Exotic species predominates in the urban woody flora of central Chile

Resumo

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.