The introductory statement of the quoted *Science Daily* item (these typically are institutional press releases reproduced verbatim) leads with unexceptional confused hyperbole but ends on a truly alarming claim: "...until now, scientists had little reason to believe that native plants could mount a successful defense."
Noting but otherwise ignoring the sociomorphic martial metaphor, whom among ecologists believes that evolutionary processes grind to a halt when environmental conditions take a minor, unprecedented turn? Granted, "minor" is context dependent, but the fact that every "invasion" is a unique, historically contingent event (rather than a generic "anthropogenic impact") means they will differ in progression and outcome. Garlic mustard is allelopathic, but we should expect that allelopathy to be a variable trait, one affected by local soils; and further expect that sensitivity to it would vary as well. That sounds like a recipe for coevelution. There is every reason to expect that someone could demonstrate coevolution between 'neophytes' and 'archaeophytes' if they went looking for it. I'm a little surprised at the claim that this is the first such demonstration. After all, unlike Blanche DuBois, life on this planet has hardly "depended on the kindness of strangers". With regard to garlic mustard in general, we will also see more findings of interest about its ever-increasing participation as an object of non-human herbivory in North American ecosystems. Something to watch for. In case you don't have access to PNAS, following is the pointy end of the results from R. A. Lankau. *Coevolution between invasive and native plants driven by chemical competition and soil biota*. *Proceedings of the National Academy of Sciences*, 2012; DOI:10.1073/pnas.1201343109 http://dx.doi.org/10.1073/pnas.1201343109 "Many theories of invasive success posit that exotic species gain ecological advantages due to their lack of coevolutionary history with the native community, for example, benefiting from enemy release because native consumers lack the necessary traits to efficiently use the new species. This idea has been considered especially important for invasive plants that produce secondary compounds that are novel to native plant, insect, and microbial communities. However, novelty cannot last forever, and the high invader abundance created by these evolutionary mismatches may in turn lead to the development of new coevolutionary relationships that, over time, act to integrate exotic species into native communities." I hope you're not surprised, either. Now if we can just get over 'the native thing' -- the idea that redistribution of biota by humans is categorically unnatural or unecological -- we'll be doing some real science. Matthew K Chew Arizona State University School of Life Sciences ASU Center for Biology & Society PO Box 873301 Tempe, AZ 85287-3301 USA Tel 480.965.8422 Fax 480.965.8330 [email protected] or [email protected] http://cbs.asu.edu/people/profiles/chew.php http://asu.academia.edu/MattChew
