EVALUATING
BIODIVERSITY &
VULNERABILITY
IB Syllabus: 4.2.1 – 4.2.7
SYLLABUS STATEMENTS
 4.2.1:
Identify factors that lead to a loss of
diversity
 4.2.2:
Describe the perceived vulnerability of
tropical rainforests and their relative value in
contributing to global biodiversity
 4.2.3:
Discuss current estimates of numbers of
species and past and present rates of species
extinction
 4.2.4:
Describe and explain the factors that
may make species more or less prone to
extinction
SYLLABUS STATEMENTS
 4.2.5:
Outline the factors used to determine a
species’ Red List conservation status
 4.2.6:
Describe the case histories of three
species: one that has become extinct, another
that is currently endangered, and a third
whose conservation status has been improved
by intervention
 4.2.7:
Describe the case history of a natural
area of biological significance that is
threatened by human activities
HOW IS BIODIVERSITY LOST?
 Natural
Processes
 Natural
 Global
 Human
hazards (volcanoes, drought, mudslide)
catastrophe's (ice age, meteor impact)
Processes
 Habitat
degradation, fragmentation & loss
 Introduction/escape
of nonnative species,
genetically modified organisms, monoculture
 Pollution
 Hunting,
collecting, harvesting. overfishing
RAIN FORESTS – A CASE STUDY
 2%
of the land surface with 50-80% of the
terrestrial species (species diversity)
 Characterized
by warm constant
temperature, high humidity & rainfall
 Vertical
stratification provides niche
diversification
 Decomposition
rates are extremely fast  little
litter, thin nutrient poor soil
 Nutrients
stored in biomass of organisms
THE THREATS TO RAINFORESTS
 Most
of destruction since 1950
 Brazil
has ½ remaining world
rainforest
 At
current rates of deforestation
Brazil’s rainforest will be gone in
40-50 years
 Total
loss yearly to deforestation
is 50,000 to 170,000 km2
 1.5
ACRES LOST PER SECOND
worldwide
 Cutting
& degradation at even
faster rates

Highest average annual deforestation of primary forests, 2000-2005, by
area. All countries
1 Brazil -3,466,000
2
Indonesia -1,447,800
3
Russian Federation -532,200
4
Mexico -395,000
5
Papua New Guinea -250,200
6
Peru -224,600
7
United States of America -215,200
8
Bolivia -135,200
9
Sudan -117,807
 10
Nigeria -82,000
AMAZON RAINFOREST

The Amazonian Rainforest covers over a billion acres, encompassing
areas in Brazil, Venezuela, Columbia and the Eastern Andean region
of Ecuador and Peru.

If Amazonia were a country, it would be the ninth largest in the world.

The Amazon Rainforest has been described as the "Lungs of our
Planet" because it provides the essential environmental world service
of continuously recycling carbon dioxide into oxygen.
 More
than 20 percent of the world oxygen is produced in
the Amazon Rainforest.
 More
than half of the world's estimated 10 million species
of plants, animals and insects live in the tropical
rainforests.
 One-fifth

of the world's fresh water is in the Amazon Basin.
One hectare (2.47 acres) may contain over 750 types of trees and
1500 species of higher plants.
 1/3
of rainforest destruction
from shifting cultivation
 Rest
cleared for pasture- then
planted with African grasses
for cattle
 When
pasture price exceeds
forest prices  incentive for
land clearing
 Government
subsidized
agriculture and colonization
 Improved
transport
 In
infrastructure for
Brazil alone, European
colonists have destroyed
more than 90 indigenous
tribes since the 1900's.
AMAZON
EFFECTS
PLANTS UNIQUELY ADAPTED TO THE
CONDITIONS THERE
WHY RAINFORESTS ARE VULNERABLE
Ecology

Pollinator relationships – reproduction
depends on other organisms

Poor, thin soils – easily eroded once trees
removed, little chance for regrowth
Location

Surrounded by rapid population growth of
developing countries – pollution, waste,
space

