In general, there are three types of indicators that are typically considered to exist:
- Condition indicators — address the state of the environment, the quality and quantity of natural resources, and the state of human and ecological health. These indicators are chosen by considering biological, chemical, and physical variables and ecological functions (eg: riparian health, water quality, fish community structure).
- Pressure indicators — also often referred to as stress indicators, describe natural processes and human activities that impact, stress, or pose a threat to environmental quality (eg: human populations, livestock operations, water allocation, industrial activity, soil erosion, etc). Note: the existence of a pressure does not necessarily suggest that there is a negative impact, but merely the potential for one.
- Response indicators — illustrate individual and collective actions or management programs implemented to halt, mitigate, adapt to, or prevent damage to the environment (eg: municipal bylaws, livestock operations regulations, education or incentive programs, watershed planning initiatives, and stewardship activities).
All three indicator types are closely related. For example, the stress of a particular pollutant entering a system may cause a change in the condition of some species (ie: population decline) which may in turn cause a response of restrictions on the discharge of the pollutant. The additional restrictions reduce the stress which improves the condition. Condition and pressure indicators are predominantly used in assessing the state of a watershed. Response indicators are more commonly used to identify the various efforts being undertaken to address known environmental concerns.
Indicators may be further categorized according to the watershed element they represent (ie: water quality, watershed hydrology, landscape, biological community). This categorization often assists in communicating the relationship between the indicator and conditions within the watershed.
Read more… about State of the Watershed indicators (con’t).