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

The macroinvertebrate fauna from 13 river catchments in St. Lucia were samp led over a two year period. Multivariate techniques were used to detect the influence of farming activities and urban developments on macroinvertebrat e community variation. Land use was the most significant correlate influenc ing the pattern of macroinvertebrate community variation. Stream chemistry was insignificant, with the exception of turbidity. Agricultural activity i n the upper and middle catchments caused middle and lower stations to suffe r more from the severity of spates and these had a deleterious affect on st ream communities. Pollution sensitive fauna were more closely associated wi th undisturbed stations. Results from a hybrid analysis suggested that a si gnificant variable was not included in the analysis. It is likely that hydr obiological data would have been a significant correlate in explaining macr oinvertebrate community variation, as the spate frequency regime has been i dentified as a significant correlate in other sub/tropical environments.