Southern Brazilian Grassland Diversity: Anti‐Disturbance Regimes Are Not Ideal and Grazing Maintains Plant Diversity

ABSTRACT Questions We experimentally test the long‐term effects of grazing management regimes on species composition, diversity, and the heterogeneity of grassland vegetation 12 years after implementation of grazing treatments, with a focus on plant life‐forms. Location Seven long‐term ecological research sites are located in southern Brazil, four in grasslands of the Pampa (PG) and three in Highland grasslands (HG). Methods The experiment was established in 2010 using a randomized block design, with sites serving as replicates. The vegetation at each site was subjected to three management treatments (continuous grazing, deferred grazing simulating rotational grazing, and grazing exclusion) in 0.5‐ha experimental plots. In spring–summer of 2021–2022, we estimated the species cover composition for each experimental plot, classifying them according to life‐forms, and recorded other variables such as vegetation height. The effects of grazing management on life‐form and species cover were examined using multivariate analysis of variance, redundancy analysis (RDA), Renyi curve, and diversity through Hill Numbers. Results The results indicate significant effects of grazing treatments on species composition, with grazing exclusion associated with greater average height of vegetation. Additionally, grazing impacts diversity profiles and life‐form abundance, with notable differences between PG and HG. Overall, continuous and deferred grazing exhibited higher diversity compared to grazing exclusion, with significant variations in diversity among treatments. Conclusion Grazing exclusion leads to a loss of grassland diversity, while diversity may not fundamentally differ between sites under continuous or deferred grazing. We demonstrated how different management strategies influence vegetation in the long term, emphasizing the importance of disturbances in maintaining grazing and the need for ongoing research to guide effective management practices.