Protecting threatened Over-seas biodiversity

The assesment tool TESSA

TESSA in figures

  • 8 ecosystem services
  • 55 method sheets
  • 3 months work
  • 6 steps
  • Used at more than 70 sites


Nature is important, not only for its aesthetic qualities but also for the benefits that people acquire from it. Over the last few decades human activities have had a huge impact on the natural environment with a consequent rapid extinction of plant and animal species. These changes have greatly influenced the way nature functions and thus benefits mankind which has resulted in certain people wanting to measure these benefits in order to demonstrate their importance and show the necessity of nature conservation.

What is TESSA?

TESSA is a toolkit for evaluating ecosystems services at the site level. Developed by BirdLife International and translated and adapted by the LPO (Ligue pour la Protection des Oiseaux – Birdlife partner in France) it is provided in the form of either PDF files or a printed version and is composed of method sheets, advice sheets and explicatory documents on each type of benefit.

Its objective!

This method allows for the identification and evaluation of the benefits to mankind of each site (ecosystem services), those such as food provision, water provision, flood prevention, climate regulation or mental and physical well-being.

TESSA allows two sites to be compared, one with the other, according to their different transformations so as to show the change in benefits, positive or negative, of each site compared to the engaged protection or management measures.

In the long term it could help decision makers in their land use plans due to the perceived value of protected or to-be-protected sites.

Its advantages!

TESSA was developed by a group of international scientists and is thus reliable and robust especially as the results are based on field data. Its use is entirely without charge and it has been simplified so as to be user friendly.

For who?

TESSA was developed for anyone involved in conservation (environmental professionals, reserve managers, those responsible for town and country planning, development organisations…) without any need to be competent in ecosystem services but simply have basic environmental knowledge.

Who benefits?

The present method allows the estimation of the value of the following ecosystem services: coastal protection, climate regulation, cultural services, cultivated foodstuffs, harvest of wild products, pollination, services associated with water and nature-based leisure activities.

For more information:

Case examples

To download the toolkit: