Understanding Ecosystem Services from a Geosciences Perspective
Human societies depend greatly on the natural environment in many ways: for food production, water supplies, erosion and flood control, and recreational opportunities, for example. However, the linkages between human societies and these benefits they derive from the environment have not always been considered explicitly when managing natural resources. To understand these linkages so that benefits from the environment can be more effectively managed, the framework of “ecosystem services” has emerged as a useful approach.
The benefits that society derives from the environment have been described in many ways, with ecosystem services initially classified into four distinct categories [Millennium Ecosystem Assessment, 2005]:
- Provisioning services are material benefits to humans, such as fiber, food, or timber.
- Regulating services are processes such as pollination, flood control, and disease control.
- Supporting services include nutrient cycling and soil formation.
- Cultural services are those aspects of species and ecosystems that provide humans with recreational, spiritual, or religious experiences.
- An example of an ecosystem service critical to society is provision of water of sufficient quantity, timing, and quality for drinking and other human requirements. A traditional ecosystem services perspective focuses on relating active vegetation management (e.g., forest thinning) or vegetation change due to disturbance (e.g., fire, insect, or drought mortality) to water resources, often emphasizing precipitation, soil moisture, and surface water flows while not necessarily considering other influential processes [e.g., Alila et al., 2009].
Explicitly expanding assessment of the service of water provision to include geosciences perspectives would in many cases lead to more robust understanding of relevant environmental processes and how to manage them for the benefit of society [Field et al., 2015]. For example, geosciences perspectives on water resources explicitly bring into consideration other key processes such as water quantity as affected by groundwater interactions with surface water, water timing as affected by subsurface flow transit times, and water quality as affected by rate-limiting biogeochemical processes [Chorover et al., 2011; Brooks et al., 2015]. This perspective is consistent with the original definition of ecosystems as one physical system [Richter and Billings, 2015].
To further highlight the utility of incorporating geosciences perspectives into considerations of ecosystem services, we discuss an example focusing on integration of biological, physical, and chemical processes associated with evolution of the “critical zone” (CZ, extending from groundwater level to the top of the vegetation canopy) and their relevance to society in the context of ecosystem services.