DOES SIZE MATTER? INFLUENCE OF THE BODY SIZE OF GAMMARUS MINUS SAY 1818 ON BENTHIC MACROINVERTEBRATE DIVERSITY AND COMMUNITY STRUCTURE IN KARST SPRINGS OF VIRGINIA AND WEST VIRGINIA

This first of its kind study sought to examine how variation in body size of sexually mature Gammarus minus, a benthic amphipod found in freshwater karst springs, covaried with measures of macroinvertebrate diversity and community structure in carbonate spring benthic communities. For each spring, three diversity indices were calculated from the macroinvertebrate inventory in addition to total macroinvertebrate richness and log abundance. Richness and log abundance were calculated for the non-insect, insect, EPT, and non-EPT components of the macroinvertebrate. Relative abundance of each component was also determined. Linear regression was used to analyze the relationship between these measures and average head length of amplexing males and females. For total community measures, only the Margalef index was significantly negatively related to head length. The richness, relative abundance, and log abundance of insects and EPT components also showed a negative relationship with head length. No other measures were significantly related to head length.