The Toolkit for Ecosystem Service Site-based Assessment (TESSA) 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.

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). Current ecosystem services included are: global climate regulation, water services (supply, quality, flood reduction), havested wild goods, cultivated goods, nature-based recreation, cultural services, pollination services, coastal protection.

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 group,

The approach is relatively low cost compared with many other tools, and does not require advanced technical skills. The toolkit is designed to be used both online and in the field and is provided as an interactive ‘user manual’ in a simple workbook structure which can be downloaded.

The methods and approaches presented in the toolkit have been tested extensively in different contexts and in countries including Burundi, Cambodia, Cameroon, Dominican Republic, Ecuador, Fiji, Grand Cayman, Kenya, Malawi, Madagascar, Mexico, Montserrat, Nepal, Sri Lanka, Uganda, UK and Vietnam, across temperate and tropical forest and wetland habitats.

TESSA was developed by collaborators from: Anglia Ruskin University, BirdLife International,  the Royal Society for the Protection of Birds, the Tropcal Biology Association, UNEP-World Conservation Monitoring Centre, the University of Cambridge and University of Southampton.

Aim of the resource: 

Increasing demand from decision-makers for information on ecosystem services has prompted efforts to offer guidance on measuring and incorporating ecosystem services into decision-making. To inform local decisions, ecosystem service assessments need to be based on data that are locally appropriate, easy to collect and relatively affordable, and can be used to produce results that are easy to communicate to decision-makers. Existing approaches to measuring ecosystem services do not fully provide for all these needs.

TESSA aims to overcome these challenges by providing relatively accessible methods for identifying which ecosystem service may be important at a site, and for evaluating the magnitude of benefits that people obtain from them currently, compared with those expected after an intervention (for instance under alternative land-uses). It aims to enable stakeholders to obtain robust and locally relevant ecosystem service information despite limited capacity, time and resources. This site-oriented focus, informed by relatively accessible methods for local data collection involving high levels of stakeholder engagement and underpinned by the consideration of the alternative state, is the ‘unique selling point’ for TESSA.

Sub/region where used: 
Scale of application: 
Practical information
UN languages in which the resource is available: 
Development stage: 
Full, working product
Contact details
Contact Name (Person or group/organization): 
Jenny Merriman / BirdLife International, Kelvin Peh / University of Southampton