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A Primer of Ecology: Understanding Species Loss Due to Deforestation and Extinction Crisis

Explore the impact of deforestation on species loss, extinction rates, and conservation strategies. Learn about biodiversity, vulnerable species, and population viability analysis. Discover solutions to prevent mass extinctions.

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A Primer of Ecology: Understanding Species Loss Due to Deforestation and Extinction Crisis

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  1. Lyme Disease Borrelia burgdorferi

  2. Species Area Curves S = CAZ (log S) = Z (log A) + (log C) From: Gotelli, N. J. 1995. A primer of ecology. Sunderland, MA: Sinauer Assoc. 1-206 p.

  3. Species Loss Due to Deforestation Based on empirical results, z typically between 0.15 and 0.35 before z = 0.15 Log # Species after z = 0.35 Log Forested Area

  4. Species Loss Due to Deforestation Number of species before deforestation Number of species after deforestation Proportion of species after deforestation High and low estimate (I.e., 10-20%) of spp. extinctions in tropics with 50% deforestation (expected in 30 years)

  5. What About The Birds? 95% “deforestation”, ~ 160 spp. of eastern forest birds, 4-5 extinctions.

  6. What About The Birds? • 160 x 0.050.25 = 75 • 85 extinctions expected • Only 50% of forest destroyed at any one time • Only ~28 birds endemic to or breed only in east coast forests • 28 x 0.50.25 = 23.5 • 4-5 extinctions expected

  7. Problems With Species-Area Approaches • What is the “real” rate of deforestation? • How many species are endemic to an area. • endemic means found only in that location • What proportion of species are found in tropical forests • Extinction rate as high as 27,000 spp. / year in tropical forests alone (Wilson, 1992)

  8. Biodiversity at the Species Level From Textbook, Primack

  9. Extinctions Since1600 • ~ 65% of these extinctions since 1850 • ~ 135 bird and mammal extinctions since 1850

  10. Review: Background Rate

  11. Are We in a Mass Extinction? current extinction rate background rate, high estimate background rate, low estimate Current extinction rate for birds and mammals ~ 65 to 200 times higher than background rate

  12. What If Things Don’t Change? Endangered, Threatened or Vulnerable (IUCN) 1130 mammals + 1180 birds = 2313 Projected extinction rate ~ 1,700 to 5,100 times higher than background rate

  13. What If Deforestation Continues?

  14. What If Climate Change Continues?

  15. What We’ve Finished • EXTINCTIONS PAST AND PRESENT • Causes of extinction • Early mass extinctions • “Blitzkrieg” in the Pleistocene • Recent extinctions

  16. What Can We Do? • Given the impending extinction crisis, what can we can do?

  17. Susceptibility to Extinction • Species with only a few populations • Species that need a large home range • Animal species with large body size • Small or declining populations • Read others in book (Primack - Chapter 8)

  18. Biology of Small Populations • Population Dynamics of Small Populations • Genetics of Small Populations • Population Viability Assessment

  19. Population Viability Analysis (PVA) • The science of determining the probability that a population will persist for a given time • We will use VORTEX

  20. The “Population” in Conservation • IUCN • Population is defined as the total number of individuals of the taxon . . . • Subpopulations are defined as geographically or otherwise distinct groups in the population between which there is little exchange (typically one successful migrant individual or gamete per year or less.

  21. “Closed Population”

  22. 2nd Homework Assignment • Identify a small animal population (< 1,000) and learn a little about it. • Full description on web page. • Do not use African Wild Dogs! • Basis for term paper project. • Due: Friday, March 2 • Note HW1 due March 1

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