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Excessive grazing pressure on rangeland vegetation reduces the basal area value of vegetation and also changes the botanic composition. This study examined the piosphere effects of livestock grazing on rangeland vegetation based on distance from a natural water source. The piosphere effects were evaluated around Karagol Lake, which is a natural water-source in Mediterranean region of Turkey. The changes in vegetation were determined within three different sites where sample plots were located at 0-1000 m, 1000-3000 m and 3000-5000 m away from the lake. The mean values of basal area in the study area were 10.71%, 14.46%, and 22.16% for three sites, respectively. The average oven-dry hay yield was 639.0 kg ha(-1), 1542.9 kg ha(-1), and 2146.3 kg ha(-1), respectively. The vegetation similarity indices of the sites indicated that the botanic composition changed with respect to increasing distance from the lake. The lowest similarity index was encountered between the site one and site three (30.31%).