City-dwelling wildlife demonstrate ‘urban trait syndrome’

Amazing stuff! How evolution adopts to and how biodiversity evolves in urban environments!

Unfortunately, there is probably a tendency of overpopulation of birds in urban areas for e.g. lack of natural predators.

"City life favors species that are adaptable and, among other things, not too fussy about what they eat. A worldwide consortium of scientists calls the resulting collection of characteristics “urban trait syndrome.”

Their study includes data from 379 cities on six continents, with the largest data set coming from the Cornell Lab of Ornithology’s eBird program. The research was published Aug. 8 in Nature Communications.

“The most pronounced changes among city-dwelling organisms are in reproduction and foraging,” said co-author Frank La Sorte, a senior researcher associate at the Cornell Lab. “For example, city birds tend to be smaller, eat a wider variety of foods and produce smaller clutches than their rural counterparts. Smaller clutch sizes in urban birds have been associated with higher survival rates and increased growth.”

But not all groups of species share the same urban trait syndrome. Beetles, birds and reptiles tend to be smaller in the most urbanized areas compared to their country counterparts. The mobility of ground beetles was higher in more urbanized areas, while that of reptiles and birds was lower. ..."

From the abstract:

"Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats, species, and functional groups. Understanding how multiple taxa respond to urbanisation globally is essential to promote and conserve biodiversity in cities. Using a dataset encompassing six terrestrial faunal taxa (amphibians, bats, bees, birds, carabid beetles and reptiles) across 379 cities on 6 continents, we show that urbanisation produces taxon-specific changes in trait composition, with traits related to reproductive strategy showing the strongest response. Our findings suggest that urbanisation results in four trait syndromes (mobile generalists, site specialists, central place foragers, and mobile specialists), with resources associated with reproduction and diet likely driving patterns in traits associated with mobility and body size. Functional diversity measures showed varied responses, leading to shifts in trait space likely driven by critical resource distribution and abundance, and taxon-specific trait syndromes. Maximising opportunities to support taxa with different urban trait syndromes should be pivotal in conservation and management programmes within and among cities. This will reduce the likelihood of biotic homogenisation and helps ensure that urban environments have the capacity to respond to future challenges. These actions are critical to reframe the role of cities in global biodiversity loss."

City-dwelling wildlife demonstrate ‘urban trait syndrome’ | Cornell Chronicle

Urbanisation generates multiple trait syndromes for terrestrial animal taxa worldwide (open access)

Fig. 2: Predicted changes in trait values per taxon along an urbanisation gradient.