Sustaining Biodiversity: The Species Approach

1
Sustaining Biodiversity The Species Approach

• Chapter 8

2
What role do humans play in the extinction of
species?

• Section 8-1

3
Extinctions are natural but sometimes they
increase sharply

• Biological extinction occurs when a species can
  no longer be found anywhere on the earth.
• The disappearance of species can weaken or break
  some of the connections in the ecosystem.
• The extinction of many species in a relatively
  short period of geologic time is called a mass
  extinction.

4
Some human activities are causing extinction
rates to rise

• Extinction is a natural process but evidence
  indicates that extinction has accelerated as the
  human population has increased, consuming huge
  quantities of resources and creating large and
  growing ecological footprints.
• Scientists from around the world have estimated
  that the current annual rate of species
  extinction is at least 100 to 1,000 times the
  background rate.
• The annual extinction rate is projected to rise
  to about 1 per year, mostly because of habitat
  loss and degradation, climate change, and other
  environmentally harmful effects of human
  activities.
• At a 1 extinction rate, 25 - 50 of the worlds
  current species could vanish by the end of this
  century.

5
Some human activities are causing extinction
rates to rise

• A projected extinction rate of 1 a year may be
  on the low side, for several reasons.
• The rate of species loss and the extent of
  biodiversity losses are likely to increase
  sharply during the next 50100 years due to
  projected growth of the human population.
• Current and projected extinction rates are much
  higher than the global average in parts of the
  world that are already highly endangered centers
  of biodiversity.
• Humans are creating a speciation crisis by
  eliminating or degrading many biologically
  diverse environments that are potential sites for
  the emergence of new species.

6
Some human activities are causing extinction
rates to rise

• Human activities might help to increase the
  speciation rates for other rapidly reproducing
  opportunist species such as weeds, rodents,
  insects, which could further accelerate the
  extinction of other species.

7
Endangered and threatened species are ecological
smoke alarms

• An endangered species has so few individual
  survivors that the species could soon become
  extinct over all or most of its natural range.
• A threatened species (vulnerable species) still
  has enough remaining individuals to survive in
  the short term, but because of declining numbers,
  it is likely to become endangered in the near
  future.
• Some species have characteristics that make them
  especially vulnerable to ecological and
  biological extinction.

8
Characteristics that can put certain species in
greater danger of extinction
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Characteristic
Examples
Blue whale, giant panda, rhinoceros
Low reproductive rate
Blue whale, giant panda, Everglades kite
Specialized niche
Elephant seal, desert pupfish
Narrow distribution
Bengal tiger, bald eagle, grizzly bear
Feeds at high trophic level
Blue whale, whooping crane, sea turtle
Fixed migratory patterns
African violet, some orchids
Rare
Snow leopard, tiger, elephant, rhinoceros, rare
plants and birds
Commercially valuable
California condor, grizzly bear, Florida panther
Large territories
Fig. 8-3, p. 154
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Percentages of various species threatened with
extinction due to human activities
11
Plants
70
34 (37 of freshwater species)
Fishes
Amphibians
30
Reptiles
28
Mammals
21
Birds
12
Fig. 8-4, p. 155
12
Why should we care about the rising rate of
species extinction?

• Section 8-2

13
Species are a vital part of the earths natural
capital

• Three major reasons why we should work to prevent
  our activities from causing the extinction of
  other species
• The worlds species provide natural resources and
  natural services that help to keep us alive and
  support human economies.
• Various plant species provide food crops,
  fuelwood and lumber, paper, and medicine.
• Preserving species also provides economic
  benefits through wildlife/eco tourism.

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Species are a vital part of the earths natural
capital

• Analysis of past mass extinctions indicates that
  it will take 510 million years for natural
  speciation to rebuild the biodiversity that we
  are likely to destroy during your lifetime.
• Many people believe that each wild species has a
  right to exist, regardless its usefulness to us.

15
How do humans accelerate species extinction?

• Section 8-3

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Loss of habitat is the single greatest threat to
species Remember HIPPCO

• HIPPCO summarizes the most important causes of
  extinction from human activities
• Habitat destruction/degradation/fragmentation.
• Invasive (nonnative) species.
• Population growth/increasing use of resources.
• Pollution.
• Climate change.
• Overexploitation.

