A capacity index to connect ecosystem condition to ecosystem services accounts

• The condition of ecosystems underpins their capacity to supply ecosystem services. • Development of ecosystem capacity accounts in the SEEA EA is underdeveloped. • We propose a methodology to create an ecosystem capacity index and capacity accounts. • A vector of capacity scores is assigned to each ecosystem asset. • Each capacity score corresponds to the capacity to supply an ecosystem service. Ecosystem services are essential for human survival and wellbeing, and the quantity and quality of the services delivered by an ecosystem are dependent on its underlying condition. With many ecosystems degraded or in poor condition, the capacity to deliver key ecosystem services can be affected. The System of Environmental Economic Accounting – Ecosystem Accounting (SEEA EA) is the international statistical framework developed to estimate and monitor changes in ecosystem extent, condition, and flow of ecosystem services. Although the condition of ecosystems underpins their capacity to supply a service, the connection between ecosystem condition and ecosystem services accounts is underdeveloped. This is because condition is usually assessed relative to an ideal reference state, whereas capacity to supply ecosystem services depends on both the condition of the ecosystem and the ecosystem service being considered. For example, a forest in one condition may have very different capacities to supply ecosystem services such as timber provisioning and recreational services. We propose a methodology to better integrate condition and ecosystem services accounts through development of an ecosystem capacity index. Building on condition accounts, we derived a capacity index and related capacity accounts, reflecting the capacity of each ecosystem asset to support the delivery of selected ecosystem services. We show that an ecosystem with a particular condition profile may have different capacity index values depending on the ecosystem service that is expected to be delivered. We provide case studies from two sites in the Republic of Ireland to illustrate the integration of capacity indices into ecosystem services accounts. This approach is an extension to ecosystem accounting that enables more rigorous connection of condition to ecosystem service supply by accounting for capacity.