Overview of Ecosystem Valuation

What are the Benefits of Ecosystem Conservation, Preservation, or Restoration?

Environmental initiatives can result in improvements that provide a wide range of economic and environmental benefits. Enumerating and measuring these benefits can be very difficult. This website provides guidance for estimating the dollar value of ecosystem benefits where this is possible, and guidance for developing non-monetary indicators of economic value where dollar measures are impossible or impractical.

Dollar Measures of Ecosystem Values:

Finding Appropriate and Practical Answers

The economic benefits of government spending raise legitimate and important public policy questions, but the answers are often ambiguous and difficult to justify. Agency staff may not always be able to provide acceptable answers - no matter how much money they spend on analysis. However, in the absence of objectively determined estimates of the benefits of environmental programs, spending decisions will be based on other factors.

This site addresses some of the important questions that agency staff must answer:

Why Estimate Ecosystem Values?

Faced with tightening budgets and growing needs for environmental actions, government agencies must make difficult decisions about how to allocate public investments to protect and restore the natural environment. In making such decisions, environmental program managers may consider many objectives, including environmental quality, threats to ecosystem integrity, and effects on people’s quality of life. This website will help those who need to make practical use of economics for these types of decisions.

Summary

Ecosystems are made up of abiotic (non-living, environmental) and biotic components, and these basic components are important to nearly all types of ecosystems. Ecosystem Ecology looks at energy transformations and biogeochemical cycling within ecosystems.
Energy is continually input into an ecosystem in the form of light energy, and some energy is lost with each transfer to a higher trophic level. Nutrients, on the other hand, are recycled within an ecosystem, and their supply normally limits biological activity. So, "energy flows, elements cycle".

The Geography of Ecosystems

There are many different ecosystems: rain forests and tundra, coral reefs and ponds, grasslands and deserts. Climate differences from place to place largely determine the types of ecosystems we see. How terrestrial ecosystems appear to us is influenced mainly by the dominant vegetation.

Controls on Ecosystem Function

Now that we have learned something about how ecosystems are put together and how materials and energy flow through ecosystems, we can better address the question of "what controls ecosystem function"? There are two dominant theories of the control of ecosystems. The first, called bottom-up control, states that it is the nutrient supply to the primary producers that ultimately controls how ecosystems function.

Biogeochemistry

How can we study which of these linkages in a food web are most important? One obvious way is to study the flow of energy or the cycling of elements. For example, the cycling of elements is controlled in part by organisms, which store or transform elements, and in part by the chemistry and geology of the natural world. The term Biogeochemistry is defined as the study of how living systems influence, and are controlled by, the geology and chemistry of the earth. Thus biogeochemistry encompasses many aspects of the abiotic and biotic world that we live in.

The Transformation of Energy

The transformations of energy in an ecosystem begin first with the input of energy from the sun. Energy from the sun is captured by the process of photosynthesis. Carbon dioxide is combined with hydrogen (derived from the splitting of water molecules) to produce carbohydrates (CHO). Energy is stored in the high energy bonds of adenosine triphosphate, or ATP (see lecture on photosynthesis).

Processes of Ecosystems

This figure with the plants, zebra, lion, and so forth illustrates the two main ideas about how ecosystems function: ecosystems have energy flows and ecosystems cycle materials. These two processes are linked, but they are not quite the same (see Figure 1).

Components of an Ecosystem

An ecosystem consists of the biological community that occurs in some locale, and the physical and chemical factors that make up its non-living or abiotic environment. There are many examples of ecosystems -- a pond, a forest, an estuary, a grassland. The boundaries are not fixed in any objective way, although sometimes they seem obvious, as with the shoreline of a small pond. Usually the boundaries of an ecosystem are chosen for practical reasons having to do with the goals of the particular study.

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