Published: Thursday May 3 2012, 09:04:45
A new study across Europe shows plants are moving to higher latitudes but such changes can lead to a reduction in species richness. This new study detailed 66 mountain summits located between the north of Europe and the southern Mediterranean Sea. First in 2001 and then in 2008 maps of plant species were taken using the same methods and procedures. Only a few summits of northern and central Europe recorded increasing species numbers, in contrast nearly all sites in the Mediterranean regions showed stagnating or declining species numbers.
Dr Harald Pauli, from the Global Observation Research Initiative in Alpine Environments (GLORIA), the study’s lead author, said, “Our results showing a decline at the Mediterranean sites is worrying because these are the mountains with a very unique flora and a large proportion of their species occur only there and nowhere else on Earth.”
Farther north in Europe more plant species are prospering on the summits, this might be an indication that these are safer sites for alpine flowers. However this is not necessarily the case since the plant species that are appearing mainly come from lower elevations and will increase greater competition pressure with the more rare cold-loving alpine flowers. There are small patches of cold habitats in the uppermost tips of Mediterranean mountains; these are like islands in much warmer lowland areas. During the summer dry conditions prevail in the lowland areas exposing the mountains to a dry season. In the mountains precipitation mainly falls as snow during the winter and spring and snowmelt is crucial for supplying water to the mountain plants during the dry growing season.
Loss of species was pronounced at the lower altitudes as plants are expected to experience water deficits much earlier than those located at higher mountain peaks. A warming of the climate and lessening of precipitation in the Mediterranean over the past decade are contributing to shrink the range over which species occur. Predictions indicate the Mediterranean region will become drier in the coming decades which have implications on species diversity in these mountain regions.
The paper, Recent Plant Diversity Changes on Europe’s Mountain Summits, is published by Science (doi: 10.1126/science.1219033).
The GLORIA network aims to establish and maintain a site-based monitoring network for the long-term observation of high mountain plants. It began in Europe about a decade ago, when the sites used in this study were established. By now, the GLORIA monitoring programme was applied by more than 100 research teams and in over 100 mountain regions on six continents. Researchers will return to their sites every five to ten years.