Evaluating Biodiversity & Vulnerability by Um9k2f4W

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									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 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
                                      Bromeliad


                             Primary Causes:
                             Rapid population growth                   Interconnected Causes
                             Poverty                                      Of Degradation &
                             Exploitive government policies
                             Exports to developed counties              Destruction of Tropical
                             Failure to include ecological services          Rainforests
                             in evaluating forest resources

              Toucan      Scarlet
                          macaw
                                                                       Revolve around
Golden lion
marmoset                                                               1. Population
                                                                          Growth
                                                                       2. Poverty
                         Orchid
                                       Secondary Causes:
                                                                       3. Government
                                       Roads                              Policy
                                       Logging
                                       Unsustainable peasant farming
                                       Cash crops
                                       Cattle ranching
                                       Tree plantations
                                       Flooding from dams
                                       Mining
 Blue morpho butterfly                 Oil drilling
                                      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 Use           Option Values            Existence Values
                           Values
Timber and other                             Future products:            Protection of
building materials   Soil fertility                                      biological
                                             Medicines                   diversity
                     Flood control
Fuelwood                                     Genetic
                                                                         Maintaining
                     Water purification      resources
Medicinal plants                                                         cultures of local
                                                                         people
                     Pollution control       Biological
Edible wild fruits                           insights
and plants                                                               Continuing
                     Recreation and
                                                                         ecological and
                     tourism                 Food sources
Fiber                                                                    evolutionary
                     Education                                           processes
                                             Building
                                             supplies
                     Ecological
                     services (pest          Future ecological
                     control,                services
                     pollination)

                     Genetic
                     information
            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 Yanomami
                   South America




    The Huli                       The Pygmies
Papua New Guniea                   Central Africa
           Prevention                   Restoration


Protect most diverse and               Reforestation
endangered areas
                                       Rehabilitation
Educate settlers about sustainable     of degraded
agriculture and forestry               areas

Phase out subsidies that encourage     Concentrate
unsustainable forest use               farming and
                                       ranching on
Add subsidies that encourage           already-cleared
sustainable forest use                 areas

Protect forests with debt-for-nature
swaps, conservation easements,
and conservation concessions

Certify sustainably grown timber

Reduce illegal cutting

Reduce poverty

Slow population growth
     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
                                     Water use and pollution
                                      and soil nutrient loss        Freshwater
              Food supply
                                                                    supply and
              and demand
                                           Water availability        demand

   Changes in                    Deforestation
                                                   Changes in
water supply and                                   precipitation      Erosion,
  temperature                                    and temperature    pollution, and
               CO2, CH4,                                             changes in
            N2O emissions                                            water flow
                                            Habitat change
                                           and fragmentation                    Forest product
  Climate change                               of habitat                        supply and
                                                                                   demand
                                             CO2 emission

                Changes in                     Loss and
               transpiration                 fragmentation         Loss and
                and albedo       Loss           of habitat      fragmentation
                                of crop
                                                                   of habitat
                               genetic
         Habitat               diversity                                         Reduced
         change                                                                 resistance
                                                                                to change
                                       Biodiversity loss
        About 1.5 - 10 million Species live
                     on Earth
          Estimates of the Numbers of Species in the World

                  Groups of          Species            Maximum             Most conservative
                  Organisms         described           estimates              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%
   67%                           Critically
Secure or                        imperiled
apparently
                                 8%
  secure
                                 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     The Ecosystem Approach

           Goal                     Goal

  Protect species from      Protect populations of
  premature extinction      species in their natural
                            habitats




         Strategies                Strategy
• Identify endangered      Preserve sufficient areas
  species                  of habitats in different
                           biomes and aquatic
• Protect their critical   systems
  habitats




          Tactics                   Tactics
• Legally protect          • Protect habitat areas
  endangered species         through private purchase
                             or government action
• Manage habitat
                           • Eliminate or reduce
• Propagate endangered       populations of alien
  species in captivity       species from protected
                             areas
• Reintroduce species
  into suitable habitats   • 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        Northern spotted   Gray wolf      Florida panther    Bannerman's
manatee        owl (threatened)                                     turaco (Africa)




Devil's hole    Snow leopard      Symphonia      Black-footed       Utah prairie dog
pupfish         (Central Asia)    (Madagascar)   ferret             (threatened)




Ghost bat       California        Black lace     Black rhinoceros   Oahu tree
(Australia)     condor            cactus         (Africa)           snail
                       Figure 22-7 (2)
                          Page 565

Grizzly bear    Kirtland's    White top       Arabian oryx    African elephant
(threatened)     warbler      pitcher plant   (Middle East)   (Africa)




Mojave desert   Swallowtail   Humpback        Golden lion     Siberian tiger
tortoise        butterfly     chub            tamarin         (Siberia)
(threatened)                                  (Brazil)
                          Figure 22-7 (3)
                             Page 565

West Virginia     Giant panda     Whooping   Knowlton         Blue whale
spring salamander (China)         crane      cactus




Mountain gorilla   Pine barrens   Swamp      Hawksbill sea   El Segundo blue
(Africa)           tree frog      pink       turtle          butterfly
                   (male)
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      Brachiopods
                Gondwana
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     Great auk   Dodo   Dusky seaside     Aepyornis
 pigeon                            sparrow       (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      Blue whale, giant panda,
(K-strategist)             rhinoceros

Specialized niche          Blue whale, giant panda,
                           Everglades kite

Narrow distribution        Many island species,
                           elephant seal, desert pupfish

Feeds at high trophic      Bengal tiger, bald eagle,
level                      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
          Range 100 years ago
          Range today
          (about 2,300 left)

Indian Tiger
Range in 1700
Range today
(about 2,400 left)

           Black Rhino
Probable range 1600
Range today
(300,000 left)
        African Elephant
         Former range
         Range today
         (34,000–54,000 left)
Asian or Indian Elephant
      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                                          94%
 Temperate evergreen forests                                          94%

       Temperate grasslands                                     72%

    Mixed mountain systems
                                                                71%

         Tropical dry forests                                   70%
   Subtropical and temperate
                 rain forests                                  67%

Cold deserts and semideserts                           55%

        Mixed island systems                           53%

           Warm deserts and                      44%
               semideserts
       Tropical humid forests                  37%

         Tropical grasslands             26%

    Temperate boreal forests           18%

                      Tundra    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
                             Habitat
                              loss

                                                  Habitat
      Overfishing
                                                degradation




                       Basic Causes
                                                        Introducing
Climate             • Population growth                  nonnative
change
                    • Rising resource use                 species
                    • No environmental
                      accounting
                    • Poverty

                                                     Commercial
  Pollution                                            hunting
                                                         and
                                                      poaching
                                         Sale of
               Predator                exotic pets
                  and                     and
              pest control             decorative
                                         plants
     Case Studies - Elephants
                    Endangered
1. Ecological pressures – shrinking habitat
2. 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 year
2. Socio-political pressures – Supply meat for
   growing east coast cities
3. 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 1987
1. Ecological pressures – shrinking habitat
2. Socio-political pressures – alligator nuisance,
   sustainable use, tourism
3. 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

								
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