The macroinvertebrate fauna of St. Lucia elucidated by canonical correspondence analysis

The macroinvertebrate fauna from 13 river catchments in St. Lucia were sampled over a two year period. Multivariate techniques were used to detect the influence of farming activities and urban developments on macroinvertebrate community variation. Land use was the most significant correlate influencing the pattern of macroinvertebrate community variation. Stream chemistry was insignificant, with the exception of turbidity. Agricultural activity in the upper and middle catchments caused middle and lower stations to suffer more from the severity of spates and these had a deleterious affect on stream communities. Pollution sensitive fauna were more closely associated with undisturbed stations. Results from a hybrid analysis suggested that a significant variable was not included in the analysis. It is likely that hydrobiological data would have been a significant correlate in explaining macroinvertebrate community variation, as the spate frequency regime has been identified as a significant correlate in other sub/tropical environments.