Development of a composite index for assessing the risk of land degradation

Land degradation in arid and semiarid rangelands is a critical global issue owing to its substantial socio-economic and environmental impacts. This study aimed to develop a composite index to assess degradation risk and identify its underlying drivers. The study aimed to develop a method to investigate degradation patterns over a 22-year period by using a case study in the semiarid rangelands and to identify vulnerable areas on which to target interventions. This case study environment has similarities to land degradation-vulnerable rangeland globally, including low and variable rainfall, fragile soils, low carrying capacity, and economic resilience. The degradation risk index we developed integrates three different indices, namely, a vegetation heterogeneity index, a dust emission index, and a soil vulnerability index to provide a comprehensive understanding of degradation risk. Our findings showed that degradation risk gradually increases spatially with increasing aridity (east to west) across the case study region, indicating that western areas face significantly higher degradation risk because of drought and soil vulnerability, emphasising the need for adaptive management. Climate variability causes the degradation risk to increase quickly during droughts. However, land management practices can mitigate these effects and contribute to more stable conditions. Unlike many existing approaches that focus on static conditions or single indicators, our approach captures both short- and longer-term climate- and management-driven fluctuations influenced by three key land degradation drivers to provide an understanding of how risk changes across time and space. The study therefore provides an improved and transferable framework for land degradation risk assessment that can be applied to arid and semiarid rangelands to support targeted management and restoration.