Littoral Zoobenthic Biomass in Lakes, and Its Relationship to Physical, Chemical, and Trophic Factors

Abstract

The hypothesis that littoral morphometry exerts a strong effect on zoobenthic biomass was tested in Lake Memphremagog, Quebec–Vermont, by regression analysis of the relationship between littoral zoobenthic biomass and littoral slope, exposure (Lake area visible from sampling site), and trophic status (micrograms of chlorophyll a per litre). Eighty-one percent of the variance in Log littoral zoobenthic biomass (LZB) could be explained by[Formula: see text]When the predictions from this relationship were compared with littoral zoobenthos estimates from other lakes, residuals were positively correlated with the calcium concentration of the water (r = 0.41) and negatively correlated with the chloride concentration (r = −0.51). The regression equation obtained for all of the sites was[Formula: see text]and explained 80% of the variation in Log LZB. Sites situated within deltas from stream inflows did not differ significantly from these that did not (ANCOVA), indicating that coarse allochthonous input from these fluvial sources was not a major factor determining littoral zoobenthic biomass in these lakes.