Community Ecology
I. Introduction
II. Multispecies Interactions with a Trophic Level
III. Multispecies Interactions across Trophic Levels
IV. Succession
V. Biodiversity: Patterns and Processes
A. The Species-Area Relationship
1. The pattern
2. The Theory of Island Biogeography
3. Why is this important? Fragmentation
4. The SLOSS debate
- The SLOSS Debate
- So, to preserve biodiversity (and the
ecosystem services it provides to humanity),
conservationists began to consider the best strategy
for maximizing the preservation of diversity...should
we preserve several small areas, or a single large
one?
- Why is this important?
- Conserving Diversity: the SLOSS debate
• Large > Small
• Minimize Edge
• Clumped
• Corridors
Wilson and Willis (1975)
- Why is this important?
Number of Species
- Conserving Diversity: the SLOSS debate
Area in Square Meters
Simberloff and Gotelli (1983)
BUT! Can we maintain all the species if they live on
different islands?
A
B
C
D
E
F
G
H
A
All species
preserved while
accommodating the
species area effect!
B
CD
EFG
H
- BUT! Can we maintain all the species if
they live on different islands?
- Probably not, because communities are
NESTED.
A
B
C
D
E
F
G
H
A
B
CD
EFG
H
- BUT! Can we maintain all the species if
they live on different islands?
- Probably not, because communities are
NESTED.
Nested Subset Structure: Species on speciespoor islands are also found on species-rich islands.
A
B
C
D
E
F
G
H
A
B
CD
EFG
H
- BUT! Can we maintain all the species if
they live on different islands?
- Probably not, because communities are
NESTED.
Nested Subset Structure: Species on speciespoor islands are also found on specie-rich islands.
NOT NESTED
A
B
C
D
E
F
G
H
A
B
A
CD
EFG
NESTED
A
AB
H
ABC
A
Community Ecology
I. Introduction
II. Multispecies Interactions with a Trophic Level
III. Multispecies Interactions across Trophic Levels
IV. Succession
V. Biodiversity: Patterns and Processes
A. The Species-Area Relationship
1. The pattern
2. The Theory of Island Biogeography
3. Why is this important? Fragmentation
4. The SLOSS debate
5. Nestedness
- Why is this important?
- Conserving Diversity: the SLOSS debate
NESTED-SUBSET STRUCTURE:
(Darlington
1957, Patterson
andand
Atmar
- "Nestedness"
(Darlington
(1957); Patterson
Atmar 1986)
(1986)
A B C D E
Communities are ‘nested’ if the
species in depauperate
assemblages are also found in
progressively more species rich
communities
A B C
A
A B CD
NESTEDNESS
(Patterson and Atmar 1986)
ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWX
ABCDEFGHIJKLMNO+QRSTUVWX
ABCDEFGHIJKLMNOPQRSTU+
ABCDEFGHIJKLM+OPQRST +
ABCDE+GHIJK++ NOP +
ABCDE+G+IJK++ NO+Q+
V
ABCDE++ HIJKL+ NO+ +
A B C D E F G H + +K L + + O P +
ABCDEFG+IJK ++ + + +
ABCDEFGHIJ ++ + + +
ABCDEFG+++ +M+
R
ABCDEF+H++ L ++ P
ABC+E+
IJ + N
ABCDEF
I
+
ABCDEF
+M
ABCDE+G
+M
ABCDEF H
+
ABCDEF H
+
ABCDEF
+
ABCD+F
L
ABCDE+
ABC ++F
L
AB+DE
AB +
F
AB +
C
C
26
24
23
21
19
13
14
12
11
10
10
9
9
7
7
7
7
7
7
6
6
5
5
4
3
2
1
1
NESTEDNESS AND NICHE SPACE
(Kodric-Brown and Brown 1993)
Goby
Gudgeon
Catfish
Hardyhead
Perch
111111111111111111111111111
111111111111111111
11111111111111
111111 111
1111111
NESTEDNESS AND NICHE SPACE
(Kodric-Brown and Brown 1993)
Goby
Catfish
Gudgeon
Hardyhead
Perch
- Why is this important?
- Conserving Diversity: the SLOSS debate
- "Nestedness" (Darlington (1957); Patterson and Atmar (1986)
- Fragmentation causes decreased diversity
- non-random loss of predators
- subsequent declines – keystone effects
- Why is this important?
- Conserving Diversity: the SLOSS debate
- "Nestedness" (Darlington (1957); Patterson and Atmar (1986)
- Fragmentation causes decreased diversity
- increased stress decreases diversity non-randomly
MYCOPHAGOUS FLY COMMUNITIES:
SPECIES-AREA AND NESTEDNESS PATTERNS
(Worthen, Carswell and Kelly 1996)
•
Small (4-6g)
•
Medium (10-15g)
•
Large (21-32g)
MYCOPHAGOUS FLY COMMUNITIES:
SPECIES-AREA AND NESTEDNESS PATTERNS
(Worthen, Carswell and Kelly 1996)
LLLLLLL LLL
LLL
MMMMM
S
L
M
MM
SS
L
MMMMMMM
S
SSSS
RICHNESS
554444444444433332222 22211111111111111
Phorid sp.
