As part of the investigations, two heathland areas on Hiddensee were subjected to experimental drought manipulations: a younger area that is regularly tended to by means of nature conservation measures and an older area that has not been tended to for a long time. The result shows: the older heather survived the drought much worse than the younger heather. The reason for this is the biology of the common heather (Calluna vulgaris), which regenerates particularly well after measures such as grazing.
Regularly maintained areas are therefore more resistant to repeated dry periods. However, regeneration from seed is endangered by periods of drought. On Hiddensee, as in other heathland areas, nature conservation measures are being adapted to the results of climate research.
The decisive factor is not merely the intensity of a single year of drought, but a prolonged period of drought over several years, which significantly increases the stress on the plants. "The drought reduces the vitality of the plants. However, if several dry spells occur in succession, the damage not only accumulates, it becomes much more severe," explains Prof. Dr. Jürgen Kreyling.
Long-term observations and global parallels
The team from Greifswald has been monitoring the development of the heath in the aftermath of dry periods for years. On the one hand by means of drought simulations that use roofs to deny the ground of rain, and on the other with long-term monitoring: individual bushes were marked and drone flights supplemented the point-based observations.
These local observations confirm the global results of the international study "Drought intensity and duration interact to magnify losses in primary productivity". It forms part of the International Drought Experiment, which involves over 170 researchers on six continents. Roof structures were installed to specifically reduce precipitation in order to simulate extreme periods of drought.
Further information
The study was coordinated by Prof. Melinda Smith and Dr. Timothy Ohlert from Colorado State University. Participants included the German Centre for Integrative Biodiversity Research (iDiv), the University of Leipzig, the Helmholtz Centre for Environmental Research (UFZ) and the Experimental Plant Ecology working group at the University of Greifswald on Hiddensee. The Greifswald working group includes Ilka Beil, Irmgard Blindow, Sven Dahlke, Jürgen Kreyling, and Andrey Malyshev.
Publication: Timothy Ohlert et al, Drought intensity and duration interact to magnify losses in primary productivity. Science 390, 284-289 (2025). https://doi.org/10.1126/science.ads8144
Press release from Colorado State University
Article in the online magazine Campus*1456 [de]
Contact at the University of Greifswald
Prof. Dr. Jürgen Kreyling
Institute of Botany and Landscape Ecology
Experimental Plant Ecology
Soldmannstraße 15, 17489 Greifswald
Tel.: +49 3834 420 4131
juergen.kreylinguni-greifswaldde