According to a study by scientists from the Czech University of Life Sciences Prague and the Leibniz Institute of Freshwater Ecology and Inland Fisheries (Berlin, Germany), climate change and land use will cause significant changes in the composition of fish communities in the river network by 2050. The article was published by the prestigious scientific journal Global Change Biology.
In this study, models of current fish stocks in the Elbe catchment area were combined with the possibilities of their spreading in a fragmented river network under the influence of predicted climate change and landscape use in 2050. These changes will lead to the loss of 24 to 94 river miles of the suitable environment of individual species while the response to environmental change will be different inter species. For example, fish species living in lowland streams will move downstream while fish from the headwater areas will move further upstream.
The spreading model suggests that the environment suitable for individual species will move too quickly for fish species to be able to compensate for changes via migration. Large species of fish will be restricted in particular by migratory obstacles, whilst species less than 20 centimetres in size will be limited by restricted migratory capabilities. The possibilities of fish to respond to environmental changes via migration are limited by the restricted permeability of the river network caused by flow barriers such as weirs and dams.
Based on the findings, the authors of the article conclude that under the influence of climate changes and landscape use, the environment in which fish can live will become limited, and that this will also lead to significant changes in the composition of fish communities in the river network.