Types of Extinction

1
Types of Extinction

• 1. Local Extinction occurs when a species no
  longer occurs in area where it was once found
• 2. Ecological Extinction occurs when so few
  members of a species are left that it can no
  longer play its ecological role where it is found
  
• 3. Biological Extinction occurs when a species
  no longer occurs anywhere on Earth. Examples

2
Passenger pigeon
Dusky seaside sparrow
Great Auk
Dodo
Aepyornis (Madagascar)
Fig. 22.6, p. 555
3
Mass Extinction vs. Background extinction

• Background extinction extinction is a natural
  process, each year a relatively small number of
  species become extinct naturally. The average is
  about one species per million per year. .0001
• Mass extinction is when there are periods when
  many organisms become extinct over thousands of
  years. These are followed by periods of adaptive
  radiation when diversity increases
• Aldo Leopold said that we know very little of the
  ecological roles of the worlds species. Until we
  know more we should use the precautionary
  principle.

4
Geological Periods
Mass extinctions
800
600
Number of families of marine animals
?
400
200
0
570
505
438
360
286
208
144
65
0
Millions of years ago
Fig. 22.10, p. 558
5
The extinction crisis

• Many scientists believe there is ample evidence
  to show
• that we are in the middle of the six mass
  extinction.
• WWF found that 34fish, 25amphibians,
  24mammals, 20reptiles, 14 plants, 12birds are
  under threat of extinction
• 11,046 plant and animal species are at risk of
  becoming extinct.
• In the US 539 species have become extinct and 33
  are threatened
• At a 1 extinction rate 1/5 of the species will
  be gone by 2030
• Many scientists believe it is higher than this

6
60
EUROPE
NORTH AMERICA
ASIA
30N
Tropic Of Cancer
Atlantic Ocean
AFRICA
Pacific Ocean
Pacific Ocean
150
90
60E
0
30W
90
120
150
0
SOUTH AMERICA
Indian Ocean
Tropic Of Capricorn
AUSTRALIA
30S
Antarctic Circle
60
ANTARCTICA
Critical and endangered
Threatened
Stable or intact
Projected Status of Biodiversity 19982018
Fig. 22.3, p. 552
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There are three main things that may make the
extinction even worse.

• We are destroying, simplifying and degrading
  coral reefs, tropical forests, wetlands and
  estuaries that have in the pass served as
  important centers for the recovery of
  biodiversity after mass extinction and reducing
  the rates of speciation
• This is the fastest that it has ever happened in
  history
• Human population will accelerate losses.

8
The difficulty in estimating the extinction rate

• 1. extinction takes a long time and is difficult
  to estimate
• 2. scientists have only identified 1.4 million
  species of the worlds 4 to 100 million
• 3. scientists know little of the species they are
  trying to document.
• The RED LIST 16,000 species at risk of
  extinction compiled by World Conservation Union

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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
Bengal tiger, bald eagle, grizzly bear
Feeds at high trophic level
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
Fig. 22.8, p. 558
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Threatened vs. Endangered

• Threatened means that it is still abundant, but
  the numbers are rapidly declining and it is
  likely to become endangered.
• Endangered when there are so few animals that
  the species could become extinct over most of its
  range.

11
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)
Fig. 22.7a, p. 556
Ghost bat (Australia)
California condor
Black lace cactus
Black rhinoceros (Africa)
Oahu tree snail
12
Grizzly bear (threatened)
Arabian oryx (Middle East)
White top pitcher plant
Kirtland's warblers
African elephant (Africa)
Mojave desert tortoise (threatened)
Swallowtail butterfly
Humpback chub
Golden lion tamarin (Brazil)
Siberian tiger (Siberia)
Fig. 22.7b, p. 557
13
West Virginia spring salamander
Giant panda (China)
Knowlton cactus
Whooping crane
Blue whale
Mountain gorilla (Africa)
Swamp pink
Hawksbill sea turtle
El Segundo blue butterfly
Pine barrens tree-frog (male)
Fig. 22.7c, p. 557
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• Critical population density (minimum viable
  population size) critical size of a population
  below which reproduction does not take place.
  Even though the this species is not extinct its
  numbers will continue to decline

