There are many disagreements as to whether or not captive breeding is a helpful tool in respect to conservation. Some say that we should concentrate on saving ecosystems, not individual species, others claim that captive-reared animals cannot be returned successfully to the wild (Sarrazin and Barbault, 1996). In this paper I hope to demonstrate that captive breeding of endangered and threatened species is beneficial to conservation.
Altered habitat. Islands contain some of the world's strangest creatures, and unfortunately are affected the worst by human presence. Two examples are New Zealand and Hawaii. Both chains of islands have been greatly altered by humans.
New Zealand. When the Polynesians arrived in New Zealand 36% of the native land birds went extinct; when the Europeans came 17% died out (Towns and Williams, 1993). The authors go on to state that 606 of the country's species are considered threatened in some way. If one takes into account the land mass as compared to the United States, New Zealand has "38 times more threatened taxa." This country has taken conservation to the heart and it recognizes the importance of captive breeding. Butler wrote that "World-wide there are now ever increasing examples of species whose continued survival depends on support from captive-breeding programmes (1992)." Two of the first captive breeding programs in New Zealand were created to re-establish the Antipodes (Cyanoramphus unicolor) and orange- fronted (C. malherbi) kakarikis (Butler, 1992). Both species bred well and could be released successfully.
The Kakapo. The kakapo (Strigops habroptilus) started its decline at the arrival of the Polynesians. This large, flightless parrot evolved in an ecosystem free of mammals. The decline is due to many possible reasons such as "hunting, collecting for specimens, habitat loss or degration and competition and predation by introduced mammals (Clout and Craig)." Being flightless is bad enough, but the males of this species also have the unfortunate habit of "booming." This loud call can be heard for miles and makes this parrot easy prey. Actually, just about every aspect of this species makes it a target for extinction. Protein-rich food can help stimulate breeding, but even when provided with it the birds rarely nest annually though it has been proven that they can (Cockrem and Rounce, 1995). At one time it was thought that the species had gone extinct. When an isolated population was discovered it was found that most of the birds were older and that males greatly outnumbered females (Clout and Craig, 1995). This difference in sex ratios is thought to be the cause of higher predation on chicks and nesting hens (Cockrem and Rounce, 1995). Translocating individual birds has saved some from predators but it has not stopped the population decline. The kakapo has already been successfully hand-reared in captivity (Sibley, 1994). The next step may be captive breeding.
Hawaii. Known as "the endangered species capital of the U.S.," Hawaii, like New Zealand, has had to deal with altered ecosystems. In 1993 The Peregrine Fund started a program to captively breed and release the 'Alala (Corvus hawaiiensis). In 1993, 1994, and 1996, five, seven, and four captive-bred crows were released into the wild population of 12 (Lieberman, 1997). The survival rate was good and TPF expects to see breeding in 1997. Honeycreepers are endangered birds in Hawaii. These birds are subject to predation by introduced species and the plants they feed on "were severely depleted by feral sheep, cattle and goats until the 1980s when most of the animals were removed (Fleischer et al. 1994)." TPF is now breeding these species as well.
Houbara Bustards. The houbara (Chlamydotis undulata) is endangered in Saudi Arabia. They are currently being bred successfully at the National Avian Research Centre (Bailey et al. 1997). It is disappearing throughout its range "from the Canary Islands, across north Africa, to the Middle East and the former USSR (Greth et al. 1993)." The causes of its decline include destruction of habitat by overgrazing of livestock and overhunting (bustards are the favorite prey of falconers, a great tradition in Saudi Arabia). Artificial insemination has been used to boost captive numbers. Each year, more chicks are produced: 1989-17, 1990-55, 1991-49, 1992-138, 1993-283 (Jalme, 1996). Released birds have also bred in the wild (Jalme, 1996).
Declining population. Species can decline for other reasons. The California condor was heavily impacted by DDT and its own slow reproductive rate. Yet, captive-breeding (started in 1987) has saved this species from extinction (Geyer et al. 1993). This species is being successfully re-released. The Spix's macaw (Cyanopsitta spixii) is the rarest macaw in the world. Only a lone male survives in the wild, and he has paired himself up with a female Illiger's (Waugh, 1997). Poaching for the illegal trade has been the main cause of this species' decline. At the time the male was discovered there were only 17 birds in captivity. Captive-breeding in several locations (including Loro Parque) has increased numbers to about 30, with second-generation captive-breedings (Silva, 1994).
Information. Captive breeding provides the opportunity to learn more about an endangered species and develop better techniques in saving others. "Most captive-breeding programmes involve species which have been incompletely studied in the wild and have often never been studied in captivity (Bailey et al. 1997)." How can we save a species if we know nothing about it? Captive-breeding provides us with this information.
Habitat restoration. Let's face it- governments can be lazy, especially the U.S. government. Often they don't want to work at restoring habitat, but when a species has been reared in captivity and is ready for release, they almost have to get things done. "It should be noted that it is often only in anticipation of the release of captive-reared birds into native habitat that the responsible agencies (federal and state) actually initiate the process of habitat management by removing the limiting factors in that habitat (pigs, mosquitoes, rats, cats, mongoose, etc.) (Lieberman, 1997)."
One helps all. Saving or "marketing" one species can help others as well. Peregrines and condors were both affected by DDT. By marketing with banner-worthy species one can eradicate the things causing harm to all species. If you try to stop oil spills to save one cute seal species you'll and end up saving everything else too. Captive breeding helps publicize problems.
Captive-breeding helps conservation in many ways, directly and indirectly. Species and ecosystems can be returned to their natural state. Reintroductions may be hard, but many have worked (condors, kakarikis, bustards, peregrines, Hawaiian crows). This is an important tool of conservation that should not be dismissed.
Want to check out my references?
What you just read was a research paper I did for one of my AVS classes. Unfortunately I couldn't include any more information because my paper would have been too long. In my search through the various journals I found a facinating (and scarey) passage in Town and Williams. It was way to big to cite in a paper so I'll include it for you here as one last little tidbit:
"New Zealand has suffered two waves of extinctions in recent times and may be about to undergo a third. The first wave coincided with the arrival of settlers from Polynesia 1000 yr BP. The resulting ecological upheaval decimated the avifauna (causing extinction of 36% of the endemic land bird species) but also affected native frogs (43-50% species depending on taxonomy), lizards (at least 2%) and an unknown number of insects. A second wave of extinctions (beginning 200 yr BP) followed the arrival of settlers from Europe (17% of endemic land birds and 3% of lizards extinguished). These two catastrophes can be attributed to ignorance of the ecological consequences of the actions of these first settlers. But if a third, and larger wave of extinctions follows, it will be in full knowledge of its causes and in the face of all efforts to avert it.
"The extent of the species conservation problem facing this country is now apparent. The most recent estimate calculates 606 New Zealand taxa (species, subspecies and forms) at risk (endangered, vulnerable, rare or regionally threatened) in a land area of 0.3 million sq km. This total could amount to about 20% of all terrestrial vertebrates and vascular plants and is additional to the species already lost. By comparison, 605 species are listed as endangered or threatened in the USA in a land area of 9.4 million sq km. Per unit of land area, New Zealand has 38 times more threatened taxa (2.26 "species"/1,000 sq km) than the USA (0.06 species/1,000 sq km), but the USA has 76 times the taxation base offered by New Zealand from which to fund remedial efforts. The USA is therefore able to pour $US 50 million annually into endangered species programmes. An equivalent level of funding in New Zealand would require almost the entire Department of Conservation budget."
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