COEXISTENCE IN A METACOMMUNITY: THE COMPETITION COLONIZATION TRADE-OFF IS NOT DEAD

Calcagno V., Mouquet N., Jarne P., and David P. (2006).

Ecology Letters, 9, 897–907, doi:10.1111/j.1461-0248.2006.00930.x

Key message : The competition–colonization trade-off model is often used to explain the coexistence of species. Yet its applicability has been severely criticized, mainly because the original model assumed a strict competitive hierarchy of species and did not allow for any preemptive effect. We considered the impact of relaxing both of these limitations on coexistence. Relaxing trade-off intensity makes coexistence less likely and introduces a minimum colonization rate below which any coexistence is impossible. Allowing for preemption introduces a limit to dissimilarity between species. Surprisingly, preemption does not impede coexistence as one could presume from previous studies, but can actually increase the likelihood of coexistence. Its effect on coexistence depends on whether or not species in the regional pool are strongly limited in their colonization ability. Preemption is predicted to favour coexistence when: (i) species are not strongly limited in their colonization ability; and (ii) the competitive trade-off is not infinitely intense. .

Niche shadows in the two-species case. For a resident species of strategy (arrow), DI is plotted as a function of cI (continuous line). Niche shadows are values for which DI is negative (dark bands). Note that there is a niche shadow for cI too different from c (the limit to dissimilarity on the left, noted cD ) and for cI too close to c (the limit to similarity, on the right, noted cS ). The value of DI when the values of c and cI are exchanged is also plotted (dashed line). In the region indicated by a grey band, the introduced species competitively excludes the resident species. Coexistence of the two species is possible only where both functions are positive (white bands). W(c, h) is the width of the left white band marked with an asterisk, between cD and c r.

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OTHER TOPICS: Aesthetics of Biodiversity, Biogeography, Macroecology & Ecophylogenetics, Experimental Evolution, Functional Biogeography, Functional Rarity, Nature for Future, Metacommunities, Metaecosystems, Reviews and Synthesis, Trophic Biogeography & Metaweb