Common metrics for lakes
An important aim of the WISER project is to support the intercalibration process. One of the first steps required by the intercalibration guidance is to derive "common metrics", i.e. biological measures created for benchmarking and comparison of national assessment systems. The WISER workpackages addressing individual organism groups (Biological Quality Elements) and ecosystem types (lakes, coastal and transitional waters) develop common metrics according to a common "Guidelines for indicator development" (Deliverable D2.2-2.pdf). All common metrics are documented in a harmonized format.
A common metric is a yardstick for comparing national assessment systems and their classification of ecological status. They quantify the structural or functional attributes of biological communities, allowing for an assessment of ecological quality. Common metrics relate to the results of the national assessment methods used in the particular intercalibration exercise and respond to the stressor (or combination of stressors) addressed. Common metrics are not meant as pan-European assessment systems replacing national methods, which are usually much better adapted to the regional situation.
Here we present the common metrics developed in WISER. A first version was available in summer/autumn 2010; since then, most of the common metrics have been updated.