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Ocean ecosystem services should be classified so they can be consistently organised within the ocean accounting framework over time. The CICES and FEGS/NESCS approaches (see Tables 36and37 and Figures 23 below) provide systematic coding structures but imply different scopes. CICES is more of a checklist of often-analyzed analysed ecosystem services and, while including many “final” services (i.e., “those directly enjoyed, consumed or used to yield human well-being” (Boyd and Banzhaf, 2007, p619)), it also includes many, such as regulating and maintenance services, that are less-directly used. It also includes services that have less direct link to ecosystem processes, such as cultivated crops. This has the benefit of being broad and therefore able to classify past studies. The newest revision also highlights those services most often associated with marine ecosystems.
FEGS/NESCS services overlap in scope only for services that are directly used and directly linked to ecosystem processes. As such, it excludes most regulating and maintenance services and cultivated products. However, since it links ecosystem types, with service categories and beneficiaries, it can support a more coherent valuation of a narrower set of services. Ongoing conclusions from the SEEA Revision process concerning ecosystem services classification will be progressively incorporated into this Guidance.
There is a risk in being over-specific in defining what counts as an ecosystem service. We likely cannot be comprehensive in detailing very specific ecosystem services (partly because we do not know how to mechanistically link ecosystems with human well-being across all possible links). Being too specific can easily reflect the values embedded in the people establishing the categorization. A more flexible classification approach that lacks a coding structure has been developed by IPBES as a conceptual basis for its assessment reports. This broad two-dimensional classification of Nature’s Contributions to People is illustrated in Figure 24below.
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