Lecture 8: Succession and
Wed, January 28, 2010
9:00 |
1. Succession |
Reading for today was Chapter 9.
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2. pulsing |
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3. intermediate disturbances |
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4.importance of biodiv |
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5.values and ethics |
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6.Losses and protection |
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7. species recovery efforts |
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1. Succession
the shifts in communities over time with a particular direction toward more complex and higher biomass communities
paradox -
- in a highly competitive world
- Why would one species prepare the environment so that another species displaces it?
primary succession - traditional view
- pattern
- gross production - respiration = net production
- secondary succession - starts with substantial natural capital
comparison of immature and marure communities
as a metaphor for the "green" economy
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2. "Pulsing"
pulsing view
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3. Intermediate disturbance hypothesis
the idea of "balance of nature" shows up many places
- equilibrium (no further change) or steady-state (same flux forward and backward)
- carrying capacity as a set level of the population
- "circle of life" - what is taken will be replaced (Disney)
- the evolution or adaptation of species to fit the environment nearly perfectly "molecular efficiency" or the "modern synthesis" in molecular biology
continual small disturbances create openings that are refilled
- allows a self-adapting complex system to respond
- leads to a landscape mosaic link
- network theory of shifting linking through preferential attachment
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4. Importance of biodiversity
as a form of natural capital
provides services and products
- go to Millenium Ecosystem Assessment
- 102/lab/short ppt
more diverse communities often have more ability to withstand stress
- resilience
- grasslands and drought
- aquatic envirornments with marsh, lake, streams
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5. Values and Ethics
in this context
values
- instrumental
- use values and non-use values
ethics
- what are the rights of a species or organism to exist
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6. Losses and protection
protection
- threatened - may decrease in level to become endangered
- endangered - may become extinct
- Endangered Species Act
- market forces
loss - major drivers of loss and extinction
- H - habitat
- I - invasives
- P - population (human)
- P - pollution
- C - climate change
- O - over exploitation
habitat
- loss of area
- degradation of quality
- fragmentation
- network connectivity (more in next lecture)
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7. Efforts to preserve species
gene or seed banks
breeding and reintroduction efforts
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decision standard that may apply
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