Relationship between macroinvertebrate fauna and environmental variables in small streams of the Dominican Republic

Field assessment methods for freshwater macroinvertebrates and water quality in tropical small-island states were assessed in the Dominican Republic. Macroinvertebrate samples were collected from 26 river sites within the Dominican Republicʹs Yaque del Norte river catchment. Environmental data on geographical, physical and chemical variables were also collected from each site. The Biological Monitoring Working Party score and total numbers of Ephemeroptera and Trichoptera were calculated for each site. Physico-chemical and biological data sets were ordinated by principal components analysis and non-parametric multi-dimensional scaling, and the biotic and abiotic data sets were correlated to determine the most influential factors determining site similarities. Macroinvertebrate assemblage structure was correlated with declining water quality: however, a high correlation between water quality and altitude confounded an unqualified interpretation of impairment.