Introduction to Ecology
CERC Certificate Program
Columbia University
Session 5 – Conservation Biology
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Introduced Species Summary
Project
• What species did you do?
– Responses?
– Why did you choose the species you did?
– Should your species be controlled? Why?
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Global Changes
• What processes are at work at present in the
planet?
• Examples
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Global Climate Change
Acid Rain
Spread of Pollution and Toxins
Spread of Biotic Pollution
• How are these occurring?
– What is the generative force behind them?
Global Change Cause
• What is the Generative
Force behind these
changes?
US!
Human Impact
• We have altered nearly all of the Earth that it is
profitable for us to do so
Why Now?
• Why has human
population growth so
escalated recently?
• What has happened to
cause this?
– When was the last large
dip in world population?
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Definition of Conservation
Biology
• Applied ecology
… but with an agenda!
• Is this truly scientific?
– Why or why not?
Agenda Items
• Why should we care about conserving biodiversity?
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Ecosystem Function
Direct Economic Uses
Indirect Economic Uses
Ethical Reasons
Aesthetic Reasons
Agenda Items
• Nearly all of these are
subjective and involve
value judgments
– Not everyone values
biodiversity
– Short-term gain may
outweigh these
considerations
• Financial, Survival
• Respect others’ views?
vs.
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Habitat Loss
• Single greatest threat to biodiversity
– Approx. 50+% of all species extinctions have
been involved habitat loss
– Island biogeography theory predicts that around
50% of species are lost with 90% habitat loss
Impacts of Habitat Modification
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Loss of Habitat
Habitat Alteration
Fragmentation
Increased Human Presence
Introduced Species
Impacts of Habitat Modification
• Loss of Habitat
– Occasionally completely
• Paving - 377,810 miles in US forests
only plus 44,000 m highways, plus ? m
suburban, etc.
– Usually remaining habitat in altered
areas is suboptimal
– Remaining individuals are stressed
and have decreased fitness
Impacts of Habitat Modification
• Habitat Alteration
– Remaining surrounding habitat
is impacted due to use of altered
habitat
– E.g., fumes, pollution, from cars
Impacts of Habitat Modification
• Fragmentation
– Key component: Edge Effects
– Impacts of fragmentation
percolate into interior
–  aridity,  wind,  openness, 
heat, change in water patterns, 
noise, etc.
– These impacts often permeate in
several hundred meters
• Distance is species specific
• Birds in Australia = 200+ m
Impacts of Habitat Modification
• Increased Human
Presence
– Alteration leads to
more alteration
– People arrive, then
their influence
expands and
intensifies
Impacts of Habitat Modification
• Introduced Species
– Other species come with
us as we fragment
– Intentionally
– Unintentionally
– Thought to be the
second strongest force
behind only
fragmentation
– More about these
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Invasive Species
• Intentional Introductions
– Crops, pets, ornamentals, ranching, etc.
• Unintentional Introductions
– Everything else
– Majority of Introductions are these
Invasive Species
• Impact on other species through many ways
– Competition, predation, parasitism, herbivory,
parasitoidism
– Species need resources to survive and
propagate
– What does this view assume about community
structure and niche availability?
Rule of Tens
• Not all species that are
introduced are
successful
• Stages of Invasion
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Introduction
Establishment
Integration
Dominance (or Pest
status or invasiveness)
Rule of Tens
• Only 10% make it
through each stage
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10,000 in a source area
1,000 introduced
100 established
10 integrated
1 pest
– Empirical observation
Transportation
Establishment
Integration
Dominance
(or Pest status)
Invasive Species
• Why can invasive
species quickly explode
in population size?
• Ecological Release
– The restrictions on pop
growth are removed in
the novel location
Invasive Species
• This phenomenon can also be used to our
benefit
• Can you think of examples?
• Biological Control of pest insects
– Parasitoid wasps
• Erosion Control
– E.g., Kudzu
• CAUTION
Heaviest Hit Location
• Hawaii
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Comprises < 0.2% of total US land area
Has more than 25% of US endangered species
Approximately 72% of recorded extinctions are in Hawaii
Hawaii has more endangered species (per area) than
anywhere else on the planet
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Disease Ecology
• Essentially a subfield
within invasion biology
– The pest is usually an
introduced species
– Bacteria, viruses, fungi,
protists, etc.
• Responsible for tracking &
controlling the spread of
novel diseases
Disease Ecology
• Examples of this
locally?
• West Nile Fever
• Malaria
• Chestnut Blight
• Dutch Elm Disease
Disease Ecology
• Novel feature here:
– Need a vector (as with other
Invasives)
– Also need host(s)
• Harder to introduce
diseases as a consequence
than other species
• Rule of tens overestimates
Emerging Infectious
Diseases (EIDs)
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
Ecotoxicology
• Definition: Spread of the scientific study of
harmful effects caused by manmade chemicals
to the natural environment
• Of particular interest are the effects on
populations, communities, and ecosystems
From Dictionary.com
Ecotoxicology
• An essential part is
the study of the
movement of
potentially toxic
substances through
food webs and
through the water
cycle
Dictionary.com
Ecotoxicology Example
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Floridian Feminized Feral Alligators
First found in early 1990s
Due to estrogen-like pollutants from sewage effluent
Main chemical culprits: pesticides, industrial compounds,
dioxins, & ingredients of plastics and detergents
– Act to either mimic estrogen or block testosterone receptors
– Suppress reproduction, by reducing their effective population size
– Possibly also occurring in Humans?
Conservation Biology
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Goals for the day
Why now?
Definition of Conservation Biology
Habitat Loss and Fragmentation
Invasive Species
Disease Ecology
Ecotoxicology
What Can We Do?
What Can We Do?
• Prioritize areas for conservation
• Restore already damaged areas
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– Called Restoration Ecology
Land-for-debt swaps
Ecosystem valuation
Captive breeding programs
Reducing our footprint
Many others….
Ecological Pyramid
• Trends down pyramid:
– Increase in geographic scale
– From single species to multiple
species
– Increasing number of ecological
factors that may be influential
– Decreasing certainty in results
Population
Community
Ecosystem
Biome
Biosphere
The Tour of Ecology Has
Concluded
• General Ecology
• Population ecology
• Community ecology
• Ecosystem ecology
• Conservation Issues
– Is there any hope for the
future?
– You determine the answer…