Land snail species richness and abundance at small scales: the effects of distinguishing between live individuals and empty shells
| Authors | |
|---|---|
| Year of publication | 2010 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Conchology |
| MU Faculty or unit | |
| Citation | |
| web | https://www.conchsoc.org/node/4846 |
| 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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