Disturbance regimes and plant community biodiversity in the heterogeneous grasslands of the Peruvian Puna

Abstract High-Andean grasslands, located between 3,500 and 5,000 m in the Tropical Andes, cover approximately 16% of South America and represent a significant proportion of the world’s alpine ecosystems. These systems support nearly one million pastoralists while harbouring a unique share of tropical alpine biodiversity. However, management practices, including overgrazing, recurrent burning, and the introduction of non-native livestock, combined with soil degradation processes, have led to widespread ecosystem deterioration. This situation has been exacerbated by the promotion of a generalized management strategy across the Puna which overlooks Puna´s ecological variability and complexity. This study aimed to characterize plant biodiversity, structure, and composition, across four Puna types in the Peruvian Andes, and to compare how different management regimes within each type affects these variables. A total of 160 plots (10 × 10 m) were surveyed during both wet and dry seasons in 2021. Data were analysed using Indicator Species Analysis, Non-metric Multidimensional Scaling, Principal Component Analysis, and multivariate regression. A total of 419 plant species were recorded, with higher diversity observed in humid Puna systems (Puno and Huánuco), particularly during the rainy season. Vegetation structure and composition were primarily driven by altitude, soil nitrogen, and minimum temperature, while species dominance patterns shifted along a gradient of grazing intensity. Disturbance level emerged as a key driver of diversity, with clear differentiation among plant communities across both environmental and management gradients. These results evidence that the Puna is best understood as a heterogeneous mosaic of ecosystems, where climatic constraints and grazing pressure interact to shape vegetation dynamics. This highlights the need for context-specific management strategies aimed at conserving biodiversity and enhancing ecosystem resilience in High-Andean grasslands.