by Staff Writers
London, UK - Low levels of invasion were in natural and semi-natural grasslands and most woodlands

Biological invasions are one of the major threats to biodiversity and in many cases they have considerable impact on economy and human health. For their effective management it is important to understand which areas and ecosystems are at the highest risk of being invaded.

The first map of the level of alien plant invasions in European Union was published in the Wiley-Blackwell journal Diversity and Distributions.
An international team of Czech, Spanish and British plant ecologists investigated species composition of vegetation in more than 50 000 sites in northwestern, southern and central Europe. In each of these sites they quantified the proportion of alien to native plant species.
"We found that the highest risk of alien plant invasions was in agricultural and urban ecosystems. Low levels of invasion were in natural and semi-natural grasslands and most woodlands, and the lowest levels in the Mediterranean evergreen vegetation, heathlands and peatlands. This pattern was quite consistent among European regions with contrasting climates, biogeography, history and socio-economic background", said senior author Milan Chytrý from Masaryk University, Brno, Czech Republic. 
"The level of plant invasions basically depends on the distribution of different ecosystem types across Europe. High levels of invasion are typical of lowland areas of western and central Europe while low levels are found in northern Europe and mountain regions across the continent. Low levels of invasion also occur in the Mediterranean region except its coastline and irrigated fields", added Petr Pyšek from the Institute of Botany Pruhonice, Academy of Sciences of the Czech Republic.
http://www.terradaily.com/reports/Invasions_By_Alien_Plants_Have_Been_Mapped_In_European_Union_999.html