Ecosystem services are the many benefits that people get from ecosystems. The living and non-living parts of nature work together to provide things like pollinating crops, keeping air and water clean, breaking down waste, and controlling floods. These services are important for people's health and happiness. They give direct and indirect help from nature, such as clean water, food, and controlling the climate.

Ecosystem services are divided into groups, a method first widely used in the early 2000s by the Millennium Ecosystem Assessment (MA) project led by the United Nations. How these groups are defined depends on the classification system used. The MA divides services into four main types. These include: provisioning services, such as producing food and water; regulating services, such as controlling climate and disease; supporting services, such as recycling nutrients and making oxygen; and cultural services, such as recreation, tourism, and spiritual satisfaction.

For example, estuarine and coastal ecosystems are types of marine ecosystems that provide all four categories of ecosystem services. First, their provisioning services include resources like fish and genetic material. Second, their supporting services include recycling nutrients and creating energy through plants. Third, their regulating services include storing carbon (which helps reduce climate change) and controlling floods. Lastly, their cultural services include activities like recreation and tourism. Sometimes, ecosystem services are evaluated by giving them a money value.

Definition

Ecosystem services are the things and benefits that ecosystems provide to humans. According to the 2006 Millennium Ecosystem Assessment (MA), ecosystem services are defined as "the benefits people obtain from ecosystems."

Gretchen Daily's original definition separated ecosystem goods from ecosystem services. However, later work by Robert Costanza and his colleagues, as well as the MA, combined all of these into one category called ecosystem services.

Categories

The classification of ecosystem services depends on the system used. The Millennium Ecosystem Assessment (MA) divides ecosystem services into four groups: regulating services, provisioning services, cultural services, and supporting services. Supporting services are considered the foundation for the other three types.

An ecosystem may not always provide all four types of services at the same time. However, because ecosystems are complex, humans usually benefit from a mix of these services. Different ecosystems, such as forests, oceans, coral reefs, and mangroves, offer services that vary in type and effect. Some services directly help human communities, like providing fresh water, food, or beauty. Others indirectly affect humans by influencing the environment, such as regulating climate change, preventing erosion, or reducing natural disasters.

By 2010, many definitions of ecosystem services were developed. To avoid counting the same services twice, the Economics of Ecosystems and Biodiversity replaced "supporting services" in the MA with "habitat services." It also defined "ecosystem functions" as the interactions within an ecosystem that enable it to provide goods and services. The Common International Classification for Ecosystem Services later grouped cultural and provisioning services separately but combined regulatory and habitat services into one category called "regulation and maintenance services."

Provisioning services are the products obtained from ecosystems. These include:
• Food (such as seafood, crops, wild plants, and spices)
• Raw materials (like wood, fuel, and fertilizer)
• Genetic resources (such as genes for improving crops or medicine)
• Biogenic minerals
• Medicinal resources (like drugs and test organisms)
• Energy (such as hydropower and biomass)
• Ornamental resources (like jewelry, pets, and souvenirs)

Forests and their management produce many wood products, such as timber, paper, and engineered wood. In 2018, global production of wood-based products reached record levels. The fastest growth in production occurred in the Asia-Pacific, North America, and Europe. Over 40% of the European Union’s land is covered by forests, and about 60% of the wood grown each year is used.

Forests also provide non-wood products, such as food, medicine, and fuel. Around 1 billion people worldwide rely on wild foods like fish, insects, and mushrooms. In the European Union, over 100 million people regularly eat wild food. More than 2.4 billion people use wood-based energy for cooking.

Regulating services are the benefits from the way ecosystems manage natural processes. These include:
• Cleaning water and air
• Storing carbon to reduce climate change
• Breaking down waste and removing toxins
• Controlling animal populations through predation
• Managing pests and diseases
• Pollinating plants
• Reducing the impact of natural disasters like floods

For example, New York City improved its water quality by restoring the Catskill Watershed instead of building a costly water filtration plant. This natural solution cost $1–1.5 billion, compared to $6–8 billion for a filtration plant and $300 million in yearly operating costs.

Pollination by bees is vital for 15–30% of U.S. food production. Many farmers use non-native honey bees for this. However, wild bees can also help pollinate crops. Intensive farming can reduce pollination services by harming bee populations. Preserving habitats like chaparral and oak woodlands near farms helps maintain pollination. Planting native flowers in urban areas or on farms can also support wild bees.

