Lecture 8: Succession and

Wed, January 28, 2010

9:00	1. Succession	Reading for today was Chapter 9.
	2. pulsing
	3. intermediate disturbances
	4.importance of biodiv
	5.values and ethics
	6.Losses and protection
	7. species recovery efforts

 

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

 

2. "Pulsing"

pulsing view

 

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

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

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

 

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)

7. Efforts to preserve species

gene or seed banks

• Berry Botanic Garden
• restoration efforts require banks of native seeds

breeding and reintroduction efforts

• Oregon Zoo
• silverspot butterfly
• tamarin
• condors- seminar on Friday 1/29 about condors
• video

 

8. The precautionary principle

decision standard that may apply