Ecological drivers of alpha and beta diversity of freshwater invertebrates in arid and semiarid Patagonia (Argentina)

EPELE, LUIS B.; BRAND, CECILIA; MISERENDINO, MARÍA LAURA

THE SCIENCE OF TOTAL ENVIRONMENT

ELSEVIER

Año: 2019 vol. 678 p. 62 - 73

0048-9697

Freshwater biodiversity is showing a global decline in relation to environmental change and there is an urgent need to quantify different facets of biodiversity to assess the conservation value of freshwater ecosystems. Identifyingthe ecological drivers of arid and semiarid Patagonian waterbodies is a critical requirement for planning action to conserve these still poorly understood habitats. We tested the responses of alpha and beta diversity of invertebrates (presence-absence, abundance, and biomass) to local, landscape, and climatic features, in 45 Patagonian freshwater bodies classified in three groups: isolated ponds, connected ponds, and lotic systems. We first compared the invertebrate community compositions of the different waterbodies. Secondly, using a co-inertia analysis we assessed the relative roles of local, landscape and climatic factors in driving variation in assemblage composition. Finally,we compared different facets of beta diversity andmodelled their responses to environmental variables (predictors), by generalized dissimilaritymodelling (GDM). Unexpectedly, lotic systemswith a total of 109 taxa, were richer than lentic ones, but isolated ponds contributed most to beta diversity and supported more unique and proportionallymore endemic species. Alpha and beta diversityweremainly driven by local features and secondly by climatic descriptors. However, these patterns shifted according to different community composition measures. Collectively, our results suggest that isolated ponds have a higher biodiversity value and would be more vulnerable than connected ponds and lotic systems to environmental changes. However, all waterbody types contributed to gamma biodiversity, reinforcing the importance of conserving a diversity of freshwater ecosystems in any landscape and articularly in arid and semiarid Patagonia. Our findings are a first step to resolving and quantifying the amount of changes occurring in atagonianwaterbodies, and are a prerequisite for predicting changes in species distributions in the face of global change.