Ecosystem Ecology

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Ecosystem Ecology Instructor Terry
Chapin Office 195 Arctic Health Phone
474-7922 Email terry.chapin_at_uaf.edu Office
hours Tuesday 900 or arrangement Classes TTH
at 945-1115 in 214 ONeill Textbook Chapin,
F.S., III, P.A. Matson, and H.A. Mooney. 2002.
Principles of Terrestrial Ecosystem Ecology.
Springer-Verlag, New York.
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Date I. CONTEXT The Ecosystem concept
(Chapter 1) Sept. 6 Climate and ocean
circulation (Chapter 2) Sept. 11 Geology and
soils (Chapter 3) Sept. 13, 18 II.
MECHANISMS Photosynthesis (Chapters 5) Sept.
20 Ecosystem Water and Energy Balance (Chapter
4) Sept. 25, 27 MID-TERM EXAM Oct.
2 Plant production processes (Chapter 6) Oct.
4, 9 Decomposition (Chapter 7) Oct. 11,
16 Plant nutrient use (Chapter 8) Oct.
18 Nutrient cycling (Chapter 9) Oct. 23,
25 Aquatic Biogeochemistry (Chapter 10) Oct.
30 Trophic Dynamics (Chapter 11) Nov. 1,
6 Community Effects on Ecosystems (Chapter
12) Nov. 8 MID-TERM EXAM Nov. 13 III.
PATTERNS Temporal variation (Chapter 13) Nov.
15, 20 Landscape heterogeneity (Chapter
14) Nov. 27 IV. INTEGRATION Global cycles
(Chapter 15) Nov. 29, Dec. 4 Ecosystem
sustainability (Chapter 16) Dec. 6,
11 Review Dec. 13 Final exam Dec. 18
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Grading policy First mid-term 20 Second
mid-term 25 Two two-minute talks (ecobites)
10 One-page paper on a key concept (5) Final
30 Class participation 10
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Course Goals

• Get you excited!!
• Understand basic principles
• Ecological interactions
• Practical and conservation implications
• Be able to explain it to your grandmother
• Get you involved
• Participate!!!

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What do you want out of the course?
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Ecosystem Ecology

• Study of interactions among organisms and their
  physical environment as an integrated system

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What is an ecosystem?

• bounded ecological system consisting of all the
  organisms in an area and the physical environment
  with which they interact
• Biotic and abiotic processes
• Social processes?
• Pools and fluxes

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Simple ecosystem model
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How big is an ecosystem? Spatial scale
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Temporal Scale

• Instantaneous
• Rain effects on soil moisture
• Light effects on photosynthesis
• Predator effects on prey activity
• Question How does temperature affect carbon
  balance?

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Temporal Scale

• Instantaneous
• Seasonal
• Production exceeds herbivory in summer
• Herbivory exceeds production in winter
• Seasonal changes in ecosystem C balance
• Question How does temperature affect carbon
  balance?

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Temporal Scale

• Instantaneous
• Seasonal
• Succession
• What is relative importance of timing of
  establishment and relative growth rate of plants
  in explaining community composition?
• Question How does temperature affect carbon
  balance?

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Temporal Scale

• Instantaneous
• Seasonal
• Succession
• Species migration
• What controls ecosystem N inputs and
  productivity?
• Question How does temperature affect carbon
  balance?

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Temporal Scale

• Instantaneous
• Seasonal
• Succession
• Species migration
• Evolutionary history
• Are aspen clones adapted to current environment?
• Question How does temperature affect carbon
  balance?

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Temporal Scale

• Instantaneous
• Seasonal
• Succession
• Species migration
• Evolutionary history
• Geologic history
• What regulates the carbon distribution between
  land and oceans?
• Question How does temperature affect carbon
  balance?

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General approaches

• Systems approach
• Top-down approach
• Based on observations of general patterns

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General approaches

• Systems approach
• Top-down
• Based on observations of general patterns
• Mechanistic approach
• Bottom-up
• Based on process understanding

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Examples of ecosystem questions

• Whats the ecosystem?
• Whats the question?
• What are the pools and fluxes?
• What are appropriate temporal and spatial scales?
• What tools would you use?

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Levels of simplifying assumptions

• Equilibrium
• Steady State
• Dynamic change
• Alternative stable states

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Ecosystem components

• Plants
• Decomposers
• Animals
• Abiotic components
• Water
• Atmosphere
• Soil minerals

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(Spatial interactions)
(Long-term security)
(Fast response)
(Fast response)
(Slow variables) (Fast variables)
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Why should we care about ecosystem ecology?

• Ecosystem ecology provides a mechanistic basis
  for understanding the Earth System
• Ecosystems provide goods and services to society
• Human activities are changing ecosystems (and
  therefore the Earth System)

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Examples of ecosystem questions

• Whats the ecosystem?
• Whats the question?
• Do you assume equilibrium? steady state?
  alternative states?
• What state factors are most important? slow and
  fast variables?
• What are important feedbacks?
• What are potential thresholds?