Genetic diversity and implications for conservation strategies of Drosera rotundifolia L. (Droseraceae) in northern Germany (Schleswig-Holstein)

Drosera rotundifolia L. is a rare carnivorous herbaceous plant which occupies wet, acidic bogs and fens. Today species which are specialists on oligotrophic and acidic habitats like D. rotundifolia have declined as a result of land use changes, land reclamation and drainage. The aim of our study was to assess patterns of genetic diversity in twelve fragmented D. rotundifolia populations of northern Germany (Schleswig-Holstein) by the use of Inter-simple sequence repeats (ISSR). ISSR is a PCR fingerprint technique, which uses microsatellite sequences as primers to generate multilocus markers. We scored 84 individuals at a total of 120 ISSR markers. We found a wide range of population genetic diversity (He = 0.109–0.247) described by the ISSR data. There was a weak relationship between genetic isolation and distance (P = 0.010) and a large (significant) proportion of genetic variation within populations (75 %, P < 0.001) and 25 % among populations. STRUCTURE analysis showed that the model with three inferred clusters (K = 3) best described the ISSR data. Some dominant clusters at each site corresponded to the results from the principal coordinate analysis (PCoA), which visualises genetic patterns of individual plants. The patterns of genetic diversity by the ISSR data showed, for some local genotypes of the D. rotundifolia populations a clear separation, pointing towards conservation strategies for each population of D. rotundifolia in northern Germany rather than for the species as a whole.