Coastal and estuarine ecosystems protect against natural disasters like floods and storms. Wetlands and mangroves absorb water and reduce flood risks. Mangroves also shield coastlines from erosion, as seen after a 1999 cyclone in India. Villages with mangroves suffered less damage than those without.

Supporting services are the services that allow other ecosystem services to exist. They have long-term effects on humans but are not always directly visible. Examples include nutrient cycling, soil formation, and habitat creation. These services enable ecosystems to provide resources, regulate processes, and support human culture. Some services can be classified as both supporting and other types of services.

Estuarine and coastal ecosystem services

Estuarine and marine coastal ecosystems are types of marine ecosystems. These ecosystems help provide four types of services in different ways. Provisioning services include items like forest products, fish and other marine life, fresh water, raw materials, and resources such as biochemical and genetic materials. Regulating services include storing carbon to help reduce climate change, treating waste, controlling diseases, and creating natural barriers. Supporting services include processes like recycling nutrients, creating habitats for living things through biological processes, and producing the first stage of food for other organisms. Cultural services include activities like inspiring people, offering places for recreation and tourism, and supporting science and education.

Coasts and the areas near and far from them are important parts of local ecosystems. Estuaries, where fresh water and salt water mix to form brackish water, provide many nutrients for marine life. Salt marshes, mangroves, and beaches support a wide variety of plants, animals, and insects that are important for the food chain. The high number of different living things leads to a lot of biological activity, which has drawn human activity for thousands of years. Coasts also provide materials that help living things survive, such as estuaries, wetlands, seagrass, coral reefs, and mangroves. These areas are homes for migratory birds, sea turtles, marine mammals, and coral reefs.

Economics

There are questions about the environmental and economic importance of ecosystem services. Some people may not understand how humans are connected to the natural environment, which can lead to misunderstandings. Even though more people are becoming aware of environmental issues today, the value of ecosystem services and how they change over time is still not well understood. Problems continue to affect ecosystems, and people face the "tragedy of the commons," where shared resources are overused. Efforts to help decision-makers compare the costs and benefits of choices now involve turning scientific knowledge into economic terms. This helps explain the effects of decisions in ways that are easier to understand. A challenge is that information collected from one place or time may not apply to another, so understanding how ecosystems work is important for making good economic choices. Factors like how hard a service is to replace or how services are grouped together can help assign economic value more effectively.

Valuing ecosystem services also involves sharing information with people, which is difficult but studied by researchers. In general, people make choices for many reasons, but patterns in their choices can show what a society values overall. Six main methods are used to assign monetary value to ecosystem services:

• Avoided cost: Services help society save money that would have been spent without them (e.g., wetlands reduce health costs by cleaning water).
• Replacement cost: Services can be replaced by human-made systems (e.g., fixing the Catskill Watershed was cheaper than building a water treatment plant).
• Factor income: Services improve incomes (e.g., better water quality increases fish catches and fishers' earnings).
• Travel cost: The cost of traveling to use a service can show its value (e.g., people pay to visit ecotourism sites).
• Hedonic pricing: Prices people pay for goods near nature can reflect service value (e.g., homes near coasts cost more).
• Contingent valuation: People are asked how much they would pay for services in hypothetical situations (e.g., visitors pay to access national parks).

A study from 1997 estimated the value of ecosystem services and natural capital worldwide to be between $16 and $54 trillion each year, with an average of $33 trillion. However, Salles (2011) noted that "biodiversity is infinitely valuable, so trying to assign a total value to nature is pointless because we cannot live without it."

By 2012, many companies did not fully understand how much they relied on ecosystems or the effects of their actions. Tools to manage the environment often focus on pollution and resource use, not on how businesses depend on ecosystems. Some tools that help companies value ecosystem services include Our Ecosystem, the 2008 Corporate Ecosystem Services Review, the ARIES project (2007), the Natural Value Initiative (2012), and InVEST (2012).

For example, the land owned by the U.S. Department of Defense provides ecosystem services like carbon storage and habitat for endangered species. As of 2020, the Eglin Air Force Base was estimated to provide about $110 million in ecosystem services each year, $40 million more than if the base were not there.

Payments for ecosystem services (PES), also called payments for environmental services, are programs that pay farmers or landowners to manage their land in ways that protect the environment. These programs are defined as "systems that reward people for providing environmental services through clear, conditional payments." They encourage conservation by linking it to economic benefits.