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Loss of habitat is the single greatest threat to
species Remember HIPPCO

• Scientists say that the greatest threat to wild
  species is habitat loss, degradation, and
  fragmentation. The greatest eliminators of
  species are, in order
• Deforestation in tropical areas.
• Destruction and degradation of coral reefs and
  wetlands.
• Replacement of biologically diverse grasslands
  with monoculture crops.
• Pollution of streams, lakes, and oceans.

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Reductions in the ranges of four species
19
Stepped Art
Fig. 8-6, p. 157
20
Loss of habitat is the single greatest threat to
species Remember HIPPCO

• Island species, often endemic species found
  nowhere else on earth, are especially vulnerable
  to extinction.
• Habitat fragmentationby roads, logging,
  agriculture, and urban developmentoccurs when a
  large, intact area of habitat is reduced in area
  and divided into smaller, more scattered and
  isolated patches, or habitat islands.
• Most national parks and other nature preserves
  are habitat islands.

21
We have introduced species that can disrupt
ecosystems

• After habitat loss and degradation, the biggest
  cause of animal and plant extinctions is the
  deliberate or accidental introduction of harmful
  invasive species into ecosystems.
• Most species introductions are beneficial to us,
  such as food crops, livestock and harvestable
  trees.
• Problems arise when introduced species have no
  natural predators, competitors, parasites, or
  pathogens to help control their numbers in their
  new habitat.

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Harmful invasive species
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Deliberately Introduced Species
Purple loosestrife
European starling
African honeybee (Killer bee)
Nutria
Salt cedar (Tamarisk)
Purple loosestrife
Water hyacinth
Japanese beetle
African honeybee (Killer Bee)
European wild boar (Feral pig)
Fig. 8-7a, p. 159
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Accidentally Introduced Species
Sea lamprey (attached to lake trout)
Argentina fire ant
Brown tree snake
Formosan termite
Zebra mussel
Fig. 8-7b, p. 159
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We have introduced species that can disrupt
ecosystems

• An estimated 7,100 species introduced into the US
  have caused ecological and economic harm.
• CASE STUDY The Kudzu Vine.
• A deliberately introduced plant species grows
  rampant in the southeastern US and is known as
  the vine that ate the South.
• In the 1930s, this vine was imported from Japan
  and planted in the southeastern US in an attempt
  to control soil erosion.

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House overtaken by kudzu
27
Some accidentally introduced species can disrupt
ecosystems

• Many unwanted nonnative invaders arrive from
  other continents as stowaways on aircrafts,
  ships, wooden packing crates, on cars, or with
  tourists.
• Terrestrial examples include
• The aggressive Argentina fire ant which has
  spread over much of the southern US. Fire ants
  can wipe out native ant populations. Fire ant
  mounds can cover fields and yards. When
  disturbed, up to 100,000 ants may attack with
  painful, burning stings. They have killed deer
  fawns, birds, livestock, pets, and at least 80
  people who were allergic to their venom.

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Some accidentally introduced species can disrupt
ecosystems

• Pythons and boa constrictors have ended up in the
  Everglades in Florida after being dumped by their
  owners. Some reach 20 feet long and 200 pounds.
  They are hard to find and kill, and they
  reproduce rapidly. They devour birds, raccoons,
  pet cats and dogs, full-grown deer and
  alligators. Tens of thousands of these snakes now
  live in the Everglades and they may spread to
  other swampy wetlands in the southern half of the
  US.

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Some accidentally introduced species can disrupt
ecosystems

• Bioinvaders also affect aquatic systems and are
  blamed for about two-thirds of fish extinctions
  in the US between 1900 and 2009
• The Great Lakes of North America have been
  invaded by more than 185 alien species. At least
  13 of the recent invading species threaten some
  native species and cause billions of dollars in
  damages.
• Fish-killing sea lamprey.
• Zebra mussel - displaced some species, depleted
  the food supply for others and clogged pipes,
  shutting down water intake pipes for power plants
  and city water supplies, jammed ship rudders, and
  grown in huge masses on boat hulls, piers and
  other solid surfaces.

30
Zebra mussels attached to a water current meter
in Lake Michigan
31
Prevention is the best way to reduce threats from
invasive species

• Scientists suggest several ways to do this
• Fund a massive research program to identify the
  major characteristics that allow species to
  become successful invaders and the types of
  ecosystems that are vulnerable to invaders.
• Greatly increase ground surveys and satellite
  observations to detect and monitor species
  invasions and to develop better models for
  predicting how they will spread and what harmful
  effects they might have.

