Monitoring the Impact of Precipitation on Vegetation Dynamics and Species Diversity in a Semi-Steppe Rangeland in Iran

Aims: Despite the critical role of semi-steppe rangelands in Iran’s agro-pastoral systems, long-term quantitative data on vegetation dynamics in response to climatic variability, particularly in the semi-steppe rangelands of Bardemar of Khuzestan Province, remain scarce.Materials & Methods: This study addresses this gap by using a random systematic method, providing a comprehensive ۷-year longitudinal dataset (۲۰۱۸-۲۰۲۴) that tracks changes in vegetation cover, productivity, and diversity. In four transects, a total of ۴۰ plots, each measuring ۱ square meter, were established to determine the density, vegetation canopy cover, plant species, and above-ground biomass. Margalef and Menhinick indices were calculated to compare species richness, and Shannon-Wiener and Simpson indices were used to assess species diversity. Finally, the Repeated Measures method was used to compare the biodiversity.Findings: The results showed that the percentage of canopy cover varied significantly between years, ranging from ۱۸.۸۰% to ۳۷.۱۰%, while above-ground production fluctuated between ۱۴۰.۵۹ and ۴۰۰.۴۹ (kg.ha⁻¹). The highest values were recorded in ۲۰۱۹ and ۲۰۲۳, corresponding to precipitation levels of ۳۱۲.۷۵ mm and ۳۲۰.۶۵ mm, respectively. Species richness (Taxa) averaged ۲.۵–۳.۶ species per plot, and the Shannon diversity index ranged from ۰.۷۶ to ۱.۰۵ across the study period. Significant correlations were found between precipitation and both vegetation cover (r = ۰.۷۰۴, p = ۰.۰۰۵) and production (r = ۰.۷۶۰, p = ۰.۰۰۲).Conclusion: This Study provides an empirical baseline for climate-responsive rangeland management in semi-arid regions. Implement short-term rest during wet years (rainfall ≥۳۰۰ mm) to enable natural seed production and recovery of the soil seed bank, offering a low-cost strategy for long-term rangeland restoration.

کلیدواژه ها:

Rangelands ، Random Systematic Method ، Canopy Cover ، Khuzestan