Assessment of Health Conditions of Mountain Rangeland Ecosystem Using Species Diversity and Richness Indices, Case Study: Central Alborz (Iran)

Based on the importance and role of species diversity and richness as a measurement of the health of an ecosystem; studying of their components can lead to evaluate the health condition of rangeland. this research was carried out in a part of highland mountainous rangeland of mount alborz range in iran. diversity and richness were assessed as an ecosystem health indicator. the study area was located between 2200 to 4200 m altitude in north of iran. the rangeland vegetation was covered by grass as the dominant species along with forbs and cushion like species. the rangeland was grazed by livestock as summer rangelands. the samples were collected in reference, key, and critical areas using transects. the data were analyzed by stepwise regression in that rangeland condition as dependant variable and vegetation form as independent variables. plant diversity and richness indices were calculated by past software. the results showed that grass species diversity had the highest correlation with the rangeland condition in key site. the cushiony species and the combination of grass and forbs had high correlations with the rangeland condition in both critical and reference sites. the key and critical rangelands had the highest and lowest diversity, respectively. the critical zone was in disequilibrium conditions so the rehabilitation of vegetation cover is recommended for the similar regions. it was concluded that long-term enclosure can decline the species diversity and richness. moderate grazing is the best tool to use the grazing land without severe reduction in abundance and biomass of species.