Ecological Processes: The
Planet's Life Support System
Environmental Sustainability Educational Resources
prepared by
Gregory A. Keoleian
Associate Research Scientist,
School of Natural Resources and Environment
Co-Director, Center for Sustainable Systems
University of Michigan
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Contents
• Percent of Species at Risk of Extinction [slide 3]
• Ecology Definition [slide 4]
• Ecosystem Definition [slide 5]
• Definition of the Precautionary Principle [slide 6]
• Ecosystem Services [slide 7-8]
• What are ecosystems worth [slide 9-14]
• Biosphere 2 [slide 15-16]
• Ecosystem threats [slide 17-18]
• Endangered Species [slide 19-20]
• Exotic Species [slide 21-26]
• Carrying Capacity, Population and Ecological Footprint
[slide 27-30]
• Ecological Engineering [slide 31-32]
• Additional Resources [slide 33-34] 2
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Ecology Definition
―Ecology is the scientific discipline that is
concerned with the relationships between
organisms and their past, present, and future
environments.‖
Source: Ecological Society of America
4
Other Definitions
• Ecosystem
– any geographic area that includes all of the
organisms and nonliving parts of their physical
environment.
• Biodiversity
– Biological diversity, or biodiversity for short,
refers to the variety of life forms at all
levels of organization, from the molecular
to the landscape level.
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*Definition of the Precautionary
Principle
• Asserts there is a 'premium' on a cautious
and conservative approach to human
interventions in the natural environment
where our understanding of the likely
consequences is limited and there are
threats of serious or irreversible damage to
natural systems and processes. (As noted by
Myers 1993 in Barbier, Burgess and Folke
1994, 172).
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Ecosystems Services
(1 of 2 slides)
• moderate weather extremes and their impacts
• disperse seeds
• mitigate drought and floods
• protect people from the sun’s harmful ultraviolet rays
• cycle and move nutrients
• protect stream and river channels and coastal shores
from erosion
• detoxify and decompose wastes
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Ecosystems Services
(2 of 2 slides)
• control the vast majority of agricultural pests
• maintain biodiversity
• generate and preserve soils and renew their
fertility
• partially stabilize climate
• purify the air and water
• regulate disease carrying organisms
• pollinate crops and natural vegetation
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WHAT ARE ECOSYSTEM
SERVICES WORTH?
• Natural ecosystems and the plants and animals
within them provide humans with services that
would be very difficult to duplicate. While it is
often impossible to place an accurate monetary
amount on ecosystem services, we can calculate
some of the financial values.
• Many of these services are performed seemingly
for "free", yet are worth many trillions of dollars,
for example:
9
Flood Protection
• Much of the Mississippi River Valley’s natural
flood protection services were destroyed when
adjacent wetlands were drained and channels
altered. As a result, the 1993 floods resulted in
property damages estimated at twelve billion
dollars partially from the inability of the Valley to
lessen the impacts of the high volumes of water.
10
Source for Medicinal Products
• Eighty percent of the world’s population relies
upon natural medicinal products. Of the top 150
prescription drugs used in the U.S., 118 originate
from natural sources: 74 percent from plants, 18
percent from fungi, 5 percent from bacteria, and 3
percent from one vertebrate (snake species). Of
the top 10 prescription medicines, 9 originate from
natural plant products.
11
Pollination Services
• Over 100,000 different animal species - including
bats, bees, flies, moths, beetles, birds, and
butterflies - provide free pollination services. One
third of human food comes from plants pollinated
by wild pollinators. The value of pollination
services from wild pollinators in the U.S. alone is
estimated at four to six billion dollars per year.
12
Pure Water
• Before it became overwhelmed by agricultural and sewage runoff, the
watershed of the Catskill Mountains provided New York City with
water ranked among the best in the Nation by Consumer Reports.
