2009 Research Highlights
2009 Research Highlights
It is commonly believed that more diverse habitats are less invasible due to niche occupation. Yet, recent evidence shows that invasibility is a much more complex issue and may be determined by multiple factors. Invasibility tends to be the highest when the existing biomass is the lowest. Also, habitat invasibility changes over time. Better understanding of what invasibility and invasiveness really mean and how to measure them is necessary. For better control and management, future research should focus more on the mass dominance of a few truly invasives rather than the total number of exotics in a habitat.
Currently, scientists working with the Eastern Forest Environmental Threat Assessment Center are collecting metadata regarding various habitat characteristics and invasibility from diverse ecosystems in U.S. forests and other ecosystems around the world to further test the generality of the above conclusions. Preliminary observations show that species-rich communities are invasible but may be so at a lesser degree, although individual component species can show highly invader-specific resistance or promotion. However, species richness apparently does not work in isolation; it has to work with species mass abundance in either measuring or determining habitat invasibility.
A community’s ability to preclude species invasions may be dependent upon a threshold level of both species richness and abundance, below which the importance of species interactions is only a weak force. Comparisons among the major community-types within and among geographic regions in the future can provide new insights for both invasion biology and management and be useful to scientists, resource managers, policymakers, and the general public.
Contact: Qinfeng Guo, research ecologist, (828) 257-4246, qinfeng.guo@usda.gov
Partners: University of Wisconsin – Madison; Brown University; University of Missouri; U.S. Geological Survey; South Florida Water Management District; Chinese Academy of Sciences; University of California-Berkeley; USGS-EROS Data Center; Nanjing University; University of Hong Kong; Taiwan National University; other USDA Forest Service units
