1. Chapter 3
Ecosystem Ecology

2. Reversing the Deforestation of Haiti
Life prior to 2010 earthquake  hard
People use forest (wood) for fuel
Effects of relying on charcoal
Deforestation rate very high and not sustainable
Deforestation - disrupts ecosystem services
U.S. Agency for International Development – has funded planting of 60 million trees
More successful: planting mango trees
Looking to find/develop alternative fuel sources
Why talk about this? All ecosystems can be influenced by human decisions

3. Ecosystem Ecology Examines Interactions Between the Living and Non-Living World
Components of ecosystem are highly dependent on climate

4. Ecosystem Boundaries Ecosystem boundaries may or may not be defined
In most ecosystems it is difficult to determine where one ecosystems stops and the next begins
Boundaries are _________________________________

5. Large vs. Small Ecosystems:

6. Ecosystem Processes Important to remember:
Even though it is helpful to distinguish between two different ecosystems, ecosystems interact with other ecosystems.

7. Energy Flows through Ecosystems
Most energy on Earth comes from _____________________
Major Players:
Producers (autotrophs)
Consumers (heterotrophs)
Herbivores
Carnivores
Remember 2nd Law of Thermodynamics

8. Photosynthesis and Respiration
Photosynthesis – producers use solar energy to convert carbon dioxide and water to glucose and oxygen
Cellular respiration – process by which other organisms gain energy from eating the tissues of producers.
Overall, producers photosynthesize more than they respire
Plants are carbon “_________________________”

9. Remember these formulas!

10. Trophic Levels, Food Chains, and Food Webs
Consumers (heterotrophs)-
Primary Consumers (herbivores)-
Secondary Consumers (carnivores)-
Tertiary Consumers (carnivores)-
Rarer

11. Food Chain

12. Trophic Levels, Food Chains, and Food Webs
Food Chain- the sequence of consumption from producers through tertiary consumers
Food Web- a more realistic type of food chain that takes into account the complexity of nature

13. Food Web

14. Trophic Levels, Food Chains, and Food Webs
Some other important key players in food webs:
Omnivores – eats both plant and animal materials
Scavengers – consume dead animals
Detritivores – break down dead tissues and waste products into smaller particles
Decomposers – organisms that complete the breakdown process;
These are all very important!

15. Ecosystem Productivity
Life in an ecosystem is dependent on the amount of energy available
Gross primary productivity (GPP) - total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time
Net primary productivity (NPP)-
** NPP = GPP – respiration**

16. Ecosystem Productivity
Cannot just measure actual value – instead we determine the rate of photosynthesis and the rate of respiration to calculate this
Look in your textbook for more details!
NPP of ecosystems range from 25-50% of GPP
This is equivalent to about 0.25% of solar energy striking planet

17. NPP Varies Among Ecosystems

18. Energy Transfer Efficiency and Trophic Pyramids
Biomass –
Standing crop - amount of biomass present in an ecosystem at a particular time
Ecological efficiency -
Some energy lost
Fairly low numbers  5-20% range; average 10%

19. Energy Transfer Efficiency and Trophic Pyramids
THIS IS NOT IN YOUR TEXTBOOK:
Trophic pyramids - Graphically represent the relative energy value of each trophic level
Important feature is that large amount of energy are lost between trophic levels to heat
Three main types
Pyramid of numbers
Pyramid of biomass – only one Chapter 3 covers
Pyramid of energy

20. Pyramid of Numbers
Illustrates the number of organisms at each trophic level
Usually, organisms at the base of the pyramid are more numerous
Fewer organisms occupy each successive level
10 % rule
Do not indicate the biomass of the organisms at each level or the amount of energy transferred between levels

21. Pyramid of Biomass
Illustrates the total biomass at each successive trophic level
Biomass: measure of the total amt of living material
Biomass indicates the amount of fixed energy at a given time
10% rule
Illustrates a progressive reduction in biomass through trophic levels

22. Pyramid of Energy
Illustrates how much energy is present at each trophic level and how much is transferred to the next level
Most energy dissipates between trophic levels
Explains why there are so few trophic levels
Energy levels get too low to support life

23. Matter cycles through the biosphere
Biogeochemical cycles - The movement of matter within and between ecosystems involving biological, geologic and chemical processes
Involves biological, geological and chemical processes
Pools
Flows
Important chemical elements to life on Earth?

24. The Hydrologic Cycle

25. The Carbon Cycle

26. The Nitrogen Cycle

27. The Phosphorus Cycle

28. Homework: Check out page 73
Calcium, Magnesium, Potassium, and Sulfur:

29. Ecosystems respond to disturbance
How do these disturbances affect the flow of matter and energy through ecosystems?

30. Chandeleur Islands in LA
Almost completely submerged by Hurricane Katrina (2005)

31. Watershed Studies
Watershed- All of the land in a given landscape that drains into a particular stream, river, lake or wetland.
Common place for scientists to conduct ecosystem studies

32. Watershed Studies
One of most thorough examples: Hubbard Brook ecosystem of NH (since 1962)
Monitoring of the hydrological and biogeochemical cycles of 6 watershed at Hubbard Brook
Investigating effects of clear cutting and subsequent suppression of plant regrowth
Control area –
Experimental area –

33. Resistance versus Resilience
Not all disturbances = disasters
Resistance- A measure of how much a disturbance can affect its flows of energy and matter.
Resilience- The rate at which an ecosystem returns to its original state after a disturbance.
High resilient
Less resilient
Restoration ecology-

34. The Intermediate Disturbance Hypothesis
The intermediate disturbance hypothesis - states that ecosystems experiencing intermediate levels of disturbance are more diverse than those with high or low disturbance levels.

35. Ecosystems Provide Valuable Services
Instrumental value – when a species has worth as an instrument or tool that can be used to accomplish a goal
See next slide
Intrinsic value –
People who believe an ecosystem to be inherently valuable may argue we have a moral obligation to protect

36. Instrumental Values of Ecosystems
Estimated that ecosystem services are worth over $30 trillion per year
Provisions- Goods that humans can use directly
Regulating services- The service provided by natural systems that helps regulate environmental conditions
Support systems- The support services that natural ecosystems provide such as pollination, natural filters and pest control
Resilience- Resilience of an ecosystem ensures that it will continue to provide benefits to humans. This greatly depends on species diversity.
Cultural services- Ecosystems provide cultural or aesthetic benefits to many people.