Tree-circles spontaneous vegetation over a long climatic gradient

Abstract

Urban flora varies between urban habitats within a city and between cities. We used a particular urban habitat - tree-circles to compare floristic differences between urban agglomerations along a long climatic gradient on a continental scale. We recorded flora of this unique habitat in seven West Balkan cities and compared it to seven cities from Western and Central Europe. On average, 91 species were found on tree-circles in every city in the Balkans (compared to 81 in continental Europe). Climate was the most important factor influencing species composition. Western and Central European tree-circles floras are much more uniform and homogeneous than Balkan ones, which have richer species pools.