The Toolkit for Ecosystem Service Site-based Assessment (TESSA) has been developed through a collaboration of six institutions with input generously provided by scientists and practitioners from multiple disciplines. The toolkit provides accessible guidance on low-cost methods for how to evaluate the benefits people receive from nature at particular sites in order to generate information that can be used to influence decision making.

TESSA is primarily aimed at conservation practitioners, although the methods may be applicable to a wide range of users, including natural resource managers (e.g. forestry, fisheries, water managers), land-use planners, development organisations (e.g. for poverty alleviation), and the private sector.
The methods in the toolkit are designed to be applicable to users from developing and developed countries, and across all terrestrial and wetland habitats (currently excluding marine areas). The current version (2.0) includes a preliminary scoping appraisal and further methods for the following services:

Coastal protection; Cultivated goods; Cultural services ; Global climate regulation ; Harvested wild goods ; Nature-based recreation; Pollination ; Water (provision, quality and flood control);

The toolkit includes:

An overview of ecosystem services, key concepts and caveats
Guidance on conducting a preliminary scoping appraisal at a site(s) to understand the important services provided by a site and to whom
Decision trees (flow charts) to lead the user to the most appropriate methods according to the characteristics of the site
Methods for measuring the ecosystem services listed above
The valuation of an ‘alternative state’ in order to compare a current and alternative state of the site and hence estimate the impact of potential or actual changes on the ecosystem services provided
Worked examples on how to derive a value (quantitative, including potentially economic, and/or qualitative) for each service, including presenting the difference in value between two states of the site
Guidance on how to synthesise the data for each service into a summary of ecosystem service change at site scale
Guidance on assessing the how benefits are spread across different beneficiary groups

TESSA is an evolving resource, and updated versions will be released subject to funding.