Evaluating Biodiversity & Vulnerability

IB Syllabus: 4.2.1 – 4.2.7

AP syllabus

Ch.22, 23, 24

Planet in Peril – episode 1

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

• 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 hazards (volcanoes, drought, mudslide)– Global catastrophies (ice age, meteor impact)

• Human 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

• 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 recyling 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.

Amazon effects

• 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 infrastructure for transport• In Brazil alone, European colonists have destroyed

more than 90 indigenous tribes since the 1900's.

Plants uniquely adapted to the conditions there

Why rainforests vulnerable

Ecology• Pollinator relationships – reproduction

depends on other organisms• Poor, thin soils – easily eroded once trees

removed, little chance for regrowthLocation

• Surrounded by rapid population growth of developing countries – pollution, waste, space

• Poor economy benefits from any resources that are harvestable

• Economic – raw materials, exports, cattle, oil & gas

• Socio-political – Pressures of population growth, subsidize tree plantations, colonization

• Ecological – Invasive species, climate change, soil degradation

General Pressures on Rainforests

BromeliadBromeliad

OrchidOrchid

RoadsRoadsLoggingLogging

Cash cropsCash crops

Cattle ranchingCattle ranching

Tree plantationsTree plantations

Flooding from damsFlooding from dams

MiningMining

Oil drillingOil drilling

Unsustainable peasant farmingUnsustainable peasant farming

Primary Causes:Primary Causes:

Rapid population growthRapid population growth

Exploitive government policiesExploitive government policiesPovertyPoverty

Exports to developed countiesExports to developed counties

Failure to include ecological servicesFailure to include ecological servicesin evaluating forest resourcesin evaluating forest resources

ToucanToucan ScarletScarletmacawmacaw

Golden lionGolden lionmarmosetmarmoset

Blue morpho butterflyBlue morpho butterfly

Secondary Causes:Secondary Causes:

Interconnected Causes Of Degradation &

Destruction of TropicalRainforests

Revolve around1. Population

Growth2. Poverty3. Government

Policy

Rodonia Brazil: Acquired by the Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on August 24, 2000, the false-color image combines near-infrared, red, and green light. Tropical rainforest appears bright red, while pale red and brown areas represent cleared land. Black and gray areas have probably been recently burned. The Jiparaná River appears blue.

Secondary results

• Clearing rainforests degrades tropical rivers– Water more turbid, silts river bottoms, nutrient

overload in estuaries, smothers offshore coral reefs

• Accelerates flooding & reduces aquifer recharge

• Affect precipitation patterns– Flow 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

Use Values Nonuse Values

Direct Use Values Indirect UseValues

Option Values Existence Values

Timber and otherbuilding materials

Fuelwood

Medicinal plants

Edible wild fruitsand plants

Fiber

Soil fertility

Flood control

Water purification

Pollution control

Recreation andtourism

Education

Ecologicalservices (pestcontrol,pollination)

Geneticinformation

Future products:

Medicines

Geneticresources

Biologicalinsights

Food sources

Buildingsupplies

Future ecologicalservices

Protection ofbiologicaldiversity

Maintainingcultures of localpeople

Continuingecological andevolutionaryprocesses

Cultural Extinction• 250 million people in 70 countries from

indigenous rainforest cultures• Hunting & Gathering, Sustainable Agriculture• Remaining tribal people are disappearing with

their lands• Irreplacable 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 HuliPapua New Guniea

The Yanomami South America

The PygmiesCentral Africa

Prevention Restoration

Protect most diverse andendangered areas

Educate settlers about sustainableagriculture and forestry

Phase out subsidies that encourageunsustainable forest use

Add subsidies that encouragesustainable forest use

Protect forests with debt-for-natureswaps, conservation easements,and conservation concessions

Certify sustainably grown timber

Reduce illegal cutting

Reduce poverty

Slow population growth

Reforestation

Rehabilitationof degradedareas

Concentratefarming andranching onalready-clearedareas

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

Freshwatersupply and

demand

Forest productsupply and

demandClimate change

Biodiversity loss

Habitatchange

Changes intranspirationand albedo Loss

of cropgenetic

diversity Reducedresistanceto change

Loss andfragmentation

of habitat

CO2 emission

Habitat changeand fragmentation

of habitat

Changes inprecipitation

and temperature

Water availability

Water use and pollutionand soil nutrient loss

CO2, CH4,

N2O emissions

Erosion,pollution, and

changes inwater flow

Loss and fragmentation

of habitat

Loss and fragmentation

of habitat

DeforestationDeforestationChanges inwater supply and

temperature

Changes inwater supply and

temperature

About 1.5 - 10 million Species live on Earth

Estimates of the Numbers of Species in the World

Source: World Conservation Monitoring Centre, Global Biodiversity - Status of the Earth's Living Resources, 1992.

