Diversity spurs diversification in ecological communities

Vincent Calcagno (1) , Philippe Jarne (2) , Michel Loreau (3) , Nicolas Mouquet (4) , Patrice David (2)

1 ISA - Institut Sophia Agrobiotech
2 CEFE - Centre d’Ecologie Fonctionnelle et Evolutive
3 SETE - Station d'écologie théorique et expérimentale
4 UMR MARBEC - MARine Biodiversity Exploitation and Conservation

Diversity is a fundamental, yet threatened, property of ecological systems. The idea that diversity can itself favour diversification, in an autocatalytic process, is very appealing but remains controversial. Here, we study a generalized model of ecological communities and investigate how the level of initial diversity influences the possibility of evolutionary diversification. We show that even simple models of intra- and inter-specific ecological interactions can predict a positive effect of diversity on diversification: adaptive radiations may require a threshold number of species before kicking-off. We call this phenomenon DDAR (diversity-dependent adaptive radiations) and identify mathematically two distinct pathways connecting diversity to diversification, involving character displacement and the positive diversity-productivity relationship. Our results may explain observed delays in adaptive radiations at the macroscale and diversification patterns reported in experimental microbial communities, and shed new light on the dynamics of ecological diversity, the diversity-dependence of diversification rates, and the consequences of biodiversity loss.

Mots clés: ecological communities; diversification; DDAR; productivité; consequences of biodiversity loss

Domaines: Sciences du Vivant [q-bio]

Vincent Calcagno, Philippe Jarne, Michel Loreau, Nicolas Mouquet, Patrice David. Diversity spurs diversification in ecological communities. Nature Communications, 2017, ⟨10.1038/ncomms15810⟩. ⟨hal-01604374⟩