Distribution Patterns of Ruderal Plant Diversity in Greece

Ruderal plant species typically occur and prevail in frequently disturbed areas especially in sites with pronounced direct or indirect human activity. In Greece ruderal taxa (both exclusive and non-exclusive) account for 23.9% of all recorded plant taxa. This study presents an analysis of the ruderal plant diversity patterns in the 13 floristic regions of Greece and different aspects of ruderal diversity related to alien taxa and to taxa of conservation interest. Although many ruderal plant taxa are common and widespread, their contribution to the diversity of each floristic region ranges between 27.8% in the North Central and 41.6% in the Cyclades region. Spatial distribution analysis revealed that the ruderal flora presents higher frequency of occurrence in major urban areas, in coastal and low to medium elevation mainland and island areas. The total number of ruderal taxa per floristic region is strongly correlated with the total number of taxa per region. The richness in exclusive ruderal taxa is highly correlated with surface area proportions of settlements and other built-up areas, as well as with artificial land, wetlands, sparsely vegetated land and shrublands. Ruderals account for a greater proportion of taxa in species-poor regions than in species-rich ones. Patterns of ruderal taxa diversity proved to be rather complicated and different spatial scales must be considered if ruderal biodiversity of the cultural landscapes in Greece is to be preserved.