The capacity of ecosystems to supply services depends on their condition.
For example, a thriving forest ecosystem can provide high levels of carbon sequestration and recreational services, while a degraded forest ecosystem might struggle to provide such services.
The System of Environmental Economic Accounting (SEEA) is the international statistical framework developed to estimate and monitor changes in ecosystem extent, condition, and flows of ecosystem services. However, in the current version of the SEEA, the authors discuss the concept of ecosystem capacity but recognised it as a topic needing further development as part of the SEEA’s research agenda.
In this context, an expert global team, including our Director, Carl Obst, has considered the definition and measurement of ecosystem capacity in greater depth and through case studies. A specific aspect of the work was the development of a methodology for an ecosystem capacity index. The ecosystem capacity index aims to better link the data recorded in ecosystem condition and ecosystem services accounts.
Using two case study sites in the Republic of Ireland, the authors illustrate the integration of the capacity index into ecosystem services accounts, creating a more rigorous connection between condition and supply of services.
The capacity index in practice
Let’s consider a hypothetical forest with a high tree cover density. This forest’s ecosystem services include wood provision, recreation and global climate regulation. But its capacity to provide each of these services varies in relation to this level of tree cover density, as follows:
- wood provision – higher capacity because there are plenty of trees grown quite close together
- global climate regulation – higher capacity because there are so many trees sequestering and storing carbon
- recreation – lower capacity because there are so many trees close together, meaning there is less space for people to move around.
The capacity index method developed in the paper allows linking individual measures of condition, such as tree cover density and species richness, with individual ecosystem services. With this understanding, alternative management regimes can be designed. For example, if the aim is to generate more global climate regulation services, the capacity index will inform the target condition levels required to achieve this.
Congratulations to authors Francesco Martini, Kathleen Conroy, Emma King, Catherine A. Farrell, Mary Kelly-Quinn, Carl Obst, Yvonne M. Buckley and Jane C. Stout on the development of this methodology that will help inform future iterations of the SEEA.