Biological Invasions (2019) 21, 99-110

Daniel Montesinos, Ryan C. Graebner and Ragan M. Callaway (2019)
Evidence for evolution of increased competitive ability for invasive Centaurea solstitialis, but not for naturalized C. calcitrapa
Biological Invasions 21 (1), 99-110
Abstract: Congeneric species with the same native and non-native ranges, but exhibiting different invasiveness, provide opportunities to assess the relative importance of factors contributing to successful invasions. For example, comparing the competitive ability of such congeners against other species from the native and non-native regions of invasive species can provide insight into the role of evolutionary experience with different competitors. We selected two congeneric Centaurea species with overlapping native and non-native ranges but with strikingly different invasive success, Centaurea solstitialis and C. calcitrapa, and conducted experiments with populations from each region using a suite of different native grass species from each region. When grown with Spanish grass species, competitive responses were 32% stronger for C. calcitrapa and 30% stronger for C. solstitialis, than when in competition with grasses native to California. Centaurea solstitialis from California had 66% higher competitive effects on grasses, all species considered together, than Spanish C. solstitialis; whereas the competitive effects of C. calcitrapa on grasses were not significantly different between C. calcitrapa ranges. Our results are consistent with the prediction that the evolution of increased competitive ability (EICA) might contribute to the devastating success of C. solstitialis in California, and that its absence might contribute to the modest naturalization of the non-invasive C. calcitrapa. Escape from the strong competitive effects and responses of grasses from Spain may also contribute to invasive success in California. Our results suggest that studies of EICA should be based on competitive tests, since biomass alone is not always a good predictor of competitive ability.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Daniel Montesinos

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Centaurea solstitialis (weed)		Spain (continental)
	Centaurea calcitrapa (weed)		Spain (continental)