Temporal niche dynamics promote biodiversity: An experimental demonstration

Background/Question/Methods

The Earth’s ecosystems are losing their biodiversity at an alarming rate, increasing the need for ecologists to understand mechanisms that generate and maintain biodiversity.  Classic niche theory suggests that only a relatively small number of species can stably coexist, while natural communities are inherently complex and contain many more species. Non-equilibrium theory, on the other hand, suggests that temporal niche may promote species coexistence, potentially allowing a large number of species to coexist. Despite its attractiveness in explaining natural complexity, this theory has never been examined experimentally.  Here we report an experimental study of evolving Pseudomonas fluorescens communities that explored the role of temporal niche dynamics in generating and maintaining biodiversity.  We allowed the ancestral genotype of P. fluorescens to evolve in the presence/absence of temporal niche, made available by alternating microcosms under shaking and non-shaking conditions. 

Results/Conclusions

We found that the ancestral morph diversified more rapidly in communities experiencing temporal niche dynamics.  Moreover, similar specialists derived from the ancestral genotypes were also more likely to coexist in these communities.  These results demonstrate the role of temporal niche dynamics in the emergence and persistence of biodiversity, and highlight the importance of evolution in the long-term maintenance of biodiversity.