Ecological condition, biodiversity and major environmental challenges in a tropical river network in the Bago District in South-central Myanmar: First insights to the unknown

Freshwater ecosystems in the Indo-Burma biodiversity hotspot face immediate threats through habitat loss and species extinction. Systems to monitor ecological status trends are therefore crucially needed. Myanmar is part of but with no past experience biomonitoring freshwaters. In this study, we aimed assess a lowland river network south-central by identifying quantifying pressures using macroinvertebrates as bioindicators. Novel data on water quality (nutrients, sediments metals), hydromorphology (Morphological Quality Index; MQI), (Litter-Siltation LSI), land use, were collected from 25 sites. The dominant rivers urban inputs untreated sewage, in-stream riparian garbage littering, run-off agricultural fields plantations, well physical degradation. Water chemistry indicated nutrients degraded streams, obvious metal pollution. LSI MQI indices high perturbation areas, respectively. Ecological was assessed first version modified Average Score per Taxon index (ASPT), while family richness within orders Ephemeroptera, Plecoptera, Trichoptera, Coleoptera Odonata (EPTCO), which tested against pressure gradient principal component regressions. ASPT had diagnostic capabilities (R2 = 0.68, p < 0.001) showed that can be used evaluate region. Biodiversity, expressed richness, also declined along 0.59, 0.041), giving support fact current land-use practices area unsustainable.