Principles of terrestrial ecosystem ecology.pdf

Table 16.3. Examples of services provided by rivers,
lakes, aquifers, and wetlands.
Water supply
Drinking, cooking, washing, and other household uses
Manufacturing, thermoelectric power, and other
industrial uses
Irrigation of crops, lawns, etc.
Aquaculture
Supply of goods other than water
Fish
Waterfowl
Clams and mussels
Nonextractive or in-stream benefits
Flood control
Transportation
Recreational swimming, boating, etc.
Pollution dilution and water-quality protection
Hydroelectric generation
Bird and wildlife habitat
Enhanced property values
Nonuser values
Data from Postel and Carpenter (1997).
decisions often ignore the value of the resource
and assume that the ecosystem service was
“free” (Daily et al. 2000).
Valuation of ecosystem services is a way to
organize information to help make such decisions
(Daily et al. 2000).Valuation of ecosystem
services requires sound ecological information
and a clear understanding of alternatives and
impacts. Ecological understanding is critical, for
example, to characterize the services provided
by ecosystems and the processes by which they
Table 16.4. Examples of ecosystem
services and valuation
methods.
Integrative Approaches to Ecosystem Management 367
are generated. This information is frequently
site specific, so local ecological knowledge is
needed. Ecological and economic information
must then be integrated to make sound decisions.
Several approaches have been used to
assign economic value to ecosystem goods
and services. These include direct valuation
approaches, by which economic worth is
assigned according to avoided costs or to
market value, and indirect approaches, which
estimate the worth of a good or service through
surveys and contingent valuation (Goulder and
Kennedy 1997) (Table 16.4). Although the
methodology is still developing, economic
valuations of the provision of goods or services
have successfully contributed to decision
making about ecosystem management at a
variety of scales (Daily et al. 2000) (Box 16.3).
Valuation of goods and services requires
both their identification and an assessment
of their temporal and spatial variability, their
vulnerability to stresses, and the extent to
which they can be predicted using simulation
models or indicators. Ecologists often have a
sense for what allows an ecosystem or landscape
to provide a given service, but we have a
limited ability to quantify that service and to
predict it in the future. When, for example,
and under what conditions, will a watershed
provide clean water? Do all mangroves protect
shorelines?
Valuation of ecosystem services is often
applied to a single variable or resource (e.g.,
Service Valuation method
Inputs that support production
Pest control avoided cost
Flood control avoided cost
Soil fertility avoided cost
Water filtration avoided cost
Sustenance of plants and animals
Consumptive uses direct valuations based on market prices
Nonconsumptive uses indirect valuations (travel cost or
contingent aluation methods)
Provision of existence values indirect valuations (contingent valuation
method)
Provision of option values empirical assessments of individual risk
aversion
Data from Goulder and Kennedy (1997).