The document compiles and assesses current ecosystems services indicators in order to inform and advance such efforts. According to the World Resources Institute, ecosystem services are the benefits that people derive from nature. Some benefits, such as crops, fish, and freshwater (provisioning services), are tangible. Others such as pollination, erosion regulation, climate regulation (regulating services) and aesthetic and spiritual fulfillment (cultural services) are less tangible. All, however, directly or indirectly underpin human economies and livelihoods). See
http://pdf.wri.org/measuring_natures_benefits.pdf for full details.