Does microgeographic thermal complexity beget biodiversity in rainforest detrital food webs?

Background/Question/Methods

The spatial complexity of light as it passes through the rainforest canopy facilitates the coexistence of species in the understory. Here we posit that the spatial heterogeneity of light that passes through to the leaf litter layer has similar effect on the biodiversity of the animals that inhabit the leaf litter. The spatial and temporal heterogeneity of temperature in litter caused by the spatial complexity of insolation may result in a greater number of microclimates that can facilitate the coexistence of species. We designed manipulated the penetrance of light to the leaf litter layer of a tropical rainforest in Costa Rica, and measured the thermal consequences of these changes and the resulting changes in the biodiversity of ants nesting within this litter.

Results/Conclusions

We found that changes in thermal regime caused a shift in species richness and density of ants, wherein greater complexity of light at very fine spatial scales increased functional and species diversity. Our findings indicate that the physical structure of the litter environment, climate, and light penetration interact with one another to account for the bulk of biodiversity at fine spatial scales in the rainforest litter community.