There are several schemes for listing and classifying ecosystem services, the most widely used and well known typology, being that developed by the Millennium Ecosystem Assessment. The Millennium Ecosystem Assessment typology, which was used by EFSA (2010), classifies ecosystem services into four categories: provisioning services (e.g. products such as food, fuel, fibre); regulating services (i.e. benefits arising from the regulation of ecosystem processes e.g. climate regulation, natural hazard regulation, water purification); supporting services (e.g. nutrient cycling, primary production, soil formation) and cultural services (i.e. non‑material benefits such as recreational, spiritual, aesthetic services) (Millennium Ecosystem Assessment, 2005b).
The Economics of Ecosystems and their Biodiversity (TEEB) project, which followed on from the Millennium Ecosystem Assessment, also grouped ecosystem services into four broad categories. However the TEEB classification replaced ‘supporting services’ with ‘habitat or supporting services’, which comprise ‘habitats for species’ and ‘maintenance of genetic diversity’ (TEEB, 2010b). More recently, there has been a proposal for a Common International Classification of Ecosystem Services (CICES), which builds on existing classifications (Haines-Young and Potschin, 2013). CICES has been developed to support the work of the European Environment Agency on environmental accounting and is linked with the UN System of Environmental Economic Accounts (SEEA). It therefore focuses on services that are used directly (i.e. final services). CICES groups services into 3 sections: provisioning (nutrients, materials, energy); regulating and maintenance (mediation of waste, toxics and other nuisances; mediation of flows; maintenance of physical, chemical, biological conditions) and cultural (physical and intellectual interactions with biota, ecosystems and land/seascapes; spiritual, symbolic and other interactions with biota, ecosystems and land / seascapes). It is a nested typology with CICES v4.3 resolving 3 sections (main service categories) via 8 divisions (main types of output or process) and 20 groups (biological, physical or cultural type or process) to 48 classes (http://cices.eu/). A cross tabulation of Millennium Ecosystem Assessment, TEEB and CICES classification systems is presented in Appendix A.
CICES has been adopted by the Mapping and Assessment of Ecosystems and their Services (MAES) process at the EU level and has been applied to six pilot studies (Maes et al, 2014). As a result of these pilots, it was concluded that the hierarchical structure of CICES was very useful to bundle services at class level and could be used for data poor systems where indicators may only be available at division or group level. However, conceptual difficulties were encountered when assessing regulation and maintenance services, especially in aquatic systems, and in addressing services delivered by agriculture (e.g. discriminating between the amount of provisioning service supplied by agro-ecosystems and the role of human energy inputs in contributing to total yield). MAES (Maes et al, 2014) suggested that separate classifications for both ecosystem functions (which underpin ecosystem services) and for ecosystem benefits or beneficiaries are developed in order to distinguish between the supply of and the demand for ecosystem services.
The ecosystem services considered in this project are listed in Table 2.1. It has been argued that ecosystem service assessments should focus on final ecosystem services to avoid double accounting in valuations (Boyd and Banzhaf, 2007). However, we have followed the EFSA (2010) approach and recent recommendations by MAES (Maes et al, 2014) by considering all types of services (i.e. including supporting and other intermediate services) and by basing our list of ecosystem services on the Millennium Ecosystem Assessment typology. This list is not exhaustive and other services may be added if sufficient information is available to evaluate their importance in specific habitats (see Step 2). Future developments may refine the list of services considered to prioritise final services for each habitat type, an approach adopted by the US EPA (Landers and Nahlik, 2013) and implied by the use of CICES by the MAES process. If required, the protection goals generated using the Millennium Ecosystem Assessment typology can be translated to the CICES typology using the information in Appendix A.
Finally, the Task Force recognised the importance of addressing biodiversity in relation to ecosystem services adopting the position that biodiversity underpins the delivery of all ecosystem services that are dependent on biotic processes and that specific components of biodiversity are explicitly addressed in many individual ecosystem services e.g. genetic resources, ornamental resources, pollination, pest control, aesthetic value etc. (Devos at al, 2015; Science for Environment Policy 2015). Biodiversity, as defined by the Convention on Biological Diversity, was considered part of natural capital and not an ecosystem service per se as its inclusion as an ecosystem service would lead to the protection of ‘everything, everywhere’, which is too generic and vague to be useful for scientific risk assessment.
Table 2.1: Ecosystem services considered in case studies. Services and explanations are taken from the Millennium Ecosystem Assessment (2005b)