More recently, a response to the Gurevitch and Padilla article involved reanalyzing IUCN Red List extinctions after "reassessing the role of invasive species in those extinctions." It's not clear just how they were reassessed, but this review came to a very different conclusion, as reflected in the title:
Clavero, M. and E. Garcý´a-Berthou. 2005. Invasive species are a major cause of animal extinctions. TREE 20:110. That entire issue (20) of TREE is focused on invasive species, and the following article in it explores how to determine if invasive species drive natives' declines in degraded ecosystems or if invasive species are just along for the ride and the degradation is the driver: Didham, R.K., J.M. Tylianakis, M.A. Hutchison, R.M. Ewers and N.J. Gemmell. 2005. Are invasive species the drivers of ecological change? TREE 20:470-474. That article was sparked by an experimental test in which removal of invasives did not result in an increase in biodiversity, suggesting invasives were just "passengers" riding along with the degradation: MacDougall, A.S. and R. Turkington. 2005. Are invasive species the drivers or passengers of change in degraded ecosystems? Ecology 86:4255. Didam et al. cautioned that different species and systems may differ, but that MacDougall and Turkington's experimental test could help determine the role of invasives in native species declines in those different situations. Personally speaking, I work on controlling invasive Lygodium spp. (climbing ferns) in Florida and while there is no evidence they have caused extinction that I know of, they climb over and blanket large swaths of land, including Everglades tree islands, smothering the trees and plants beneath. The explosive growth of Lygodium spp. in Florida is astonishing and there are lots of instances of its growth in abundance in remote, otherwise-undisturbed areas. I think Lygodium spp. could provide a test to whether invasive species could be a driver in native biodiversity decline. Cheryl Millett --- Teresa Woods <[EMAIL PROTECTED]> wrote: > A couple articles to consider: > > Gurevitch, J. and D.K. Padilla. 2004. Are invasive > species a major cause > of extinctions? TREE 19:470-474. > > Davis, M. 2003. Biotic globalization: does > competition from introduced > species threaten biodiversity? BioScience > 53:481-489. > > I couldn't believe the conclusions of these articles > when I read them > last year, but they did bring home the message that > if indeed invasives > are causing extinctions, even community level ones, > we need to be > documenting them in ways other than anecdotally. > Hence, my question > about relevant publications. I'd love to see them. > As I said, even > ones that show a correlation, as causation is > justifiably hard to show. > > I am not as familiar with aquatic invasives except > to know that some > like zebra mussels are extremely aggressive and > destructive. But > regarding plants, invasives are often linked with > disturbed habitats, > and it may be that habitat destruction is the > primary cause of local > extinctions, and the invasives follow as the "final > nail in the coffin > (Gurevitch and Padilla 2002)." It is also likely > that the extinction > trajectories are definitely occuring but are > longer-term, and just > haven't reached the end yet. > > The link to the NYTimes article was, as I said, > meant to fan the flames > here -- not that I agree in any way with him, but to > put on the table > what landscape designers and architects are surely > also being > influenced by -- even if from, as has been correctly > pointed out, a > very biased point of view. > > So my query still stands -- is there empirical > evidence supporting the > sense that most of us have that invasives are > causing native > extinctions? I'd love to have evidence to > contradict the NYTimes > author's view. > > Teresa > > Teresa Woods > Graduate Assistant > Division of Biology > 232 Ackert Hall > Kansas State University > Manhattan, KS 66506 > 785-532-9834 > [EMAIL PROTECTED] > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
