British Sign Language Glossaries of Curriculum Terms

BSL Environmental Science Glossary - Biotic index definition

Definition: The biotic index is a measure of the amount of pollution present based on the presence and abundance of a specific living organism in a certain habitat. The presence and amount of lichen on a rock in a given area is an indicator of the presence or absence of acid rain. Healthy, abundant lichen means there is little to no acid rain present in the area. A lack of lichen means there is sufficient acid rain present to affect its growth. A river that has a lot of aquatic invertebrates means that the river is clean and the aquatic invertebrates are healthy. Few invertebrates mean that the water is polluted. So, the biotic index is a measure of pollution in a habitat.