What is an ecological indicator species?

An ecological indicator species is defined as a species whose presence, absence, or abundance reflects a specific set of environmental conditions or the health of an ecosystem. These species are particularly sensitive to changes in environmental conditions, such as pollution levels, habitat alteration, or climate change, making them useful for assessing the health and stability of their habitats. For example, certain types of amphibians can indicate the presence of pollutants in water bodies, while specific plant species may highlight particular soil conditions or climate factors.

In contrast, while a species that is always present in ecosystems might contribute to an understanding of that ecosystem, it does not necessarily provide specific information about environmental conditions. Similarly, while species used in biological control programs play a role in managing pest populations, they do not serve as indicators of ecosystem health. Lastly, a species that is abundant in urban environments does not inherently indicate specific ecological conditions, as abundance can vary widely due to human influence, habitat modification, and other factors unrelated to ecosystem health.