Different patterns of resource use between two coexisting freshwater calanoid species

Abstract

Patterns of resource use (i.e. dietary richness, breadth and overlap) for the coexisting but differently sized species Calamoecia lucasi and Boeckella minuta were examined in specimens collected from Wallerawang Reservoir between April 1986 and September 1987. Significant differences in the dietary richness and dietary breadth were found between the species. Dietary overlap, as measured by Schoener's index, fluctuated within a relatively low range throughout the time interval. The effective resource partitioning may account for the perennial coexistence of these species. Since the degree of resource overlap cannot be directly related to the extent of competition, further experimental studies are necessary to determine how important the resource partitioning is in processes structuring associations of calanoid species.