New metrics for linking trait patterns to niche differentiation

Background/Question/Methods

Can we use functional traits to identify niche-based processes of community assembly? Despite the large number of empirical papers on the topic, the record is mixed. One of the possible reasons is the continued use of predictions of trait distribution that date back to the 60s.

Results/Conclusions

My simulations of classical and recent competition models show that species do not disperse uniformly along trait axes. Instead, clustered or seemingly random patterns may arise. However, there seems to be a stronger pattern to be found in the trait distribution of individuals rather than species. In response to this, I apply metrics based on time-series analysis and spatial statistics, and show that patterns become more detectable when species abundance is considered as well as traits. The new metrics I apply have much higher power in rejecting neutral and random null models than the metric most commonly used in the empirical literature.

My ongoing research attempts to find consistency of pattern across models. This would indicate a universal signature of niche-based community assembly that survives confounding influences of factors such as fitness differences, immigration, and stochasticity. So far, there seems to be promise in periodicity of species abundances along the trait axis.