1. Chapter 7 Distribution and Abundance:
Most speciessmall geographical area, few wide spread
Polar specieslarger range
Widespread species are more abundant than species with small geographic range

2. Generalists: eat a variety of food Specialists: eat only a few food
Chapter Opener
Generalists: eat a variety of food
Specialists: eat only a few food
Rapport’s rule: from the polar to
the equatorial latitudes, mammal
geographic range sizes decreased.
Siberian Tiger: Km/night
Lion in Africa: km2

3. Figure 7-1
Moss, Tetraphis

4. Range size 1370 NA bird species Korean p: 220,000 km2
Figure 7-2
Range size
1370 NA bird species
Korean p: 220,000 km2
1499 vascular plant species (British)

5. Range size and latitude
Figure 7-3
Range size and latitude
523 species of N. American
mammals
South Korea: km2
Low latitude species have
Smaller ranges in N. America: following Rapport’s rule

6. Each points is one species n=81, Minimal at 10- 20: not
Figure 7-4
Each points is one species n=81,
Minimal at : not
supporting Rapport’s rule
Woodpeckers’ range

7. Not supporting Rapport’s rule
Figure 7-5
38 elevation classes
614 species of trees in
Himalaya in Nepal
Not supporting Rapport’s rule

8. Shallow marine fish Need data Blue: upper critical temp.
Figure 7-6
Need data
Shallow marine fish
Blue: upper critical temp.
Red: lower critical temp.
Tolerance of temp minimal
at polar and trophical.
Climatic variability hypothesis: temperate fish should
have the widest temperature limits

9. Interaction of topography and temp.
Figure 7-7
Interaction of topography and temp.
3839 species of native birds
in America.
Not supporting Rapport’s rule
Tsuga canadensis in Alabama

10. strongly in warmer climates
Figure 7-8
Lowland: <1000m
3839 bird species
from Americas,
Topography affects
range sizes much more
strongly in warmer climates
About 50 % (topography and temperature) about 50 % (biotic, glaciation, etc)

11. Range size and abundance?????? 263 species of British moth
Figure 7-9
Range size and abundance??????
263 species of British moth
More wide spread species
are typically more
abundant. Hanski’s rule
Each dot represents
one species.
=Hanski’s Rule
Distribution is the number of trap sites.

12. Range size and abundance
Figure 7-10
Range size and abundance
Geese and ducks
of the world.
More wide spread species
are typically more
abundant. Hanski’s rule

13. Ecological specialization model Local population model
Skip There are three main explanations of why distribution and abundance maybe correlated
Sampling model
Ecological specialization model
Local population model

14. Two closely related species in the two genera Draba and Erigeron
Figure 7-11
Two closely related species in the two genera Draba and Erigeron
Arrow: range of
rare species,
Rare species:
5 times
abundant
Arrow: range of
rare species,
Rare species:
twice abundant
The prediction of a strong positive relationship between
distribution and abundance does not always hold

15. Individual species declining in abundance
Figure 7-12
Individual species declining in abundance
Common species
rare species go in any direction

16. Negative relationship between abundance and distribution
Figure 7-13
Negative relationship between
abundance and distribution
Breeding Bird SURVEY
20 years of declining abundance
During the decline in abundance,
geographic range has been increasing.