Box 1.4. Criteria for Effective Ecological Indicators

An effective ecological indicator should:

• Provide information about changes in important processes
• Be sensitive enough to detect important changes but not so sensitive that signals are masked by natural variability
• Be able to detect changes at the appropriate temporal and spatial scale without being overwhelmed by variability
• Be based on well-understood and generally accepted conceptual models of the system to which it is applied
• Be based on reliable data that are available to assess trends and are collected in a relatively straightforward process
• Be based on data for which monitoring systems are in place
• Be easily understood by policy-makers

Source: Millennium Ecosystem Assessment
  Ecosystems and Human Well-being: Biodiversity Synthesis (2005), p.21