Changing Land Use and Population Density Are Degrading Water Quality in the Lower Mekong Basin

Establishing reference conditions in rivers is important to understand environmental change and protect ecosystem integrity. Ranked third globally for fish biodiversity, the Mekong River has world’s largest inland fishery providing livelihoods, food security, protein local population. It therefore of paramount importance maintain water quality biotic integrity this ecosystem. We analyzed land use impacts on constituents (TSS, TN, TP, DO, NO3−, NH4+, PO43−) Lower Basin. then used a best-model regression approach with anthropogenic land-use as independent variables parameters dependent variables, define absence human activities (corresponding intercept value). From 2000–2017, population percentage crop, rice, plantation cover increased, while there was decrease upland forest flooded forest. Agriculture, urbanization, density were associated decreasing health In several sites, Thailand Laos had higher NH4+ concentrations compared conditions, Cambodia TP values than showing degradation. TSS dry season Cambodia, but lower wet Laos. This study shows how deforestation from agriculture conversion increasing urbanization pressure causes decline Basin, provides first characterization its tributaries.