Shallow Water Habitats
Human Effects - Selecting and Using Indicators
The following information, which is excerpted with few changes from the OzCoasts website, provides a useful overview of how indicators are selected for management of coastal and estuarine ecosystems.
What are environmental indicators?
Environmental indicators are physical, chemical, biological or socio-economic measures that best represent key elements of a complex ecosystem or environmental issue.
Types of Indicators
Useful indicators are thought to have meaning beyond the measures they represent and their trends are expected to yield valuable information about important aspects of the environment. Indicators are usually classified into different groups or types – for example, biophysical indicators, human pressure indicators and coastal management indicators. Indicators may then be further sub-divided into types, for example water quality indicators, sediment quality indicators, habitat extent and quality indicators, biotic indicators and ecosystem integrity indicators.
Selection of Indicators
Selection of indicators is a key step in defining water or sediment quality objectives, managing ecosystems and designing monitoring programs. It requires an understanding of ecosystem function, which is best achieved through a combination of traditional and advanced environmental studies and state-of-the-art numerical modeling. In the absence of such investigations and applications, hypotheses in the form of conceptual models: e.g. land clearing (a causal pressure) leads to increased sediment loads in estuaries (a stress) and elevated turbidity levels and seagrasses loss (responses) in the receiving water body
Some Precautions
Monitoring of biological, chemical and physical variables can potentially indicate important changes in coastal systems. However, there are some limitations and these should be considered in indicator-related applications:
- there can be a major gap between indicating change and determining cause and effect,
- misleading or erroneous conclusions can be drawn when interpretations based on indicators become overly-simplified, and
- the monitoring of indicators is not a substitute for a comprehensive research program.
To learn more about how environmental indicators can be used to improve management of coastal and estuarine ecosystems, please refer to the following:
European Union Water Framework Directive
Gibson , G.R., M. L. Bowman, J. Gerritsen and B. D. Snyder. 2000. Estuarine and Coastal Marine Waters: Bioassessment and Biocriteria Technical Guidance. EPA 822-B-00-024. U.S. Environmental Protection Agency, Office of Water, Washington, DC.
Karr, J. R. and E. W. Chu. 1999. Restoring Life in Running Waters. Island Press, Washington, DC.