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Prevention is the best way to reduce threats from
invasive species

• Identify major harmful invader species and
  establish international treaties banning their
  transfer from one country to another, as is now
  done for endangered species, while stepping up
  inspection of imported goods to enforce such
  bans.
• Require cargo ships to discharge their ballast
  water and replace it with saltwater at sea before
  entering ports, or require them to sterilize such
  water or to pump nitrogen into the water to
  displace dissolved oxygen and kill most invader
  organisms.
• Educate the public about the environmentally
  harmful effects of releasing exotic plants and
  pets into the environment near where they live.

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Ways we can slow or prevent the spread of
invasive species
34
Population growth, overconsumption, pollution,
and climate change can cause species extinctions

• Past and projected human population growth and
  excessive and wasteful consumption of resources
  have greatly expanded the human ecological
  footprint, impacting other species.
• Pollution also threatens some species with
  extinction, as has been shown by the unintended
  effects of certain pesticides.
• Each year pesticides kill about 20 of the
  honeybee colonies that pollinate almost 33 of
  U.S. food crops, kill more than 67 million birds
  and 614 million fish each year, and threaten
  about 20 of the countrys endangered and
  threatened species.

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Population growth, overconsumption, pollution,
and climate change can cause species extinctions

• The pesticide DDT can be biomagnified about 10
  million times in an estuary food chain, causing
  animals such as the osprey, brown pelican and
  bald eagles to die.
• Projected climate change could help drive a
  quarter to half of all land animals and plants to
  extinction by the end of this century.

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Bioaccumulation and biomagnification
37
DDT in fish-eating birds (ospreys) 25 ppm
DDT in large fish (needlefish) 2 ppm
DDT in small fish (minnows) 0.5 ppm
DDT in zooplankton 0.04 ppm
DDT in water 0.000003 ppm, or 3 ppt
Fig. 8-11, p. 162
38
CASE STUDY Where Have All The Honeybees Gone?

• About one-third of the U.S. food supply comes
  from insect-pollinated plants, and honeybees are
  responsible for 80 of that pollination.
• A 30 - 40 drop in U.S. honeybee populations has
  been reported since the 1980s, due to
• Pesticide exposure.
• Parasitic mites - can wipe out a colony in hours.
• Invasion by Africanized honeybees.
• A virus traced to Israel, and a certain fungus.
• Poor nutrition because of a decrease in the
  natural diversity of flowers and other plants on
  which bees feed.

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CASE STUDY Where Have All The Honeybees Gone?

• In 2010, about 34 of commercial honeybee
  colonies in the U.S. were lost in part to colony
  collapse disorder (CCD), causing adult bees to
  mysteriously disappear.
• Strategies to help honeybee populations
• Beekeepers are reducing CCD by practicing
  stringent hygiene, improving the diets of the
  bees, and trying to reduce viral infections.
• Cut back on use of pesticides, especially at
  midday when honeybees are most likely to be
  searching for nectar.
• Make our yards and gardens into buffets for honey
  bees by planting native plants that they like.
• Bees need places to live, so some homeowners are
  purchasing bee houses from their local garden
  centers.

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Illegally killing, capturing, and selling wild
species threatens biodiversity

• Some protected species are poached for their
  valuable parts or are sold live to collectors.
• The global illegal trade in wildlife brings in an
  average of at least 600,000 an hour and at least
  66 of all live animals smuggled around the world
  die in transit. Organized crime has moved into
  illegal wildlife smuggling because of the huge
  profits involved.
• Examples include
• A highly endangered, live mountain gorilla is
  worth 150,000.

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Male mountain gorilla
42
Illegally killing, capturing, and selling wild
species threatens biodiversity

• The pelt of a critically endangered giant panda
  can bring 100,000.
• A poached rhinoceros horn can be worth 25,000
  per pound. Rhinoceros are killed only for their
  horns.
• About 25,000 African elephants are killed
  illegally each year for their ivory tusks despite
  an international ban on the sale of poached ivory
  since 1989.
• A coat made from the fur of the Indian or Bengal
  tiger can sell for as much as 100,000 in Tokyo,
  and the body parts of a single tiger are worth as
  much as 70,000. Without emergency action to
  curtail poaching and preserve their habitat, few
  if any tigers may be left in the wild within 20
  years.