When the water fell below quality standards, the City investigated
what it would cost to install an artificial filtration plant. The estimated
price tag for this new facility was six to eight billion dollars, plus
annual operating costs of 300 million dollars - a high price to pay for
what once was free. New York City decided instead to invest a
fraction of that cost ($660M) in restoring the natural capital it had in
the Catskill’s watershed. In 1997, the City raised an Environmental
Bond Issue and is currently using the funds to purchase land and halt
development in the watershed, to compensate property owners for
development restrictions on their land, and to subsidize the
improvement of septic systems.
13
Estimated Value
• Value of Ecosystem Services = $33 trillion
– range: 16 - 54 trillion
– 1.8 x Global GNP
• Majority of the value of these services is
outside the market system
source: Costanza, et al. Nature 1997
14
Biosphere 2
15
16
Ecosystem services are severely
threatened through:
• growth in the scale of human enterprise
(population size, per-capita consumption,
and effects of technologies to produce
goods for consumption) and
• a mismatch between short-term needs and
long-term societal well-being.
17
Human activities that disrupt,
impair, or reengineer ecosystems:
• runoff of pesticides, fertilizers, and animal wastes
• pollution of land, water, and air resources
• introduction of non-native species
• overharvesting fisheries
• destruction of wetlands
• erosion of soils
• deforestation
• urban sprawl
18
Endangered Species
• 735 U.S. species of plants are listed.
• 496 U.S. species of animals are listed.
• 11 U.S. species of plants are currently
proposed for listing.
• 74 U.S. species of animals are currently
proposed for listing.
19
Endangered
Florida panther
20
Exotic Species
• "Exotic" species—organisms introduced
into habitats where they are not native
– are severe world-wide agents of habitat
alteration and degradation.
– a major cause of biological diversity loss
throughout the world, they are considered
"biological pollutants."
21
• Invasive species threaten biodiversity,
habitat quality, and ecosystem function.
– second-most important threat to native species,
behind habitat destruction
• contributed to the decline of 42% of U.S.
endangered and threatened species.
– introduced species also present an ever-
increasing threat to food and fiber production.
– In the United States, the economic costs of
nonnative species invasions reach billions of
dollars each year.
22
Sea lamprey on lake trout
23
Lake trout with scar from
sea lamprey
24
Zebra mussels washed up on beach
25
26
Carrying Capacity
• Maximum population size that a given area
can sustain
• Estimate’s of the earth’s carrying capacity
vary widely
– ranging from 1 - 1000 billion people (Cohen
1995)
27
World Population Size:
Estimates and Fertility Variants (billions)
Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.
28
Source: Living Planet Report 2000
29
Have we exceeded the Earth’s
Carrying Capacity?
• In 1996 there were 2.2 ha per person of biologically
productive land on the planet
– a total of 12.6 billion hectares, covering 1/4 of the
Earth’s surface
• 1.3 billion ha cropland
• 4.6 billion ha grazing land
• 3.3 billion ha forest land
• 3.3 billion ha fishing grounds
• 0.2 billion ha built-up land
• World average footprint was 2.85 ha per person 30
Ecological Engineering
• defined as "the design of the human society with its natural
environment for the benefit of both" (Mitsch & Jorgensen,
1989).
• integrates various existing environmental fields such as
classical ecology, agro-ecology, and restoration ecology.
• used to design low-impact systems for waste treatment,
food and energy production, habitat restoration and other
benefits.
• should provide useful services for human society while at
the same time retaining their function as an ecosystem.
31
Constructed Wetlands for Wastewater Treatment
32
Additional Resources
• Ecology
– Ecological Society of America
• http://esa.sdsc.edu/
• Endangered Species
– US Fish and Wildlife Service
• http://endangered.fws.gov/wildlife.html
33
• Exotic Species
– Sea Grant
• http://www.seagrant.umn.edu/exotics/index.html
• Ecological Engineering
– International Ecological Engineering Society
• http://www.iees.ch/
– American Ecological Engineering Society
• http://swamp.ag.ohio-state.edu/ecoeng/AEES_a.html
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