Context dependency is an emerging topic that is challenging our understanding of the factors shaping biodiversity in metacommunities. From a stream perspective, the idea is that moving from one catchment to the next, often completely different metacommunity patterns and dynamics are found. This is making finding general inferences in stream metacommunity ecology difficult. This is an idea touched on back in the 90’s by John Lawton - that there is so much contingency at this intermediate ground of communities (for instance, between population ecology and macroecology) to make formulation of general theories a major undertaking.
We looked at biodiversity patterns in five benthic invertebrate data sets, from two catchments in central Germany, with the aim of exploring context dependency in these systems. We disentangled the variation explained in three biodiversity metrics: taxonomic richness, Simpson’s diversity and local contribution to beta diversity (LCBD; a measure of the uniqueness of a site) in relation to proxies of network position and habitat conditions. Overall, patterns were highly variable between different data sets in our study, indicating that factors shaping biodiversity patterns in these systems are highly context dependent. We finish by emphasising the importance of considering multiple replicate, rather than single, metacommunities, given this level of context dependency.
Tonkin, J. D., J. Heino, A. Sundermann, P. Haase, and S. C. Jähnig. 2016. Context dependency in biodiversity patterns of central German stream metacommunities. Freshwater Biology DOI:10.1111/fwb.12728.