Publication details

Land snail species richness and abundance at small scales: the effects of distinguishing between live individuals and empty shells



Year of publication 2010
Type Article in Periodical
Magazine / Source Journal of Conchology
MU Faculty or unit

Faculty of Science

Field Zoology
Keywords Fen; sampling quadrats; densities; species estimates
Description This paper considers the numbers of species and individuals of terrestrial snails in small plots (quadrats) of different sizes (0.0625 m2, 0.25 m2, 0.56 m2) in three types of treeless fen sites differing in calcium content. It compares the results of considering only live individuals or of combining these with empty shells. In two of the three sizes of plots and all fen (mineral level) types there was a clear increase of species when empty shells were included. In very calcium rich sites, empty shells contribute significantly to a summary of the fauna in the plot over several years, and can improve the inventory efficiency of sampling. However, when comparisons are made among sites with different soil chemistry, estimates of densities and relative abundances will be distorted, because shells decay at different rates among them. Hence, in any studies concerned with densities or spatial heterogeneity within sites it is necessary to distinguish between live individuals and empty shells.
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