Indicator species. Some poison-sensitive animals communicate. Indicators show similar-habitat organisms. Indicators include microorganisms, plants, and animals.
Indicator Species
River Otters are a freshwater indicator species. River otters are susceptible to food chain issues, hence water contamination can cause population declines.
River Otters
Nesting in old-growth trees contributes to their decline. The bird can't reproduce without nesting materials. Healthy old-growth woods have more spotted owls.
Spotted Owls
Salmon stage in fresh and saltwater. Ecosystem disturbances reduce salmon populations. Salmon migration indicates healthy streams. Water quality reduces salmon populations.
Salmon
Salamanders have wet skin. Their skin absorbs moisture and pollutants to be healthy. Salamanders are dry. Drought dries up their skin.
Salamanders
Bats die from light, metal, and dryness. Human actions may have damaged the ecology or weather if bat populations are unstable or unhealthy. Climate change affects bat populations.
Bats
Mussels are affected by water changes. Scientists examine water oxygen levels, temperature, and acidity. Mussels' health and population will drop if these factors alter substantially.