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Poached white rhinoceros
44
Illegally killing, capturing, and selling wild
species threatens biodiversity

• More than 60 bird species, mostly parrots, are
  endangered or threatened because of the wild-bird
  trade.
• The pet trade is depleting populations of many
  amphibians, various reptiles, some mammals, and
  many tropical fishes. For each fish caught alive,
  many more die, and the cyanide used to stun
  tropical fish also kills the coral polyps that
  build reefs.
• Some exotic plants are endangered when they are
  gathered to for houseplants and landscapes.
  Collectors may pay 5,000 for a rare orchid or
  15,000 for a saguaro cactus.

45
Rising demand for bush meat threatens some
African species

• Indigenous people in much of West and Central
  Africa have sustainably hunted wildlife for bush
  meat, a source of food, for centuries.
• In the last two decades, bush meat hunting in
  some areas has skyrocketed as hunters try to
  provide food for rapidly growing populations or
  to make a living by supplying restaurants with
  exotic meats.
• Bush meat hunting has led to the local extinction
  of many wild animals, driven one species of
  colobus monkey to complete extinction, and been a
  factor in reducing some populations of
  orangutans, chimpanzees, elephants, and
  hippopotamuses.

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CASE STUDY A Disturbing Message from the Birds

• Approximately 70 of the worlds known bird
  species are declining in number.
• The primary culprits appear to be habitat loss
  and fragmentation.

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How can we protect wild species from extinction?

• Section 8-4

48
International treaties and national laws can help
to protect species

• The 1975 Convention on International Trade in
  Endangered Species (CITES) is a far-reaching
  treaty signed by 174 countries that bans the
  hunting, capturing, and selling of threatened or
  endangered species.
• The Convention on Biological Diversity (CBD),
  ratified by 190 countries (but as of 2011, not by
  the United States), legally commits participating
  governments to reversing the global decline of
  biodiversity and to equitably sharing the
  benefits from use of the worlds genetic
  resources.

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The U.S. Endangered Species Act

• The Endangered Species Act of 1973 (ESA amended
  in 1982, 1985, and 1988) was designed to identify
  and protect endangered species in the United
  States and abroad.
• Under the ESA, the National Marine Fisheries
  Service (NMFS) is responsible for identifying and
  listing endangered and threatened ocean species,
  while the U.S. Fish and Wildlife Service (USFWS)
  is to identify and list all other endangered and
  threatened species.
• Any decision to add or remove a species on the
  list must be based on biological factors alone
  without consideration of economic or political
  factors.

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The U.S. Endangered Species Act

• The ESA forbids federal agencies (except the
  Defense Department) to carry out, fund, or
  authorize projects that would jeopardize an
  endangered or threatened species, or destroy or
  modify its critical habitat.
• For offenses committed on private lands, fines as
  high as 100,000 and 1 year in prison.
• Between 1973 and 2011, the number of U.S. species
  on the official endangered and threatened species
  lists increased from 92 to more than 1,320.

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The U.S. Endangered Species Act

• Since 1982, the ESA has been amended to give
  private landowners economic incentives to help
  save endangered species living on their lands.
• Some believe that the ESA should be weakened or
  repealed, and others believe it should be
  strengthened and modified to focus on protecting
  ecosystems.
• The ESA and international agreements have been
  used to identify and protect endangered and
  threatened marine species such as seals, sea
  lions, sea turtles, and whales.

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CASE STUDY Protecting Endangered Sea Turtles

• Six of the worlds seven sea turtle species are
  critically endangered or endangered.
• Two major threats to sea turtles are loss or
  degradation of beach habitat (where they come
  ashore to lay their eggs and the young hatch),
  and the legal and illegal taking of their eggs.

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Endangered leatherback sea turtle tangled in a
fishing net
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CASE STUDY Protecting Whales A Success Story .
. . So Far

• Easier to kill due to their large size and their
  need to come to the surface to breathe.
• Whalers killed an estimated 1.5 million whales
  between 1925 and 1975, driving 8 of the 11 major
  species to commercial extinction and driving the
  blue whale, the worlds largest animal, to the
  brink of biological extinction.
• The International Whaling Commission estimates
  some whale species are recovering, but many
  conservationists fear that opening the door to
  any commercial whaling may weaken international
  disapproval and legal sanctions.
• Despite the ban on whaling, more than 28,000
  whales were hunted and killed between 1986 and
  2010, mostly by the nations of Japan, Norway, and
  Iceland, which have openly defied the ban.

