Genetic structure of the rare moss species Rhodobryum ontariense in Vojvodina (Serbia) as inferred by isozymes

Abstract

Rhodobryum ontariense (Kindb.) Kindb. (Bryaceae, Bryophyta) is a rare moss, only recently discovered in Serbia (at Deliblatska Sands). After a revision of the genus Rhodobryum in Serbia, it was concluded that all high-mountain records belong to R. roseum, while R. ontariense is confined to the one known locality at Deliblatska Sands. It is listed in the bryophyte red-list of Serbia and Montenegro. Within the single known locality we have counted 15 small sub-populations over a total surface area of 6 hectares. The species is always in sterile condition and has been recorded only on dunes exposed to the north, at the edge of shrub-grassland transition interspersed with fragments of steppe vegetation. No propagules are known. This raised the question of whether the population was once continuous, or whether vectors exist that spread detached plants or fragments to establish new subpopulations. To answer this question an isozyme analysis was performed to estimate the genetic structure of this isolated population. Based on the isozyme forms of superoxide dismutase and peroxidase at least six haplotypes were determined within the population. It can be concluded that the present patches of the moss do not derive from one subpopulation. Some kind of short-distance dispersal exists, but it remains unclear what structures act as propagules and what is the vector for them.