biodiversity three levels of biodiversity how many species are there? what are the values of...

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?

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)

What is Biodiversity?

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)

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!

• Ecosystems and the species living in them have enormous economic value to humans – $33 trillion per year

• This is known as Earth’s biological wealth

• Wild species have many types of values besides dollar values

What are the values of Biodiversity?

Why do we care if it disappears?

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

• If all species created by God then all have value

• We (humans) are in charge of God’s creation; it’s not here just for us but for him

• Similar ideas found in Judaism, Islam

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

Values of Biodiversity:Drugs 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

• Success stories include rosy periwinkle from Madagascar- used to make cancer drugs that treat childhood leukemia and Hodgkin’s disease

• Many medicinal plants yet to be discovered

Nature’s PharmacyNature’s Pharmacy

RauvolfiaRauvolfia sepentina, Southeast AsiaTranquilizer, high blood pressure medication


FoxgloveDigitalis purpurea, EuropeDigitalis for heart failure


Pacific yewTaxus brevifolia, Pacific NorthwestOvarian cancer


CinchonaCinchonaledogeriana

South AmericaQuinine for malaria treatment


Rosy periwinkleCathranthus roseus, MadagascarHodgkin's disease, lymphocytic leukemia


Neem treeAzadirachta indica,IndiaTreatment of many diseases, insecticide,spermicide


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 rivet…we don’t know which one will make the whole ship fall apart

Values of Biodiversity:Aesthetic and Cultural

Benefits

•Outdoor Activities

•Psychological and Emotional well- being

•Spiritual

•Economic Value

• Ecotourism is a growing industry

• Species can have value if they are beautiful, awe-inspiring

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)

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

• Two best-monitored groups of world’s 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

Fig. 9-5, p. 188

Fish

Mammals

Reptiles

Plants

Birds

34% (51% offreshwater species)

24%

20%

14%

12%

Percentages of Various Types of Organisms Percentages of Various Types of Organisms Threatened with Extinction by Human ActivitiesThreatened with Extinction by Human Activities

Types of Species ExtinctionTypes of Species Extinction

Local extinctionLocal extinction

Ecological extinctionEcological extinction

Biological extinctionBiological extinction

Fig. 9-2, p. 185

Passenger pigeon

Great auk Dodo Dusky seaside sparrow

Aepyornis(Madagascar)

Some Prematurely Extinct SpeciesSome Prematurely Extinct Species

Endangered and Endangered and Threatened Threatened

SpeciesSpecies

EndangeredEndangered species- in immediate species- in immediate danger of extinction over all or part of danger of extinction over all or part of their rangetheir range

ThreatenedThreatened species- not in danger species- not in danger yet but vulnerable to becoming yet but vulnerable to becoming endangeredendangered

Grizzly bear(threatened)

Arabian oryx(Middle East)

White top pitcher plant

Kirtland's warbler African elephant(Africa)

Mojave deserttortoise (threatened)

Swallowtail butterfly

Humpback chub Golden lion tamarin (Brazil)

Siberian tiger(Siberia)

Endangered and Threatened SpeciesEndangered and Threatened Species

West Virginiaspring salamander

Giant panda(China)

Knowlton cactus

Mountain gorilla(Africa)

Swamp pinkPine barrens tree frog (male)

Hawksbill sea turtle

El Segundo blue butterfly

Whooping crane Blue whale

Endangered and Threatened SpeciesEndangered and Threatened Species

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)

Ghost bat (Australia)

California condor Black lace cactus Black rhinoceros(Africa)

Oahu tree snail

More Endangered and Threatened SpeciesMore Endangered and Threatened Species

Characteristic Examples

Low reproductive rate(K-strategist)

Specialized niche

Narrow distribution

Feeds at high trophic level

Fixed migratory patterns

Rare

Commercially valuable

Large territories

Blue whale, giant panda,rhinoceros

Blue whale, giant panda,Everglades kite

Many island species,elephant seal, desert pupfish

Bengal tiger, bald eagle,grizzly bear

Blue whale, whooping crane,sea turtles

Many island species,African violet, some orchids

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

California condor, grizzly bear, Florida panther

Characteristics of Extinction-prone Characteristics of Extinction-prone SpeciesSpecies

