Wonder of nature: Konstanz pond is blooming again after 20 years!

Wonder of nature: Konstanz pond is blooming again after 20 years!

When a hot summer hit the region in the early 2000s, disaster struck a small pond on the University of Konstanz campus. The pond dried out completely in 2003 due to a layer of clay that was too thin. The floor cracked, which permanently damaged the waterproofing. Campus University of Konstanz reports that over two decades later, a restoration initiative was launched under the leadership of Gregor Schmitz, of the Botanical Garden of the University of Konstanz, and Lothar Damaschek of the State Office for Assets and Construction, Office of Konstanz. This measure is part of the “Nature Positive Universities” initiative, which the University of Konstanz has joined, with the aim of creating new biotopes in the campus area.

The restoration began in January 2024 with the detailed recording of the soil profile and the measurement of the old clay layer. At the end of January, excavation work was carried out to remove and adjust the defective clay layer, with high-quality clay being brought in from a construction pit in the Paradies district of Konstanz. The new layer is thicker than the previous one and is intended to meet ecological requirements in the long term.

Diversity of return

As part of the restoration, structural elements such as tree trunks and pieces of roots were added and an initial planting of rushes and clumps of clumps of sedge algae was carried out. The deepest point of the pond now measures 70 cm, which makes it easier for the animals to overwinter. The first observations followed in the summer of 2024: young water frogs and flat-bellied dragonflies returning to the newly revitalized body of water was an important milestone. Nature adds that biodiversity is suffering drastically in many places and there is a risk that around 1 million species are threatened with extinction.

In the spring of 2025, Schmitz counted 108 spring frog spawning balls in the pond. Various species of amphibians can be found here, including mountain newts and pond newts. At least four species of swimming beetles were also identified, while larvae of leaf-bellied dragonflies and a particular species of caddisflies were observed. Despite the positive developments, the ponds will continue to have to be supplied with water from the Botanical Garden this year due to a dry spring.

Biodiversity crisis in a global context

The efforts in Konstanz are not only important locally, but are part of a much higher context. The EU Parliament adopted its biodiversity strategy in June 2021, with the aim of restoring and adequately protecting global ecosystems by 2050. European Parliament emphasizes that at least 30 percent of the EU's marine and land areas should be protected, while ten percent must remain largely untouched.

The urgency is evident: biologists warn of the impending sixth phase of mass extinction, which is being accelerated by human activities. Preserving biotopes like those created in Konstanz is an important measure to slow the loss of biodiversity. It remains to be hoped that the positive effects of the Konstanz pond will set a precedent and serve as an example for similarly threatened ecosystems.