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4.2 Evaluating Biodiversity and Vulnerability

4.2 Evaluating Biodiversity and Vulnerability. Extinction and threats to biodiversity. Remember Extinct is FOREVER!!. Causes of Extinction . Two major causes Natural Causes (Non-Human) Human Causes. Natural Causes (Non-Human). Volcanic Eruptions Drought Meteors Glaciers and ice age

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4.2 Evaluating Biodiversity and Vulnerability

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  1. 4.2 Evaluating Biodiversity and Vulnerability Extinction and threats to biodiversity

  2. Remember Extinct is FOREVER!!

  3. Causes of Extinction • Two major causes • Natural Causes (Non-Human) • Human Causes

  4. Natural Causes (Non-Human) • Volcanic Eruptions • Drought • Meteors • Glaciers and ice age • Competition and Predation

  5. Human Causes (HIPPO) • H-Habitat destruction and fragmentation • I- Introduced species • P-Pollution • P-Practices of agriculture • O-Over hunting Dodo Bird – Extinct

  6. Habitat Destruction/ Fragmentation • Degradation: reducing the quality of available habitat • Ex. Logging, agriculture, sewage • Fragmentation: splitting a single large, contiguous system into many disconnected areas • Ex. Putting a road through a wilderness area, or building a dam across a river • Loss: Disappearing of an entire habitat • Ex. Paving natural area for building sites, converting prairies to farmland or residential subdivisions

  7. Invasive Species (Alien, exotic, non-native) • Organisms that are living in an environment outside of its normal range or natural environment • Many are transported by accident • Biocontrol: Species transported intentionally to control other “problem” species populations • Characteristics: • Fast growth/reproduction • Live in wide range of environments • Usually harmful to environment • Outcompete native organisms for local food sources • Leads to extinction of native organisms

  8. Examples of Invasive Species • Asian Carp • Kudzu • Rabbits • Starlings • Cane Toads

  9. Kudzu • “the vine that ate the South” and “The Green Menace”. • Grow up to 1 foot in a day! • Introduced from Japan as quick ground cover to prevent soil erosion

  10. Asian Carp

  11. Asian Carp • Originally imported to clear algae from catfish ponds in the southern USA, • Flooding allowed some carp to escape into the Mississippi River and its tributaries where they quickly became MANY carp • Pose a strong threat to the Great Lakes

  12. Rabbits • “The introduction of a few rabbits could do little harm and might provide a touch of home, in addition to a spot of hunting.” -Thomas Austin in 1859 (Released 24 rabbits) • 1950 ~ 600 million rabbits • 1951 ~ 100 million Government Drugged Watering Hole

  13. Starlings • Today starlings are blamed for agricultural losses of up to $800 million annually in the United States, as well as being implicated in a number of deadly plane crashes. • ~ 60 were released in New York’s Central Park in 1890.

  14. Cane Toad

  15. Cane Toad • Good Example of biocontrol! • In 1937 cane toads were released in Australia's sugar cane plantations to control insect populations • By 1938 ~60,000 cane toads left sugar cane fields for more natural habitat (ate all majority of insect populations and outcompeted native amphibians for food) • Can grow up to 15 inches and eat anything!

  16. Pollution • Toxins added to the environment lead to a loss or degradation of habitat.

  17. Practices of Agriculture • Farming causes habitat loss and reduces biodiversity because of… • Monoculture: Farming of only one crop on a large scale • Pesticides: Often lethal to many non-pest species • Herbicides: Lethal to species other than the weeds

  18. Over Hunting • Collecting, and harvesting wild populations: unregulated, it can diminish local populations or even drive some to extinction • Tasmanian tiger • dodo • North American sea mink • Prairie buffalo • Blue whale

  19. Rates of Extinction • Fossil Records reveal average “lifetimes” of species. • Extinction occurs naturally and is referred to as the background rate of extinction • Humans have lead to a 1000x extinction rate • Estimated 137 species lost each day • 50,000 species a year

  20. Mass Extinctions • The Earth has experienced 5 mass extinctions

  21. Extinction Events • Extinction # 1 ~445 MYA Ordovician Stage – Dramatic loss of sea level due to forming Antarctica -57% Extinct • Extinction # 2 ~ 370 MYA Devonian Stage – Changes in sea level and global cooling stage -50% Extinct • Extinction #3 ~250 MYA Permian Stage- Breaking up of Pangea change ocean currents- 83% Extinction • Extinction #4 ~200 MYA Triassic Stage – Climate warming from volcanic eruptions -48% Extinct • Extinction #5 ~65 MYA Cretaceous – Asteroid impacting the earth – 50% Extinct

  22. Average Lifespan of mammals • Mammals: ~ 1 million years • With approximately 5,000 mammals the background rate is 1 every 200 years • In past 400 years 89 extinctions have been recorded. • 45x background rate. • Over 50 extinctions have occurred in the past century • 100x background rate

  23. Characteristics of Vulnerable Species • Organisms that are… • Limited habitat • Extremely specialized niche • Low reproductive potential • Require a large territory • Migratory • Valuable economically (hunted) • Vulnerable to pollution • Incompatible with civilization • may be more likely to go extinct

  24. Rainforest Vulnerability • Contain ½ of Earth’s known species • Most species have specialized niches • Humans disrupt environment for logging • Changing one part of ecosystem alters the entire web of relationships • Breakdown of rainforest likely lead to extinction of 10% worlds species in 25 years • Regeneration rate is slow due to poor soil quality (rapid year round nutrient cycling depletes soil)

  25. 4.2.5 Red List Criteria

  26. Red List Criteria • IUCN (International Union for Conservation of Nature) • Red list used to determine extinction risk • Specific Aims: • Provide system that can be applied consistently • Improve evaluation of different factors which affect the risk of extinction

  27. Factors used to determine list • Population size: how many organisms of the species still exist? • Reduction in population size: are the numbers falling rapidly or slowly? • Numbers of mature individuals: if many of the remaining individuals are already at or past their reproductive peak, the species is likely to decline even further • Geographic range and fragmentation: • wide geographic range makes the species less prone to extinction • fragmented habitat makes it more difficult for populations to interbreed • Quality of habitat: degraded habitat supports fewer individuals

  28. Categories Extinct (Ex) – No reasonable doubt that the last individual has died. Determined after exhaustive surveys of animals known range and expected habitats Endangered (E)- Survival is unlikely if causal factors continue operating. Drastically reduced populations and habitat

  29. Categories Vulnerable (V) – Near endangered if causal factors continue. Numbers are abundant but are under threat from serious factors (overexploitation, habitat destruction) Rare (R) – Small world populations that are at risk. Unexpected threat could easily cause a critical decline (small geographic disturbance) Unknown (K) – Suspected to fit in one of the above categories but there is a lack of information

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