Nature's services

The physical environment and species which interact with it form natural units or "ecosystems". Healthy ecosystems provide us with the air that we breath, the water that we drink and the food that we eat. These are only some of the more obvious "services" which we rely upon from ecosystems. Other services include the regulation of our global climate, supporting nutrient cycling and even the inspiration behind many of our cultural traditions.

The Millennium Ecosystem Assessment  grouped ecosystem services into four broad categories:

• provisioning (e.g. food)
• regulating (e.g. climate modification)
• supporting (e.g. pollination)
• cultural (e.g. recreation).

The UK National Ecosystem Assessment  has investigated the services provided by ecosystems in detail: in 2011 it published its Synthesis of the Key Findings  .