Creating new habitats for rare plants and thus making meadows more species-rich again, for example - this is what vegetation scientist and nature conservation expert Rainer Buchwald and his students are working towards.
On this May morning, Rainer Buchwald has put on his wellies. The meadow in the Haarenniederung, where he is going, is wet from the night's rain. Buchwald and student Sarah Höbel trudge through the tall grass, searching for the individual flowers of buttercups and sorrel among the lush greenery. Suddenly they both stop. "Here it is - the rattle pot," says Buchwald excitedly, pointing to a cluster of small plants with lemon-yellow flowers.
The nature conservation expert and the budding landscape ecologist have arranged to meet up this morning to see how the rattle plant population is developing. Meadows harbouring this plant are an exception in Oldenburg. The rattle plant, whose ripe seeds rattle in the calyx when the wind blows, has become rare throughout Germany. The Federal Agency for Nature Conservation has placed it on the "Red List" of endangered plants. Buchwald and Höbel are working to ensure that the plant can spread again.
The rattle pot is an example of a fundamental problem: over 1,000 of the approximately 5,500 native ferns and flowering plants are considered endangered according to the "Red List", and a further 65 are extinct or lost. It is often human activities - such as the destruction of habitats, environmental pollution or climate change - that jeopardise the species. Experts have long been talking about a biodiversity crisis that, like the climate crisis, is having a fundamental impact on us humans.
"The biodiversity crisis is happening quietly."
In north-west Germany, intensive agricultural use in recent decades has reduced the diversity of species in meadows. On heavily fertilised areas, a few grasses and fast-growing herbs such as sorrel and buttercup are crowding out less competitive species. Frequent or premature mowing harms annual plants such as rattle. They only survive if they flower, form seeds before mowing and can thus reseed themselves.
Buchwald, who has held the professorship of vegetation science and nature conservation at the university since 2005, is concerned about the loss of species. "Biodiversity is vital for our livelihoods," he emphasises. Colourful meadows, for example, provide food for insects, which in turn act as pollinators to ensure that we have food such as fruit and vegetables. The genetic diversity of wild plants is also important, for example for breeding crops. However, few people notice "when another species ends up on the Red List", says the expert. "The biodiversity crisis tends to happen quietly."
The university lecturer therefore considers it an important task to convey the value of biodiversity to students and at the same time introduce them to practical issues of nature conservation. Restoration ecology is at the centre of this: "Many landscapes are so degraded today that they cannot regenerate themselves," he explains. They need to be restored, renaturalised.
Combining research, teaching and nature conservation
This is also happening with the formerly heavily utilised grassland along the Haaren. Thanks to Buchwald and students of environmental sciences and landscape ecology, the rattle pot has been able to re-establish itself there. The team painstakingly collected rattle pot seeds from one of the two remaining sites in Oldenburg and planted them on the meadow. In order to allow the summer root plant and other flowering plants to thrive, the only mowing will not take place until the beginning of July - a condition imposed by the city of Oldenburg, which has leased the meadow to a farm.
The researchers and students working with Buchwald are looking after other endangered plant populations and sites in Oldenburg that are to become more species-rich again, for example on the airbase. The team is cooperating closely with the city, which is providing funding for the planting. "As a university, we take on the monitoring and analyse the soil chemistry, for example, in final theses - also in order to find good locations for the species that we want to reintroduce," he explains.
It is important to Buchwald that research, teaching and nature conservation go hand in hand in this way. He wants to make a difference. For example, he has spent a long time researching how meadows that are neither particularly wet nor dry can be renaturalised. "Such mesophilic meadows were not protected for a long time. Now they have been protected biotopes in Lower Saxony since last autumn. That's a huge success; nature conservation has been fighting for this for 20 years," he says.
In ten years, the meadow could be really colourful.
Buchwald estimates that only around ten to twelve plant species have been found in a monitoring sample area of the meadow in the Haarenniederung. In addition to the rattle pot, other species are therefore being colonised, such as the snake knotweed or the bunchgrass. Nevertheless, the great rattle has already begun to spread. Before mowing, Master's student Höbel will count exactly how many plants there are already. She will then collect seeds from a third of the faded plants in order to distribute them to other locations.
Höbel enjoys the work, which she carries out as part of a work contract. "I like being out in nature. And it feels good when the plant population develops positively," she says. For Buchwald, too, working for biodiversity is not just a matter of the mind. "Every area with a certain abundance of flowers and species makes me happy," he says and lets his gaze wander over the meadow: "It could be really colourful here too in ten years' time."