Poor economy benefits from any
resources that are harvestable
GENERAL PRESSURES ON RAINFORESTS
 Economic
– raw
materials, exports, cattle,
oil & gas
 Socio-political
– Pressures
of population growth,
subsidize tree plantations,
colonization
 Ecological
– Invasive
species, climate change,
soil degradation
Interconnected
Causes Of
Degradation &
Destruction of
Tropical
Rainforests
Bromeliad
Primary Causes:
Rapid population growth
Poverty
Exploitive government policies
Exports to developed counties
Failure to include ecological services
in evaluating forest resources
Toucan
Revolve around
1. Population
Growth
2. Poverty
3. Government
Policy
Scarlet
macaw
Golden lion
marmoset
Orchid
Blue morpho butterfly
Secondary Causes:
Roads
Logging
Unsustainable peasant farming
Cash crops
Cattle ranching
Tree plantations
Flooding from dams
Mining
Oil drilling
SECONDARY RESULTS
 Clearing
rainforests degrades tropical rivers
 Water
more turbid, silts river bottoms, nutrient
overload in estuaries, smothers offshore coral reefs
 Accelerates
recharge
 Affect
 Flow
flooding & reduces aquifer
precipitation patterns
of moisture to downwind areas is reduced
WHY ARE THEY SPECIAL? OR…
Why
should we care?
Some
biogeographers claim that loss of
tropical rainforests is no more important
than loss of old growth forests in EU & NA
1.
Important ecological & environmental
services
2. Instrumental values  medicines from
plants
3.
Cultural value
Instrumental Values of Tropical Forest
Ecosystems
Nonuse Values
Use Values
Direct Use Values
Timber and other
building materials
Fuelwood
Medicinal plants
Edible wild fruits
and plants
Fiber
Indirect Use
Values
Option Values
Future products:
Soil fertility
Medicines
Existence Values
Protection of
biological
diversity
Flood control
Water purification
Pollution control
Recreation and
tourism
Education
Ecological
services (pest
control,
pollination)
Genetic
information
Genetic
resources
Biological
insights
Food sources
Building
supplies
Future ecological
services
Maintaining
cultures of local
people
Continuing
ecological and
evolutionary
processes
CULTURAL EXTINCTION
 250
million people in 70 countries from
indigenous rainforest cultures
 Hunting
& Gathering, Sustainable Agriculture
 Remaining
tribal people are disappearing
with their lands
 Irreplaceable
loss of ecological & cultural
knowledge – most medicine men 70+ years
old
 Need
protection & ownership of land to
survive
 BUT
 that stands in the way of progress
The Yanomami
South America
The Huli
Papua New Guniea
The Pygmies
Central Africa
Prevention
• Protect most diverse and
endangered areas
• Educate settlers about
sustainable agriculture and
forestry
• Phase out subsidies that
encourage unsustainable
forest use
• Add subsidies that encourage
sustainable forest use
• Protect forests with debt-fornature swaps, conservation
easements, and conservation
concessions
• Certify sustainably grown
timber
• Reduce illegal cutting
• Reduce poverty
• Slow population growth
Restoration
• Reforestation
• Rehabilitation
of degraded
areas
• Concentrate
farming and
ranching on
alreadycleared areas
BIODIVERSITY WILL DECREASE
FROM…
1.
Environmental Stress
2.
Large environmental disturbance
3.
Extreme environmental conditions
4.
Severe limitation of an essential nutrient,
habitat, or other resource
5.
Introduction of a nonnative species
6.
Geographic isolation
Food supply
and demand
Changes in
water supply and
temperature
CO2, CH4,
N2O emissions
Water use and pollution
and soil nutrient loss
Freshwater
supply and
demand
Water availability
Deforestation
Changes in
precipitation
and temperature
Erosion,
pollution, and
changes in
water flow
Habitat change
and fragmentation
of habitat
Climate change
Forest product
supply and
demand
CO2 emission
Changes in
transpiration
and albedo
Habitat
change
Loss
of crop
genetic
diversity
Loss and
fragmentation
of habitat
Biodiversity loss
Loss and
fragmentation
of habitat
Reduced
resistance
to change
ABOUT 1.5 - 10 MILLION SPECIES LIVE
ON EARTH
Estimates of the Numbers of Species in the World
Groups of
Organisms
Species
described
Maximum
estimates
Most conservative
estimates
Viruses
5,000
500,000
500,000
Bacteria
4,000
3,000,000
400,000
Fungi
70,000
1,500,000
1,000,000
Algae
40,000
10,000,000
200,000
Plants
250,000
500,000
300,000
Vertebrates
45,000
50,000
50,000
Nematodes
15,000
1,000,000
500,000
Molluscs
70,000
180,000
200,000
Crustaceans
40,000
150,000
200,000
Arachnids
75,000
1,000,000
750,000
Insects
950,000
100,000,000
8,000,000
Source: World Conservation Monitoring Centre, Global Biodiversity - Status of the Earth's Living Resources, 1992.
18000 to 50000 species lost per year
1 species lost every 20 minutes
Estimates differ but over 50 species lost per day is probably accurate
Stop the Clock – www.conservation.org/act
1%
Probably extinct
7%
Critically
imperiled
67%
Secure or
apparently
secure
8%
Imperiled
16%
Vulnerable
1%
Other
Current Classification of Species
HOW CAN WE REDUCE
BIODIVERSITY LOSS?

