Kürşad ÖZKAN 1 and Halil SÜEL 2 1 Department of Soil Ecology, Suleyman Demirel University, 32260, Isparta, Turkey e-mail: kursadozkan@gmail.com 2 Faculty of Forestry, Suleyman Demirel University, 32260, Isparta, Turkey e-mail: halil_suel@hotmail.com ENDEMIC PLANT SPECIES IN A KARSTIC CANYON MEDITERRANEAN REGION, TURKEY: RELATION TO RELIEF AND VEGETATION DIVERSITY ABSTRACT: Data collected from 85 sample plots in Yazili Canyon Nature Park (deep, lime- stone valley; length - 6 km, area – 600 ha, height – 100–400 m) located in Mediterranean region (Turkey) yielded 24 endemic vascular plants. The endemic plant diversity and all vascular plant di- versity indices were calculated for each sample plot using Simpson index. Regression analysis was performed between environmental factors, plant diversity and canopy closure. Endemic plant diversity showed a positive correlation with vas- cular plant diversity, and a negative correlation with slope position and altitude. A significant quadric relationship was observed between the endemic plant diversity and aspect variable. RDA (redundancy analysis) and CCA (canonical cor- respondence analysis) based on linear regressions were applied to determine the environmental fac- tors affecting the distribution of endemic species, and the best model based on total variance ex- plained was selected. According to RDA based on linear regression, habitat selection of endemics is strongly correlated with aspect, slope position and altitude. Lower altitude zone (300–500 m), the north aspect and lower slope including valley bottom of Yazili canyon were observed to be the most suitable areas for endemics. KEY WORDS: karstic valley, vegetation-en- vironmental relationships, biodiversity, endemics The identification of endemics as well as determination of the potential areas pos- sessing rich endemic species diversity is very important for preparing and improving the priority plans for the natural ecosystem pro- tection and management. Endemic species are generally distributed in selective eco- logical habitats, being especially frequent in places which are isolated and not affected by a regional-scale catastrophic disturbance for a long time (Kiziroglu et al. 1992). The natural and potential areas of the endemic species occurrence must be known for the effective application of protection strate- gies. Turkey is one of the richest countries in terms of endemic species having more than 3,000 endemic taxa, a number greater than total number of endemics in the European continent (E k i m et al. 2000). There are different types of protected areas in Turkey: national parks, nature parks, na- tional monuments and areas of nature. Many of them belong to HABITAT (Convention on Conservation of European Wildlife and Nat- ural Habitats) and CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) conventions, and Turkish Red Data Book of Plants (E l k im et al. 2000) prepared according to the IUCN POLISH JOURNAL OF ECOLOGY (Pol. J. Ecol.) 56 4 709–715 2008 Short research contribution journal 16.indb 709 journal 16.indb 709 2009-01-13 10:59:52 2009-01-13 10:59:52