Evaluating Biodiversity

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Evaluating Biodiversity Vulnerability

• IB Syllabus 4.2.1 4.2.7
• Planet in Peril episode 1

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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

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• 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

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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

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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

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The threats to rainforests

• Most of destruction since 1950
• Brazil has ½ remaining world rainforest
• At current rates of deforestation Brazils
  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

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• 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

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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.
  

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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.

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Plants uniquely adapted to the conditions there
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Why rainforests 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

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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

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• Interconnected Causes
• Of Degradation
• Destruction of Tropical
• Rainforests
• Revolve around
• Population Growth
• Poverty
• Government Policy

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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.
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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

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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

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Instrumental Values of Tropical Forest Ecosystems
Nonuse Values
Use Values
Direct Use Values
Indirect Use Values
Option Values
Existence Values
Future products
Protection of biological diversity
Timber and other building materials
Soil fertility
Medicines
Flood control
Fuelwood
Genetic resources
Maintaining cultures of local people
Water purification
Medicinal plants
Pollution control
Biological insights
Edible wild fruits and plants
Continuing ecological and evolutionary processes
Recreation and tourism
Food sources
Fiber
Education
Building supplies
Ecological services (pest control, pollination)
Future ecological services
Genetic information
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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

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The Yanomami South America
The Huli Papua New Guniea
The Pygmies Central Africa
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Prevention
Restoration
Protect most diverse and endangered
areas Educate settlers about sustainable agricult
ure and forestry Phase out subsidies that
encourage unsustainable forest use Add subsidies
that encourage sustainable forest use Protect
forests with debt-for-nature swaps, conservation
easements, and conservation concessions Certify
sustainably grown timber Reduce illegal
cutting Reduce poverty Slow population growth
Reforestation Rehabilitation of
degraded areas Concentrate farming and ranching
on already-cleared areas
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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

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Water use and pollution and soil nutrient loss
Freshwater supply and demand
Food supply and demand
Water availability
Changes in precipitation and temperature
Erosion, pollution, and changes in water flow
CO2, CH4, N2O emissions
Habitat change and fragmentation of habitat
Forest product supply and demand
Climate change
CO2 emission
Changes in transpiration and albedo
Loss and fragmentation of habitat
Loss of crop genetic diversity
Reduced resistance to change
Habitat change
Biodiversity loss
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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
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Current Classification of Species
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How can we reduce biodiversity loss?

• 2 main approaches ecosystem or species directed
• Preventing premature extinction of species
• Preserving restoring ecosystems which provide
  habitats and resources for the worlds species

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The Species Approach
The Ecosystem Approach
Goal
Goal
Protect populations of species in their
natural habitats
Protect species from premature extinction
Strategies
Strategy

• Identify endangered species
• Protect their critical habitats

Preserve sufficient areas of habitats in
different biomes and aquatic systems
Tactics
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

• Legally protect endangered species
• Manage habitat
• Propagate endangered species in captivity
• Reintroduce species into suitable habitats

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Endangered vs. Threatened

• Organisms are classified for conservation
  purposes Traditionally into 2 groups
• Endangered
• So few individuals that it could become extinct
  over all of its natural range
• Without protection ? critically endangered ?
  extinct
• Threatened
• Still abundant in range but declining numbers
• Ecological warning signs

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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/

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Figure 22-7 (1)Page 564
Florida manatee
Northern spotted owl (threatened)
Bannerman's turaco (Africa)
Gray wolf
Florida panther
Devil's hole pupfish
Black-footed ferret
Snow leopard (Central Asia)
Symphonia (Madagascar)
Utah prairie dog (threatened)
California condor
Black lace cactus
Oahu tree snail
Ghost bat (Australia)
Black rhinoceros (Africa)
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Figure 22-7 (2)Page 565
White top pitcher plant
Kirtland's warbler
Grizzly bear (threatened)
Arabian oryx (Middle East)
African elephant (Africa)
Mojave desert tortoise (threatened)
Swallowtail butterfly
Humpback chub
Golden lion tamarin (Brazil)
Siberian tiger (Siberia)
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Figure 22-7 (3)Page 565
West Virginia spring salamander
Knowlton cactus
Whooping crane
Giant panda (China)
Blue whale
Swamp pink
Pine barrens tree frog (male)
Hawksbill sea turtle
El Segundo blue butterfly
Mountain gorilla (Africa)
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EXTINCTION
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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.

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3 Types of Extinction

• Local extinction (extirpation) ? species no
  longer found in an area where it was once found
• Still found elsewhere ( population extinction)
• Ecological extinction ? so few members of a
  species are left that it can no longer play its
  ecological role in the ecosystem
• Biological extinction ? species is no longer
  found anywhere on the earth

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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
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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

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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

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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

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Premature extinction from human causes
Passenger pigeon
Dusky seaside sparrow
Great auk
Dodo
Aepyornis (Madagascar)
Main factors ? Overhunting, Habitat Destruction
Introduction of Exotic Species
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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

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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

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Range 100 years ago
Range today (about 2,300 left)
Indian Tiger
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Range in 1700
Range today (about 2,400 left)
Black Rhino
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Probable range 1600
Range today (300,000 left)
African Elephant
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Former range
Range today (34,00054,000 left)
Asian or Indian Elephant
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Vulnerability of ecosystems

• Diversity ? at species, genetic, ecological or
  functional levels
• Remember, Diversity Stability
• Resilience ? Ability of a living system to
  restore itself to original condition after being
  exposed to a minor outside disturbance
• Inertia ? ability of a living system to resist
  being disturbed or altered

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Biome
of Area Disturbed
Temperate broadleaf forests
94
Temperate evergreen forests
94
Temperate grasslands
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Mixed mountain systems
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Tropical dry forests
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Subtropical and temperate rain forests
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Cold deserts and semideserts
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Mixed island systems
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Warm deserts and semideserts
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Tropical humid forests
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Tropical grasslands
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Temperate boreal forests
18
Tundra
0.7
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Leading causes of wildlife depletion extinction

• Habitat loss, fragmentation or degradation
• Agriculture, urban development, pollution
• Prevent dispersal, mating, gene flow
• Deliberate or accidental introduction of
  non-native species
• Rapid reproduction, no competitors, no predators,
  upset energy flow

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Habitat loss
Habitat degradation
Overfishing
Basic Causes
Introducing nonnative species
Climate change

• Population growth
• Rising resource use
• No environmental accounting
• Poverty

Commercial hunting and poaching
Pollution
Sale of exotic pets and decorative plants
Predator and pest control
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Case Studies - Elephants

• Endangered
• Ecological pressures shrinking habitat
• Socio-political pressures recovery of elephants
  in smaller habitats widespread habitat
  destruction, other species now poached for ivory
• Economic pressures poaching for ivory
• Ecological Role keystone species, maintains
  grassland community by removing trees
• Consequences loss of ecosystem type

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Case Studies Passenger Pigeon

• Extinct September 1, 1914
• Ecological pressures clearing virgin forests
  for agriculture lost food nests, 1 egg laid per
  year
• Socio-political pressures Supply meat for
  growing east coast cities
• 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

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Case Studies American Alligator

• Recovered June 4 1987
• Ecological pressures shrinking habitat
• Socio-political pressures alligator nuisance,
  sustainable use, tourism
• 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

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Alligator mississippiensis
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Remember

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

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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 gt 10 years

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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

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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?
• Inbreeding increased the chances of deformity
  from recessively inherited diseases
• Identical genes gives identical vulnerability to
  disease
• Weakened physiology exaggerated recovery time
  from activity makes them vulnerable

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References

• www.rainforestweb.org
• www.redlist.org