Good news for rivers in Britain
Scientists from Cardiff University have found that Britain's urban rivers are the cleanest they've been in over two decades.
The 21-year study of over 2,300 rivers measured the presence of clean-river invertebrates - a yardstick for river health - which during the days of heavy industry and poor sewage treatment had declined considerably, but now appear to be making a comeback.
Although climate change has warmed British rivers by around 1-2 degrees over recent decades, the findings suggest that improved pollution control has managed to offset its damaging effects on river ecosystems. This indicates that society can prevent some undesirable climate change effects on the environment by improving habitat quality.
Dr Ian Vaughan and Professor Steve Ormerod from the University's School of Biosciences analysed changes in the occurrence and spread of insects, snails and other mini-beasts from major rivers between 1991 and 2011. The researchers then asked whether water quality, temperature or river flow best explained the biological changes they observed.
Among 78 types of organisms examined, 40 have become more prevalent in English and Welsh rivers while 19 have declined. Overwhelmingly, these trends were explained by reductions in gross pollution rather than warming or changing flow caused by climate change.
Improving water quality has allowed some clean-water organisms from upland rivers to return to previously polluted lowland rivers, and may even explain some northwards movement previously attributed to climate-change.
Church reflection on the river Tay in Scotland image via Shutterstock.
Read more at ScienceDaily.