Management and policy

Although money is still used to value ecosystem services, challenges in making and managing policies are large and difficult. Managing shared natural resources has been studied a lot by experts. From identifying problems to finding practical and lasting solutions, many obstacles remain. Choices must balance needs today and in the future, and leaders often work with incomplete information. Current laws are often not enough because they focus on human health instead of protecting ecosystems. In 2000, an idea called the Ecosystem Services Framework (ESF) was proposed. This framework combines environmental and social and economic factors to help institutions make better decisions using information from many fields.

By 2005, local and regional groups were managing services like pollination and resources like water. Another method that became popular in the 1990s is trading ecosystem services. People can buy credits for activities like protecting forests or restoring ecosystems. Some companies now sell these credits and even sell shares on stock markets, linking conservation to economic opportunities. However, clear land rights are needed for these efforts, which are often missing in developing countries. In places where forests are cut down, conflicts between groups who use the land are common. Global efforts also face problems, like unequal pay for services or misuse of resources. In 2001, a new approach focused on protecting areas rich in biodiversity. Recognizing that saving ecosystems helps protect species, experts suggested combining goals to improve success. This could help by using networks that connect ecosystems and finding money from different investors.

For example, by 2013, people were studying the value of ecosystem services from shellfish like oysters. These animals, which are low in the food chain, support many other species by doing important jobs. Some shellfish even change their environment, making them "ecosystem engineers." Their work helps humans by cleaning water and reducing pollution. By 2018, the idea of ecosystem services had not yet been added to international laws.

Despite this, the United Nations has a goal to protect and use ecosystem services wisely. Ecosystem services are estimated to add $125 trillion to $140 trillion to the economy each year. However, these services are at risk because of climate change and other human activities. By 2100, climate changes could reduce ecosystem services by about 9% worldwide.

Ecosystem-based adaptation (EbA) includes ways to help people deal with climate change by managing ecosystems. The Convention on Biological Diversity defines EbA as using nature to help people adapt to climate effects. EbA includes protecting and restoring ecosystems like forests and wetlands to reduce risks from climate changes, such as extreme weather. These methods can work alone or with other solutions, like building dams or using early warning systems.

Decisions about ecosystem services are complex, involving nature, technology, society, and money. These choices must consider many types of information, include all opinions from people like scientists, residents, and organizations, and measure effects on all areas. These decisions are often about locations, have many goals, and use uncertain data. Usually, the best science combined with people’s values helps guide decisions.

One study used computer models to help manage water in New Mexico by considering people’s opinions but not uncertainty. Another study used math methods to predict land use changes, treating people’s opinions as random. A third study used a system that combines scientific data and people’s input to help place energy devices off the coast of Oregon. These methods show how to handle uncertain information and people’s opinions in decisions. Maps and satellite data can help track the health of ecosystems, which helps plan and monitor activities.

In the Baltic countries, scientists, conservationists, and local leaders are using a combined planning method for grasslands. They are creating a tool using maps and computer systems to help planners choose the best way to manage grasslands. This tool looks at both natural and social factors to find the best solutions for each area.

History

The idea that humans rely on Earth's ecosystems dates back to the beginning of human history. However, the term "natural capital" was first introduced by E. F. Schumacher in 1973 in his book Small is Beautiful. Early recognition of how ecosystems support human life can be traced to at least 400 BC, when the philosopher Plato noted that removing trees could cause soil to erode and water sources to dry up. Modern ideas about ecosystem services began in 1864 when George Perkins Marsh argued that Earth's natural resources are not endless, using examples of changing soil fertility in the Mediterranean. It was not until the late 1940s that three authors—Henry Fairfield Osborn, Jr., William Vogt, and Aldo Leopold—helped people understand the importance of depending on the environment.

In 1956, Paul Sears highlighted the role of ecosystems in breaking down waste and recycling nutrients. In 1970, Paul Ehrlich and Rosa Weigert discussed "ecological systems" in their environmental science textbook, warning that human activities could harm the systems that sustain life.

The term "environmental services" was used in a 1970 report on critical environmental problems, which listed services such as insect pollination, fishing, climate control, and flood prevention. Over time, variations of this term were used, but "ecosystem services" became the standard term in scientific writing.

In the 1990s, two important books were published: Nature's Service by Gretchen Daily, which influenced discussions about ecosystem services, and The Value of the World's Ecosystem Services and Natural Capital by Costanza et al., which was the first study to estimate the economic value of ecosystem services.

The concept of ecosystem services has continued to grow, now including goals related to society, the economy, and protecting nature.