Vincent de Leijster

12 Chapter 1 1.2 Ecosystem services The term ‘ecosystem services’ has influenced the scientific discourse and practice since it was first defined in economic terms by Costanza et al. (1997). In this publication, ecosystem services were economically valuated; inspired by earlier definitions by Daily, Elrich and Mooney, the term ‘ecosystem services’ was defined as the services and goods that are produced by ecological functions and processes and which directly or indirectly benefit human populations (Costanza et al., 1997). Furthermore, it was proposed as a methodology to calculate the value of the services and goods that are produced by ecosystem services, which was at the time estimated to be around $33 trillion per year on a global scale. It has often been criticized as a narrow view that overemphasizes the idea that nature is serving human beings rather than aiming to protect nature for its intrinsic value (Kenter, 2018). Nevertheless, the ecosystem services concept is nowadays also frequently used to provide a structure to estimate overall ecological performance and functionality in systems that relate to human activities without translating it to economic value (Kearney et al., 2017). The Millennium Ecosystem Assessment (MEA, 2005) embraced the term in the assessment of quantifying the effects of ecosystem change on human well-being and concluded that as early as 2005 more than 60% of the ecosystem services were being degraded. Fourteen years later, the Intergovernmental Panel for Biodiversity and Ecosystem Services concluded that the supply of many ecosystem services had only degraded further (IPBES, 2019). The MEA defined four main categories of ecosystem services, namely provisioning services, regulating services, cultural services and supporting services (Costanza et al., 2017). Provisioning services relate to goods that have been produced by ecosystem services, such as the production of food, fiber, and timber. Regulating services relate to ecological processes that regulate certain systems, for example pollination, pest control, flood control, and water purification. Cultural services are non-material services with esthetic or spiritual values derived from nature, such as recreation, cultural heritage, and religious values. Supporting services are ecological processes that do not directly benefit human beings but support the ecosystem in its functioning, primary productivity, nutrient cycling, and habitat provisioning for biodiversity. IPBES has now proposed the term ‘nature contributions to people’ and aims for a more inclusive and less utilitarian assessment of the relationship between people and nature by better including indigenous knowledge and by considering that ‘contributions’ may be both positive and negative. In this thesis I use the term ‘ecosystem services’ because this was the mainstream approach at the start of the study, and therefore its classification was used in the set-up of the study.