Are cities different? Patterns of species richness and beta diversity of urban bird communities and regional species assemblages in Europe

Abstract

Aim To compare macroecological patterns between bird communities of European cities and regional species assemblages in the surrounding landscape, and to reveal geographical trends in the urbanization of native avifauna. Location Forty‐one towns and cities in continental Europe. Methods We compiled data on the species richness and community composition of urban avifauna from 41 European city breeding bird atlases, and of species assemblages comprising nine grid cells (each about 50 km × 50 km) from the EBCC Atlas of European Breeding Birds (hereafter regional assemblages). Species–area relationships (SARs), latitudinal trends in diversity and the distance decay of community similarity were compared using regression models (generalized linear models). Observed urban communities were compared with randomly assembled ones to reveal systematic effects of the urban environment on native bird communities across Europe. We employed variance partitioning to quantify the relative effect of environmental parameters and the spatial position of cities on species richness. Results The species–area relationships did not differ significantly between cities and regional assemblages. Species richness of both types of communities increased towards higher latitudes, although the relationship was unimodal for regional assemblages, in contrast to cities. The increase in beta diversity with distance was on average less pronounced in cities than in regional assemblages, and was lower between individual cities than between communities of the same size randomly drawn from regional species assemblages. Moreover, average beta diversity was lower in northern cities, which are characterized by a relatively higher proportion of species from regional species pools. Main conclusions The species–area relationship and latitudinal trends are largely congruent between cities and the regional assemblages. However, city avifaunas tend to be relatively more uniform across space, revealing biotic homogenization. Urban communities in northern cities are more uniform as a higher proportion of bird species breeds in cities.

How Should Beta-Diversity Inform Biodiversity Conservation?

“…Among birds, urbanization decreases the distance decay of compositional similarity between cities [58,59]. In insects, 185 urbanization reduces beta-diversity because heterogeneous assemblages of specialists disappear from cities, while consistent suites of tolerant species persist.…”

“…[65]. Effects like these may account for why, among European birds, urban species-area relationships are as steep as rural relationships [58]. 205…”

Scale dependence of biotic homogenisation by urbanisation: a comparison of urban bird communities between central Argentina and northern Finland

“…Cassey et al 2008). Although the homogenising effect of urbanisation may be evident at large geographical scales (Clergeau et al 2001;Ferenc et al 2014;Filloy et al 2015;Ibáñez-Álamo et al 2016;Murthy et al 2016), some studies have suggested that it may disappear at smaller regional scales (Jokimäki & Kaisanlahti-Jokimäki 2003;Kühn & Klotz 2006;Marchetti et al 2006;Sorace & Gustin 2008;Luck & Smallbone 2011;Tryjanowski et al 2015).…”

How small cities affect the biodiversity of ground-dwelling mammals and the relevance of this knowledge in planning urban land expansion in terms of urban wildlife

“…There are few studies of biodiversity in small cities, e.g. for plants (Wang et al 2014), birds (Ferenc et al 2014;Sorace and Gustin 2010;Helden et al 2012), fish (Peressin and Cetra 2014) and insects (Magura et al 2004;Elek and Lövei 2007;Helden et al 2012, ). Indeed there is a lack of review articles on this subject and many groups of animals have yet to be studied in terms of the effects of urbanization.…”