1. EXTINCTION PROCESSES EXTINCTION PROCESSES v Rare species are at risk

2. EXTINCTION PROCESSES EXTINCTION PROCESSES v Rare species are at risk

3. EXTINCTION PROCESSES EXTINCTION PROCESSES v Rare species are at risk due to: – environmental stochasticity u Random variation in habitat quality u Extreme cases = catastrophes

4. Environmental Stochasiticity Examples – variable rate of increase Muskox population on Nunivak Island, 1947-1964 (Akcakaya et al. 1999)

5. Environmental Stochasiticity - Example of random K v Serengeti wildebeest data set – recovering from Rinderpest outbreak –Fluctuations around K possibly related to rainfall

6. EXTINCTION PROCESSES EXTINCTION PROCESSES v Rare species are at risk due to: – demographic stochasticity u Random variation birth/death rates – “good” years and “bad” years

7. EXTINCTION PROCESSES EXTINCTION PROCESSES v Rare species are at risk due to: – genetic stochasticity u Random variation in gene freq. due to: – Genetic drift – Bottlenecks – inbreeding

8. EXTINCTION PROCESSES EXTINCTION PROCESSES A. Specialization – habitat restriction u proboscis monkeys and mangrove swamps

9. EXTINCTION PROCESSES EXTINCTION PROCESSES A. Specialization – habitat restriction – range restriction u golden-lion tamarins

10. EXTINCTION PROCESSES EXTINCTION PROCESSES A. Specialization – habitat restriction – range restriction – body size and home-range size u maned wolf Photo by Pete Oxford

11. EXTINCTION PROCESSES EXTINCTION PROCESSES A. Specialization B. Catastrophes – earthquakes, asteroids – 5 mass extinctions – Cretaceous-Tertiary extinctions

12. EXTINCTION PROCESSES EXTINCTION PROCESSES A. Specialization B. Catastrophes – the human catastrophe – humans have caused 75% of extinctions since 1600

13. HUMANS AND EXTINCTION HUMANS AND EXTINCTION A. Role of Overexploitation – Lessons from North America

14. HUMANS AND EXTINCTION A. Role of Overexploitation – Bison A. Role of Overexploitation – Bison presettlement: ca. 60 million presettlement: ca. 60 million used food, hides used food, hides weapon against Native Americans weapon against Native Americans by 1889: only 600 by 1889: only 600

15. HUMANS AND EXTINCTION HUMANS AND EXTINCTION A. Role of Overexploitation B. Role of Exotics – introduced organisms – cause of 20% of extinctions since 1600

16. HUMANS AND EXTINCTION HUMANS AND EXTINCTION B. Role of Exotics – Feral Pigs u game species u destroy understory and groundcover u effect on brown honeycreeper u expensive to exterminate Po’ouli, n = 3 on 2/03

17. HUMANS AND EXTINCTION HUMANS AND EXTINCTION B. Role of Exotics – Domestic Cats u domesticated to kill pests u in 1/3 of U.S. households u humans support high densities

18. HUMANS AND EXTINCTION HUMANS AND EXTINCTION v Cats: Effects on Native Wildlife – Wisconsin: 19 million songbirds, 140,000 game birds per year – Great Britain: 50 million small mammals per year – Australia: endangerment of eastern barred bandicoot Photo: Ian McCann

19. HUMANS AND EXTINCTION HUMANS AND EXTINCTION C. Role of Human Population Size – most abundant mammal (Suzuki) – currently about 6.7 billion – stabilize at ~9 billion by 2042

20. HUMANS AND EXTINCTION C. Role of Human Population Size – Habitat Destruction – Habitat Disturbance – The “human footprint” on habitats is today’s biggest threat to mammals 1. Human density 2. Land transformation 3. Access to areas 4. Electrical power infrastructure

21. CONSERVATION AND HUMAN RESOURCE USE  Humans use ca. 40% of total terrestrial NPP www.usda.gov

22. CONSERVATION AND HUMAN RESOURCE USE  Humans use ca. 40% of total terrestrial productivity  Land pre-empted for agriculture and cities: extinction of 5% of land mammals Richmond, VA – USDA photo

23. CONSERVATION AND HUMAN RESOURCE USE  Humans use 20-30% of total terrestrial productivity  Agriculture pre-emption: extinction of 5%  Energy pre-emption: extinction of 10% more of land mammals Texas oil wellsRussian coal power plant

24. CONCLUSION  Conservation will fail unless: – human population is controlled – human resource use is moderated