DNA-based assessment of environmental degradation in an unknown fauna: the freshwater macroinvertebrates of the Indo-Burmese hotspot

New methods are required for biomonitoring of poorly known tropical ecosystems, but biological assessments of environmental status are limited by insufficient information on taxonomy, composition, and ecology of local communities. The current work applies DNA-based assessment to establish the impact of various types of anthropogenic disturbances on the freshwater macroinvertebrates in an understudied biodiversity hotspot in South Asia, an area that attracts increasing attention for the loss of aquatic ecosystems.
We sampled 16 river systems in the Chittagong Hill Tracts region of Bangladesh and characterised habitat intactness based on a set of 14 environmental parameters associated with habitat quality and human activities. Whole-community metabarcoding was used to investigate the distribution of hypothetical species-level clusters (Operational Taxonomic Units, OTUs) across sites of different impacts.
We found >900 DNA clusters of insects, decapods and molluscs, dominated by Diptera...