Does the Density of Dead Shells Predict the Density of Living Anguispira cumberlandiana Lea 1840 (Gastropoda: Discidae)?

Abstract

ABSTRACT Population densities of calciphilic land snails are hard to quantify because the snails stay lodged deep within limestone cracks for much of the year. We tested the hypothesis that the density of empty shells from dead snails (“dead shell”) of Anguispira cumberlandiana predicts the density of living snails. If such a relationship exists, surveys of dead shell density could be used as estimates of the density of living animals, thus facilitating the study and management of this genus of high conservation value. We established a sampling grid on a limestone outcrop on the Cumberland Plateau in south-eastern Tennessee and estimated live and dead snail abundance at 50 sampling points. Our hypothesis was supported overall, but the predictive value of dead shell was not perfect: about half of the variation in the density of living snails was not explained by variation in dead shell density. We conclude that dead shell density can be used as a statistical predictor of live snail density, but not as a pe...