Comparative assessment of LFA and RHA metrics in explaining ecosystem functions and multifunctionality across...

Rangelands provide essential ecological functions such as biomass production, carbon and water regulation, nutrient cycling, and biodiversity conservation, yet their integrity is increasingly threatened by climate change and grazing pressures. Reliable assessment of ecosystem functions (aboveground biomass, soil conservation factor, soil organic carbon, soil respiration, and microbial biomass carbon) and multifunctionality is therefore critical for sustainable management. This study comparatively evaluated two widely used assessment approaches, the Rangeland Health Assessment (RHA) and Landscape Function Analysis (LFA), across five bioclimatic rangelands in Iran. Ecosystem multifunctionality was quantified using standardized measures of key functions, and linear models were applied to examine the explanatory power of RHA and LFA metrics. Results showed that the explanatory power of models (R²) generally increased with the number of functions included, although the magnitude of this increase varied across regions and metrics. Structural indicators such as rangeland health, soil/site stability, and hydrologic function showed the highest ability to explain multifunctionality in Mediterranean and Semi-steppe regions. In contrast, Desert and Cold regions exhibited weaker and more variable relationships. Overall, the findings demonstrate that targeted combinations of key functions, together with sensitive structural indicators, can substantially improve monitoring efficiency and provide a robust scientific basis for rangeland management under diverse climatic conditions.