Rock glacier and solifluction lobes groundwater as nutrient sources and refugia for unique macroinvertebrate assemblages in a mountain ecosystem of the North Patagonian Andes

Abstract

Relict periglacial landforms play an important ecosystem role in mountain regions and are becoming relevant in the global context of climate change. In the eastern region of the North Patagonian Andes, many relict periglacial landforms, such as rock glaciers and solifluction lobes, are distributed in mountain watersheds, including the La Hoya mountain watershed. In this watershed, we analyzed hydrochemistry and macroinvertebrate communities across water sources, associated to different landforms (rock glaciers, solifluction lobes, debris slopes, wet meadows, and the collector stream). The results showed that the highest concentrations of nitrates and soluble reactive phosphorus were registered on springs associated with rock glaciers and solifluction lobes, coincident with low water temperature. Macroinvertebrate taxonomic richness was highest in the collector stream and wet meadows. While rock glaciers and solifluction lobes supported low diversity, their assemblages were unique (highest Local Contribution to Beta Diversity). In summary, rock glaciers and solifluction lobes are the principal nutrient contributors to the La Hoya watershed and provide refuge for unique and potentially cold-adapted macroinvertebrates. Due to ongoing climate change in cold environments, ice glaciers and mountain permafrost may disappear or be reduced. In this context, relict periglacial landforms, such as rock glaciers or solifluction lobes, could act as climate change refugia. This assumption requires support from further research at broader scales; nevertheless, our work suggests that the potential ecological and conservation value of relict periglacial landforms should not be underestimated.