The phylogenetic and functional diversity of regional breeding bird assemblages is reduced and constricted through urbanization

• Urbanization broadly affects the phylogenetic and functional diversity of natural communities through a variety of processes including habitat loss and the introduction of non-native species. Due to the challenge of acquiring direct measurements, these effects have been studied primarily using ‘space-for-time’ substitution where spatial urbanization gradients are used to infer the consequences of urbanization occurring across time. The ability of alternative sampling designs to replicate the findings derived using space-for-time substitution has not been tested. Here, we contrastthe phylogenetic and functional diversity of breeding bird assemblages in 58 cities worldwide with the corresponding regional breeding bird assemblages estimated using geographic range maps. Our findings indicate that urban areas are associated with lower phylogenetic diversity, lower phylogenetic beta diversity, a reduction in the least evolutionary distinctspecies, and the complete loss of the most evolutionarily distinct species. We found no evidence that these effects were related to the presence of non-native species. At a function level, our findings indicate that urban areas were associated with fewer aquatic species, fewer small and especially large bodied species, fewer narrowly and especially broadly distributed species, fewer herbivores, and fewer aquatic foraging species. Conversely, urban areas were associated with a greater prevalence of passerines, doves and pigeons, granivores, species that forage in association with vegetation or in the air, and species with more generalized associations with foraging strata. In total, our findings indicate that urbanization is associated with the overall reduction and constriction of phylogenetic and functional diversity, results that largely replicated those generated using space-for-time substitution, increasing our confidence in the quality of the combined inferences. When direct measurements are unavailable, our findings emphasize the value of developing independent sampling methods that broaden and reinforce our understanding of the ecological implications of urbanization.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Keyword

Land and Water Resources Engineering

Mark- och vattenteknik

Publication and Content Type

ref (subject category)

art (subject category)