On eco-evolutionary dynamics of phenologies in competitive communities and their robustness to climate change

Abstract

Global changes currently cause temporal shifts in the favourable conditions for different phases of species life cycles. Phenologies characterizing temporal presence, may adapt through heritable evolution in response to these changes. Given a community context, this evolution may cause a change in the phenology overlap and thus a change of interspecific interactions such as competition. Using a model in which phenologies compete and coevolve, we study the conditions under which diversity emerges, as well as their annual distribution. We find that the environment richness (food quantity, light, pollinators...) and competition constrain the diversity and spread of phenologies. A robust pattern of phenologies distribution emerges consistent with Swedish flowering observations. Once a stable community is reached, we apply a progressive change in environmental conditions. We found that adaptation eventually restored diversity, but that the simulated change often led to numerous extinctions due to increased competition. The percentage of diversity lost depends on the speed of change and on the initial diversity. Phenologies already pre-adapted to the new environmental conditions drive the restoration of diversity after the change. We finally study a spatial version of the model in which local communities are organized along an environmental gradient. Pre-change, allowing dispersal decreases the local adaptation of phenologies to their local fixed environmental conditions. Dispersal however largely enhances the maintenance of biodiversity in changing environments, though its benefits are not homogeneous in space. Evolution remains the only rescue mechanism for southern phenotypes.