The Toolkit for Ecosystem Services Site-based Assessment (TESSA) provides practical step-by-step guidance for conducting an ecosystem services assessment at the site scale. TESSA particularly emphasizes the importance of comparing estimated ecosystem service values for alternative states of a site (for example, before and after conversion to agriculture) so decision-makers can assess the net consequences of such a change and better understand how decisions affect the ecosystem services that people depend on. The toolkit targets non-expert users with limited expertise and resources. The methods have been developed through expert consultation and are grounded in scientific approaches but are also designed to be simple enough to be useful to practitioners in the field. TESSA has been used across a range of habitats around the world. TESSA is available for download at http://tessa.tools.
Webinar by Jenny Merriman of BirdLife International