• Energy Research

Climate change is rapidly driving global biodiversity declines. How wetland macroinvertebrate assemblages are responding is unclear, a concern given their vital function in these ecosystems. Using a data set from 769 minimally impacted depressional wetlands across the globe (467 temporary and 302 permanent), we evaluated how temperature and precipitation (average, range, variability) affects the richness and beta diversity of 144 macroinvertebrate families. To test the effects of climatic predictors on macroinvertebrate diversity, we fitted generalized additive mixed-effects models (GAMM) for family richness and generalized dissimilarity models (GDMs) for total beta diversity. We found non-linear relationships between family richness, beta diversity, and climate. Maximum temperature was the main climatic driver of wetland macroinvertebrate richness and beta diversity, but precipitation seasonality was also important. Assemblage responses to climatic variables also depended on wetland water permanency. Permanent wetlands from warmer regions had higher family richness than temporary wetlands. Interestingly, wetlands in cooler and dry-warm regions had the lowest taxonomic richness, but both kinds of wetlands supported unique assemblages. Our study suggests that climate change will have multiple effects on wetlands and their macroinvertebrate diversity, mostly via increases in maximum temperature, but also through changes in patterns of precipitation. The most vulnerable wetlands to climate change are likely those located in warm-dry regions, where entire macroinvertebrate assemblages would be extirpated. Montane and high-latitude wetlands (i.e., cooler regions) are also vulnerable to climate change, but we do not expect entire extirpations at the family level.

Given the multiple stressors affecting freshwater ecosystems and the limited resources devoted to their management, effective conservation of freshwater biodiversity requires regional prioritization. Patagonian wetlands are essential for regional biodiversity and the economy, but they are still far from reaching global conservation targets and many of them could disappear due to climate change. Our study aimed at prioritizing wetlands based on aquatic and terrestrial biodiversity, their conservation status and vulnerability to climate change. First, we identified 43 priority wetlands containing all aquatic biodiversity collected in 82 Patagonian wetlands located over a 1500 km north–south gradient, by using the software Marxan. Then, we ranked within priority wetlands according to their conservation status (low priority if they were already protected; medium priority if not), importance for terrestrial biodiversity conservation (high priority) and vulnerability to climate change. Highly ranked priority wetlands in National Parks (low priority), contained diverse wetlands (57% aquatic taxon richness), including a large proportion of rare species (33%). High priority wetlands are oases of water in an arid and semiarid steppe, containing not only a large proportion of the aquatic biodiversity, but also acting as a refuge for terrestrial flora and fauna. Different management actions are proposed according to wetland priority level (e.g. fencing, creation of artificial ponds), and since 20% of medium priority and 36% of high priority wetlands are expected to disappear by 2050, their inclusion in conservation or restoration plans needs to be carefully evaluated.