1. Climate and Biomes
Evolution and Adaptation
Population Ecology

2. Attributes of Populations
Population Ecology
Attributes of Populations
- Population: A group of potentially interbreeding organisms at the same time and place, that share a common gene pool.
- Population size : number of individuals
- Population Growth Rate: change in number over time, as a function of
(birth +immigration)- (death + emigration)
- Population density : number per unit area
- Range/distribution: geographic area over which the individuals are dispersed.
- Population Structure:
- age class structure
- sex ratio
- genetic structure
- spatial structure (pattern of how individuals are distributed through the range)

3. Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance – the Niche Concept
Fremont’s Leather flower

4. Attributes of Populations Distributions A. Determining Factors
Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance
range
Realized and fundamental niches
Zones of optima, tolerance, intolerance
soil moisture
temperature
performance
Typically, populations have higher density under optimal conditions

5. Attributes of Populations Distributions A. Determining Factors
Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal

6. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration

7. 1. Environmental Tolerance North Sea bottom trawl data
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change
North Sea bottom trawl data
Increase in southerly species of little commercial value; decrease in abundance of commercially valuable north sea species
(dogfish, ling)

8. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change
Changes in elevational range
cooler
warmer

9. Craig Moritz,1,2. James L. Patton,1,2 Chris J. Conroy,1 Juan L
Craig Moritz,1,2* James L. Patton,1,2 Chris J. Conroy,1 Juan L. Parra,1,2 Gary C. White,3 Steven R. Beissinger1, Impact of a Century of Climate Change on Small-Mammal Communities in Yosemite National Park, USA. Science 322:

10. Craig Moritz,1,2. James L. Patton,1,2 Chris J. Conroy,1 Juan L
Craig Moritz,1,2* James L. Patton,1,2 Chris J. Conroy,1 Juan L. Parra,1,2 Gary C. White,3 Steven R. Beissinger1, Impact of a Century of Climate Change on Small-Mammal Communities in Yosemite National Park, USA. Science 322:

11. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change
5. Niche Modeling and Invasive Species

12. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.

13. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.
Invaded 40 yrs ago – aquarium plant dumped into canals in Florida

14. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.

15. Problems:
Doesn’t account for biological aspects of the environment
- maybe the native range is limited by competition/predation
- separated from that competitor/predator, the range may increase
Water Hyacinth
“Biological Control Agent”
Neochetina eichhorniae

16. Problems:
Doesn’t account for biological aspects of the environment
- maybe the native range is limited by competition/predation
- separated from that competitor/predator, the range may increase
Doesn’t account for the possibility of adaptation
gypsy moth spread
1868 – Medford, MA

17. A. Determining Factors
B. Dispersion – how organisms in a population are spaced

18. B. Dispersion
- Regular
Low variance

19. B. Dispersion - Regular - intraspecific competition - allelopathy
- territoriality

20. B. Dispersion - Clumped - patchy resource - social effects
- limited dispersal
High variance

21. B. Dispersion - Random - canopy trees, later in succession
Normal distribution

22. B. Dispersion
- Complexities
Varies with type of dispersal

23. B. Dispersion
- Complexities
Varies with life-history stage

24. B. Dispersion - Complexities
Varies with spatial scale and resource distribution

25. 1. Correlates with Niche Parameters – greatest at center of range
C. Population Density
1. Correlates with Niche Parameters – greatest at center of range
Density of Dickcissel, a prairie songbird

26. C. Population Density 2. Habitat Selection
Fretwell – Lucas model of habitat selection (1972)

27. 3. Maintenance of Marginal Populations
C. Population Density
3. Maintenance of Marginal Populations
Why don’t these adapt to local conditions?

28. D. Modeling the Spatial Structure of Populations
1. Metapopulation Model
Subpopulation inhabit separate patches of the same habitat type in a “matrix” of inhospitable habitat..
- immigration causes recolonization of habitats in which population went extinct. So, rates of immigration and local extinction are critical to predicting long-term viability of population.

29. D. Modeling the Spatial Structure of Populations 2. Source-Sink Model
Subpopulations inhabit patches of different habitat quality, so there are ‘source’ populations with surplus populations that disperse to populations in lower quality patches (‘sinks’).

30. D. Modeling the Spatial Structure of Populations 3. Landscape Model
Subpopulations inhabit patches of different habitat quality, so there are ‘source’ populations with surplus populations that disperse to populations in lower quality patches (‘sinks’). However, the quality of the patches is ALSO affected by the surrounding matrix… alternative resources, predators, etc. And, the rate of migration between patches is also affected by the matrix between patches… with some areas acting as favorable ‘corridors’

31. E. Macroecology
“Top-down” approach – what can the large scale patterns in abundance, density, and diversity tell us?

32. E. Macroecology 1. Some General Patterns
- Species with high density in center of range often have large ranges

33. E. Macroecology 1. Some General Patterns
- Species of large organisms have smaller populations

34. E. Macroecology 1. Some General Patterns
- And of course, food limits size/density relationships

35. E. Macroecology 1. Some General Patterns
- energy equivalency rule: pop’s of biologically similar organisms consume the same amount of energy/unit area, but process it in different ways depending on body size….LATER

36. E. Macroecology 2. The shapes of ranges
- Abundant species have ranges running E-W; rare species have N-S ranges

37. E. Macroecology 2. The shapes of ranges
So, if a species has an E-W range, it will probably cross many habitats; signifying that the species is an abundant generalist.

38. E. Macroecology 2. The shapes of ranges
So, if a species has an E-W range, it will probably cross many habitats; signifying that the species is an abundant generalist.
If a species has a N-S distribution, it may be a rare specialist limited to one habitat zone.

39. E. Macroecology 2. The shapes of ranges
So, if a species has an E-W range, it will probably cross many habitats; signifying that the species is an abundant generalist.
If a species has a N-S distribution, it may be a rare specialist limited to one habitat zone.
An independent test would be to make predictions about Europe.

40. E. Macroecology 2. The shapes of ranges
An independent test would be to make predictions about Europe.

41. E. Macroecology 2. The shapes of ranges
An independent test would be to make predictions about Europe.
Abundant species run N-S, and rare species run E-W, as predicted by topography and the generalist-specialist argument.