What are the four categories of ecosystem services according to the Millennium Ecosystem Assessment?

• A. Provisioning, regulating, supporting, and cultural services.
• B. Provisioning, regulating, supporting, and aesthetic services.
• C. Nutritional, medicinal, recreational, and cultural services.
• D. Ecological, economic, social, and political services.

Answer: (A)

The four-category framework of ecosystem services used by the Millennium Ecosystem Assessment groups benefits into provisioning, regulating, supporting, and cultural services. Provisioning services are tangible goods that ecosystems provide, like food, water, medicines, and materials. Regulating services cover the control of environmental processes such as climate moderation, flood protection, disease regulation, and water purification. Supporting services are the underlying ecological processes that enable all other services—things like soil formation, photosynthesis, nutrient cycling, biodiversity maintenance, and pollination. Cultural services include non-material benefits from ecosystems, such as recreation, aesthetics, inspiration, and traditional knowledge.

This classification is the standard reference because it separates direct goods (provisioning) from their regulatory and ecological supports, and from human-centered benefits (cultural), making it easier to analyze how ecosystems sustain people. The other options mix or rename categories in ways that don’t align with the MA framework—for example, using aesthetic as a standalone category, or grouping into ecological, economic, social, and political services, which aren’t the four MA categories.