Capacity as "virtual stock" in ecosystem services accounting.

Interest in ecosystem services accounting is growing exponentially. There are many un-solved issues that need to be addressed, the notion of capacity is among them. International guidelines suggest that capacity should constitute the link between the ecosystem assets accounts and the ecosystem services accounts. In order to address this issue, the authors use Supply and Use table for ecosystem services to show the relationship between (i) ecosystem assets and (ii) capacity, intended as "virtual stock" of individual ecosystem services. It is in fact important to distinguish ecosystem assets from capacity as "virtual stock": a comparison between asset accounts for natural resources and capacity is presented to clarify this difference. This novel approach is described together with its implications in order to feed further developments and discussion.