Water regulation and soil retention services in semiarid ecosystems of southeastern Iran, 2018–2020

Abstract

Water regulation and soil retention are regulating services that play an important role in the sustainability of arid ecosystems. A study was carried out to assess the potential of semiarid plant communities in providing water regulation and soil retention ecosystem services. Concrete plots were made around plants and bare surface (control) to measure sediment and runoff after each rainfall event from 2018 to 2020. The potential of plant communities in providing water regulation and soil retention services was estimated using density and the mean area of patches. The shrub–grasses and shrub–annuals communities had the highest and lowest potential for providing water regulation and soil retention services, showing the plant communities with priority for conservation and restoration, respectively. Land degradation was the most important factor affecting these services in the region. Soil retention and water regulation were, respectively, reduced 50% and 50%, 62% and 70%, and 75% and 90% in areas with moderate, high and severe degradation compared to areas with low degradation. Rainfall events with depth higher than 15 mm significantly reduced these services in all plant communities. However, proper management moderated the effects of heavy rains in the shrub–grasses plant community. Therefore, ecosystems must be managed in the way that assures the greatest density of cushion semishrubs to have the highest potential in providing water regulation and soil retention services.