The rare broad-leaved orchid (Dactylorhiza majalis) is a strikingly flowering orchid species that grows mainly in nutrient-poor wetlands such as floodplains, fens and wet meadows and has thrived in Upper Lusatia for centuries. The habitats of this orchid have declined dramatically in the past due to persistent fertilizer input from agriculture, intensive grazing and the draining of biotopes. As almost a third of the world's remaining populations occur in Germany, the Federal Agency for Nature Conservation (BfN) currently classifies D. majalis as a "species of concern". Climate change may act as an additional damaging factor in the future and lead to further population losses during prolonged dry periods, especially in the summer months. The Native Orchid Working Group (AHO) in Germany recently drew attention to this new potential threat by selecting the broad-leaved orchid as Orchid of the Year 2020.

A research group from the HSZG (Faculty of Natural and Environmental Sciences, Department of Biotechnology and Ecology and Environmental Protection), which has been investigating twelve populations of the broad-leaved orchid at various locations in Upper Lusatia since 2014, has now published its findings as a specialist 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 primarily investigated the question of the fertility of D . majalis and whether there is evidence that the species has adapted to local site factors. To this end, special laboratory methods in the form of biochemical seed analyses, microscopic chromosome examinations and DNA marker technologies were used, whereby the local environmental factors were identified based on the indicator values of the locally occurring plant communities. Surprisingly, 85 to 95 % of the seeds analyzed were sterile, which could be explained by observed chromosomal irregularities during maturation division in the macrospores. The data could be divided into two collectives of different fertility, which differed both on the basis of the site factor continentality and on the basis of a genetic marker. Because the orchid seeds in the Lusatian Mountains were significantly more fertile compared to the orchid seeds in the heath and pond landscape, the scientists assume that they have discovered an advantageous genetic adaptation to the suboptimal continental climate conditions in the mountains. With regard to the protection and future management of the broad-leaved orchid, they call for the fertility of the populations in Upper Lusatia to be monitored at regular intervals from now on for longer-term forecasts. Particular attention should be paid to some very small populations whose survival is at risk.

Text: Markus Brugger