WOODY PLANTS IN URBAN BIOTOPES: STUDIES IN PATRAS (GREECE)

The trees and shrubs (planted and spontaneous) of a Greek city were studied in urban structural units for the first time. The spectra, combination, frequency and consistency of species were assessed, considering the relationships between plant ecology, biotope structure and land-use. Eight urban structural units were studied over a total area of 237.44 ha, and 218 woody plants were recorded. In all the examined structural units, more non-native species were recorded than native ones. The proportion of native trees is higher than that of native shrubs. Non-native species also dominate the spontaneous groups. Spontaneous diffusion could only be identified for 17.9% of the cultivated species. The most common woody species of Patras city are Morus alba L., Nerium oleander subsp. oleander, Ailanthus altissima (Miller) Swingle and Ficus carica subsp. carica. Species appearing in all study areas, i.e. with 100% consistency, were not observed. Acer pseudoplatanus L. proved to be a characteristic species only within the structural type of multi-storeyed semi-detached housing. The urban biotopes of the city of Patras can be differentiated according to the number of species present, but not according to their species composition.