Exotic plant species alter ecosystem productivity
Biologists have reported an increase in biomass production in ecosystems colonized by non-native plant species. In the face of climate change, these and other changes to ecosystems are predicted to become more frequent, according to the researchers.
In their joint publication in the journal Ecology Letters German and American biologists have reported an increase in biomass production in ecosystems colonised by non-native plant species. In the face of climate change, these and other changes to ecosystems are predicted to become more frequent, according to the researchers.All over the world, plant and animal species are increasingly encroaching upon ecosystems where they don’t belong as a result of human influence. This phenomenon is known as a biological invasion. Observational studies on biological invasions show that the invasion of non-native plant species can alter ecosystems. One important aspect of this is biomass production: compared to intact ecosystems, the productivity of ecosystems with non-native species is considerably higher. “In such purely observational studies however, it is not possible to differentiate between cause and effect,” says Dr. Harald Auge from the Helmholtz Center for Environmental Research (UFZ). “The question is whether exotic plant species prefer to colonise more productive ecosystems, or whether increased productivity is a result of the invasion.”To get to the bottom of this question, UFZ researchers joined forces with colleagues from the Martin-Luther University Halle-Wittenberg, the University of Montana, the University of California and the US Forest Service and staged invasions by setting up experimental sites in three disparate grassland regions -in Central Germany, Montana and California, on which 20 native plant species (from the respective region) and 20 exotic plant species were sown. Researchers investigated whether and to which extent herbivorous small mammals such as mice, voles or ground squirrels as well as mechanical disturbance to the soil would influence exotic plant species colonizing ability.”The experimental design was exactly the same for all three regions to ensure comparability. We wanted to find out whether superordinate relationships were playing a role, irrespective of land use, species compositions and climate differences,” explains Dr Auge. …
For more info: Exotic plant species alter ecosystem productivity