Community ecology: Size, Space, Distributions
Dr. Dan Simberloff
a) Darwin’s naturalization hypothesis
b) species/genus ratios and related statistics - islands
c) Gause’s competitive exclusion principle
d) limiting similarity
- invasion
e) priority effects
f) minimum size ratios, equal size ratios - islands
1903-1991
Peter Grant
*
“Species of similar size (body mass ratios
< 1.5 coexist less frequently in local
communities and overlap less in their
geographic distributions than expected
on the basis of chance, suggesting that
their co-occurrence is precluded by
interspecific competition.”
Smith, C.L. 1978. Coral reef fish communities: A compromise
view. Environmental Biology of Fishes 3(1): 109-128.
1975
Image from: Diamond, J.M. 1978.
Niche shifts and the rediscovery
of interspecific competition: Why
did field biologists so long
overlook the widespread
evidence for interspecific
competition that had already
impressed Darwin? American
Scientist 66(3): 322-331.
1994 American Naturalist
Dipodomys spectabilis, banner-tailed kangaroo rat
Dipodomys ordii, Ord’s kangaroo rat
Perognathus flavus, silky pocket mouse
Perognathus parvus, Great Basin pocket mouse
Dipodomys microps,
Dipodomys ordii,
chisel-toothed kangaroo rat
Ord’s kangaroo rat
Chihuahuan Desert
1968 Systematic Zoology
mainland:
island:
size
a) Darwin’s naturalization hypothesis
b) species/genus ratios and related statistics - islands
c) Gause’s competitive exclusion principle
d) limiting similarity
- invasion
e) priority effects
f) minimum size ratios, equal size ratios – islands
- character displacement and release
Bill Brown
1922-1997
Edward O. Wilson
1922-
Peter Grant
From Brown and Wilson 1956:
Systematic Zoology 1956
Ehrlich, P. and Holm, R. 1963. The process of evolution. New York:
McGraw-Hill.
from P. Grant 1972
Biol. J. Linn. Soc.
spread of the small Indian mongoose
grey mongoose +
ruddy mongoose +
small Indian mongoose
small Indian
mongoose alone
small Indian mongoose skull length
from Simberloff et al. 2000
a) Darwin’s naturalization hypothesis
b) species/genus ratios and related statistics - islands
c) Gause’s competitive exclusion principle
d) limiting similarity
- invasion
e) priority effects
f) minimum size ratios, equal size ratios
- islands; character displacement and release
g) displacement in morphospace
Bob Ricklefs
Joe Travis
Auk, 1980
Moulton, M.P. and Lockwood, J.L. 1992. Morphological dispersion of introduced Hawaiian finches:
Evidence for competition and a Narcissus effect. Evolutionary Ecology 6: 45-55.
a) Darwin’s naturalization hypothesis
b) species/genus ratios and related statistics - islands
c) Gause’s competitive exclusion principle
d) limiting similarity
- invasion
e) priority effects
f) minimum size ratios, equal size ratios
- islands; character displacement
g) displacement in morphospace
h) assembly rules/species combinations
1975
Jared Diamond
Diamond’s “community assembly rules”:
1975
“checkerboard
combinations”
- Diamond 1975, p.
423
Assembly rule # 5:
“Some pairs of species never coexist, either by themselves
or as part of a larger combination.”
= “checkerboard distributions”
Colored image from: http://www.ecologycenter.us/speciesrichness/evidence-from-negatively-associated-distributions.html
Ed Connor
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SITES
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Michael Collins
1
3
2
Malaita
4
San Cristobal
5
Rennell
Mayr, E. and Diamond, J. 2001. The Birds of Northern Melanesia. Oxford: Oxford University Press.
Checkerboard
Allopatry
Accipiter – 5 species, 5 checkerboards
1 = Bukida
3 = Malaita
2 = New
Georgia
4 = San
5
A. fasciatus only in Rennell group; no other species in Rennell group
4 checkerboards
Cristobal
Accipiter – 5 species, 5 checkerboards
A. imitator
= Bukida
= New
Georgia
= Malaita
= San
Cristobal
A. [gentilis]
A. fasciatus only in Rennell group; no other species in Rennell group
4 checkerboards
Accipiter – 5 species, 5 checkerboards
A. imitator
= Bukida
= New
Georgia
= Malaita
= San
Cristobal
A. [gentilis]
a) A. [gentilis] largely montane in Solomons; A. imitator in lowlands.
b) A. [gentilis] twice as big as A. imitator; different diet or foraging mode.
Gleaning flycatcher guild
5 species, 0 checkerboards
Monarcha. melanopsis
M. [manadensis]
Myiagra ferrocyanea
Pachycephala. implicata
P. pectoralis
Checkerboard
Allopatry
Barriers to dispersal across groups of islands may produce
regionally allopatric species