Am. Nat. 173, 579–588 (2009)

It has long been thought that for many species, local populations are adapted to their local areas and would show greater fitness there than anywhere else. However, some transplant studies have shown 'out of town' organisms doing better than the natives.

Joe Hereford, now at the University of Maryland, College Park, looked at 74 transplant studies containing 777 estimates of local adaptation. He found that species showed local adaptation 71% of the time, and that, in general, native populations were 45% fitter than transplanted populations. And species displaying high local adaptation were not always very unfit when transplanted.