Bioindicator

Species that reveals the status of an environment

A bioindicator is any species or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot.

This keyword could refer to multiple things. Here are some suggestions: