Imagine a world in which freshwater was as precious as diamonds, in which a perennial garden would only bloom after hiring a specially trained pollinator, or in which food prices had increased a thousand-fold because soils were scarce and lacking in nutrients. That’s a vision of a world losing its ecosystem services.
The reality, thankfully, is that ecosystem services are still freely available the world over, supporting life in myriads of dynamic ways. However, ecosystem services, which derive from and support functioning ecosystems, are beleaguered as never before.
The Definition of Ecosystem Services
Many people recognize that the complex interdependent nature of ecosystems means that they “function,” or in other words, are greater than the sum of their parts. In the same way that a human body with heart, blood, and vessels intact is dead without a heartbeat, an ecosystem with its parts intact will die without ongoing functions: nutrient cycles, energy transformations such as photosynthesis or predator-prey relationships, and physical processes such as flooding and deposition.
“Ecosystem services” denotes a relatively large subset of ecosystem functions: those that benefit humans in direct and indirect ways. They also include much of what is traditionally recognized as natural resources. The Millennium Ecosystem Assessment Conceptual Framework report (2005) defines ecosystem services as “the benefits people obtain from ecosystems.” These include “products such as food, fuel, and fiber; regulating services such as climate regulation and disease control; and nonmaterial benefits such as spiritual or aesthetic benefits.”
The Environmental Protection Agency's Ecosystem Services Research Program (accessed Jan. 17, 2010) defines them as "the many life-sustaining benefits we receive from nature . . . These ecosystem services are important to our health and well-being, yet they are limited and often taken for granted as being free."
In their book, The Law and Policy of Ecosystem Services (p. 15, Island Press, 2007), authors J.B. Ruhl, Steven Kraft, and Christopher Lant emphasize “it is important not to confuse ecosystem functions, which are ubiquitous, with ecosystem services, which are the consequence of only some ecosystem functions. The critical difference between the two . . . is that ecosystem services have relevance only to the extent human populations benefit from them. They are purely anthropocentric.”
Overuse and Degradation Indicate a Need to Value and Protect Ecosystem Services
According to the Millennium Assessment, human population and consumption levels have led to such a high level of demand for ecosystem services that tradeoffs are now the rule. For example, a hydropower project can mean the loss of flooding which supports a river’s downstream native biological diversity, nutrient deposition, and recreational values. Rising demand also translates into degraded services. For example, the overdrawn nature of many underground aquifers increases the depth and cost of drilling wells and can also affect terrestrial vegetation.
Although ecosystem services have long been recognized, teasing out the difference between what constitutes service versus function makes it difficult to adequately protect and plan for them. Free-market economies use a policy system that often relies on cost/benefit analysis to rationalize and justify regulation. If the economic value of an ecosystem service is unknown or in dispute, how can it hope to prevail against the meticulously calculated value of multimillion-dollar developments, new sources of fuel, or crops and forest products in high demand?
In short, recognition of the value of ecosystem services is growing worldwide. This growing awareness is spurring economic research into the costs of losing ecosystem services as well as the development of markets, such as pollutant trading schemes, to monetize them.
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