Taxonomic and Functional Responses of Macroinvertebrates to Hydrological Changes and Invasive Plants in an NW Patagonia Riparian Corridor (Argentina)

Abstract

This study assessed the taxonomic and functional diversity of aquatic macroinvertebratecommunities in Chacabuco stream, a 5500 ha pioneering open conservation ranch of NahuelHuapi National Park in Argentina, focusing on the effects of seasonal hydrological regimesalong a willow-invaded corridor. Sampling was conducted during the spring of 2018 andthe summer and spring of 2019, covering high (spring) and low (summer) water levels.Results showed no significant differences in taxonomic diversity between hydrologicalperiods (p = 0.6), and similar taxonomic diversity during the low- and high-water periods of2019 due to an extreme drought event. Functional diversity varied significantly (p = 0.009)between hydrological periods, and a significant difference in taxonomic diversity betweeninvasive and native plots (p = 0.0001, R = 0.53) was found, while functional diversityrevealed less distinction (p = 0.02, R = 0.08). Functional diversity does not follow thesame pattern, showing opportunistic taxa such as predators and collectors equally presentduring both periods, sign of resilience of these FFGs over the others. This pioneeringstudy in the region highlighted the importance of exploring both taxonomic and functionaldiversity in riparian ecosystems to assess the impact of seasonal hydrological regimes alonga willow-invaded corridor and develop a more comprehensive understanding of riparianecosystem health.