Direct and indirect effects of glaciers on aquatic biodiversity in high Andean peatlands Quenta, E. Molina-Rodriguez, J. Gonzales, K. /Rebaudo, François Casas, J. Jacobsen, D. /Dangles, Olivier aquatic biodiversity environmental heterogeneity glacial influence high Andean peatlands peatland area tropical Andes The rapid melting of glacier cover is one of the most obvious impacts of climate change on alpine ecosystems and biodiversity. Our understanding of the impact of a decrease in glacier runoff on aquatic biodiversity is currently based on the glacier-heterogeneity-diversity' paradigm, according to which there is high -diversity at intermediate levels of glacial influence due to the high degree of environmental heterogeneity caused by glacier water. This -diversity pattern generates high levels of between-site aquatic community variation (high diversity) and increases regional diversity (-diversity). There is a rich conceptual background in favor of this paradigm, but empirical data supporting it are scarce. We investigated this paradigm by analyzing the different diversity patterns (, and -diversity) of four aquatic groups (zooplankton, macroinvertebrates, algae and macrophytes) living in high-elevation peatlands (>4500m above sea level). We sampled 200 pools from 20 peatlands along a glacier gradient in the Cordillera Real of Bolivia. We performed structural equationmodeling (SEM) to analyze the potential mechanisms underlying the observed diversity patterns. Intermediate levels of glacial influence (15-20% cover) resulted in high heterogeneity, but -diversity responded to glacial influence only for the zooplankton group (Cladocera). Our SEM analysis did not identify environmental heterogeneity as a significant variable explaining the relationship between glacier and -diversity. Peatland area had a strong positive effect on heterogeneity and diversity. -diversity was significantly associated with glacier gradient, and 12.9% of the total regional diversity (-diversity) was restricted to peatlands with a high degree of glacial influence. These species might be lost in a context of glacial retreat. These findings provide new insight into the potential effects of glacial retreat on the aquatic environment and biodiversity in the peatlands of the tropical Andes. 2016 text https://www.documentation.ird.fr/hor/fdi:010067764 fdi:010067764 Quenta E., Molina-Rodriguez J., Gonzales K., Rebaudo François, Casas J., Jacobsen D., Dangles Olivier. Direct and indirect effects of glaciers on aquatic biodiversity in high Andean peatlands. 2016, 22 (9), 3196-3205 EN BOLIVIE ANDES ZONE TROPICALE