Mass migration towards poles has begun: new Science metastudy shows species move on average 17.6 kilometres per decade

Today new climate migration insights were published in Science. They show the process is happing three times as fast as an older (2003) Science metastudy had predicted and close to the actual latitudinal speed of climate change over the last decades in Europe and North America.

In mountainous areas species respond to climate change by moving upslope. Over the last 40 years this has happened at an average speed of 12.2 meters per decade. [In mountains the median migration speed is 11.0 meters per decade, the median latitudinal speed is 16.9 kilometers.]

These are findings of a team of researchers who have examined 54 studies that met comparability criteria and that brought together migratory data of over 2000 plant and animal species since 1970.

The data do show a lot of noise. Some species have even moved towards warmer climates, whereas the Eurasian butterfly Polygonia c-album, known in the UK as the Comma, has already moved 220 kilometres to the north.

Geographical barriers

Such noise can partially be explained through geography. Seas, rivers, mountains, human infrastructure and different landscape types hinder fluent migration patterns, increasing the challenge for especially non-flying animals and slow-growing plants, like trees. Of course species from Arctic and alpine ecosystems may have no potential refuge at all [pity penguins and polar bears don't mix well].

The possible failure to find new suited habitats makes continued climate change an important driver behind the world’s biodiversity crisis.

To compensate for the temperature effects of climate change terrestrial species will have to migrate on average 50-60 kilometers towards the poles for every 0.5 degrees Celsius of warming. In mountains each warming of 0.5 degrees requires species to move 100 meters further uphill, in order for full populations to remain in their respective climatic zones and not to lose habitat.

© Rolf Schuttenhelm | www.bitsofscience.org

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