E&E Seminar: Climatic refugia in the coldest neotropical hotspot, the Andean páramo

The Andean páramo is the most biodiverse high-mountain region on Earth and past glaciation dynamics during the Quaternary are greatly responsible for its plant diversification. Here, we aim at identifying potential climatic refugia since the Last Glacial Maximum (LGM) in the páramo, according to plant family, biogeographic origin, and life-form.

The páramo region in the Northern Andes.

We built species distribution models for 664 plant species to generate range maps under current and LGM conditions, using five General Circulation Models (GCMs). For each species and GCM, we identified potential (suitable) and potential active (likely still occupied) refugia where both current and LGM range maps overlap. We stacked and averaged the resulting refugia maps across species and GCMs to generate consensus maps for all species, plant families, biogeographic origins and life-forms. All maps were corrected for potential confounding effect due to species richness.

We found refugia to be chiefly located in the southern and central páramos of Ecuador and Peru, especially towards the páramo ecotone with lower-elevation forests. However, we found additional specific patterns according to plant family, biogeographic origin and life-form. For instance, endemics showed refugia concentrated in the northern páramos.

Main conclusions
Our findings suggest that large and connected páramo areas, but also the transitional Amotape-Huancabamba zone with the Central Andes, are primordial areas for plant species refugia since the LGM. This study therefore enriches our understanding on páramo evolution and calls for future research on plant responses to future climate change.