Is adaptation associated with long-term persistence beyond a geographic range limit?

Area of Science:

• Ecology
• Evolutionary Biology
• Plant Science

Background:

• Species range shifts are crucial for adapting to climate change.
• Coastal dune plants (Camissoniopsis cheiranthifolia) were used to study adaptation to new habitats.
• Previous work showed high fitness but delayed reproduction in beyond-range transplants.

Purpose of the Study:

• To test for adaptation to beyond-range conditions in experimental populations of C. cheiranthifolia.
• To investigate if genetic variation and environmental heterogeneity drive adaptation.
• To determine if adaptation is necessary for persistence in novel environments.

Main Methods:

• Experimental populations of C. cheiranthifolia were transplanted within and beyond their poleward range limit in 2005.
• Descendants (after 10 generations) from beyond- and within-range populations were transplanted to multiple sites.
• Fitness and reproductive timing were assessed across different sites.

Main Results:

• Individuals from beyond-range populations did not show increased fitness at beyond-range sites, indicating no adaptation.
• Beyond-range descendants did not suffer reduced fitness within the native range.
• Reproduction was delayed beyond the range, but this was not favored more strongly, and descendants did not differ in timing.

Conclusions:

• Adaptation to beyond-range environments was not detected after 10 generations.
• Persistence in novel habitats may not necessitate adaptation.
• Lack of adaptation could facilitate rapid species range shifts in response to climate change.