Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1Slide 1

CHAPTER 7: COMMUNITY ECOLOGY

STRUCTURESPECIES INTERACTION

SUCCESSIONSUSTAINABILITY

Slide 2Slide 2Slide 2Slide 2Slide 2Slide 2Slide 2

COMMUNITIES AND STRUCTURE

ISLAND BIOGEOGRAPHY

SPECIES TYPES IN COMMUNITIES

SPECIES INTERACTIONS

PLANT SUCCESSION

STABILITY AND DISTURBANCE

TOPICS AND CONCEPTS CHAPTER 7

Slide 3Slide 3Slide 3Slide 3Slide 3Slide 3Slide 3

COMMUNITY STRUCTURE

Structure can be thought of as:Physical – for example the diameter of trees, canopy cover and layers of vegetation or tree partitioning by various animal species such as finches.Spatial patterns – populations dispersed randomly, clumped or uniformly.Biodiversity

Abundance - the number of individuals of a species in an areaRichness - the number of different species in an area which is a

useful measure of the variety of ecological niches or genetic variation in a community. It decreases as we go from the equator towards the poles

Genetic – gene frequency; number of alleles, etc.Habitat changes – frequency of habitat changes through a fixed distanceTrophic level complexity – number of food chains (webs) in a systemNumber and types of services provided by natural capital – for example water purificationProductivity (discussed in chapter 4, pp. 79-81)

Slide 4Slide 4Slide 4Slide 4Slide 4Slide 4Slide 4

mft

10

50

20

30100

Tropicalrain forest

Coniferousforest

Deciduousforest

Thornforest

Tall-grassprairie

Short-grassprairie

Desertscrub

Thornscrub

Figure 7-2Page 141

COMPARISON OF PHYSICAL STRUCTURE OF THE WORLD'S TERRESTRIAL BIOMES

Slide 5Slide 5Slide 5Slide 5Slide 5Slide 5Slide 5

Click to view animation.

Species by latitude animation.

Animation

Slide 6Slide 6Slide 6Slide 6Slide 6Slide 6Slide 6

Figure 7-3Page 142

Sp

ecie

s D

iver

sity

Sp

ecie

s D

iver

sity

1,000

100

10

Latitude

80ºN 60 40 20 0

200

100

0

90ºN 60 30 0 30ºS 60

Latitude

WHAT AFFECTS BIODIVERSITY? LATITUDE?

Slide 7Slide 7Slide 7Slide 7Slide 7Slide 7Slide 7Number of individuals per diatom species

Nu

mb

er o

f d

iato

m s

pec

ies Unpolluted

stream

Pollutedstream

Figure 7-4Page 142

HOW DOES POLLUTION AFFECT DIVERSITY?

Slide 8Slide 8Slide 8Slide 8Slide 8Slide 8Slide 8

1000Percentage disturbance

Sp

ecie

s d

iver

sity

Figure 7-13Page 154

Slide 9Slide 9Slide 9Slide 9Slide 9Slide 9Slide 9

• THEORY OF ISLAND BIOGEOGRAPHY – diversity of isolated area is a function of:– Factors that influence diversity on islands are:

• Size

• Degree of isolation (distance from mainland)

• Age of island

– Species reach equilibrium where immigration rate equals extirpation rate (not extinction!!!)

– Galapagos are a classic example of this. San Juans follow this model. What about the Hawaiian Island chain?

Slide 10Slide 10Slide 10Slide 10Slide 10Slide 10Slide 10

High

Low

Rat

e o

f im

mig

rati

on

or

exti

nct

ion

Equilibrium number

Immigration and extinction rates

Number of species on island

(a)

Figure 7-5 (1)Page 143

© 2004 Brooks/Cole – Thomson Learning

Slide 11Slide 11Slide 11Slide 11Slide 11Slide 11Slide 11

High

Low

Rat

e o

f im

mig

rati

on

or

exti

nct

ion

Small island

Effect of island size

Number of species on island

(b)

Large island

Figure 7-5 (2)Page 143

© 2004 Brooks/Cole – Thomson Learning

Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12Slide 12

High

Low

Rat

e o

f im

mig

rati

on

or

exti

nct

ion

Far island

Effect of distance from mainland

Number of species on island

(c)

Near island

Figure 7-5 (3)Page 143

© 2004 Brooks/Cole – Thomson Learning

Slide 13Slide 13Slide 13Slide 13Slide 13Slide 13Slide 13

Click to view animation.

Animation

Area and distance effects interaction.

