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Are We Treating the Symptom or the Cause of the Problem? Often rush into captive propagation without addressing limiting factor – “Headstarting” Sea Turtles.

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Presentation on theme: "Are We Treating the Symptom or the Cause of the Problem? Often rush into captive propagation without addressing limiting factor – “Headstarting” Sea Turtles."— Presentation transcript:

1 Are We Treating the Symptom or the Cause of the Problem? Often rush into captive propagation without addressing limiting factor – “Headstarting” Sea Turtles (Tate 1990) rear until old enough to avoid predation on nesting grounds Better to protect nesting ground – Hatcheries and barges for Salmon damns, habitat loss, fishing, etc are cause – May be justified to learn about propagation and control Mariana Crow

2 Removing the Cause of Decline This is really the crux of endangered species conservation Requires detailed observation and likely experimentation to fully understand reason for decline – Brown tree snake was not immediately recognized – Condor limiting factors required telemetry to ID not 1080, not disturbance at nest, not shooting, likely lead poison because Condors need open habitat to find food and hunters/ranchers common there

3 Facing the Evil Quartet Typically we are up against – habitat destruction/degradation – exotics – trophic cascades – overharvest – contaminants Contaminants and overharvest are easiest to remove or reduce

4 Recovery after Agent of Decline Removed Stop Over harvest – whales, alligator Remove Pesticides – Peregrine, Bald Eagle, Brown Pelican Remove Pesticides and Modify Habitat Needs – Mauritius Kestrel (Jones et al. 1991) 1974-----4 birds 1991-----127-145 birds

5 A Complex Example of Addressing Limiting Factors Rhinos in Africa http://gurukul.ucc.american.edu/Ted/RHINOBLK.HTM http://gurukul.ucc.american.edu/Ted/RHINOBLK.HTM Destruction of habitat, hunting, illegal trade in products (folk medicine, dagger handles) – reduction in numbers from 65,000-100,000 in 1960s to ~3,000 today regulations (CITES) scientific study of medicinal effects Leader of Yehman using agate handle dagger shoot to kill poacher policy De-horning Ranching to flood market

6 Little Progress with Rhinos Can’t change old beliefs quickly – medicinal effects of horn Value of horn in poor countries makes risk of death worth it De-horning not very effective (Berger 1998, Rachlow and Berger 1997) – grow back (possible sustainable harvest?) – killed out of spite – even small portion of horn near skull valuable – dehorned mothers less able to defend calfs from hyenas Need to work at both ends of trade routes

7 Hope with One-horned Rhinos (Dinerstein 2003) Rhinos in India-Nepal are increasing with creation of Royal Chitwan National Park – Community pride, ecotourism, natural resource benefits to residents, Royal family of Nepal leadership General approach – Design landscapes with large, protected cores – Introduce powerful economic incentives, legislation, awareness – Identify bold leadership to rally political will Translocation Redistribution of park revenue to locals Resettlement or land transfer

8 Exotics are Very Difficult to Control Disease, Snakes – Technology not adequate to control – Buy time by “marooning” (Williams 1977) release small numbers of species with poor dispersal ability in isolated habitat (typically islands) 700 islands off New Zealand – Saddleback, Kakapo (flightless parrot), Takahe (Rail) Buys time until feral introduced mammals can be removed Guam Rail released on Rota

9 Conservation in New Zealand

10 Marooning on Islands

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12 Tiritiri Matangi

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14 Predator Removal

15 Improve Nesting Success

16 Translocation

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18 Supplements

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20 Revegetation and Recolonization

21 Little Barrier Island in Distance

22 Mainland Strategies

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26 Revegetation

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28 Native Parrot Habitat

29 It will be more difficult 7.4 billion (2016)

30 References Dinerstein, E. 2003. The return of the unicorns. Columbia University Press, NY. Williams, GR. 1977. Marooning--a technique for saving threatened species from extinction. International Zoo Yearbook 17:102-106.


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