Phylogenetic diversity efficiently and accurately prioritizes the conservation of aquatic macroinvertebrate communities

Abstract

AbstractLand degradation is a leading cause of biodiversity loss yet its consequences on freshwater ecosystems are poorly understood, exacerbating difficulties with assessing ecosystem quality and the effectiveness of restoration practices.Many monitoring programs rely on macroinvertebrates to assess the biotic effects of degradation and/or restoration and management actions on freshwater ecosystems. The ratio of Observed (O) to Expected (E) macroinvertebrate taxa at a given site—O/E—is often used for this purpose, despite the amount of modeling and data required to generate expectations and difficulties quantitatively assessing the degree of degradation at a site.Despite widespread use in academic biology, phylogenetic diversity is rarely applied in management, regardless of empirical correlations between phylogenetic diversity and management targets such as ecosystem structure and function.We use macroinvertebrate data from 1,400 watersheds to evaluate the potential for phylogenetic metrics to inform evaluations of management practices. These data have been collected since 1998, and have been used to determine the effectiveness of conservation management for the maintenance and restoration of riparian and aquatic systems.Phylogenetic diversity detected degradation as effectively as O/E, despite not having baseline ‘expectation’ data. Site disturbance, road density, and broader environmental drivers such as mean annual temperature strongly predicted site phylogenetic diversity, providing concrete management objectives to increase site health.Synthesis and applications. Management efforts targeted solely at taxonomic metrics, such as O/E, have been successfully used to manage sites. We show here that phylogenetic diversity metrics can support such efforts by providing additional information about the kind of species at sites. Given the ease with which such approaches can be applied, we call on others to use them to supplement existing prioritization schemes.