LENGTH - BIOMASS AND ENERGY RELATIONSHIPS OF TERRESTRIAL GASTROPODS IN NORTHERN FOREST ECOSYSTEMS

Length-biomass models are a convenient and time-efficient method of es timating the biomass of invertebrates. Our purpose was to develop such a model for terrestrial gastropods that adequately predicted gastropo d dry tissue biomass (Y) on the basis of animal length (X). The power equation Y = 0.172X(1.688) (r(2) = 0.s5) proved to be the best model f or this purpose. Gastropod dry tissue biomass was 6.52 +/- 1.58 mg (me an +/- 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, becau se densities of gastropods in both the litter and underlying soil can reach 1607/m(2), our results suggest that published values for total a nimal biomass (4.9 g/m(2)) and caloric energy (10(4) cal/m(2)) in bore al forest ecosystems are underestimated.