1. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
3. Net Secondary Productivity
- assimilations efficiencies – A/I
carnivores: 80-90%
(no cell walls to deal with)

2. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
3. Net Secondary Productivity
- assimilations efficiencies – A/I
carnivores: 80-90%
seed eaters: 60-80%
herbivores grazers (leaf-eaters): 60-70%
browsers (woody twigs and buds): 30-40%

3. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
3. Net Secondary Productivity
- assimilations efficiencies – A/I
carnivores: 80-90%
seed eaters: 60-80%
herbivores grazers (leaf-eaters): 60-70%
browsers (woody twigs and buds): 30-40%
detritivores: 15%

4. Low AE? Must eat more to get energy needed.
Horse – ‘hindgut ruminant’ – less efficient, high throughput
Cattle – ‘foregut ruminant’ – more efficient, can eat less.

5. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
N:P :: 50:1
Ecosystem Ecology
I. Introduction
II. Energy Flow
A. Productivity
Only get twice the N they need.
3. Net Secondary Productivity
- affected by nutrient ratios, growth rates, and most limiting variable. May need to eat a lot to get enough of the limiting variable; but then may get too much of other stuff.
N:P :: 15:1
Get 6x the N they need
BOTH EAT PHYTOPLANKTON
(100:1 :: N:P)
Fast growing; need higher ratio of Phosphorus for DNA synthesis.

6. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
3. Net Secondary Productivity
- Net Production Efficiency = P/A

7. NSP
What might this depend on???
NPP

8. Ecosystem Ecology I. Introduction II. Energy Flow A. Productivity
0.5%
Birds
Ecosystem Ecology
I. Introduction
II. Energy Flow
A. Productivity
0.7%
Shrews
3. Net Secondary Productivity
- net production efficiency = P/A
6-10%
Most
Mammals
Up to 75% for sedentary poikilotherms

9. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids

10. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
- ecological efficiency: NSP/NPP (5-20%)
NPP of Secondary Carnivores
Loss due to 2nd Law
NPP of Primary Carnivores
NPP of HERBIVORES
NPP of Producers (PLANTS)

11. a. trophic "pyramids"
This is why large carnivores are RARE, and why they have large RANGES
NPP of Secondary Carnivores
Loss due to 2nd Law
NPP of Primary Carnivores
NPP of HERBIVORES
NPP of Producers (PLANTS)

12. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
Detrital Foodchains
Predators
Herbivores

13. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
Detrital Foodchains
NPP
Detritivores
Herbivores
Temperate forest: 1.5% - 2.5%
Old-field Habitat: 12%
Open Ocean (Plankton): 60-99%

14. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
Detrital Foodchains
‘Biomass Accumulation Ratios’
If we know the mean ‘standing crop’ of biomass from year to year, and we know the net productivity, we can calculate how long, on average the biomass persists:
BAR (per year) = (biomass/m2) / (npp of biomass / m2 / yr)

15. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
Detrital Foodchains
‘Biomass Accumulation Ratios’
If we know the mean ‘standing crop’ of biomass from year to year, and we know the net productivity, we can calculate how long, on average the biomass persists:
BAR (per year) = (biomass/m2) / (npp of biomass / m2 / yr)
Forests: ~ 20 years Tropical leaf litter: 3 months
Phytoplantkon: ~20 days Temperate leaf litter: 2-20 years

16. Ecosystem Ecology I. Introduction II. Energy Flow Productivity
Trophic Pyramids
Detrital Foodchains
BAR
Human Concerns

17. E. Human Concerns

18. E. Human Concerns: NPP

19. E. Human Concerns: NPP

20. E. Human Concerns
500% increase in 50 years, with population increase of 250%

21. E. Human Concerns
A doubling of meat production per capita

22. E. Human Concerns
25% of catch by weight discarded

25. E. Human Concerns

26. E. Human Concerns
6-10 lbs of feed for 1 lb increase in cattle weight
2-5 lbs of fish meal for 1 lb increase in farmed fish weight

27. input calories converted to calories able to be utilized by humans
Edible kilocalories produced from kilocalories of energy required for cultivation are:
18.1% for chicken,
6.7% for grass-fed beef,
5.7% for farmed salmon
0.9% for shrimp.
123% for potatoes
250% for corn
415% for soy
input calories converted to calories able to be utilized by humans
E. Human Concerns
So, for every 100 calories of energy we put in to raise chickens, we get 18 calories of energy produced in chicken meat cal into soy, 415 calories out.

28. E. Human Concerns
Food production, per capita
(400 kg per year is healthy minimum)

29. SO HOW DID WE DO IT?

30. E. Human Concerns
EXTENSIFICATION – MORE AREA

31. E. Human Concerns
EXTENSIFICATION – MORE AREA

32. E. Human Concerns
The best land has already been used; further expansion in marginal areas is costly and requires more supplementation

33. E. Human Concerns
47% of historical forested land has been converted
21% is ‘virgin forest’

34. E. Human Concerns
INTENSIFICATION – yield=kg/m2 area

35. E. Human Concerns

36. E. Human Concerns
The best land has already been used; further expansion in marginal areas is costly and requires more supplementation. Also, degraded soils require supplementation

37. E. Human Concerns
Global NPP (dry mass) = 224 billion tons. 59% is terrestrial, and of this, 35-40% is controlled by humans, either eaten directly or fed to animals we will consume
1 species
10-30 million species