A Study of Benthic Communities in Some Saline Lakes in Saskatchewan and Alberta, Canada

Abstract

AbstractThe spring benthos of 22 lakes ranging from 1–88 gl−1 salinity contained 58 species of macroinvertebrates, but only 23 species occurred in waters >3 gl−1. The amphipod Hyalella azteca and the chironomids Procladius freemani, Chironomus nr. muratensis and Cryptochironomus spp. were important at lower salinities (1–12 gl−1) whereas the chironomids Tanypus nubifer, Cricotopus ornatus and Chironomus nr. annularis dominated at moderate salinities (5–30 gl−1) and dolichopodid and ephyrid dipterans were the only species in hypersaline lakes (>50 gl−1). Diversity decreased significantly with increased salinity.Mean dry biomass ranged from 0–9.12 gm−2, showing little correlation with salinity, though hyposaline lakes often had elevated values and hypersaline lakes very low values. Shallow lakes (<5 m) had significantly lower standing crops. There were long term changes in biomass (over 45 years) in some lakes due to cultural eutrophication or secular changes in salinity. Chironomids were by far the dominant contributors to biomass at salinities to 50 gl−1, above which dolichopodid and ephyrid dipterans dominated.The lakes were classified into four groups—subsaline, hyposaline, shallow hypo‐mesosaline and hypersaline, reflecting the importance of salinity and also relative depth as major controlling factors.