include considering initiation age of the leisure activity, lifetime leisure/recreational experience, and societal factors influencing gender-specific participation in cognitive leisure activities.