Peatland responses to climate change in the Central Peruvian Andes

Abstract

The high central Andes have undergone significant hydroclimatic changes in recent decades, affecting ecosystems through glacier retreat, temperature variations, and shifts in precipitation type (e.g., rain, snow, and hail). Andean peatlands play a crucial role in water regulation and biogeochemical cycles and are highly sensitive to climate change. Here we reconstruct Late Holocene changes in organic matter (OM) accumulation and preservation over the last ~2500 years in a peatland of the south-central Peruvian Andes (4210 m a.s.l.) using the 96- cm APA01 core. We integrate bulk organic geochemistry with continuous X-ray fluorescence (XRF) core scanning, centered log-ratio (clr) transformation, principal component analysis (PCA), and accumulation-rate estimates. A key finding is the close temporal coherence between peat PC1-clr (a proxy for OM dynamics) and the decadal snow accumulation record from Quelccaya Ice Cap, indicating that peat carbon dynamics closely track the regional high-elevation moisture balance. Dry phases such as the Medieval Climate Anomaly (MCA) coincide with reduced OM accumulation, whereas cooler and wetter conditions during the Little Ice Age (LIA) favor enhanced OM preservation. Warming phases, such as the MCA, after LIA, and recent decades, showed high clastic mineral input possibly linked to an increased proportion of rain-to-snow precipitation and land use. These results highlight the sensitivity of Andean peatlands to hydroclimatic variability and underscore the vulnerability of their carbon storage and hydrological functions under ongoing climate change.