| Abstract |
Lao PDR, a landlocked country in the lower Mekong River basin of Southeast Asia, has
been considered a global biodiversity hotspot with a high level of biological endemism. In recent
years, urban development and industrialization have affected the water quality of freshwater ecosystems
in Lao PDR. However, the assessment of water quality in the country is primarily focused
on a physicochemical method, while the application of a multimetric index (MMI) approach using
benthic macroinvertebrates for biomonitoring in rivers and streams has not been established. MMI,
based on benthic macroinvertebrates, is a biomonitoring tool that considers the effects of multiple
anthropogenic impacts on benthic macroinvertebrate metrics associated with their biological attributes
(e.g., taxa richness, composition, pollution tolerance, habits, and functional feeding) and aggregates
individual metrics into a single value for assessing the water quality and health conditions
of aquatic ecosystems. Here, we developed an MMI based on macroinvertebrate communities collected
during 2016–2018 from 10 localities of streams and wadeable rivers in Lao PDR. Of the 54
potential metrics tested, 35 candidate macroinvertebrate metrics representing richness, composition,
trophic structure, habit, and tolerance to pollution were selected, while 19 metrics were excluded.
Of the 35-candidate metrics, a total of 11 core metrics (Total taxa, EPT taxa, Ephemeroptera
taxa, %Diptera, %Plecoptera, %Tolerant, Beck’s biotic index, %Intolerant, Filterers taxa, %Sprawlers,
and %Burrowers) were finally selected for the development of MMI based on their sensitivity,
redundancy, and easy-to-apply tool for the biomonitoring program. These metrics can be used to
distinguish the reference (seven sites) from stressed conditions (seven sites). In addition, the final
MMI scores classified 40 sampling sites into four classes of water quality, including excellent (25%),
good (10%), fair (60%), and poor (5%), which the conventional physicochemical method could not
clearly distinguish. The Lao MMI developed in this study is an effective tool for evaluating the
water conditions of sites affected by human activities, particularly agricultural areas, and, thus, is
appropriate for use in future studies for assessing the ecological conditions of rivers and streams in
the Mekong region. |
Publication
Journal Publication
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