Can ecosystem services lead ecology on a transdisciplinary pathway?

The discipline of ecology has evolved through several phases as it has developed and defined itself and its relationship with human society. While it initially had little to do with human concerns, it has become more applied, and is today more integrated with the human element in the way it conceptualizes complex social-ecological systems. As the science has developed, so too have its relationships with other disciplines, as well as people and processes outside the domain of science. However, it is unclear how far ecology has progressed in developing these relationships and where it should best focus its efforts in the future in order to increase its relevance and role in society. The concept of ecosystem services (the benefits people get from nature) has the potential to further this integration and clarify ecology's role and relevance in society, however doubt remains as to whether the concept has helped ecology in developing disciplinary and societal relationships. This review assesses the progress of ecology in relation to a transdisciplinary knowledge hierarchy (empirical, pragmatic, normative and purposive) where all levels of the hierarchy are coordinated on the basis of an overall purpose introduced from the purposive level down. At each of the levels of the knowledge hierarchy, the principles of transdisciplinarity, ecology's progress, the contribution of ecosystem services to this progress and future directions for a transdisciplinary ecology are explored. Ecology has made good progress in developing an interdisciplinary dialogue between the natural and social sciences and sectors. It is well-integrated with empirical and pragmatic disciplines and coordinates research at these two levels. At the normative level, the absence of collaborative frameworks and planning instruments is a major gap limiting the influence that ecology can have on land and resource use decisions at this level. At the purposive level, ecology has limited interactions with a narrow set of values associated with ecological ethics and economics. There is an obvious need for ecology to engage with the purposive disciplines of philosophy, ethics and theology, but also a need for ecological research to transform itself into a social process dealing with values and norms of both society and science. Ecosystem services have helped ecology to make links with many disciplines at the empirical and pragmatic levels, provided a useful concept and framework for interactions at the normative level requiring further examination, and helped make values explicit, allowing ecologists to begin to interact with the purposive level. The Western ecological economic origins of the ecosystem service concept presents a potential constraint to interactions at the purposive level, and must be considered and addressed if ecosystem services are to further the development of a transdisciplinary ecology, the joint ecology-society debate and the formulation and execution of policy.