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

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

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

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) birds birds

A Complex Example of Addressing Limiting Factors Rhinos in Africa Destruction of habitat, hunting, illegal trade in products (folk medicine, dagger handles) – reduction in numbers from 65, ,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

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

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

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

Conservation in New Zealand

Marooning on Islands

Tiritiri Matangi

Predator Removal

Improve Nesting Success

Translocation

Supplements

Revegetation and Recolonization

Little Barrier Island in Distance

Mainland Strategies

Revegetation

Native Parrot Habitat

It will be more difficult 7.4 billion (2016)

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