Land degradation decision trigger points to minimise soil erosion in rangelands

Predicting when vegetation cover (the sum of photosynthetic and non-photosynthetic vegetation) drops below soil erosion protection thresholds is vital for reducing land degradation. This study developed a potential for land degradation (PoLD) framework to identify decision-trigger points that warn of low cover 4–8 months before cover may fall below a critical threshold. Using the PoLD framework, property-specific benchmark cover targets (BC) were set at the second decile of the annual lowest monthly cover between January 2001 and March 2024 for 24 properties in western New South Wales. Instead of a static wind erosion target (e.g. 50%), a BC target is place-based, more achievable, and better suited to semi-arid rangelands where 50% cover may not be attainable. Regression analysis of cover levels for months with the peak pasture growth identified a trigger month (TM) and trigger cover level (TC) for each study property. When the cover during the TM drops below the TC, it is likely to fall below the BC in the next 4–8 months. Monitoring cover levels in the TM can warn whether a change in land management is required to maintain cover and avoid land degradation. The framework is flexible and can be applied at various scales, pixel sizes, and data types. The PoLD framework provides a warning of low cover 4–8 months before cover drops below BC levels in 89% of years. PoLD is a new objective decision-making framework that can help land managers prevent land degradation.