THE INFLUENCE OF ENVIRONMENTAL FACTORS ON THE DISTRIBUTION AND COMPOSITION OF PLANT COMMUNITIES IN KIZILIRMAK VALLEY-BLACK SEA REGION, TURKEY

Abstract

The aim of this study is to explore the influence of environmental factors on the distribution of plant associations in Kizilirmak Valley, in northern Turkey. This paper provides a quantitative analysis of the vegetation environment relationships for a study site in this valley. 130 vegetation plots were sampled and analysed using two-way indicator species analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA) in order to identify the principal vegetation communities and determine the environmental gradients associated with these. Eleven associations and six sub-associations were found by using TWINSPAN. There were three main vegetation groups, namely sclerophyllous, xerophyllous and mesophyllous according to TWINSPAN dendrogram, in Kizilirmak valley. The principal DCA axes represent gradients of elevation, relative humidity and soil pH. Shannon diversity index and species richness were also calculated for studied plant associations.