Biodiversity

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• Biodiversity
• Three levels of Biodiversity
• How many species are there?
• What are the values of biodiversity?
• What threatens biodiversity?
• How do we protect biodiversity?
• How do biologists estimate extinction rates?
• How do humans affect extinction rates?

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What is Biodiversity?

• Three Levels
• Genetic Diversity- variety of different versions
  of the same genes within a species
• Species Diversity- number of different kinds of
  organisms within a community or ecosystem
• Ecological Diversity- richness and complexity of
  biological community (number of niches, trophic
  levels, ecological processes)

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How many Species Exist?

• Nobody knows for sure- millions still need to be
  studied
• 1.7 million presently known
• Estimates of actual number range from 10-50
  million
• Most in the tropics (hot spots)

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Why are so many species unidentified and
unstudied?

• Biologists know most about large species
• Smaller groups poorly studied
• Biodiversity concentrated in tropics but most
  fieldwork concentrated in temperate regions
• Biggest need is study of insects in tropical
  areas!

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What are the values of Biodiversity?Why do we
care if it disappears?

• Ecosystems and the species living in them have
  enormous economic value to humans
• 33 trillion per year
• This is known as Earths biological wealth
• Wild species have many types of values besides
  dollar values

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Two Major Types of Species Value

• Instrumental Value
• Existence or use benefits another entity
• Also called anthropocentric value

• Intrinsic Value
• Has value for its own sake
• Does not have to be useful to have value
• Arguments for intrinsic value in different
  religions

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• If all species created by God then all have value
• We (humans) are in charge of Gods creation its
  not here just for us but for him
• Similar ideas found in Judaism, Islam

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Values of Biodiversity Food Agriculture

• Ecologists estimate that up to 80,000 edible wild
  plants could be used by humans
• Also may be useful as genetic material to improve
  domestic crops

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Values of BiodiversityDrugs and Medicines

• More than half of all prescriptions contain some
  natural ingredients
• Value of these products is 30 billion per year
• Indigenous people are rarely acknowledge or
  compensated for these products

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• Success stories include rosy periwinkle from
  Madagascar- used to make cancer drugs that treat
  childhood leukemia and Hodgkins disease
• Many medicinal plants yet to be discovered

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Natures Pharmacy
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Natures Pharmacy
Rauvolfia
Rauvolfia sepentina, Southeast
Asia Tranquilizer, high blood pressure
medication
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Natures Pharmacy
Foxglove
Digitalis purpurea, Europe Digitalis for heart
failure
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Natures Pharmacy
Pacific yew
Taxus brevifolia, Pacific Northwest Ovarian
cancer
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Natures Pharmacy
Cinchona
Cinchona ledogeriana
South America Quinine for malaria treatment
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Natures Pharmacy
Rosy periwinkle
Cathranthus roseus, Madagascar Hodgkin's
disease, lymphocytic leukemia
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Natures Pharmacy
Neem tree
Azadirachta indica, India Treatment of many
diseases, insecticide, spermicide
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Values of Biodiversity Ecological Benefits

• Organisms perform many services in their
  ecosystems
• Soil formation
• Waste disposal
• Air and water purification
• Nutrient cycling
• Pest control
• Spaceship Earth- every species is a rivetwe
  dont know which one will make the whole ship
  fall apart

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Values of BiodiversityAesthetic and Cultural
Benefits

• Outdoor Activities
• Psychological and Emotional well- being
• Spiritual
• Economic Value

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• Ecotourism is a growing industry
• Species can have value if they are beautiful,
  awe-inspiring

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What Threatens Biodiversity?Natural Causes

• 99 of all species that ever existed have gone
  extinct
• Mass extinctions have wiped out vast numbers of
  species many times before
• Current rate of extinction is fastest it has ever
  been (1000-10,000x higher than natural rate)

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How Bad is It?

• 12,259 species known by IUCN (World Conservation
  Organization) to be threatened with extinction
• Sample of 47 common farmland and woodland birds
  monitored in 18 European countries show 71
  decline from 1980-2002

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• Two best-monitored groups of worlds animals are
  mammals and birds
• Every 4th mammal (24) and every 8th bird (12)
  facing high risk of extinction
• Across European continent
• 42 of mammals threatened
• 15 of birds threatened
• 45 of butterflies, 30 of amphibians, 45 of
  reptiles, 52 of freshwater fish threatened

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Percentages of Various Types of Organisms
Threatened with Extinction by Human Activities
34 (51 offreshwater species)
Fish
24
Mammals
20
Reptiles
14
Plants
Birds
12
Fig. 9-5, p. 188
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Types of Species Extinction

• Local extinction
• Ecological extinction
• Biological extinction

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Some Prematurely Extinct Species
Passenger pigeon
Great auk
Dodo
Dusky seaside sparrow
Aepyornis (Madagascar)
Fig. 9-2, p. 185
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Endangered and Threatened Species

• Endangered species- in immediate danger of
  extinction over all or part of their range
• Threatened species- not in danger yet but
  vulnerable to becoming endangered

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Endangered and Threatened Species
White top pitcher plant
Kirtland's warbler
Grizzly bear (threatened)
Arabian oryx (Middle East)
African elephant (Africa)
Swallowtail butterfly
Humpback chub
Siberian tiger (Siberia)
Mojave desert tortoise (threatened)
Golden lion tamarin (Brazil)
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Endangered and Threatened Species
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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More Endangered and Threatened Species
Florida manatee
Northern spotted owl (threatened)
Bannerman's turaco (Africa)
Gray wolf
Florida panther
Devil's hole pupfish
Snow leopard (Central Asia)
Black-footed ferret
Symphonia (Madagascar)
Utah prairie dog (threatened)
Ghost bat (Australia)
Black rhinoceros (Africa)
Oahu tree snail
California condor
Black lace cactus
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Characteristics of Extinction-prone Species
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
California condor, grizzly bear, Florida panther
Large territories
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Problems Estimating Extinction Rates