Problems Estimating Problems Estimating Extinction RatesExtinction Rates

Extinction not easily documented over timeExtinction not easily documented over time

Many species remain unidentifiedMany species remain unidentified

Little is known about most identified speciesLittle is known about most identified species

Estimating Extinction RatesEstimating Extinction Rates

Estimates from records and fossilsEstimates from records and fossils

Species-area relationshipSpecies-area relationship

Models to estimate risks of extinction for a Models to estimate risks of extinction for a particular speciesparticular species

Estimates of extinction rates can vary Estimates of extinction rates can vary depending on available data and what depending on available data and what assumptions are usedassumptions are used

Causes of Premature ExtinctionCauses of Premature Extinction

““HIPPO”HIPPO”

Habitat destruction and fragmentationHabitat destruction and fragmentation

Invasive (alien) speciesInvasive (alien) species

Population growth (humans)Population growth (humans)

PollutionPollution

OverharvestingOverharvesting

Fig. 9-7, p. 190

Habitat loss

Habitat degradation and fragmentation

Introducing nonnative species

Overfishing

Climate change

Predator and pest control

Pollution

Commercial hunting and poaching

Sale of exotic pets and decorative plants

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

Secondary Causes

Basic Causes

Causes of Premature ExtinctionCauses of Premature Extinction


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

Fig. 9-8a, p. 191

Indian Tiger

Range 100 years agoRange today(about 2,300 left)

Reduced RangesReduced Ranges

Fig. 9-8b, p. 191

Black Rhino

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


Fig. 9-8c, p. 191

African Elephant

Probable range 1600Range today (300,000 left)


Fig. 9-8d, p. 191

Asian or Indian Elephant

Former rangeRange today(34,000–54,000 left)


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

What about World’s Ecosystems?

• World’s 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 world’s coral reefs already gone,

another 1/3 under threat


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)

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 repose…Before 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.”


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

Confiscated Products From Confiscated Products From Endangered SpeciesEndangered Species

Fig. 9-18, p. 199


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

Purple looselife European starling African honeybee(“Killer bee”)

Nutria Salt cedar(Tamarisk)

Marine toad Water hyacinth Japanese beetle Hydrilla European wild boar(Feral pig)

Deliberately Introduced SpeciesDeliberately Introduced Species

Sea lamprey(attached to lake trout)

Argentina fire ant Eurasian muffleBrown tree snake Common pigeon(Rock dove)

Formosan termite Zebra mussel Asian long-hornedbeetle

Asian tiger mosquito Gypsy moth larvae

Accidentally Introduced SpeciesAccidentally Introduced Species

KudzuKudzu

1918

2000

Fire Ant InvasionFire Ant Invasion

Reducing Threats from Reducing Threats from Nonnative SpeciesNonnative Species

Prevention is bestPrevention is best

Identify the characteristics of nonnative speciesIdentify the characteristics of nonnative species

Identify vulnerable ecosystemsIdentify vulnerable ecosystems

Thoroughly inspect importsThoroughly inspect imports

Establish appropriate international lawsEstablish appropriate international laws

Discharge of ballast waters from ships Discharge of ballast waters from ships


Diseases

Pollution

•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

•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

Fig. 9-16, p. 197

DDT in fish-eatingbirds (ospreys)

25 ppm

DDT in largefish (needle fish)2 ppm

DDT in smallfish (minnows)0.5 ppm

DDT in water0.000003 ppm,or 3 ppt

DDT inzooplankton0.04 ppm

Biomagnification of DDTBiomagnification of DDT

Litter Kills SealsLitter Kills Seals

Fig. 9-19, p. 200


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

biodiversity three levels of biodiversity how many species are there? what are the values of...

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