Community EcologyCommunity Ecology

Mr. Clark

Bethpage HS

Key ConceptsKey Concepts

Community structureCommunity structure

Roles of speciesRoles of species

Species interactionsSpecies interactions

Changes in ecosystemsChanges in ecosystems

Stability of ecosystemsStability of ecosystems

Community StructureCommunity Structure

Appearance

Species diversity

Species richness

Niche structure

Edge effects

Species DiversitySpecies Diversity

• Species richness

• Species evenness

• Shannon- Weiner Index

BiodiversityBiodiversity

LatitudeLatitude

DepthDepth

PollutionPollution

Theory of island biogeographyTheory of island biogeography

Ants Birds

Ants Birds

Click to view animation.

Types of two species interactions animation.

Sp

ecie

s D

iver

sity

Sp

ecie

s D

iver

sity

100

10

Latitude

80ºN 60 40 20 0

100

0

90ºN 60 30 0 30ºS 60

Latitude

(a) Ants(b) Breeding birds

Number of individuals per diatom species

Nu

mb

er o

f d

iato

m s

pec

ies Unpolluted

stream

Pollutedstream

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)

© 2004 Brooks/Cole – Thomson Learning

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

© 2004 Brooks/Cole – Thomson Learning

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

© 2004 Brooks/Cole – Thomson Learning

Immigration(near island)

Immigration(far island)

Extinction

Click to view animation.

Area and distance effects interaction.

General Types of SpeciesGeneral Types of Species

NativeNative

Non-native (exotic or alien)Non-native (exotic or alien)

IndicatorIndicator

KeystoneKeystone

FoundationFoundation

Keystone Species

sperm

Eggs

Sexualreproduction

Fertilized eggdevelopment

Organ formation

Egg hatches

Tadpole

TadpoledevelopsInto frog

Young frogAdult frog(3 years)

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

Wandering leaf insect

Hind wings of io mothresemble eyes of a much larger animal

Predator Camouflage

Species Interactions: CompetitionSpecies Interactions: Competition

Interspecific competitionInterspecific competition

PredationPredation

ParasitismParasitism

MutualismMutualism

CommensalismCommensalism

Resource partitioningResource partitioning

Predators

Defense Strategies

Sharp Edges

Poison Ivy

Spines

Animal Defenses

Bright Color Warning

Click to view animation.

Gause's competition experiment interaction.

Resource Partitioning and Niche SpecializationResource Partitioning and Niche Specialization

Species Interactions: PredationSpecies Interactions: Predation

PredatorPredator

PreyPrey

Prey acquisitionPrey acquisition

Predator avoidancePredator avoidance

Symbiotic Species Interactions: Parasitism Symbiotic Species Interactions: Parasitism

Parasite Parasite

Host Host

Important ecological roles of parasites Important ecological roles of parasites

Symbiotic Species Interactions: MutualismSymbiotic Species Interactions: Mutualism

Pollination mutualismPollination mutualism

Nutritional mutualism Nutritional mutualism

Gut inhabitant mutualismGut inhabitant mutualism

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

Click to view animation.

Types of two species interactions animation.

Symbiotic Species Interactions: CommensalismSymbiotic Species Interactions: Commensalism

Species interaction that benefits one and has little or no effect on the other

Species interaction that benefits one and has little or no effect on the other

Example: Small plants growing in shade of larger plants

Example: Small plants growing in shade of larger plants

Ecological Succession: Communities in TransitionEcological Succession: Communities in Transition

Primary successionPrimary succession

Secondary successionSecondary succession

Pioneer speciesPioneer species

Successional speciesSuccessional species

Click to view animation.

Two types of ecological succession animation.

Primary SuccessionPrimary Succession

Secondary SuccessionSecondary Succession

The Rate of SuccessionThe Rate of Succession

FacilitationFacilitation

InhibitionInhibition

ToleranceTolerance

Ecological Stability and SustainabilityEcological Stability and Sustainability

Disturbance Disturbance

Climax community Climax community

Inertia Inertia

Constancy Constancy

Resilience Resilience

Precautionary principle Precautionary principle

Table 8-1Page 158Table 8-1Page 158Table 8-1 Ecosystem Characteristics at Immature and Mature Stages of Ecological Succession

Characteristic

Ecosystem Structure

Plant size

Species diversity

Trophic structure

Ecological niches

Community organization(number of interconnecting links)

Ecosystem Function

Biomass

Net primary productivity

Food chains and webs

Efficiency of nutrient recycling

Efficiency of energy use

Immature Ecosystem(Early Successional Stage)

Small

Low

Mostly producers, few decomposers

Few, mostly generalized

Low

Low

High

Simple, mostly plant herbivorewith few decomposers

Low

Low

Immature Ecosystem(Late Successional Stage)

Large

High

Mixture of producers, consumers, and decomposers

Many, mostly specialized

High

High

Low

Complex, dominated by decomposers

High

High

Click to view animation.

Resources depletion and degradation interaction