Environmental Engineering Reference
In-Depth Information
considerable: it has been assessed in the billions of U.S. dollars (Costanza et
al. 1997; Daily 1997).
Consideration of ecosystem serv-
ices fall into two broad categories.
The first category—material goods—
subsumes contributions with tangible
financial value such as new, improved
foods, plant based pharmaceuticals,
germ plasm infusion for agriculture,
raw materials for industry, bioenergy,
and so on.These goods can be traded
on markets and the markets set values
directly through supply and demand pricing.The second category—func-
tions—typically do not have a direct marketable value because they cannot
be easily sold. Functions contribute toward economic and financial well-
being by sustaining components of ecosystems on which major economies
depend (e.g., soil production for farming, clean drinking water, etc.); or by
creating opportunities to reduce production costs within those economies
(e.g., the above case of herbivore-mediated boreal forest regeneration). In
the case of nonmarketable services, the linkages between biodiversity and
functions are often less immediate or less direct than they are for material
goods and so the linkages require some elaboration—the purpose of this
chapter.
Ecosystem functions are both diverse and ubiquitous.The nature and
level of the function varies with the make-up and diversity of species in an
ecosystem. Ecologists have identified upward of nine classes of function
ranging from sustaining ecological cycles (e.g., carbon and nitrogen) to
maintaining long-term sustainability of ecosystems (Myers 1996). Below, I
highlight specific examples from five categories that have been the focus
of experimental research.
The recognition that biodiversity
offers humankind important servic-
es has led to a sea change in think-
ing about the linkages among bio-
diversity, ecosystem function, and
the economic value of services aris-
ing from those functions.
•
Ecosystem stability and resilience
•
Biomass production and minimizing production costs
•
Crop pollination
•
Pest control
•
Resisting invasive species
