生態系統服務

The value of nature to people has long been recognized, but in recent years, the concept of ecosystem services has been developed to describe these various benefits. An ecosystem service is any positive benefit that wildlife or ecosystems provide to people. The benefits can be direct or indirect—small or large. The Millennium Ecosystem Assessment (MA), a major UN-sponsored effort to analyze the impact of human actions on ecosystems and human well-being, identified four major categories of ecosystem services: provisioning, regulating, cultural and supporting services. 1. Provisioning Services When people are asked to identify a service provided by nature, most think of food. Fruits, vegetables, trees, fish, and livestock are available to us as direct products of ecosystems. A provisioning service is any type of benefit to people that can be extracted from nature. Along with food, other types of provisioning services include drinking water, timber, wood fuel, natural gas, oils, plants that can be made into clothes and other materials, and medicinal benefits. 2. Regulating Services Ecosystems provide many of the basic services that make life possible for people. Plants clean air and filter water, bacteria decompose wastes, bees pollinate flowers, and tree roots hold soil in place to prevent erosion. All these processes work together to make ecosystems clean, sustainable, functional, and resilient to change. A regulating service is the benefit provided by ecosystem processes that moderate natural phenomena. Regulating services include pollination, decomposition, water purification, erosion and flood control, and carbon storage and climate regulation. 3. Cultural Services As we interact and alter nature, the natural world has in turn altered us. It has guided our cultural, intellectual, and social development by being a constant force present in our lives. The importance of ecosystems to the human mind can be traced back to the beginning of mankind with ancient civilizations drawing pictures of animals, plants, and weather patterns on cave walls. A cultural service is a non-material benefit that contributes to the development and cultural advancement of people, including how ecosystems play a role in local, national, and global cultures; the building of knowledge and the spreading of ideas; creativity born from interactions with nature (music, art, architecture); and recreation. 4. Supporting Services The natural world provides so many services, sometimes we overlook the most fundamental. Ecosystems themselves couldn't be sustained without the consistency of underlying natural processes, such as photosynthesis, nutrient cycling, the creation of soils, and the water cycle. These processes allow the Earth to sustain basic life forms, let alone whole ecosystems and people. Without supporting services, provisional, regulating, and cultural services wouldn't exist. Wetlands are one of the most threatened ecosystems in the United States. We have lost more than 50 percent of wetlands in the contiguous United States. Just a quick overview of some of the services provided by wetlands shows how important they are to people and why we should work to protect and restore them. Many of the fish we rely on for food spend at least part of their life cycle in wetland habitats. Wetlands retain and control flood waters. Wetland plants absorb nutrients and chemicals from the water, and they act as a natural filtration system. Wetland plants and soils store large amounts of carbon that, if released, would contribute to climate change . Wetlands are also a vital habitat for migratory birds , fish , and mammals , and their loss impacts recreation and biodiversity . A new storymap connects the dots between extreme weather and climate change and illustrates the harm these disasters inflict on communities and wildlife. Take the Clean Earth Challenge and help make the planet a happier, healthier place. Get a list of highly impactful plants that are