D. putrida
L. varia
D. tripunctata
M. dimidiata
D. falleni
Muscid sp.
Leptocera sp. ‘B’
Leptocera sp. ‘A’
1111+1111111111111111 111
111111111111
111+111111111+1111111 1
+1 1 1 1 1 11 1 1 1 1 11 + 1 1+ ++ ++ 1 1 11
11++++++1111111
11
1
++
1
1
++ 1
1
1+
1
++ 1 1
MYCOPHAGOUS FLY COMMUNITIES:
DIFFERENCES IN DESICCATION TOLERANCE?
(Worthen and Haney 1999)
41.5
D. putrida
41.0
40.5
D. falleni
40.0
D. tripunctata
39.5
39.0
13
15
20
25
30
33
o
ACCLIMATION TEMPERATURE (oC)
EFFECT OF DESICCATION ON NESTEDNESS
(Worthen, Jones and Jetton 1998)
76 6 6 5 5 5 5 5 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
L. varia
Phorid
D. falleni
Muscid
D. putrida
1x x1 1 1 1 1 1 1 1x1 x 1 1 1 x 1 1 x 1 1 1 1 1x x x x x 1 x 1 x x1 1
1111111111
x1 1 1 1 x x x 1 x 1 1 1 1 1 x 1 x x 1 1 1 x x 1 x x x x x x x 1 x 1 1 1 1
1111
1x 1 1 1 1 1 1 1x x x1 x 1 1 x1 1 x x x 1 1 x
11
11
11 1 1x 1 1 1 1x x xx 1 x1 xx xx 1 xx 1 1
1
1
1x 1 x 1 1 1 1 1 1 x x x x x 1 x1 x x x x1 x x
111
Mycetophilid
xx x1 x x x 1 x x x x x x 1 x x x x x x 1 x x x x x x1 x x 1 1 x x x x x
1111
S. alternatus
11 1 1x 1 1x x1 xx x 1 x xx xx xx x x xx x1 x xx xx x xx xx x 1
Tipulid
11 1xx x xx xx 1 1 x 1 xx xx xx 1 x x xx xx 1 x xx xx x xx xx 1
D. tripunctata x x x x 1 x x x x x 1 x 1 x x x 1 1 1
M. dimidiata x x x x x x x x x x 1 1 x x x x x x x x x x x x x 1
Cecidomyiid 1 1 x x x x x x x x x x x x x x x x x x x x x x x 1
D. neotest.
x1 x x x x x x x 1 x x x x x x1
N = 231
P&A (1986) RANDOM1 = 265.4 + 23.4
z = -1.45 ns
EFFECT OF DESICCATION ON NESTEDNESS
(Worthen, Jones and Jetton 1998)
4432222222222111111111111111111
L.varia
Phorid
Muscid
Tipulid
D. putrida
M. dimidiata
Psychodid
S. alternatus
N = 22
1x11xx1111111
1111111
x1xx11xxx 1111
11111111
1xxxxx111 xxxx111
x11 11
11x1
xx1
1
1
P&A (1986) RANDOM1 = 45.1 + 10.5
z = -2.15*
THE EFFECT OF AN INDUSTRIAL SPILL ON THE
MACROFAUNA OF THE UPPER ENOREE
(Worthen, Haney, Cuddy, Turgeon and Andersen 2001)
The Upper Enoree River
NESTEDNESS, STRESS, AND THE STRUCTURE OF
LARVAL ODONATE ASSEMBLAGES
C9 C8 T4
Distance
Richness
7.2
7
6.3
5
C7 C6 C5 C4 T1
3
4.7
3
3.4
3
2.4
3
1.8
3
T2
2
T3
1
C3
1
0.7
1
N
Cordulegaster
Progomphus
Macromia
Boyeria
Gomphus
Stylurus
Hagenius
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
x
1
1
1
x
1
1
1
x
1
1
1
1
1
1
x
1
1
1
1
R1 = 10.41 + 3.78;
N = 4, ns
x + 1.96 sd = 2.59 to 17.82
Not nested
1
0
0
0
4
0
0
0
NESTEDNESS, STRESS, AND THE STRUCTURE OF
LARVAL ODONATE ASSEMBLAGES
C9 C8 C7 C6 C5 C4 C3
Distance
Richness
7.2
7
6.3
5
4.7
3
3.4
3
2.4
3
1.8
3
0.7
1
N
Cordulegaster
Progomphus
Macromia
Boyeria
Gomphus
Stylurus
Hagenius
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
R1 = 3.00 + 1.50;
N = 0, p < 0.05
x + 1.96 sd = 0.04 to 8.98
Nested
0
0
0
0
0
0
0
Summary: Causes of nestedness
- nested niche space
- differences in dispersal capabilities
-differences in extinction probabilities
As these are the same factors that cause the species-area relationship,
itself, we should not be surprized that communities distributed across
habitats of different size are often nested, too.