Extinction Class 5 Jan 26, 2009 Last Class Today - - PowerPoint PPT Presentation

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Extinction Class 5 Jan 26, 2009 Last Class Today - - PowerPoint PPT Presentation

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Extinction Class 5 Jan 26, 2009 Last Class Today Endemism Species Ecosystem Role Estimating extinction Extinct Species Rate of Extinction Cause of

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Extinction

Class 5 Jan 26, 2009 Last Class

  • Today

Endemism

  • Species’ Ecosystem Role

Extinct Species

  • Estimating extinction

Rate of Extinction

  • Cause of Extinction Number of

Species Species Area relationship

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Geologic Extinctions

Cambrian explosion Paleozoic Triassic explosion

Ordovician Devonian Permian Triassic Cretaceous

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Ecosystem Roles

Dominant Species – Very common and have a strong effect on other members of the community.

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Ecosystem Roles

Dominant Species – Very common and have a strong effect on other members of the community. Ecosystem Engineers – Modify habitat; presence or absence will change community

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Ecosystem Roles

Dominant Species – Very common and have a strong effect on other members of the community. Ecosystem Engineers – Modify habitat; presence or absence will change community Keystone Species – species that has a greater impact on community than would be expected by its overall biomass.

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Ecosystem Roles

Keystone Species – species that has a greater impact on community than would be expected by its overall biomass.

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Case Study:

Sea Otters & Sea Urchins

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Case Study:

Sea Otters & Sea Urchins

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Causes of Extinction

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Measuring Current Extinctions

Direct observation are difficult Indirect observation: species - area relationship

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Estimating extinction rates

Log(Number

  • f species S)

Log(Area A)

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Estimating how many species go extinct

Log(Number

  • f species S)

Log(Area A)

using z=.15 (this is arbitrary) deforestation = 1.8% per year (Anow / Aoriginal = 98.2/100) 10 million species (Soriginal) Snow = 9,973,000

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Causes of extinction?

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Causes of extinction

Habitat destruction habitat loss (less area = fewer species)

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Causes of extinction

Habitat destruction habitat loss (less area = fewer species) habitat fragmentation

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Causes of extinction

Habitat destruction habitat loss (less area = fewer species) habitat fragmentation Edge effects

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Causes of extinction

Habitat destruction Habitat loss (less area = fewer species) Habitat fragmentation Edge effects Isolation

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Exotic species

Exotic species: species introduced to regions outside of their native range Invasive species: an exotic species with strongly increasing populations (and most often detrimental effect on the native species or habitats)

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Exotic species

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Invasive species

Introduced to Guam, predated and eradicated all native endemic bird species Introduced to the South- East USA for their edible leaves and pretty flowers. Overgrowing forests, changing native habitats Introduced through boats into Great Lakes, clogging up water intakes, removing food more effective out of water column than natives.

Brown tree snake Kudzu Zebra mussel

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Pollution

Point sources Non-Point sources

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Pollution

Air Global warming Acid rain Ozone depletion, smog, ....

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Water

Pollution

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Heavy metal

Water Body Species Women of childbearing age, young children (# of meals) All Other Individuals (# of meals)* Lake Iamonia Largemouth Bass One per month One per week Lake Jackson Black Crappie, Bluegill, Largemouth Bass One per month One per week Lake Miccosukee Bluegill Largemouth Bass Two per week One per month Two per week One per week Lake Munson Black Crappie, Redear Sunfish One per month One per week Moore Lake Largemouth Bass One per month One per week

http://www.myfloridaeh.com/community/fishconsumptionadvisories/FWFGuide.htm

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Water Toxins Nutrients eutrophic vs oligotrophic

Pollution

PRESS RELEASE, JULY 26, 2004 LOUISIANA UNIVERSITIES MARINE CONSORTIUM AVERAGE SIZE "DEAD ZONE" IN ANYTHING BUT AN AVERAGE YEAR The coast-wide extent of the Louisiana "dead zone" mapped this week is slightly larger than average at 15,040 km2 (5,800 square miles). The long-term average since mapping began in 1985 is 13,000 km2 (5,000 square miles). The river flow and the offshore conditions prior to the mapping cruise were anything but normal and were more reminiscent of the Great Mississippi River Flood of 1993. The river in 2004 peaked in discharge several times in January, February March and May, followed by a prolonged above average flow that persisted from June into July, as in 1993.

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Exploitation

Commercial Recreational

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Incidental Exploitation

Bycatch: albatross, whales, .... Predator control in parks Recreation Pets

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Diseases

(Atelopus zeteki) www.clemetzoo.com/conservation/project_golden_frog.asp

Chytrid, a fungus, is believed to be one of the sources for amphibian decline

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Causes of extinction

Habitat destruction Exotic species Pollution Exploitation Diseases