Exploring the biotic homogenisation and diversity resistance hypotheses: the understorey of non-native and native woodland canopies in three urban areas of Europe

Exploring the biotic homogenisation and diversity resistance hypotheses by assessing the effect of non-native black locust canopy on understorey species turnover.

Location: Berlin, the Venetian metropolitan area, and Rome.

We modelled the zeta (ζ) expression of diversity to compare the understorey species turnover between the non-native black locust and native woodland canopies across multiple sites and through predictors of anthropogenic pressure (road and built-up density) and interior conditions (tree basal area and mean height). In Rome black locust showed the lowest survivability and cover and did not produce any homogenisation of the understorey. In Berlin and in the Venetian metropolitan area, black locust caused understorey homogenisation, although with a low intensity in Berlin. Under black locust canopies, distance between sites and road density were more consistently associated with species turnover, across urban areas and multiple sites. Under native canopies in Berlin...