BIOLOGICAL INVASIONS AND ECOSYSTEM PROCESSES - TOWARDS AN INTEGRATION OF POPULATION BIOLOGY AND ECOSYSTEM STUDIES

Biological invasions by exotic species alter the composition and community structure of invaded areas. There is increasing evidence that they can also alter properties of whole ecosystems, including productivity, nutrient cycling, and hydrology. The exotic actinorrhizal nitrogen-fixer Myrica faya alters primary successional ecosystems in Hawaii Volcanoes National Park by quadrupling inputs of nitrogen, the nutrient limiting to plant growth. Biological invaders change ecosystems by differing from native species in resource acquisition and/or resource use efficiency, by altering the trophic structure of the area invaded, or by altering disturbance frequency and/or intensity. Where exotic species clearly affect ecosystem-level properties, they provide the raw material for integrating the methods and approaches of population and ecosystem ecology. -from Author