2 main approaches – ecosystem or species
directed
1.
Preventing premature extinction of species
2.
Preserving & restoring ecosystems which
provide habitats and resources for the
world’s species
The Species Approach
Goal
The Ecosystem Approach
Goal
Protect species from
premature extinction
Protect populations of
species in their natural
habitats
Strategies
Strategy
• Identify endangered
species
• Protect their critical
habitats
Tactics
• Legally protect
endangered species
• Manage habitat
• Propagate endangered
species in captivity
• Reintroduce species
into suitable habitats
Preserve sufficient areas
of habitats in different
biomes and aquatic
systems
Tactics
• Protect habitat areas
through private purchase
or government action
• Eliminate or reduce
populations of alien
species from protected
areas
• Manage protected areas
to sustain native species
• Restore degraded
ecosystems
ENDANGERED VS. THREATENED

Organisms are classified for conservation
purposes Traditionally into 2 groups
1.
Endangered
•
So few individuals that it could become extinct
over all of its natural range
•
Without protection  critically endangered 
extinct
Threatened
2.
•
Still abundant in range but declining numbers
•
Ecological warning signs
RED DATA BOOKS
 List
the species in the red – the ones most in
jeopardy of extinction
 Various factors contribute to identifying species as
threatened, of concern, endangered, extinct
 Examples
- population size, reduction of
population size, numbers of mature individuals,
geographic range and degree of fragmentation,
quality of habitat, area of occupancy, probability
of extinction
 http://www.iucnredlist.org/
FIGURE 22-7 (1)
PAGE 564
Florida
manatee
Northern spotted
owl (threatened)
Gray wolf
Florida panther
Devil's hole
pupfish
Snow leopard
(Central Asia)
Symphonia
(Madagascar)
Black-footed
ferret
Ghost bat
(Australia)
California
condor
Black lace
cactus
Black rhinoceros
(Africa)
Bannerman's
turaco (Africa)
Utah prairie dog
(threatened)
Oahu tree
snail
FIGURE 22-7 (2)
PAGE 565
Grizzly bear
(threatened)
Kirtland's
warbler
White top
pitcher plant
Arabian oryx
(Middle East)
African elephant
(Africa)
Mojave desert
tortoise
(threatened)
Swallowtail
butterfly
Humpback
chub
Golden lion
tamarin
(Brazil)
Siberian tiger
(Siberia)
FIGURE 22-7 (3)
PAGE 565
West Virginia
Giant panda
spring salamander (China)
Mountain gorilla
(Africa)
Pine barrens
tree frog
(male)
Whooping
crane
Knowlton
cactus
Swamp
pink
Hawksbill sea
turtle
Blue whale
El Segundo blue
butterfly
EXTINCTION RATES
Evidence
for the fossil record
clearly shows changes in life
throughout history.
Scientists
estimate that 99.9% of all
species ever in existence are now
extinct
MASS EXTINCTIONS
Epoch
Cause
Species Lost
Precambrian
Glaciation
Stromatolites
Cambrian
O2 Depletion
Olnellids
Ordovician
Glaciation of
Brachiopods
Gondwana
Meteor, Glaciation Early corals
Devonian
Permian
286-248MYA
End Cretaceous
Pangea
Holocene
Humans
Trilobites (90-95%
of marine species)
Meteor, Volcanoes Dinosaurs (85% of
all species)
All forms
PREMATURE EXTINCTION FROM
HUMAN CAUSES
Passenger
pigeon
Western Black Rhino
Tasmanian Tiger
Dodo
 Humans
Caused 322 Animal Extinctions in Past
500 Years
 Main
factors: Overhunting, Habitat Destruction, &
Introduction of Non-native Species
WHICH SPECIES ARE MOST
VULNERABLE?
 Vulnerability
 Numbers
of species affected by …
– low numbers = automatic risk
 Degree
of specialization = generalists adapt better
than specialists
 Distribution
= widely distributed organisms, may
migrate out of harms way & different effects by
area
 Reproductive
potential – if low = vulnerable
 Reproductive
behaviors – how complex, picky, …
 Trophic
level – higher are more vulnerable to
biomagnification & trophic cascades
Characteristic
Examples
Low reproductive rate
(K-strategist)
Blue whale, giant panda,
rhinoceros
Specialized niche
Blue whale, giant panda,
Everglades kite
Narrow distribution
Many island species,
elephant seal, desert pupfish
Feeds at high trophic
level
Bengal tiger, bald eagle,
grizzly bear
Fixed migratory patterns
Blue whale, whooping crane,
sea turtles
Rare
Many island species,
African violet, some orchids
Commercially valuable
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
Large territories
California condor, grizzly
bear, Florida panther