Ecosystems send out warning signals before breaking down
A warning signal can take the form of sudden, extreme variations in the amount of algae in a lake. There are numerous theories on these warning signals from Nature, but they have not been scientifically tested in practice until now.
“We have evaluated the warning signals globally and found that they often work but, unfortunately, they also do not point to the same results. Above all, we see that longer series of measurements and a great deal of expert knowledge are required in order to establish with certainty that an ecosystem is heading for breakdown”, says Lars-Anders Hansson, limnologist at the Faculty of Science in Lund.
Research teams based in Sweden, Germany and Austria worked together to achieve the results within the framework of the EU-funded Limnotip programme. The researchers have analysed series of measurements from lakes which have already transformed from one condition to another. By working backwards through time, they have investigated which warning signals were present before the ecosystem broke down.
“Our studies offer some hope that warning signals do exist and can be used in practice. This provides an opportunity to take measures before a catastrophic breakdown occurs”, says Lars-Anders Hansson.
The findings are presented in the scientific journal PNAS.