+

Community EcologyA biological community is an assemblage of

populations of various species living close enough for potential interaction

© 2011 Pearson Education, Inc.

+Figure 54.2

A. distichus perches onfence posts and othersunny surfaces.

A. insolitus usuallyperches on shadybranches.

A. ricordii

A. aliniger

A. insolitus

A. distichusA. christophei

A. cybotesA. etheridgei

Resource partitioning

+Figure 54.3

Chthamalus

Balanus

EXPERIMENT

Balanusrealized niche

Chthamalusrealized niche

High tide

Low tide

High tide

Chthamalusfundamental niche

Low tideOcean

RESULTS

Ocean

Resource Partitioning

Realized v Fundamental Niches

Competitive Exclusion

+Figure 54.4 G. fuliginosa G. fortis

Los Hermanos

G. fuliginosa,allopatric

G. fortis,allopatric

Sympatricpopulations

Santa María, San Cristóbal

Beakdepth

Beak depth (mm)161412108

0

20

40

60

0

20

40

60

0

20

40

60

Daphne

Per

cen

tag

es o

f in

div

idu

als

in e

ach

siz

e cl

ass

Character Displacement

+Figure 54.5

(a) Cryptic coloration (b) Aposematic coloration

Canyon tree frog Poison dart frog

(c) Batesian mimicry: A harmless species mimics a harmful one. (d) Müllerian mimicry: Two unpalatable species mimic each other.

Hawkmothlarva Cuckoo bee

Yellow jacket

Green parrot snake

+Interspecific competition

© 2011 Pearson Education, Inc.

+Figure 54.9

(a) Salt marsh with Juncus (foreground) (b)

With Juncus Without Juncus0

2

4

6

8

Nu

mb

er o

f p

lan

t sp

ecie

s

Facilitation

+Figure 54.10

Community 1A: 25% B: 25% C: 25% D: 25%

Community 2A: 80% B: 5% C: 5% D: 10%

A B C D

Species Richness and Relative Abundance

+Figure 54.11

Soil pH876543

2.2

2.4

2.6

2.8

3.0

3.2

3.4

9

Sh

ann

on

div

ers

ity

(H

)

3.6

RESULTS

+ Carnivore

Carnivore

Herbivore

Carnivore

Plant

A terrestrial food chain

Carnivore

Carnivore

Carnivore

Zooplankton

Phytoplankton

A marine food chain

Quaternaryconsumers

Tertiaryconsumers

Secondaryconsumers

Primaryconsumers

Primaryproducers

Figure 54.13

+Figure 54.14

Humans

Spermwhales

Smallertoothedwhales

Baleenwhales

Crab-eaterseals

Leopardseals

Elephantseals

SquidsFishesBirds

Carniv-orous

plankton

Cope-pods

Euphau-sids(krill)

Phyto-plankton

+Figure 54.17 EXPERIMENT

RESULTS

With Pisaster (control)

Without Pisaster(experimental)

Year

’73’72’71’70 ’69 ’68 ’67 ’66 ’65 ’64 1963 0

5

10

15

20

Nu

mb

er o

f sp

ecie

sp

res

ent

+Figure 54.18

(a) Sea otter abundance

(b) Sea urchin biomass

100

80

60

40

20

0O

tter

nu

mb

er(%

max

. co

un

t)

400

300200100

0Gra

ms

per

0.25

m2

Nu

mb

er p

er0.

25 m

2

02468

10

1972 1985 1989 1993 1997Year

(c) Total kelp densityFood chain

+Figure 54.19

Ecosystem Engineers

+Figure 54.22-4

Pioneer stage, withfireweed dominant

Spruce stage

Alaska

1760

GlacierBay

1860

1907

1941

Dryas stage

Alder stage

1

4

2

3

0 5 10 15Kilometers

Glacial retreat and primary succession: Glacier Bay, Alaska.

+

Successional stagePioneer Dryas Alder Spruce

0

10

20

30

40

50

So

il n

itro

gen

(g

/m2)

60

Figure 54.23

+Figure 54.27

(a) Immigration and extinction rates

Number of species on islandEquilibrium number

Ra

te o

f im

mig

rati

on

or

ex

tin

cti

on

(b) Effect of island size

Number of species on island

Ra

te o

f im

mig

rati

on

or

ex

tin

cti

on

Small island Large islandNumber of species on island

(c) Effect of distance from mainland

Far island Near island

(near i

sland)

Extinctio

n

Extin

ctio

n

(far i

slan

d)

(far island)

(near island)

Imm

igration

Imm

igration(la

rge

isla

nd)

Extinctio

n

Extin

ctio

n

(sm

all i

slan

d)

(small island)

(large island)

Imm

igrationImm

igration

Extin

ctio

nImm

igration

Ra

te o

f im

mig

rati

on

or

ex

tin

cti

on

Island Biogeogrpahy: Island Equilibrium Model

+

Area of island (hectares)(log scale)

Nu

mb

er

of

pla

nt

sp

ec

ies

(lo

g s

ca

le)

10 100 103

10

5

25

104 105 106

50

100

200

400

RESULTSFigure 54.28

Species Richness v Island Size in the Galapagos

+How is Lyme Disease a question for Community Ecologists?