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Why preserve wild species

• Economic and medical importance
• 90 of todays food crops were domesticated from
  wild plants
• Genetic engineers require existing wild species
  as sources of genetic material to develop new
  crop strains
• They supply lumber, dyes, paper, fuel, fiber,
  oils, rubber
• 40 of all medicines (worth 200 billion dollars
  per year) were derived from living organisms that
  mainly come from the rainforests

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Scientific and Ecological importance of Wild
Species

• Every species can help scientists understand how
  life evolved and functions
• Produce oxygen, absorb pollutants, moderate
  climate, recycle nutrients, store solar energy,
  detoxify toxins, natural pest control
• Provide genes for future evolution

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Aesthetic and Recreational Importance of Wildlife

• Biophelia love of nature
• A source of beauty, wonder, joy and recreational
  pleasure
• Americans spend 18.2 billion per year on
  ecotourism
• Save them because Mrs. Sealy likes them

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It is Ethically important to preserve wild species

• Each species has a right to exist unrelated to
  its usefulness to us
• It is ethically wrong for us to hasten the
  extinction of any species, and we have the
  ethical responsibility to protect species from
  premature extinction.

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Causes of premature Extinction

• 1. Underlying Causes
• - population growth
• - Economic systems that fail to value the
  ecological services
• - High per capita resource use.

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Causes of Premature Extinction

• HIPPO
• H habitat degradation and fragmentation
• I invasive species
• P pollution
• P population of humans increasing
• O overharvesting and poaching

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Direct causes

• Habitat Loss and Fragmentation
• In order of decreasing impact worst
  rainforests, coral reefs, wetlands, grasslands,
  pollution of freshwater.
• Habitat fragmentation (1st) increases exposed
  surface area making animals more vulnerable to
  predator, disease, etc. (2nd) patches are to
  small to support viable populations (3rd) creates
  barriers that limit species ability to colonize
  new areas.

The map shows important Aspen stands (shown in
red), the open Birch (with some Aspen) wood mix
(shown in orange) and commercial conifer
woodlands. The commercial conifer woodland at
Balliefurth forms an effective barrier and block
to Aspen species dispersal and movements in
Strathspey.
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. Direct causes

• Commercial Hunting and Poaching Illegal sale of
  species, 12 billion per year organized crime has
  been getting involved in smuggling
• Bushmeat hunting wild animals for food is
  depleting many of the great apes and monkeys

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. Direct causes

• Over fishing Only large fish are caught-all
  other animals are thrown back dead or dieing
  (overcatch)- drift-net fishing is the worst,
  everything that touches this invisible curtain
  of death dies

24
. Direct causes

• Predator and Pest Control People exterminate
  species that compete for food and game animals.
  Wolves, prairie dogs, parakeets, elephants,
  coyotes.

25
. Direct causes

• Market for exotic Pets and decorative Plants For
  every live animal captured and sold 50 others are
  killed. Birds, amphibians, mammals, reptiles and
  tropical fish, exotic plants like cacti and

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. Direct causes

• Climate Change and Pollution Global warming and
  toxic chemicals

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. Direct causes

• Non-Native Species Can be accidental or
  deliberate, some have no natural predators,
  competitors or parasites so they take over the
  ecosystem and crowd out other species called
  native species

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Stopping Invasive Species

• 1. do not allow wild animals to escape
• 2. Inspect imported goods
• 3. Ships replace ballast water with fresh
  seawater before entering ports
• 4. Do not trade plants or animals from overseas
• 5. Do not dump your aquarium into local waterways
• 6. Clean your recreational gear before heading
  home, such as boots, kayaks, mountain bikes, dive
  gear etc.

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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
Fig. 22.13, p. 564
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III. Approaches to Protecting Species Against
Extinction

• Ecosystem approach legally protect wilderness
  areas
• Species approach protecting endangered species
  by identifying them and giving them legal
  protection
• Wildlife management approach manage game species
  for sustainable yield. Using hunting laws,
  harvest quotas etc.

