Exotic species predominates in the urban woody flora of central Chile

Abstract

The expansion of cities promotes the replacement of local biotas with exotic species causing a decrease in global diversity. As urbanization continues to expand, efforts directed towards the conservation within urban landscapes could support regional biodiversity conservation. The biogeographic region of central Chile displays a native flora of global importance because of its high endemism. Up to date, studies analysing the composition of the floras within the cities are scarce. The present study aims at characterizing the compositional and distributional patterns of the ornamental flora of five cities of central Chile (La Serena, Valparaíso, Santiago, Rancagua, and Talca). For this purpose, we sampled several streets and squares recording all woody species. The species were then characterized by their biogeographical origin and incidence. It was recorded 302 species of which approx. 86% were exotic and 14% were native, a consistent pattern found in the five cities studied; these results contrast with the European urban flora, where native species can usually overcome 50% of the plant species. Almost half of the exotic species had their origin in Asia (including Australasia, Temperate, and Tropical Asia), Europe, and North America. Consequently, the representation of the regional flora within the urban context is low for central Chile, with the native species registered, accounting for only 0.81% of the total species described for the country. Urban habitats could support regional biodiversity conservation, so a shift towards sustainable urban planning could promote local biological conservation.