Comparison of plant diversity and species richness under three level of utilization in rangelands of Khabr National Park and vicinities

Proper and efficient management of range ecosystems requires adequate knowledge on grazing intensity and its effects on plant diversity. To compare the plant diversity at reference (RA), key (KA) and, critical (CA) areas of Khabr National Park and vicinities, this study was conducted on an area of 6000 hectares. Plant diversity was determined by using Shannon Index and species richness was determined by rarefaction method. To count species number in 3 locations of RA, KA, and CA, 120 plots of 1 by 0.5 m, and to estimate canopy cover, 120 plots of 2 by 1.5 were used by systematic-random sampling. Expected species richness were 32, 24, and 14 for these areas to provide inequalities of RA > KA > CA. The mean coefficients of Shannon Index was 1.97 in RA, 1.83 in KA, and 1.05 in CA, so diversities of RA and KA were not significant (p>0.05) and both of these areas were significantly different from CA (p<0.05). The species richness in CA was declined considerably due to overgrazing and improper seasonal grazing. Also the proportion of unpalatable species was increased in this area.