Slide 14Slide 14Slide 14Slide 14Slide 14Slide 14Slide 14

• SPECIES TYPES IN COMMUNITIES– Keystone (flying fox)

– Indicator (amphibians)

– Exotic or invasive (Himalayan blackberry)

– Top predator (killer whales, lions, wolves)

Slide 15Slide 15Slide 15Slide 15Slide 15Slide 15Slide 15

Figure 7-6Page 145

sperm

Eggs

Sexualreproduction

Fertilized eggdevelopment

Organ formation

Egg hatches

Tadpole

TadpoledevelopsInto frog

Young frogAdult frog(3 years)

AMPHIBIANS ARE GOOD INDICATOR SPECIES

Slide 16Slide 16Slide 16Slide 16Slide 16Slide 16Slide 16

• SPECIES INTERACTIONS

– Commensalism

– Mutualism

– Competition

– Predation

– Parasitism – role in macroevolution with the development of eukaryotic cell (predate, exploit to coexistence)

Slide 17Slide 17Slide 17Slide 17Slide 17Slide 17Slide 17

Slide 18Slide 18Slide 18Slide 18Slide 18Slide 18Slide 18

Nu

mb

er o

f in

div

idu

als

Nu

mb

er o

f in

div

idu

als

Resource use

Resource use

Species 1 Species 2

Regionof

niche overlap

Species 1 Species 2

Figure 7-7Page 147

© 2004 Brooks/Cole – Thomson Learning

COMPETITION LEADS TO RESOURCE PARTITIONING

Slide 19Slide 19Slide 19Slide 19Slide 19Slide 19Slide 19

Figure 7-8Page 148

HERE THE RESOURCEPARTITIONED IS

LOCATIONSON THE TREE

Slide 20Slide 20Slide 20Slide 20Slide 20Slide 20Slide 20

Span worm Bombardier beetle

Viceroy butterfly mimicsmonarch butterfly

Foul-tasting monarch butterfly

Poison dart frog When touched, the snake caterpillar changes shape to look like the head of a snake

Figure 7-9Page 150

Wandering leaf insect

Hind wings of io mothresemble eyes of a much larger animal

DIFFERENT TYPES OF MIMICRY TO AVOID PREDATORS

MIMICRY IS LOOKING OR ACTING LIKE OTHER SPECIESTO AVOID BEING EATEN. 2 TYPES ARE

MULLERIAN AND BATESIAN

Slide 21Slide 21Slide 21Slide 21Slide 21Slide 21Slide 21

Figure 7-10Page 151

Oxpeckers and black rhinoceros Clown fish and sea anemone

Mycorrhizae fungi on juniper seedlings in normal soil

Lack of mycorrhizae fungi on juniper seedlings in sterilized soil

EXAMPLES OF

MUTUALISM

Slide 22Slide 22Slide 22Slide 22Slide 22Slide 22Slide 22

COMMUNITY DYNAMICS

• PLANT SUCCESSION MODELS– The book gives primary and secondary models (a spectrum in reality). Primary

succession is like cooking from scratch, secondary is when the structure is changed, but the ecosystem is able to rebuild from what is left. Plant invasion of cooling lava is a good example of primary; regeneration after fires is a good example of secondary.

Three basic models more realistic (especially when stochastics are considered) are– Facilitation or relay floristics (Clemens vs. Gleason)– Inhibition– Competition

• STABILITY– Persistence – resistance to being disturbed or altered– Constancy – ability to keep population numbers within limits imposed by

available resources– Resilence – ability of community to recover after disturbance– Restoration (back to original form and function) vs. rehabilitation (fix it up and

restore partial function.

Slide 23Slide 23Slide 23Slide 23Slide 23Slide 23Slide 23

Time

Small herbsand shrubs

Heath mat

Jack pine,black spruce,

and aspen

Balsam fir,paper birch, and

white spruceclimax community

Exposedrocks

Lichensand mosses

Figure 7-11Page 152

PRIMARY ECOLOGICAL SUCCESSIONFACILITATION (RELAY FLORISTICS) MODEL

DEVELOPED BY CLEMENS

Slide 24Slide 24Slide 24Slide 24Slide 24Slide 24Slide 24

Time

Annualweeds

Perennialweeds and

grasses

ShrubsYoung pine forest

Mature oak-hickory forest

Figure 7-12Page 153

SECONDARY ECOLOGICAL SUCCESSION

Slide 25Slide 25Slide 25Slide 25Slide 25Slide 25Slide 25

THIS IS THE END OF CHAPTER 7THE TEST WILL COME FROM THESE LECTURE

SLIDES!!!!!!

USE THE TEXT TO CLEAR UP POINTS OR TOPICS THAT ARE NOT

CLEAR TO YOU. THANKS FOR STUDYING ENVIRNOMENTAL

SCIENCE