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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

Fig. 22.5, p. 555
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Use Treaties

• 1975 Convention on International Trade in
  Endangered Species (CITES). Signed by 169
  countries. Lists 900 species that cannot be
  commercially traded as live specimens or wildlife
  products because they are in danger of
  extinction. It also lists 28,000 species whose
  international trade is monitored and regulated
  because they are at risk of becoming threatened.
  Problems enforcement is difficult and spotty,
  convicted violators often pay only small fines,
  member countries can exempt themselves from
  protecting any species that is on the list, much
  of the highly profitable trade of these animals
  goes on in countries that have not signed the
  treaty.

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Treaties

• The Convention on Biological Diversity Signed
  during the 1992 Rio Earth Summit. Ratified by 188
  countries. The US has refused to ratify this
  treaty, which has hindered progress. Countries
  commit to preserving wild species

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Use Laws

• Endangered Species Act (1973, 2006) makes it
  illegal for Americans to trade, kill or use any
  product from an endangered species. (Unless for
  scientific purpose or enhance the survival of the
  species. Currently the list has over 1,260
  species (60 animals 40 plants)
• Also makes it illegal for state or federal
  governments to authorize any project that will
  jeopardize an endangered species.
• 1,260 on the list, 50-85 added every year
• Fish and Wildlife and National Marine Fisheries
  put together the list
• All species that are listed are required to have
  a critical habitat needed for its survival and
  recovery only ¼ currently have a plan

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Bad Politics

• In 1996 this act was almost replaced by U.S
  Congress who were being backed by timber, mining,
  and private industry.
• Tried to make wildlife protection voluntary on
  private land
• Attempted to have government pay landowners if
  their land was unusable in order to protect an
  endangered species regulatory taking
• Make it harder and more expensive to list newly
  endangered species by tying up government
  wildlife officials in hearings and pre-review
  panels
• Allowing secretary of the interior the power to
  allow a listed species to become extinct -God
  Squad
• give landowners exemptions from the law, and
  prohibiting the public from commenting or filing
  lawsuits to change poorly designed habitat
  conservation plans. HCPs

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• Opponents say ESA has been unsuccessful
  because only a few species have been removed from
  the list. However, many populations have
  stabilized 40

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Strengthen the ESA

• Find out what ecosystems we have.
• Protect most endangered ecosystems.
• Offer financial incentives to private landowners
  to protect species.
• Operates on very limited funds. So we need to
  decide which species to save. Environmentalists
  want the following considered
• Have the best chance for survival.
• Have the most ecological importance to the
  ecosystem.
• Potentially useful for agriculture, medicine or
  industry.
• Some say we dont have enough info to make these
  decisions.

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Encouraging Private Landowners to Protect Species

• Use Habitat Conservation plans which allow
  landowners to kill a certain number of endangered
  species in exchange for protecting species. This
  could include setting aside part of the species
  habitat as a preserve, paying to relocate the
  species, paying the government money to set up a
  suitable habitat elsewhere.
• safe Harbor agreements- voluntary agreement to
  maintain habitat in exchange for technical
  assistance and assurances of no further future
  restrictions
• candidate conservation agreements agree to save
  species not yet listed in exchange for govt
  subsidies

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Conservation

• Conservation Easements The Nature Conservancy
  has preserved 10,800 square miles by buying the
  land.

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• Wildlife Refuges 508 refuges, 20 endangered
  species inhabit them.

41

• Gene Banks Botanical Gardens storing seeds
  under refrigeration. Expensive, doesnt work with
  all seeds, to little storage capacity.

42
Zoos

• Zoos focus on large charismatic animals rely on
  egg pulling captive breeding. Most
  reintroductions fail. Lack of space money cant
  support the minimum of animals needed to
  sustain the pop.

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Wildlife Management

• 1.Manipulation of wildlife populations for their
  welfare human benefit.
• 2. 90 is devoted to producing surpluses of game
  animals game birds.
• 3.Wildlife manages the growth of plant species
  that are the best cover food for game animals.
  
• 4. Sport hunting sport-hunting laws to manage
  populations of game animals- like limits on age,
  sex, number, etc. Proponents of hunting claim we
  need to keep down the of deer because there is
  a population explosion. Opponents say a surplus
  is deliberately created and that the deer is used
  as a smoke screen to hunt many other animals.
• Management of Migratory Waterfowl ducks, geese,
  song birds that fly in north-south routes called
  flyways. International Treaties to protect
  habitats, regulate hunting Bonn Germany