Population dynamics of six land snail species in experimentally fragmented grassland
Article first published online: 26 SEP 2008
© 2008 The Authors. Journal compilation © 2008 British Ecological Society
Journal of Animal Ecology
Volume 78, Issue 1, pages 236–246, January 2009
How to Cite
Stoll, P., Oggier, P. and Baur, B. (2009), Population dynamics of six land snail species in experimentally fragmented grassland. Journal of Animal Ecology, 78: 236–246. doi: 10.1111/j.1365-2656.2008.01478.x
- Issue published online: 11 DEC 2008
- Article first published online: 26 SEP 2008
- Received 26 February 2008; accepted 22 August 2008; Handling Associate Editor: Tim Coulson
- multi-species approach;
- 1The fragmentation of natural habitats is generally considered to be a major threat to biodiversity. Different species may respond differently to habitat fragmentation, depending on species-specific traits such as body size, dispersal ability, mating system, and habitat requirement.
- 2The population sizes, extinction and recolonization frequencies of six naturally occurring land snail species (Cochlicopa lubrica, Vertigo pygmaea, Pupilla muscorum, Punctum pygmaeum, Helicella itala, and Trichia plebeia) were examined over 3 years in an experimentally fragmented nutrient-poor, calcareous grassland in the northern Swiss Jura mountains using a mark–recapture technique. Fragments of different size (0·25 m2, 2·25 m2, and 20·25 m2) were isolated by a 5-m wide strip of frequently mown vegetation. Control plots of corresponding size were situated in adjacent undisturbed grassland.
- 3Experimental grassland fragmentation influenced the population size in all snail species except H. itala, which is the species with the biggest shell and it is also active under mild conditions in winter. However, fragmentation affected different species to a different extent.
- 4Extinction (= disappearance from a plot) frequency increased with time, decreasing population size and decreasing plot size in all species. Large populations had a lower extinction probability than small populations. Fragmentation increased the probability of extinction, which also differed among snail species. The effect of plot size on extinction probability was still significant even after the effect of population size had been taken into account.
- 5Fragments and control plots did not differ in recolonization frequencies when all six species were considered. However, fragmentation influenced recolonization frequency when the two species with large shells (H. itala and T. plebeia) were excluded from the analysis.
- 6Our study shows that small-scale grassland fragmentation affects different land snail species to a different extent. This finding strengthens the claim for multi-species approaches to obtain general predictions of fragmentation impact.