An ecosystem represents a dynamic community where living organisms, including plants, animals, and microorganisms, interact with each other and their physical surroundings. These intricate networks, which range in size from a small pond to the entire planet, form the life-support systems for all life on Earth. The interactions within them provide the necessary conditions for survival, including a livable climate, breathable air, and drinkable water.
What Ecosystems Do For Us and the Planet
Ecosystems provide a suite of benefits, often categorized as ecosystem services, that are important to human life and planetary function. The most direct of these are provisioning services, which are the tangible products people can extract from nature. These include:
- A vast array of foods like fruits, fish, and crops
- Drinking water
- Timber for construction
- Plants that form the basis of clothing and medicines
Beyond tangible goods, ecosystems deliver regulating services that maintain a stable and clean environment. Forests and oceans act as immense carbon stores, absorbing carbon dioxide and regulating the global climate, while wetlands function like natural sponges, controlling floods and filtering pollutants. Other processes like pollination by animals are responsible for the reproduction of many crops, and decomposition by bacteria and fungi breaks down waste, returning nutrients to the soil.
Underpinning all other services are supporting services, which are the natural processes required for ecosystems to function. These include the continuous cycling of nutrients like nitrogen and phosphorus, the formation of fertile soil, and primary production through photosynthesis. Without these processes, ecosystems would be unable to provide the provisioning, regulating, or cultural benefits that societies depend on.
Why Variety of Life Matters in Ecosystems
The variety of life, known as biodiversity, is a component of healthy and stable ecosystems. This variety exists at multiple levels, from the genetic differences within a single species to the diversity of species and entire ecosystems. A high level of biodiversity makes ecosystems more resilient, meaning they are better able to withstand and recover from disturbances like extreme weather events, pest outbreaks, or disease.
This resilience stems from a principle often called the “insurance effect.” In a diverse ecosystem, multiple species may perform similar functions, a concept known as functional redundancy. If one species is lost or its population declines, others can compensate, ensuring that processes like pollination or nutrient cycling continue. For instance, a forest with many different tree species is more likely to survive a pest outbreak than a monoculture forest.
Greater genetic diversity within species also enhances their ability to adapt to changing environmental conditions, such as those brought on by climate change. This variety provides the raw material for natural selection, allowing populations to evolve and persist through environmental shifts. This buffer enhances the capacity of ecosystems to adapt and maintain their functions over the long term.
Our Direct Dependence on Healthy Ecosystems
Human societies are built upon the services that healthy ecosystems provide, linking our survival and economies to the environment. Our food security, for example, relies on soil formation and fresh water. More than 75% of global food crops depend on animal pollination, a service with an estimated annual value in the hundreds of billions of dollars.
Human health is also linked to ecosystem functions. Clean air and fresh water are direct outputs of well-functioning ecosystems. Over half of modern medicines are derived from natural sources like plants and fungi, meaning biodiversity loss can limit the discovery of future treatments.
Economies also rely heavily on natural resources. Industries like forestry, fishing, and tourism depend on the health of the ecosystems they draw from. Additionally, coastal habitats like mangroves provide flood control that protects infrastructure, avoiding billions of dollars in storm damage.
When Ecosystems Suffer, We Suffer
When ecosystems are degraded, the consequences are felt across human society. The loss of regulating services increases our vulnerability to natural disasters. For instance, the destruction of coastal wetlands removes natural barriers that protect communities from storm surges, increasing risks for millions. Similarly, deforestation on steep slopes can lead to soil erosion and devastating landslides.
The decline of services also carries economic costs. The loss of pollinators puts hundreds of billions of dollars in crop production at risk. Industries like fishing and tourism suffer directly when fish stocks are depleted or natural landscapes are spoiled.
Environmental degradation has direct impacts on human health. Water contamination from pollution can lead to outbreaks of diseases like cholera and typhoid. Air pollution from burning fossil fuels and deforestation contributes to respiratory and cardiovascular diseases.