Bioindicators are species or chemicals used to monitor the health of an environment or ecosystem. They are any biological species or group of species whose function, population, or status can be used to determine ecosystem or environmental integrity. An example of such a group are the copepods and other small water crustaceans present in many water bodies. Such organisms are monitored for changes (chemical, physiological, or behavioural) that may indicate a problem within their ecosystem.
Depending on the organism selected and their use, there are three types of bioindicators:
1. Plant indicators
2. Animal indicators
3. Microbial and chemical indicators
Plant Indicators—The presence or absence of certain plant or other vegetative life in an ecosystem can provide important clues about the health of the environment-(environmental preservation).
Lichens-(not a plant), found on rocks and tree trunks, are organisms comprising both fungi and algae. They respond to environmental changes in forests, including changes in forest structure-(conservation biology), air quality, and climate. The disappearance of lichens in a forest may indicate environmental stresses, such as high levels of sulfur dioxide, sulfur-based pollutants, and nitrogen-oxides. The composition and total biomass of algal species in aquatic systems serves as an important metric for organic pollution and nutrient loading such as nitrogen and phosphorus.
Animal indicators, and toxins
Animal Indicators—An increase or decrease in an animal population may indicate damage to the ecosystem caused by pollution. For example, if pollution causes the depletion of important food sources, animal species dependent upon these food sources will also be reduced in number-population decline. Overpopulation, can be the result of opportunistic species growth. In addition to monitoring the size and number of certain species, other mechanisms of...