Evolution in diverse systems
Most studies of evolutionary dynamics concern single species or perhaps pairs of interacting species. However, virtually all organisms live in diverse systems of many co-occurring species, whose interactions are likely to profoundly influence the evolution of component species. Using mathematical models, we have shown that diversity can inhibit evolutionary responses to environmental change. We also test these ideas using diverse laboratory mesocosms of bacteria and developing further models.
The effect of diversity on evolution in a changing environment (from De Mazancourt et al. 2008). Y-axis = temperature; X-axis = time (generations). A single species in a single patch (left) almost dies out but recovers and adapts to the new temperature (colours = phenotype, i.e. optimum temperature; dotted line = temperature of the patch). The same species in an environment of sixteen patches (centre) diversifies into ecotypes specialised on several different patches, but dies out in its initial patch. When patches are initially occupied by sixteen different species (right), surviving species disperse to patches with conditions matching their initial phenotype, rather than adapting to change in their original patch. The light blue species evolves far less in the diverse system.
Lawrence, D., Bell, T., Barraclough, T.G. 2016. The effect of immigration on the adaptation of microbial communities to warming. American Naturalist. 187:236-248
Barraclough, T.G. 2015. How do species interactions affect evolutionary dynamics across whole communities? Ann. Rev. Ecol. Evol. Syst. 46:25–48
Fiegna, F., Moreno-Letelier, A., Bell, T., Barraclough, T.G. 2015. Evolution of species interactions determines microbial community functioning in new environments. ISME J. 9: 1235-1245
Lawrence D, Fiegna F, Behrends V, Bundy JG, Phillimore AB, Bell T, Barraclough TG. 2012. Species interactions alter evolutionary responses to a novel environment. PLoS Biol 10:e1001330
Perron GG, Lee AE, Wang Y, Huang WE, Barraclough TG. 2012. Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations. Proc. Roy. Soc. Lond. B 279:1477-1484
de Mazancourt, C., Johnson E., and Barraclough, T.G. 2008. Biodiversity inhibits species’ evolutionary responses to changing environments. Ecology Letters. 11: 380-388