The ecological niche is one of the most fundamental concepts in all of ecology. Niches define the traits of organisms, and thus are subjected to evolution, define an organism’s behavior and physiology, and determine its’ population dynamics. They further define how organisms interact with their environment and with each other through interspecific interactions. Finally, niches link organism traits to their roles in determining the diversity of communities and the functioning of ecosystems. Despite the niche concept’s pervasiveness throughout ecology, it has not always fulfilled its potential. Indeed, the deterministic conceptualizations of ecological processes that are fundamental to niche theory have continually received considerable scrutiny and debate. This has manifest in opposing world-views which hold that niche-related processes can be overridden by stochastic fluctuations in environmental conditions and/or dispersal and ecological drift.

Results/Conclusions

Here, I discuss how the niche concept has been broadened to include both environmental and demographic stochasticity, which provides a richer foundation for ecology than either the foundation of complete determinism inherent to niche theory or complete stochasticity inherent to the neutral theory. In this context, a more complete niche theory can provide important information by what it can, as well as what it can not, explain in nature. For example, one can define neutral community assembly as a ‘null model’ to discern the relative importance of determinism relative to stochasticity as the deviation in community structure. I illustrate the value of this approach by exploring patterns of community assembly and the relative roles of determinism and stochasticity among habitats that vary in their environmental conditions.