Vegetation Cover Dynamics in Saline High-Altitude Wetlands of the Andes for Environmental Factors

Abstract The vegetation of high Andean wetlands in hyperarid environments is typically azonal; however, differentiated responses between permanent and temporary vegetation cover have been observed, driven by environmental factors. These responses create dynamic boundaries in vegetation cover, complicating the monitoring, assessment, and management of wetlands. Using the Tilopozo wetland as the study area, we aimed to identify permanent vegetation cover and evaluate its stability over time and determine changes in temporary vegetation cover and the environmental factors that influence them. The surface covered with vegetation was analyzed using six time-series from 1985 to 2019 based on the normalized difference vegetation index. The stability of permanent vegetation cover was assessed using the Kappa coefficient, while temporary vegetation cover was correlated with environmental factors (precipitation, evapotranspiration, and water table levels). Vegetation maps were used to determine the dominant species for both types of cover. The results revealed that permanent vegetation exhibited high temporal stability, with Kappa coefficients ranging from “very good” to “excellent,” dominated by Schoenoplectus americanus and Baccharis juncea , two strict hygrophilous species. Conversely, temporary vegetation cover was significantly influenced by precipitation and evapotranspiration and composed of transitional hygrophilous species such as Distichlis spicata and Tessaria absinthioides . These findings present an approach to delineate stable boundaries and estimate the maximum potential extent of wetlands (dynamic boundaries), and assessing their spatiotemporal variability and the environmental drivers of these changes. This information is crucial for the effective management and conservation of wetland ecosystems in these environments.