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Ecological Processes: The Planet's Life Support System

Environmental Sustainability Educational Resources

prepared by

Gregory A. KeoleianAssociate 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]

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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

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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:

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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.

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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.

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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.

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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.

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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

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Biosphere 2

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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.

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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

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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.

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Endangered

Florida panther

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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."

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• 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.

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Sea lamprey on lake trout

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Lake trout with scar from sea lamprey

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Zebra mussels washed up on beach

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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)

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World Population Size: Estimates and Fertility Variants (billions)

Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

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Source: Living Planet Report 2000

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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

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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.

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Constructed Wetlands for Wastewater Treatment

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Additional Resources

• Ecology – Ecological Society of America

• http://esa.sdsc.edu/

• Endangered Species– US Fish and Wildlife Service

• http://endangered.fws.gov/wildlife.html

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• 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