The primary aim ofthis project was to use a range of molecular markers to estimate genetic diversity levels of a range ofcommon plant species in peatbogs, in cut and uncut areas of six differentbogs across Northern Ireland. The main species studied were the moss Polytrichum commune, the ericaceous angiosperm Calluna vulgaris, and the sedge Eriophorum vaginatum. For the moss, levels of genetic diversity were lower in fragmented populations, as predicted by population genetic theory. For the two higher plant species, no decrease in genetic diversity was found at the cut sites. Calluna vulgaris showed an increase in genetic diversity at cut sites, possibly associated with the effects of a substantial, soil seed bank, while for Eriophorum vaginatum all populations examined had a similar level of genetic diversity. The differences observ~d between the three species can be related to their different life . history traits. E. vaginatum and C. vulgaris are long lived species with the capacity for clonal growth and any detrimental effect of habitat fragmentation is likely to take many more generations to become apparent, if such an effect is to be observed. P. commune is a bryophyte where the haploid gametophyte is the dominant generation, with a short life span and a small dispersal distance compared to C. vulgaris and E. vaginatum, it is not unexpected that such a species would be the first to display the detrimental signs of habitat fragmentation. Based on the findings ofthis study, recommendations are made for the efficient conservation and management of peat bogs.