The species richness-productivity relationship: Time to stop searching for a "true" pattern?

Contrary to the past belief that the species richness-productivity relationship (SRPR) is characterized by a single "true" pattern, several analyses have shown that a heterogeneous distribution of SRPRs exists and that the patterns' distribution of a SRPR is sensitive to the directness of the estimates of productivity. A simple conceptual model demonstrates that taking into account underlying relationships connecting productivity with species richness produces a heterogeneous distribution of relationships. We suggest that the search for a single pattern for SRPR has reached a dead end, and that we should direct our research focus to exploring the mechanisms responsible for the various SRPRs.