Characterization of water stress in Patagonian peatlands. A study of two peatlands on Chiloé Island, Chile

Peatlands are recognized for their ability to capture, store, and recharge water, but their hydrological functioning can be altered by Sphagnum moss and peat extraction activities. This study investigates water storage and hydrological regulation in bogs subjected to Sphagnum moss and peat extraction on Chiloé Island, Chile. The dynamics of water table depth (WTD) were to analyze and related to anthropogenic interventions. Optical bands were used to derived from unmanned aerial vehicles (UAVs) as indicators of water stress and water depth. The results indicate significant differences in water table depth (WTD) between disturbed and undisturbed areas of the peatlands. In the bog characterized by marked topographic heterogeneity, WTD did not reach the surface in areas subjected to Sphagnum moss extraction, suggesting a reduction in water storage capacity and greater susceptibility to harvesting negative effects. Moderate-strong correlations between WTD and UAV-derived data were observed in both bogs. Furthermore, the prediction of WTD using a multiple linear regression model presented an acceptable fit for the bog with topographic variation (R² = 0.63, RMSE = 7.81 cm). However, poor model performance was observed for the bog located in a topographically homogeneous environment. This research contributes to the hydrological characterization of Sphagnum peatlands in Patagonia and enhances our understanding of the impacts of extractive activities, providing information to support public policy and the management of these wetland ecosystems.