News

Crayfish Reintroduction Project in the Koblenz City Forest

In the spring, we set out early in the morning together with our partners from Schleswig-Holstein to collect the stone crayfish from the mating pond near Koblenz. To do this, we first slowly drained the water from the pond and then waited until the first stone crayfish ventured out of their hiding places. In fact, we managed to recover the majority of the stone crayfish, some of which were females carrying fertilized eggs. The eggs from the captured females were carefully removed from their swimmerets using tweezers and transferred to incubation boxes for transport. Both the females and the males were then returned to the donor water body. The eggs, in turn, were transferred to incubators for hatching. Now we must wait until the juvenile stone crayfish hatch, grow into summer juveniles, and can then be released into suitable waters. Stay tuned to see how the journey of our stone crayfish continues!

Stone Crayfish Reintroduction Project in the Koblenz City Forest

Since the native stone crayfish (Austropotambius torrentium) is threatened with extinction both across Europe and locally, a project has been underway for ten years in the Koblenz City Forest to breed stone crayfish for species conservation. Starting this year, our working group is also providing scientific support for this project. After the mating pond was cleaned and filled with water in early fall, our colleagues set out to search for suitable parent animals in the donor water. This search took place over several days and began at dusk. After successfully collecting males and females in a 1:2 ratio, they were placed in the mating pond to mate. Now it’s up to the animals to successfully mate over the winter! In the spring, the stone crayfish will then be removed from the pond and returned to the donor water. Before that, however, the fertilized eggs will be stripped from the females so they can be incubated under controlled conditions. But more on that next year!

Biodiversity in Water Bodies Under Threat

In many habitats, biodiversity is declining at an alarming rate. The reasons for this include ongoing habitat loss, the intensification of agriculture, pollution, climate change, and many other factors. These effects can be studied particularly well in water bodies. They are always located at the lowest point of the landscape and absorb the influences of their surroundings.

A Europe-wide study on biodiversity trends in water bodies, conducted with the participation of Trier University of Applied Sciences, has just been published in the renowned scientific journal Nature. “Streams and rivers in particular are hotspots of biodiversity; a multitude of microorganisms live in the riverbed, especially insect species, mussels, snails, crayfish, and worms. These form the food base for fish and also play an important role in the water’s self-purification capacity and other processes,” explains Prof. Dr. Stoll from the Environmental Campus at Trier University of Applied Sciences, one of the study’s authors.

The current study analyzes water body data from 22 European countries covering the period from 1968 to 2020. The study shows that, contrary to the general trend in the surrounding landscape, biodiversity in water bodies increased between 1980 and 2010. The authors attribute this to improvements in water quality resulting from the construction of wastewater treatment plants and extensive waterway restoration projects during this period. The water systems that warmed the least due to climate change and whose watersheds had the lowest proportion of development and farmland showed the greatest increases in biodiversity over the past decades.

However, over the past decade, from 2010 to 2020, a decline in these increases in aquatic biodiversity was observed across Europe. The authors attribute this to a decline in restoration efforts. In addition, they note that positive renaturation effects are now increasingly being overshadowed by climate change, which leads to more extreme flooding and longer periods of drought. The intensification of agriculture is also having a noticeable impact on our water bodies.

Prof. Dr. Stoll therefore urges that renaturation efforts in and around our water bodies be stepped up again. “Data from the past decades show that consistent water protection can counteract the general trend of biodiversity loss. In particular, upgrading wastewater treatment plants and restoring natural riparian zones help aquatic organisms. Natural riparian vegetation also provides shade, which mitigates the rise in water temperature caused by climate change.”

The Birkenfeld Environmental Campus and the Hunsrück-Hochwald National Park will participate as one of 200 survey sites worldwide within the “LIFEPLAN – A Planetary Inventory of Life” project. LIFEPLAN investigates the current state of biodiversity around the world; using various methods, we are compiling the most ambitious, global, standardized dataset of biodiversity across a wide range of taxonomic groups to date. The following equipment is in use:

Camera traps for recording mammals

Audio recorders for documenting birds and bats

Cyclone samplers, which filter fungal spores and pollen from the air

Malaise traps for targeted insect sampling

The resulting findings will be used to make accurate predictions about the evolution of biodiversity under future scenarios.

This ambitious project is funded by the European Research Council as part of the European Union’s 2020 Research and Innovation Program.

For more information, visit www.helsinki.fi/en/projects/lifeplan.