Ecosystem service

Ecosystem services are the many benefits that humans receive from the natural environment. These benefits come from the complex connections between living and non-living components in an ecosystem.

Nature provides both direct benefits, like the food we eat, and indirect benefits, such as climate regulation. These services are essential for human well-being and survival. Without these natural processes, our societies would struggle to function. Scientists study these services to understand how much we depend on the Earth's health.

Researchers often group these services into four main categories. The Millennium Ecosystem Assessment (MA) popularized this classification in the early 2000s. The first group is provisioning services, which are the physical products we harvest. These include food, water, and raw materials like timber.

The second group is regulating services. These occur when ecosystems control natural processes, such as pollination or flood control. The third group is supporting services. These are the fundamental processes, like nutrient cycling, that allow all other services to exist. Finally, cultural services include non-material benefits like tourism, recreation, and spiritual joy.

Provisioning services provide the actual goods that humans use every day. These include crops, seafood, and medicinal resources like pharmaceuticals. Forests are a massive source of these products. For example, they provide timber for construction and wood for fuel. In 2018, the global trade of wood-based products reached its highest value ever. This included products like sawnwood, pulp, and paper.

Beyond wood, forests provide wild foods like mushrooms and edible insects. Around 1 billion people worldwide depend on these wild foods for nutrition. Additionally, 2.4 billion people use wood-based energy for cooking.

Regulating services help keep the environment stable and safe. One important example is water purification. In New York City, authorities restored the Catskill Watershed to clean their drinking water. They used natural processes like soil absorption and microbial recycling. This natural solution cost between $1 billion and $1.5 billion. This was much cheaper than building a new filtration plant, which would have cost $6 to $8 billion.

Another example is pollination. In the United States, bees are responsible for 15% to 30% of food production.

Ecosystems also act as vital buffers against natural disasters. Coastal ecosystems like mangroves and wetlands protect land from storms and floods. Mangrove forests protect shorelines from erosion caused by currents and tides. During a 1999 cyclone in India, villages surrounded by mangroves suffered less damage than those without them. Wetlands help by retaining large amounts of water, such as rain or snowmelt. They release this water slowly, which decreases the likelihood of sudden floods.

This regulation helps protect human homes and infrastructure.

Supporting services are the foundation of all other ecosystem services. They involve long-term processes that maintain the conditions for life. One key service is nutrient cycling. This is the movement of nutrients like carbon, nitrogen, and phosphorus through an ecosystem.

These nutrients are absorbed by organisms and then released back into the environment when they die and decompose. Another supporting service is primary production. This is the creation of organic matter through photosynthesis or chemosynthesis. This process forms the base of all food webs and produces the oxygen that humans and animals need to breathe.

Understanding these services has changed how we value nature. In the past, researchers like Gretchen Daily distinguished between ecosystem goods and services. Later, Robert Costanza and the Millennium Ecosystem Assessment combined them into one category. Some newer systems, like The Economics of Ecosystems and Biodiversity, have even updated these names. For instance, they replaced "Supporting Services" with "Habitat Services" to avoid double-counting during audits. These evolving definitions help scientists and leaders make better decisions about protecting our planet.