• Extinction not easily documented over time
• Many species remain unidentified
• Little is known about most identified species

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Estimating Extinction Rates

• Estimates from records and fossils
• Species-area relationship
• Models to estimate risks of extinction for a
  particular species
• Estimates of extinction rates can vary depending
  on available data and what assumptions are used

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Causes of Premature Extinction

• HIPPO
• Habitat destruction and fragmentation
• Invasive (alien) species
• Population growth (humans)
• Pollution
• Overharvesting

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Causes of Premature Extinction
Habitat loss
Pollution
Overfishing
Habitat degradation and fragmentation
Commercial hunting and poaching
Climate change
Introducing nonnative species
Sale of exotic pets and decorative plants
Predator and pest control
Secondary Causes

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

Basic Causes
Fig. 9-7, p. 190
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What Threatens Biodiversity?Habitat Destruction

• Number one reason for the current increase in
  extinctions
• Habitats most in danger include tropical and
  temperate forests, wetlands, and prairies

Spotted Owl
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Reduced Ranges
Indian Tiger
Range 100 years ago
Range today (about 2,300 left)
Fig. 9-8a, p. 191
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Reduced Ranges
Black Rhino
Range in 1700
Range today (about 2,400 left)
Fig. 9-8b, p. 191
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Reduced Ranges
African Elephant
Probable range 1600
Range today (300,000 left)
Fig. 9-8c, p. 191
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Reduced Ranges
Asian or Indian Elephant
Former range
Range today (34,00054,000 left)
Fig. 9-8d, p. 191
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What Threatens Biodiversity?Habitat Fragmentation

• Reduction of habitat into smaller, more scattered
  patches
• Many species need large territories to exist
• Divides population into small, vulnerable groups
• Causes edge effect
• Related to island biogeography

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What about Worlds Ecosystems?

• Worlds forests house almost ½ global
  biodiversity
• They are disappearing at rate of 0.8 per year
• Estimated 80 of original forest that covered
  Earth has been cleared, damaged, or fragmented
• Tropical forests vanishing at 4 per year
• U.S. has lost more than 90 of its once
  species-rich wetlands
• 1/3 of worlds coral reefs already gone, another
  1/3 under threat

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What Threatens Biodiversity?Hunting and Fishing

• Overharvesting is responsible for the depletion
  or extinction of many species
• Examples include passenger pigeon, bison, whales
• Overfishing continues to threaten many species

Bison (above) and dodo (right)
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John James Audubon on the Passenger Pigeon

• The air was literally filled with pigeons the
  light of noon-day was obscured as by an eclipse,
  the dung fell in spots, not unlike melting flakes
  of snow and the continued buzz of wings had a
  tendency to lull my senses to reposeBefore
  sunset I reached Louisville, distance from
  Hardensburgh 55 miles. The pigeons were still
  passing in undiminished numbers, and continued to
  do so for three days in succession.

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What Threatens Biodiversity?Commercial Products
and Live Specimens

• Includes both live specimens (pet trade) and
  parts of species
• Powdered rhino horn sells for 28,000 per kg
• Other examples are tigers, elephants, tropical
  fish and birds, plants such as wild ginseng

Endangered Black Rhino
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Confiscated Products From Endangered Species
Fig. 9-18, p. 199
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What Threatens Biodiversity?Predator and Pest
Control / Invasive Spp.

• Animals can be harmed because they are considered
  pests, or because they are victims of another
  pest control effort
• Examples include prairie dogs, coyotes, bobcats
• Invasive species (more than 4500 in the U.S.)
  include
• Zebra mussels Kudzu
• Purple loosestrife Round goby
• Asian long-horned beetle

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Deliberately Introduced Species
Purple looselife
European starling
African honeybee (Killer bee)
Nutria
Salt cedar (Tamarisk)
Marine toad
Water hyacinth
Japanese beetle
Hydrilla
European wild boar (Feral pig)
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Accidentally Introduced Species
Sea lamprey (attached to lake trout)
Argentina fire ant
Eurasian muffle
Brown tree snake
Common pigeon (Rock dove)
Formosan termite
Zebra mussel
Asian long-horned beetle
Asian tiger mosquito
Gypsy moth larvae
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Kudzu
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Fire Ant Invasion
1918
2000
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Reducing Threats from Nonnative Species

• Prevention is best
• Identify the characteristics of nonnative species
• Identify vulnerable ecosystems
• Thoroughly inspect imports
• Establish appropriate international laws
• Discharge of ballast waters from ships

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• Examples include chestnut blight and distemper in
  black-footed ferret
• When a new disease is introduced it may throw off
  the balance of the whole system

What Threatens Biodiversity?Diseases
Pollution

• Often a greater threat in higher trophic levels
  because of bioaccumulation (marine mammals, birds
  of prey)
• Common pollutants include pesticides and other
  toxic chemicals, and lead

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Biomagnification of DDT
DDT in fish-eating birds (ospreys) 25 ppm
DDT in large fish (needle fish) 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. 9-16, p. 197
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Litter Kills Seals
Fig. 9-19, p. 200
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What Threatens Biodiversity?Genetic Assimilation

• Rare species can become even more rare when they
  crossbreed with other species that are more
  numerous and more hearty.
• Examples are wolves, trout, and salmon