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We can establish wildlife refuges and other
protected areas

• In 1903, President Theodore Roosevelt established
  the first U.S. federal wildlife refuge at Pelican
  Island, Florida, to help protect birds such as
  the brown pelican from extinction.
• The National Wildlife Refuge System grew to 553
  refuges by 2011.
• More than three-fourths of the refuges serve as
  wetland sanctuaries that are vital for protecting
  migratory waterfowl.

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We can establish wildlife refuges and other
protected areas

• One-fifth of U.S. endangered and threatened
  species have habitats in the refuge system, and
  some refuges have been set aside for specific
  endangered species, such as Floridas Key deer,
  the brown pelican, and the trumpeter swan.
• Harmful activities to wildlife such as mining,
  oil drilling, and use of off-road vehicles occur
  in nearly 60 of the nations wildlife refuges.
• Wildlife refuges receive little funding a third
  of them have no staff, and structures in some
  refuges are in disrepair.

57
Gene banks, botanical gardens, and wildlife farms
can help to protect species

• Gene or seed banks preserve genetic information
  and endangered plant species by storing their
  seeds in refrigerated, low-humidity environments.
• More than 100 seed banks worldwide collectively
  hold about 3 million samples, however
• Some species cannot be preserved in gene banks.
• The banks are expensive to operate and can be
  destroyed by fires and other mishaps.
• A new underground vault on a remote island in the
  Arctic will eventually contain 100 million of the
  worlds seeds and will not be vulnerable to power
  losses, fires, storms, or war.

58
Gene banks, botanical gardens, and wildlife farms
can help to protect species

• The worlds 1,600 botanical gardens and arboreta
  contain living plants, representing almost
  one-third of the worlds known plant species but
  only about 3 of the worlds rare and threatened
  plant species.
• Some endangered or threatened species are raised
  on farms for commercial sale, such as alligator
  farms in Florida and butterfly Papua New Guinea.

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Zoos and aquariums can protect some species

• Zoos, aquariums, game parks, and animal research
  centers are being used to preserve some
  individuals of critically endangered animal
  species, with the long-term goal of reintroducing
  the species into protected wild habitats.
• Two preserving techniques are
• 1. Egg pulling, where wild eggs laid by
  critically endangered bird species are collected
  and then hatched in zoos or research centers.

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Zoos and aquariums can protect some species

• 2. Captive breeding, where some or all of the
  wild individuals of a critically endangered
  species are captured for breeding in captivity,
  with the aim of reintroducing the offspring into
  the wild.
• Limited space and budgets restrict efforts to
  maintain breeding populations of endangered
  animal species that are large enough to avoid
  extinction through accident, disease, or loss of
  genetic diversity due to inbreeding.

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The precautionary principle

• Biodiversity scientists call for us to take
  precautionary action to help prevent premature
  extinctions and loss of biodiversity.
• The principle advocates that when substantial
  preliminary evidence indicates that an activity
  can harm human health or the environment, we
  should take precautionary measures to prevent or
  reduce such harm even if some of the
  cause-and-effect relationships have not been
  established scientifically.

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The precautionary principle

• Using limited financial and human resources to
  protect biodiversity based on the precautionary
  principle involves dealing with three important
  questions
• How do we allocate limited resources between
  protecting species and protecting their habitats?
• How do we decide which species should get the
  most attention in our efforts to protect species?
• How do we determine which areas of land and water
  are the most critical to protect?

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Three big ideas

• We are greatly increasing the extinction of wild
  species by destroying and degrading their
  habitats, introducing harmful invasive species,
  and increasing human population growth,
  pollution, climate change, and overexploitation.
• We should avoid causing the extinction of wild
  species because of the economic and ecological
  services they provide, and because their
  existence should not depend primarily on their
  usefulness to us.
• We can work to prevent the extinction of species
  and to protect overall biodiversity by using laws
  and treaties, protecting wildlife sanctuaries,
  and making greater use of the precautionary
  principle.