Macroinvertebrate-Based Biomonitoring of Coastal Wetlands in Mediterranean Chile: Testing Potential Metrics Able to Detect Anthropogenic Impacts

Abstract

Coastal wetlands are suffering from anthropogenic alterations worldwide. Aquatic monitoring based on macroinvertebrates has been successfully used to assess the ecological condition of many aquatic systems worldwide. Nonetheless, studies are still insufficient for the coastal wetlands of the South Pacific. Here, we present a preliminary attempt to select metrics based on aquatic macroinvertebrates to incorporate into coastal wetlands biomonitoring in the Chilean Mediterranean ecoregion. We sampled 25 sites in ten coastal wetlands during the austral spring of 2019. We used an integrated index that considers both human activities at catchment and at local scales to identify sites less or more disturbed. We tested a total of 70 metrics (either traditional or new metrics) representing different aspects of community structure/composition, functions and tolerance to pollution. Two metrics were finally retained: detritivore abundance (traditional metric) and geometric mean body size (new metric). These metrics were able to detect sites impacted by human activities. Thus, they might be considered as candidate metrics for the biomonitoring of these systems and to develop future indices. Moreover, because of their generality, they might also be applicable to coastal wetlands in other Mediterranean regions, including sites where taxonomic identification is still a challenge.