Indicator Species - Definitions

Definitions

Lindenmayer et al. suggest 7 alternative definitions of indicator species:

1. a species whose presence indicates the presence of a set of other species and whose absence indicates the lack of that entire set of species;
2. a keystone species, which is a species whose addition to or loss from an ecosystem leads to major changes in abundance or occurrence of at least one other species
3. a species whose presence indicates human-created abiotic conditions such as air or water pollution (often called a pollution indicator species)
4. a dominant species that provides much of the biomass or number of individuals in an area
5. a species that indicates particular environmental conditions such as certain soil or rock types
6. a species thought to be sensitive to and therefore to serve as an early warning indicator of environmental changes such as global warming or modified fire regimes (sometimes called a bioindicator species)
7. a management indicator species, which is a species that reflects the effects of a disturbance regime or the efficacy of efforts to mitigate disturbance effects.

Type 1, 2, and 4 have been proposed as indicators of biological diversity and types 3, 5, 6, and 7 as indicators of abiotic conditions and/or changes in ecological processes.