Grazing Modulates Vegetation Diversity and Productivity Responses to Photovoltaic Microhabitats in an Alpine Steppe on the Qinghai-Tibet Plateau

The rapid expansion of photovoltaic (PV) infrastructure across the Qinghai-Tibet Plateau is reshaping land-use patterns in alpine grasslands. However, how PV-induced microhabitats and grazing jointly influence vegetation remains poorly understood. We conducted a field experiment in an alpine steppe to systematically examine how PV microhabitats and grazing management influence vegetation productivity and diversity. The results showed that grazing exclusion markedly increased aboveground biomass (AGB), plant height, and belowground biomass (BGB), with these gains being significantly greater under the photovoltaic (UPV) than between the photovoltaic (BPV). Although UPV shading significantly reduced biomass and coverage, it elicited shade-avoidance elongation, a response strongly modulated by grazing management. The interaction between PV-induced microhabitats and grazing management was highly significant for all diversity indexes: UPV promoted diversity under grazing exclusion but suppressed it under grazing exclusion, whereas the opposite was observed in the BPV microhabitat. Under both grazing and grazing-exclusion conditions, PV microhabitats reversed the diversity-productivity relationship. This study reveals that the restorative advantage of the shaded UPV microhabitat is strongly grazing-dependent. Short-term grazing exclusion efficiently restores vegetation productivity, particularly UPV, providing a robust scientific basis for the synergistic management of ”photovoltaic and ecological pasture” systems on the Qinghai-Tibet Plateau.