The rare broad-leaved marsh orchid (Dactylorhiza majalis) is a strikingly flowering orchid species that grows primarily in nutrient-poor wetlands such as river floodplains, fens, and wet meadows, and has thrived in Upper Lusatia for centuries. Due to persistent fertilizer runoff from agriculture, intensive grazing, and the drainage of habitats, the habitats of this orchid have declined dramatically in the past. Since nearly one-third of the world’s remaining populations are found in Germany, the Federal Agency for Nature Conservation (BfN) currently classifies D. majalis as a so-called “species of special responsibility.” Climate change may act as an additional threat in the future and, in the context of prolonged dry spells—especially during the summer months—lead to further population declines. The Working Groups on Native Orchids (AHO) in Germany recently drew attention to this new potential threat by selecting the broad-leaved marsh orchid as the Orchid of the Year 2020.

A research group at the HSZG (Faculty of Natural and Environmental Sciences, Departments of Biotechnology and Ecology and Environmental Protection), which has been studying twelve populations of the broad-leaved orchid at various sites in Upper Lusatia since 2014, has now published its findings as a research article in the internationally peer-reviewed journal *Biologia* (“Analyses of sexual reproductive traits in *Dacytlorhiza majalis*: a case study from East Germany,” Schubert et al., 2020). The scientists focused primarily on investigating the fertility of D. majalis and whether there is any information that indicates the species has adapted to local site conditions. To this end, they employed specialized laboratory methods, including biochemical seed analyses, microscopic chromosome examinations, and DNA marker technologies, with local environmental factors identified based on the indicator values of the locally occurring plant communities. Surprisingly, 85 to 95% of the seeds examined were sterile, a finding that could be explained by observed chromosomal irregularities during meiosis in the macrospores. The data could be divided into two groups with different fertility levels, which differed both in terms of the site factor “continentality” and a genetic marker. Because the orchid seeds in the Lausitz Mountains were significantly more fertile compared to those in the heath and pond landscapes, the scientists conclude that they have discovered a beneficial genetic adaptation to the suboptimal continental climatic conditions in the mountains. With regard to the conservation and future management of the broad-leaved marsh orchid, they call for the fertility of populations in Upper Lusatia to be monitored at regular intervals from now on to enable longer-term projections. Particular attention should be paid to a few very small populations whose survival is at risk.

Text: Markus Brugger