Length–biomass and energy relationships of terrestrial gastropods in northern forest ecosystems

Length–biomass models are a convenient and time-efficient method of estimating the biomass of invertebrates. Our purpose was to develop such a model for terrestrial gastropods that adequately predicted gastropod dry tissue biomass (Y) on the basis of animal length (X). The power equation Y = 0.172X 1.688 (r 2 = 0.85) proved to be the best model for this purpose. Gastropod dry tissue biomass was 6.52 ± 1.58 mg (mean ± SE) and, based on gastropod densities ranging from 2 to 38/m 2 reported in the literature, snails and slugs active on the surface of the forest floor accounted for 2.5 and 6% of the total animal biomass and energy, respectively, of boreal forest ecosystems. However, because densities of gastropods in both the litter and underlying soil can reach 1607/m 2 , our results suggest that published values for total animal biomass (4.9 g/m 2 ) and caloric energy (10 4 cal/m 2 ) in boreal forest ecosystems are underestimated.