Chapter 6: Biotic Resources
(A Tired Planet)
Ecosystem Structure & Function
•Ecosystem structure refers to the individuals and communities
of plants and animals of which an ecosystem is composed , plus
their age and distribution, and the associated abiotic resources
•Ecosystem functions can be
thought of as emergent
phenomena; these functions
create a whole that is greater
than the sum of its individual
parts
•Example: coral reefs
Interlude: Risk, Uncertainty, Ignorance
Risk: You know the possible outcomes and the probabilities. A
calculable, insurable cost.
(50% chance of dying by age 60 for a smoker)
Pure uncertainty: You know the possible outcomes, but not the
probabilities
(March Madness brackets)
Absolute uncertainty: You don’t even know the possible outcomes
(What will a collapsed ocean ecosystem look like?)
Renewable Resources
Renewable resources are the elements of ecosystem structure
that provide the raw materials for economic processes
Fish, Timber, Soil, Air, Water…
Growth/Sustainable Yield Curve
•Critical Concepts:
•Sustainable yield is the net annual reproduction from a given stock
•Critical dispensation point (minimum viable population)
•Carrying capacity (equilibrium around which a population has stabilized)
•Usefulness
•Pedagogical device
•Idea of maximum sustainable yield
•Concept of harvest in proportion to
resource stocks
•Drawbacks
•High degree of uncertainty: population, reproductive rates, external factors
•Dynamic process
•Not useful for setting quotas
Ecosystem Services
1. Ecosystems are funds that provide services.
2. Ecosystems renew by capturing solar energy.
3. Ecosystem services, unlike man-made fund-services, do
not ‘wear out.’ They also cannot be stockpiled.
4. However, we cannot predict how our presence, use, and
abuse impacts a complex ecosystem.
5. Keep in mind that situation matters: a degraded,
stressed forest in an urban setting might be more useful
than one hundreds of miles away in a park…
Ecosystem Services
•“It is impossible to create something from nothing; all economic
production requires a flow of natural resources generated by a stock of
natural capital…Even abiotic stocks (i.e., elements and fossil fuels) can
only be extracted and consumed at some cost to the ecosystem. In
other words, production requires inputs of ecosystem structure.
Ecosystem structure generates ecosystem function, which in turn
provides services. All economic production thus has an impact on
ecosystem services, and because this impact is unavoidable, it is
completely internal to the economic process.” (Daly & Farley 107)
Ecosystem Services
Ecosystem services are ecosystem functions that have value to human
beings.
•Carbon sequestration by forests
•Climate regulation
•Storm protection
•Water supply protection
•Pollination
•Erosion control
When we fail to appreciate ecosystem services…
•Dust Bowl
•2006 tsunami
•India’s dead cows
(http://www.nytimes.com/2006/03/28/international/asia/28vultures.html)
Waste Absorption Capacity
Raw materials are converted into high-entropy waste.
Waste absorption capacity is fixed; waste flows are determined by us.
Greater capacity to absorb biological waste (evolution!!) than manmade chemical waste.
Great Pacific Garbage Patch
80% of ocean trash originates on
land
90% of ocean trash is plastic
20 billion pounds per year of trash
ends up in the ocean
Ocean Ecosystem Services
More diverse ocean ecosystems are more stable and more productive.
Oceans and coastal ecosystems provide:
•Food source
•Waste absorption, waste detoxification, filtering
•Flood control
•Nutrient cycling
•Cultural/aesthetic values
(Worm et al. 2006, Science)
Oceans & Maximum Sustainable Yield
When we harvest biological stock from an ecosystem, we are changing
the capacity of the ecosystem to produce more stock & the capacity for
the ecosystem to provide services critical to our survival.
30% of currently fished species considered collapsed in 2003
Predicted collapse of all currently fished species by 2048 (Worm et al
2006)
http://endoftheline.com/
Have we reached the critical depensation point?
Biosphere II
http://en.wikipedia.org/wiki/Biosphere_2
• Biosphere 2 is a 3.14acre (12,700 m2)[1]
structure originally built
to be an artificial,
materially-closed
ecological system in
Oracle, Arizona
• $200 Million to provide
ecosystem services for 8
people.
• And yet… It failed.
What does the word “Hubris” mean?