engleski

Relation between floristic diversity and geometrical, geographical and demographical characteristics of some islands in the northern Dalmatia (eastern Adriatic, Croatia)

Eastern Adriatic islands, as a part of the Mediterranean basin, with more than 1000 islands and islets, have a high biodiversity. Unfortunately, even until present time not all of the islands have been floristically researched, while some of the islands have only poor floristic data. Nevertheless, many of Croatian islands have comprehensive data of vascular flora. Recently, the number of plant species on Croatian islands has been put in relation with island areas according to a wellknown model of SAR (species-area-relation). Although the study of species-area relationship, in general, has been used successfully to predict island biodiversity, the influence of other island characteristics on species number has received less attention. Because islands are considered intrinsically more fragile than mainland areas, this research aimed to investigate if plant diversity can be related to island geography and geometry, but also demographical characteristics. Island shape metrics (e.g. fractal dimension, shape index, etc.) were measured for a set of islands in the middle part of eastern Adriatic, and geographical characteristics (area, elevation, distance to nearest island etc.) were taken into the analysis. Demographical data was used as indicator of anthropological influence on biodiversity. Regression analysis was made using the number of plant species in relation to geography, geometry and demographical characteristics of islands. Plant species number has shown positive relations to different parameters taken into regression analysis. However, the strongest relation was noticed with demographical data, what can be connected to land abandonment recorded on the researched islands.

Mediterranean; islands; flora; SAR; shape metrics

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