Number of the month: 302 peaks

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When scientists study the impact of climate change, they discover time and time again that rising temperatures are also affecting the number of plant and animal species on our planet. Many studies have already demonstrated that numerous species will die out as temperatures rise. Just the opposite is happening at the top of Europe's mountains, however, as researchers led by Professor Manuel Steinbauer from the Department of System Paleobiology at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Dr Sonja Wipf from the WSL Institute for Snow and Avalanche Research discovered. The study they published recently proves that the number of plant species on mountain summits all over Europe has increased.

For the purposes of their study, the researchers climbed a total of 302 peaks to survey populations of plant species: in the Alps, the Pyrenees, the Carpathian mountains and on mountains in Scotland and Scandinavia. They then compared their findings with historical records made by hundreds of botanists dating back as many as 145 years. As the biologist Manuel Steinbauer explains: "More and more species are moving from lower elevations to regions at higher altitudes where they were unable to survive a few decades ago."

Accelerated colonisation

Purple saxifrage has been discovered by researchers on 145 peaks.

The research findings highlight not only the fact that species diversity on mountain summits has increased. The rate at which new species are colonising higher altitudes has also accelerated. While 1.1 new species were added on average between 1957 and 1966, the number was five times as high between 2007 and 2016. "The greater the global warming effect, the more sharply the number of species rose", reports Steinbauer.

The new species that are now being found on mountain peaks are on average larger and therefore more competitive than traditional summit species and may crowd out the old species sooner or later, the researchers believe. This is not known for sure, however – or at least not for all species. "There are species for example that have adapted very well to sparse and craggy habitats", says Steinbauer. The researchers are confident that they – in some cases at least – will prevail in the longer run over the new arrivals, which tend to settle in warmer sites with sufficient topsoil cover.

Decisive factor: the need for warmth

The degree to which the temperature requirements of a species affect its population numbers has also been shown by a study run by scientists at Senckenberg Nature Research Society. The study revealed that populations of warm-dwelling birds, butterflies, soil organisms and lichens have grown in Germany since 1980.

Looking ahead to the future

Scientists at German research institutions are focusing not only on historical changes in species diversity, however. They are also looking ahead to the future. Bio- and geoscientists from the FAU and the University of Bayreuth are looking into how the ecosystem in Ecuador is influenced by the way land is used – as pasture, for instance. After all, land use affects climate at the regional level, and thus also species diversity. For tropical highlands like the Andes in Ecuador, however, it is still not known exactly which effects occur. Through their research, the German scientists now hope to help strengthen the ecosystem – so as to minimise species decline.

Palaeontology at the GeoZentrum Nordbayern at FAU

In the Palaeontology Department at GeoZentrum Nordbayern at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), scientists study the evolution of ecosystems over long periods. They attempt to identify which environmental factors had a major bearing on the emergence and disappearance of species during the course of the Earth's history and what impact climate change is likely to have on ecosystems in the future.

www.gzn.nat.fau.eu > Palaeontology