You would have thought with so much hype surrounding ecosystem services we would be able to agree on a definition by now. However, there are still a multitude of different definitions with their own categorisation systems. We have not reached a consensus on which is the most useful.
Though it may seem rather esoteric, this issue is fundamental and affects the science we do and how we do it. Without a strong definition we also run the risk of developing a concept which is nebulous and of little practical use.
Differences between National Ecosystem Assessments
The best examples I have found recently of the differences in definition are those of National Ecosystem Assessments, which have proliferated in Europe since the report on The Economics of Ecosystems and Biodiversity (TEEB).
Each of these national assessments rightly focuses on the services considered most important or at risk for that particular country. However, the areas of focus sometimes seem to be a combination of ecosystem services and what people would often call ‘natural resources.’ For example, the Spanish National Ecosystem Assessment considered mineral extraction to be an ecosystem service1.
Part of the problem with definition is the deliberate muddying of the water by people wanting to claim their work is relevant to ecosystem services, even when it isn’t. The other part of the problem is people’s genuine confusion about what constitutes an ecosystem service.
The best definition (in my opinion…)
The view that I have come to is that defining ecosystem services as ‘the aspects of ecosystems utilized (actively or passively) to produce human well-being’ seems to be the most logical approach. Along with this definition Fisher et al2 use the categories intermediate and final services to divide between services based on their role in providing the goods that we use.
This system avoids the problems of the MEA and TEEB categorisations of supporting and habitat services by pointing out that many types of service can be intermediate depending on the final service you are considering. For example, if you are interested in the benefit of clean water provision, water regulation may be considered an intermediate service. However, if you were interested in fish production water provision would move to an intermediate service.
This system allows biodiversity, ecosystem processes & functions to be defined as intermediate or final services, or as ecosystem goods, where relevant. This definition enables neat compartmentalisation and although it is fairly simple it can be applied in many different situations.
The dangers of poor definition
Allowing a wishy-washy definition of ecosystem services to proliferate allows people to claim their work is more relevant than it is (naming no names). Many people have really only investigated intermediate services without considering how they link to final services and subsequently how they affect human well-being. Without these crucial links the relevance of work on ecosystem services is drastically reduced.
The vital thing about ecosystem services, the thing that makes it different from traditional ecology and conservation, is the explicit consideration of human well-being. By getting further away from this central tenet we do the field a disservice. Without clear definition we may well see the term go the same way as ‘sustainability’ which means all things to all people and not very much to most.