Niche relations and association analysis of southern Swedish mire hepatics

Abstract

Bryophytes of all mire types present in an area of southern Sweden were sampled in 600 small plots, each including at least one hepatic species. Ecological preferences for the hepatics were estimated using ordination, tests of log-likelihood ratio for contingency tables, and calculations of niche breadths. Preferences for the 20 most frequent hepatic species are presented. It is concluded that the hepatic species exhibit a similar ecological diversity to other taxonomic groups of bryophytes. Aneura pinguis, Cladopodiella fluitans, Gymnocolea inflata and Mylia anomala have a narrow ecological amplitude in the mire habitat, whereas some small species, e.g. Calypogeia sphagnicola, Cephalozia spp., Cephaloziella elachista and Kurzia pauciflora, have wider ecological amplitudes. The term ‘compromise strategy’ is introduced for the hepatics that rely on habitats created by other living bryophytes and ‘avoidance strategy’ for those hepatics that instead prefer peat or litter as the substratum. Frequently fertile Cephalozia species are adapted to the latter strategy whereas species that are usually sterile coexist predominantly with Sphagnum. Hepatics grow more often among Sphagnum spp. in the sections Sphagnum and Acutifolia than in the section Cuspidata.