Toolkit for Ecosystem Service
Site-Based Assessment

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Understanding the impacts on natural capital and ecosystem services of actual and potential changes in state at individual sites is important for promoting better planning decisions to support both biodiversity conservation and ecosystem service delivery. This approach has been relatively little used because it has been assumed that ecosystem services are technically difficult and expensive to measure.

This toolkit is designed to overcome this obstacle by providing practical guidance on how to identify which services may be significant at a site of interest, what data are needed to measure them, what methods or sources can be used to obtain the data and how to communicate the results.

The toolkit emphasizes the importance of comparing estimates for alternative states of a site (for example, before and after conversion to agriculture) so that decision-makers can assess the net consequences of such a change, and hence the benefits for human well-being that may be lost through the change or gained by conservation.

The toolkit has attempted to find a balance between simplicity and utility of developing convincing information for decision-makers and therefore excludes consideration of some of the more advanced concepts in ecosystem services. This is so that it can be used by non-experts, yet still provide scientifically robust information.

For more information on the toolkit, please refer to the additional resources below.

Information Resources

TESSA is currently available in English (Version 3.0) and French (Version 1.2).

To request a copy of the toolkit, please fill in the following details. The information you provide will help the toolkit compilers to understand how it is being used and by whom and where, in order to shape its further development.



Organisation type
Private sector / Corporate
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Purpose - Please give a comprehensive explanation of how you intend to use the TESSA toolkit

How did you hear about TESSA?
 Word of mouth
 Peer review literature
 Conference or event
 Online search engine
 Printed promotional material (e.g. leaflet, postcard)
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Terms of use - Please read the terms of use, disclaimer and errors and omissions statement here

I accept and agree to be bound by the TESSA terms of use

The compilers of TESSA are collating data derived from its application for meta-analysis, to evaluate at a broad scale the contribution that information on ecosystem services can make to biodiversity conservation. Would you be interested in contributing, potentially as a coauthor, and for your results to be considered for use in this way? If you wish, any data you provide will be made anonymous and not explicit to location or organisation

YES I would like the opportunity for the results of my application of TESSA to be put to wider use

Privacy - BirdLife International will process your data in accordance with the UK Data Protection Act 1998. You can find the details of our privacy policy committed to protecting your personal data (

The TESSA Tool will be updated periodically so please refer back to this website regularly to continue to access the latest content.
If you have any queries or require clarification regarding the Toolkit for Ecosystem Service Site-based Assessment please contact

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The Toolkit for Ecosystem Service Site-based Assessment (TESSA) has been compiled by the following organisations

The development of TESSA was supported by the following organisations