Hypervolume concepts in niche- and trait-based ecology

Hutchinson's n-dimensional hypervolume concept for the interpretation of niches as geometric shapes has provided a foundation for research across different fields of ecology and evolution. There is now an expanding set of applications for hypervolume concepts, as well as a growing set of statistical methods available to operationalize this concept with data. The concept has been applied to environmental, resource, functional trait, and morphometric axes and to different scales, i.e. from individuals, species, to communities and clades. Further, these shapes have been variously interpreted as niches, ecological or evolutionary strategy spaces, or proxies for community structure. This paper highlights these applications' shared mathematical framework, surveys uses of the hypervolume concept across fields, discusses key limitations and assumptions of hypervolume concepts in general, provides a critical guide to available statistical estimation methods, and delineates the situations where hypervolume concepts can be useful.