Pampa Galeras Vicuña Reserve a New Equilibrium State? Range Condition and Ecological Carrying Capacity

Zárate R.F.; Flores E.R. · Journal of Rangeland Science (2026) · DOI: 10.57647/jrs-2026-1601.10

Resumen

The rangelands of the Pampa Galeras National Reserve (Peru) span 22,231 hectares (ha), of which 7,932 ha constitute the rigid zone—an area exclusively for vicuña (Vicugna vicugna mensalis) grazing—while the remaining 14,299 ha serve as a buffer zone for mixed vicuña–cattle grazing. Since the 1960s, this landscape has played a pivotal role in the recovery of the vicuña population from near extinction, offering a valuable opportunity for research on its ecology and management. Previous inventories indicated that the rangelands remained in poor conditions for vicuña grazing, despite relatively stable population densities. This study evaluated the ecological status and estimated the vicuña units (UV) that the rigid zone could support using an ecological site framework. Fifteen ecological sites were identified using geographic information systems and remote sensing, and each was assessed for floristic composition, rangeland condition, and trends. Results indicated that 86% of the sites were in poor conditions, and 35% exhibited a negative trend—evidenced by the presence of pedestalled plants, invasive species, and low litter—suggesting that many sites may have crossed abiotic thresholds and shifted into alternative stable states. The current ecological carrying capacity (C) of the rigid zone was estimated at 3,763 UV (0.47 UV/ha/year), which is below the potential carrying capacity (Cp) of 4,982 UV (0.60 UV/ha/year). Notably, when Ck was exceeded, vicuña numbers plummeted from 4,987 to 2,218 UV, indicating low resilience in the rangeland–vicuña system. Multiple limiting factors were identified, including interspecific competition, poor soil potential, harsh weather, and the lack of an adaptive rangeland-wildlife management strategy. Establishing an adaptative monitoring and management program based on key and reference areas is strongly recommended.

Instituciones: Universidad Nacional Agraria La Molina