speciesrich

Speciesrich is an informal ecological descriptor used to denote a habitat, community, or landscape that contains a high number of different species in a defined area or sample. The term is a compound of species and rich and is commonly written as species-rich or species rich. It is not a formal taxonomic term but a qualitative label applied in ecological writing, biodiversity assessments, and conservation planning.

In practice, species richness refers to the count of distinct species (often denoted S) observed in a given area. Species-rich systems are those with large S values relative to comparable habitats. Because species richness is sensitive to sampling effort, it is usually accompanied by standardized survey methods and may be complemented with other diversity metrics, such as Shannon or Simpson indices, which include information on species abundance and evenness.

Ecologically, higher species richness is frequently associated with greater functional redundancy, potential resilience to disturbance, and broader ecosystem functioning, though these relationships are context dependent and not universal. Tropical forests, coral reefs, and many wetland systems are often described as species-rich, reflecting their comparatively high documented biodiversity.

Factors promoting species richness include large habitat area, structural complexity, productive or heterogeneous environments, low disturbance frequency, and historical biogeographic processes. Limitations of the concept include sampling bias, detection probability, and the fact that richness alone does not capture species abundances or ecological roles.

See also: species richness, biodiversity, speciation, ecosystem function.