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

Abstract

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