Analýza vztahu druhové bohatosti měkkýšů (Mollusca) a velikosti vzorkovací plochy na minerotrofních slatiništích

Bc. Nicole Černohorská, Ph.D.

Master's thesis

Analysis of relationships between the number of molluse species and sampling area size on spring fens

Abstract:

The relationship between mollusc species richness and area was studied at 28 Western Carpathian treeless spring fen sites, differing in their mineral richness. In each site a set of three small nested quadrates of 25x25, 50x50 a 75x75 cm2 (the larger plot always containing the smaller plots) was sampled, from which mollusc data as well as vascular plant and bryophyte data were collected. Principal differences in the numbers of mollusc specimens and species were found when considering only live molluscs or empty shells as well. These differences were most marked at the more mineral-rich fen sites, where empty shells tend to accumulate over very long periods of time; at mineral-poor fen sites the empty shells dissolve relatively quickly due to low pH values. The number of species of each taxonomical group always increased with the increasing area. However, there were some differences in the species-area curves among the three taxonomical groups as well as among the three mineral types of fens. They, however, always fit a straight line in log-log space and differed in mainly only the rate of increase (expressed in z values which define the slope of the curves). Bryophytes had the lowest z values of all, but tended to increase towards mineral-poor sites, where the overall bryophyte species richness increased as well. Molluscs, on the contrary, had the highest z values of the three taxonomic groups, especially in mineral-rich sites, where molluscs have their optimum, and also, unexpectedly, in mineral-poor sites, which turned out to be only a result of the sampling effect. Vascular plants, having their highest species richness in moderately mineral-rich sites, had the curve with the highest z value there. This study is focused on small-scale species-area relationships, which have received very little attention, especially concerning animal species. For molluscs, no such fine-scale study has yet been carried out.

Keywords

species-area relationships, small scale, molluscs, spring fens

Language used: Czech

Date on which the thesis was submitted / produced: 16. 5. 2008

Thesis defence

• Date of defence: 17. 6. 2008
• Supervisor: prof. RNDr. Michal Horsák, Ph.D.

Masaryk University

Faculty of Science

Master programme / field:
Biology / Systematic Biology and Ecology