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

18000 to 50000 species lost per year1 species lost every 20 minutesEstimates differ but over 50 species lost per day is probably accurateStop the Clock – www.conservation.org/act

67%Secure orapparently

secure

1%Other

16%Vulnerable

8%Imperiled

7%Critically imperiled

1% Probably extinct

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 The Ecosystem Approach

Goal

Protect species frompremature extinction

Strategies

• Identify endangered species

• Protect their critical habitats

Tactics

• Legally protect endangered species

• Manage habitat

• Propagate endangered species in captivity

• Reintroduce species into suitable habitats

Goal

Protect populations ofspecies in their naturalhabitats

Strategy

Preserve sufficient areasof habitats in differentbiomes and aquaticsystems

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

2. Threatened• 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 Bannerman's turaco (Africa)

Devil's hole pupfish

Snow leopard(Central Asia)

Black-footed ferret

Symphonia(Madagascar)

Utah prairie dog(threatened)

Ghost bat(Australia)

California condor

Black lace cactus

Black rhinoceros(Africa)

Oahu tree snail

Figure 22-7 (2)Page 565

Grizzly bear(threatened)

Arabian oryx(Middle East)

White top pitcher plant

Kirtland's warbler

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 Virginiaspring salamander

Giant panda(China)

Knowlton cactus

Mountain gorilla(Africa)

Swamp pink

Pine barrens tree frog (male)

Hawksbill sea turtle

El Segundo blue butterfly

Whooping crane

Blue whale

EXTINCTION

Evidence from the past

• The fossil record remains first and foremost among the databases that document changes in past life on Earth.

• The fossil record clearly shows changes in life through almost any sequence of sedimentary rock layers.

• Successive rock layers contain different groups or assemblages of fossil species.

3 Types of Extinction

1. Local extinction (extirpation) species no longer found in an area where it was once found

• Still found elsewhere (= population extinction)

2. Ecological extinction so few members of a species are left that it can no longer play its ecological role in the ecosystem

3. Biological extinction species is no longer found anywhere on the earth

Mass Extinctions Epoch Cause Species Lost

Precambrian Glaciation Stromatolites

Cambrian O2 Depletion Olnellids

Ordovician Glaciation of Gondwana

Brachiopods

Devonian Meteor, Glaciation Early corals

Permian Pangea Trilobites

End Cretaceous Meteor, Volcanoes Dinosaurs

Holocene Humans All forms

Permian mass Extinction

- Permian Period (286-248 million years ago) Formation Of Pangea

- Terrestrial faunal diversification occurred in the Permian

- 90-95% of marine species became extinct in the Permian (largest extinction in history)

- Causes? = Formation of Pangea reduced continental shelf area, glaciation, Volcanic eruptions

The End-Cretaceous (K-T) Extinction

- Numerous evolutionary radiations occurred during the Cretaceous (144-65 million years ago) 1st appearance of dinosaurs, mammals, birds, angiosperms

- A major extinction occurred at the end of the period- 85% of all species died in the End-Cretaceous (K-T) extinction (2nd largest in history)

- Causes? = Meteor impact in the Yucatan, Volcanic eruption both supported geolocially, cause climate change, atmospheric changes

Extinction Rates• Biologists estimate that 99.9% of all species ever in

existence are now extinct– Background extinction – local environmental changes

cause species to disappear at low rate– mass extinction – catastrophic, widespread (25 – 75%

of existing species– mass depletion – higher than background but not mass

• Cause temporary biodiversity reductions but create vacant niches for new species to evolve

• 5 million years of adaptive radiation to rebuild diversity after extinction

Premature extinction from human causes

Passenger pigeon

Great auk Dodo Dusky seaside sparrow

Aepyornis(Madagascar)

Main factors Overhunting, Habitat Destruction &Introduction of Exotic Species

Differences in Cause of Extinction

Historically most mass extinctions were caused by

• Catastrophic Agents- such as meteorite impacts and comet showers,

• Earth Agents- such as volcanism, glaciation, variations in sea level, global climatic changes, and changes in ocean levels of oxygen or salinity

Currently a mass extinction is being caused by the actions of 1 species Us

Which species are most vulnerable?

