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A systems approach to restoring degraded drylands

James, Jeremy J., Sheley, Roger L., Erickson, Todd, Rollins, Kim S., Taylor, Michael H., Dixon, Kingsley W.
Journal of applied ecology 2013 v.50 no.3 pp. 730
arid lands, data collection, ecological invasion, indigenous species, introduced species, invasive species, land restoration
Functional differences between native and exotic species are often presumed to be one factor responsible for plant invasion. Accordingly, invasion occurs when a niche is vacated an an exotic species enters the community that is able to exploit available resources. Differences in trait values between native and exotic invasive species may or may not be large, depending on the specific context of the comparison and the distinction necessary to trigger invasioin is unknown. We used a meta-analysist approach to determine the magnitude of difference between navite and exotice invasive species for various traits examined in previous studdies. We suggest that ecologically meaningful differences in trait values between a native and exotic invasive species are greater than differences between co-occurring natives. We identified significant differences between native and exotic invasive species but the effect size was not significantly greater than the effect size between native species. Consequently, these differences may not be important for invasion at the broadest scale. Our analysis indicates that traits may be most useful in predicting invasion in certain environments only (i.e. trait by environment interactions), that ecologists are not necessarily measuring the correct traits (regeneration traits are poorly represented in the data set), or other mechanisms of invasions more important.