Walking barrier
A migration barrier describes various obstacles for animals that hinder their habitat - sometimes even their further development. A distinction must be made between unintentional and intentional migration barriers.
Unintentional interference
In near-natural waters, the diverse habitat on the shore is often characterized by the active migration of amphibians and rodents . A migration barrier is an often non-natural narrowing of a watercourse along its bank. These are mostly caused by culverts , i.e. bridge structures or underpipes. For wild animals that migrate parallel to the water, they often represent an insurmountable obstacle. Berms built into the passage , which are constantly above the mean flood , provide a remedy. The so-called migration barrier density is one of the criteria for assessing the quality of a body of water according to the WFD .
For animals living in the water, especially fish, there are migration barriers in the form of dams and weirs , which cannot always be overcome using fish ladders and not for all fish species .
Intentional interventions
To protect the animals there are also walking barriers that are fully useful to the animals. So-called amphibian fences are set up along busy roads before the spawning season . The animals that fall into the depressions are regularly collected by volunteers and released on the other side of the road, mostly on the edge of rivers or lakes.
Individual evidence
- ↑ River information system of the State Environment Agency North Rhine-Westphalia ( Memento of the original from February 25, 2014 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Protection options. Recommendations of the BUND