• Vulnerability of species affected by …– Numbers – 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)

Specialized niche

Narrow distribution

Feeds at high trophic level

Fixed migratory patterns

Rare

Commercially valuable

Large territories

Blue whale, giant panda,rhinoceros

Blue whale, giant panda,Everglades kite

Many island species,elephant seal, desert pupfish

Bengal tiger, bald eagle,grizzly bear

Blue whale, whooping crane,sea turtles

Many island species,African violet, some orchids

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

California condor, grizzly bear, Florida panther

Indian Tiger

Range 100 years ago

Range today(about 2,300 left)

Black Rhino

Range in 1700

Range today(about 2,400 left)

African Elephant

Probable range 1600

Range today(300,000 left)

Asian or Indian Elephant

Former range

Range today(34,000–54,000 left)

Vulnerability of ecosystems

1. Diversity at species, genetic, ecological or functional levels

** Remember, Diversity = Stability **

2. Resilience Ability of a living system to restore itself to original condition after being exposed to a minor outside disturbance

3. Inertia ability of a living system to resist being disturbed or altered

Biome % of Area Disturbed

Temperate broadleaf forests

Temperate evergreen forests

Temperate grasslands

Mixed mountain systems

Tropical dry forests

Subtropical and temperate rain forests

Cold deserts and semideserts

Mixed island systems

Warm deserts and semideserts

Tropical humid forests

Tropical grasslands

Temperate boreal forests

Tundra

94%

94%

72%

71%

70%

67%

55%

53%

44%

37%

26%

18%

0.7%

Leading causes of wildlife depletion & extinction

1. Habitat loss, fragmentation or degradation

• Agriculture, urban development, pollution• Prevent dispersal, mating, gene flow

2. Deliberate or accidental introduction of non-native species

• Rapid reproduction, no competitors, no predators, upset energy flow

Overfishing

Habitatloss

Habitatdegradation

Introducingnonnativespecies

Commercialhunting

andpoaching

Sale ofexotic pets

anddecorative

plants

Predatorand

pest control

Pollution

Climatechange

Basic Causes

• Population growth• Rising resource use• No environmental

accounting• Poverty

Case Studies - Elephants

Endangered 1. Ecological pressures – shrinking habitat2. Socio-political pressures – recovery of

elephants in smaller habitats = widespread habitat destruction, other species now poached for ivory

3. Economic pressures – poaching for ivory

• Ecological Role – keystone species, maintains grassland community by removing trees

• Consequences – loss of ecosystem type

Case Studies – Passenger Pigeon

Extinct September 1, 1914 1. Ecological pressures – clearing virgin forests for

agriculture lost food & nests, 1 egg laid per year2. Socio-political pressures – Supply meat for

growing east coast cities3. Economic pressures – easy capture in large

dense flocks, roosts markets in the east

• Ecological Role – once most numerous bird on the planet

• Consequences – linked to spread of lyme disease

Case Studies – American Alligator

Recovered June 4 19871. Ecological pressures – shrinking habitat2. Socio-political pressures – alligator nuisance,

sustainable use, tourism3. Economic pressures – confused with American

Crocadile hunted for skins

• Ecological Role – keystone predator, gator holes in everglades, top carnivore

• Consequences – loss of fish & bird populations & change whole everglades ecosystem structure / now healthy systems

Alligator mississippiensis

Remember

• That current changes in species numbers will be exacerbated by global warming

When is endangered really “in danger”

• Is there a number where the population is too small to survive?

• MVP = minimum viable population the smallest number of individuals necessary to ensure the survival of a population in a region for a specified timer period

• Time range typically 10-100 years• Most indications are that a few thousand

individuals is the MVP if time span is > 10 years

Genetic Bottlenecks

• If populations recover from times with small numbers other problems can persist

• Genetic bottlenecks• Think of a traffic bottleneck many cars

approach and stop, only a few get through.• Same with genes – genetic diversity is

dramatically reduced• When populations are reduced to small

numbers interbreeding occurs and genetic diversity plummets

Cheetahs• A few thousand years ago cheetahs

experienced a population crash• They have since recovered but they are

almost all genetically identical• Why is this a problem?

1. Inbreeding increased the chances of deformity from recessively inherited diseases

2. Identical genes gives identical vulnerability to disease

3. Weakened physiology – exaggerated recovery time from activity makes them vulnerable

References

• www.rainforestweb.org

• www.redlist.org