Spatiotemporal variation of glacier dynamics and its relationship with changes in high mountain ecosystems in the Cordillera Blanca, Peru

Abstract

In high mountain ecosystems, glaciers, lakes and wetlands play an important role in local water resources, where a variation in glacier dynamics can affect the rest of the ecosystem components due to their hydrological connections. The objective of the study was to analyze the relationship of glacier dynamics with lakes and wetlands in Llullan, Quillcay and Yanayacu catchments of Cordillera Blanca (Peru) in the period from 1989 to 2019. Using Geographic Information Systems (GIS) and remote sensing, a multitemporal analysis was carried out using Landsat satellite images, and subsequently linear correlation was calculated and a Principal Component Analysis (PCA) was applied. The results of glacier dynamics parameters indicated a loss of between 22 and 56% of glacier area; from 24 and 63% of glacier volume; glacier front retreat varied between 10 and 18 m yr-1; and Equilibrium Line Altitude (ELA) rose from 137 and 227 m. The lake dynamics evidenced growth between 5 and 82% of their area and between 2 and 151% of their volume; and permanent wetlands showed a tendency to increase over time (from 44 and 289%). PCA indicated that PC1 and PC2 explained between 71 and 91% of the total variance of the original 7 variables, and glacier dynamics were found to have a good-very good inverse correlation with lake dynamics (between 0.62 and 0.99) and good with wetland dynamics (from 0.64 and 0.69). The study reflected the interconnectivity of high mountain ecosystem elements, where an acceleration of glacier retreat would trigger lakes and wetlands to reach their maximum capacity in shorter periods and begin to retreat earlier than expected.