The Loss of BiodiversityThe Loss of BiodiversityESC 556 Week 9

Causes and ConsequencesCauses and ConsequencesProminent species & causes

◦Endangered Species◦Overexploitation by humans

Causes and ConsequencesCauses and ConsequencesObscure species & causes

◦Habitat destruction◦Plants & insects◦Loss of free services◦Loss of genetic diversity

Habitat DestructionHabitat Destruction

Thousands threatened vs. a few overexploited◦Plowing, logging, overgrazing, flooding,

draining….Dependence on habitats

◦Birds mature tropical forests◦Bats caves◦Trout Can’t breed in acidic or too

warm water

Human impactHuman impactNPP

◦3% of NPP – by one species◦Direct + indirect use (40%)

2/5ths of terrestrial food production Fires, conversion (forest pasture), non-used

NPP

Human population projectionSeas

◦Whales & fishes◦Extinction crisis not as bad◦Open seas safer

Ecosystem ServicesEcosystem ServicesGas cycle disruptionDeforestation

◦Freshwater supplies, increases danger of floods

Insects – pollination of cropsBiological pest controlSubterranean organisms – fertility

of soilAffected without being endangered

Number of PopulationsNumber of PopulationsEnsure persistence vs. short term

changes ◦Spread the risk

Genetic diversity◦Evolutionary potential in the long

term◦Lost even without extinction

ConsequencesConsequencesFood

◦Climate change, soil erosion, water supplies, decline of pollinators, pest problems

Benefits from genetic diversityDiseases

◦e.g. air pollution

SolutionsSolutionsHuman PerceptionNatural reserves not adequate

◦Scarcity, climate changeControl of human population

growthTechnologyAttitudes – public awareness

Planetary KillerPlanetary KillerGradual & subtle declineRed List by IUCN

◦Extinct◦Extinct in the wild◦Critically endangered

Sumatran rhino◦Endangered

Indian rhino◦Vulnerable◦Near threatened◦Least Concern

Red ListRed List

Some CausesSome CausesPoaching

◦Black RhinosOverharvesting

◦FishIntroduction problem

◦Rats, ants, mosquitoes, weedsConversion of natural

environmentsGlobal warming

Trees as critical casesTrees as critical cases976/100,000Living deadOne or few individual / species

◦Chinese hornbeam◦Hibiscus

Concentrated endangerment◦Juan Fernandez islands

20 species < 45 indivs

Historical Extinctions by Historical Extinctions by HumansHumansExtinction without discovery

◦Po’ouliIslands

From the top of the foodchain downBig birds, seals, penguins, songbirds, fish,

shellfish

Australia & New ZealandAustralia & New ZealandAustralia

◦16/263 mammals extinct by European settlers

◦34 in the Red List◦Aboriginals – 60,000 years ago◦Large Mammals first◦Ground birds/tortoises

New Zealand◦Polynesians◦No mammals

Rabbits, deer, rhinos◦Moas, New Zealand Eagle

MadagascarMadagascar88 millions years of isolationMega animals

◦Giant lemur◦Elephant birds

1100 AD, first human settlements

MauritusMauritusDodo

◦Extinct in 80 years

Mediterranean AreaMediterranean AreaAncestral humans

◦Tortoises + marine shellfishAgriculture effects in the Fertile

CrescentWoolly mammoth, woolly rhino,

Irish elk

Africa & Asia◦Cradle of human species◦Humans as native species

Filter principle of conservation biology

Extinction ratesExtinction rates1000 – 10000x1/million year

◦1/500,000 years for mammals◦1/6 million years for echinoderms

Current Extinction RatesCurrent Extinction RatesCount the number of extinctions

observed◦Birds/flowering plants

Assume the endangered species go extinct◦¼ mammals, 1/8 birds

Projections/models◦Habitat- species relationships◦Descent patterns through the red list◦Survival probabilities of species

PVA

Some more solutionsSome more solutionsCaptive breeding

◦California condor◦Mauritus kestrel

Natural reservesLegislation

◦CITES