Species migration between marine regions

Biodiversity changes as seas grow warmer

We will see an expansion of marine biodiversity ­– but only in some regions. Some ecosystems will lose their biodiversity. Due to rising sea temperatures, some species will spread to other regions and unique ecosystems will become less diverse. These are the findings of an international study involving palaeobiologists from FAU which have recently been published in the journal Nature Climate Change. Moreover, the researchers identified marine regions where nature conservation would be particularly promising.

Evaluation of data on approximately 13,000 marine species

This study is based on a previous study carried out by Prof. Dr. Wolfgang Kießling, Chair for Palaeoenvironmental Research at FAU, which was published in the journal Nature (Press release on the previous study). The international team conducting the previous study developed a model which can be used to predict at what speed and in which direction climate zones will shift in the future, and which regions species will migrate to. In their latest study, the researchers expanded this model. They also considered the temperature tolerances of marine species to calculate the specific impact that these changes in the seas will have based on current climate change forecasts until the end of the 21st century.

For their simulations, the researchers used data on approximately 13,000 marine species, from molluscs and fish to mammals, investigating a number of species ten times higher than comparable studies. Due to this large set of data, the study provides comprehensive information on biodiversity and produced global patterns which show how these compositions are likely to change in the future. Two different scenarios were simulated. The first scenario was based on conservative assumptions regarding global warming caused by greenhouse gas emissions. In the second scenario, the worst-case scenario, it was assumed that energy input would have increased by 8.5 watts per square metre until 2100 compared to the reference value of 1850.

Marine regions at risk of less biodiversity

The researchers were able to identify a recurring pattern. According to this pattern, biodiversity will increase in many marine regions. Many species will migrate to a region and a smaller number of species will become extinct. ‘The fact that global warming is proceeding swiftly will make it easier for many species to spread to new regions. If the usual rivals or predators of these species are not present in the region they migrate to, they may even supersede the native species’, says Kießling. He goes on to state that due to this development, the species compositions of hitherto unique ecosystems will become less diverse until the end of this century, the worst-case scenario being an enormous loss of biodiversity near the equator.

Focus nature conservation on specific regions

The predicted changes in marine biodiversity present a huge challenge for nature conservation requiring proactive measures across territorial borders. In their study, the researchers suggest specific regions in which nature conservation would have a particularly large impact: regions in which major predicted changes in biodiversity are interlinked with human interference. These regions include the Mediterranean, the Caribbean, the Philippines, Taiwan, and China. Other promising regions for conservation include the Northwest Atlantic, Russia, Alaska, Antarctica, and Canada. ‘Our findings show that – although the global impact will be enormous given the current speed of climate change – these effects could at least be curtailed if global warming was reduced’, says Kießling.

Further information:

Prof. Dr. Wolfgang Kießling
Phone: +49 9131 8522690
wolfgang.kiessling@fau.de