Environmental Problems, Their Causes, and Sustainability 1

ity, with the aim of reintroducing the offspring into thewild.Other techniques for increasing the populations ofcaptive species include artificial insemination, surgicalimplantation of eggs of one species into a surrogatemother of another species (embryo transfer), use of incubators,and cross-fostering (in which the young of arare species are raised by parents of a similar species).Scientists also use computer databases of the familylineages of species in zoos and DNA analysis to matchindividuals for mating—a computer dating service forzoo animals—and to prevent genetic erosion throughinbreeding.Proponents urge zoos and wildlife managers tocollect and freeze cells of endangered species for possiblecloning. They believe that such miniature frozenzoos could play a role in bringing back depletedspecies in the future.The ultimate goal of captive breeding programs isto build up populations to a level where they can bereintroduced into the wild. However, before conservationbiologists attempt a reintroduction they study thefactors that originally caused the species to become endangered,whether these factors still exist, and whetherthere is enough suitable habitat available.After more than two decades of captive breedingefforts, only a handful of endangered species havebeen returned to the wild. Examples shown in Figure12-3 include the black-footed ferret, California condor,Arabian oryx, and golden lion tamarin. Most reintroductionsfail because of lack of suitable habitat,inability of individuals bred in captivity to survive inthe wild, or renewed overhunting or capture of somereturned species.Lack of space and money limits efforts to maintainpopulations of endangered animal species in zoos andresearch centers. The captive population of each speciesmust number 100–500 individuals to avoid extinctionthrough accident, disease, or loss of genetic diversitythrough inbreeding. Recent genetic research indicatesthat 10,000 or more individuals are needed for an endangeredspecies to maintain its capacity for biologicalevolution.According to one estimate, using all the space inthe 201 accredited U.S. zoos for captive breeding couldsustain only about 100 large animal species on a longtermbasis. Thus the major conservation role of zooswill be to help educate the public about the ecologicalimportance of the species they display and the need toprotect habitat.Public aquariums that exhibit unusual and attractivefish and some marine animals such as seals anddolphins also help educate the public about the needto protect such species. In the United States, more than35 million people visit aquariums each year. However,public aquariums have not served as effective genebanks for endangered marine species, especially marinemammals that need large volumes of water.Instead of seeing zoos and aquariums as sanctuaries,some critics see most of them as prisons for oncewild animals. They also contend that zoos and aquariumsfoster the false notion that we do not need to preservelarge numbers of wild species in their naturalhabitats.Some people criticize zoos and aquariums forputting on shows with animals wearing clothes, ridingbicycles, or performing tricks. They see this as fosteringthe idea that the animals are there primarily to entertainus by doing things people do and in the processraising money for their keepers.Conservation biologists point out that zoos,aquariums, and botanical gardens, regardless of theirbenefits and drawbacks, are not biologically or economicallyfeasible solutions for most of the world’scurrent endangered species and the much larger numberexpected over the next few decades.12-9 RECONCILIATIONECOLOGYWhat Is Reconciliation Ecology? RethinkingConservation StrategyReconciliation ecology involves finding ways to sharethe places we dominate with other species.In 2003, ecologist Michael L. Rosenzweig wrote thebook Win-Win Ecology: How Earth’s Species Can Survivein the Midst of Human Enterprise (Oxford UniversityPress). He strongly supports the eight-point programof Edward O. Wilson to help save the earth’s naturalhabitats by establishing and protecting nature reserves(p. 221). He also supports the species protection strategiesdiscussed in this chapter.But he contends that in the long run these approacheswill fail for two reasons. One is that currentreserves are devoted to saving only about 7% of nature.To Rosenzweig the real challenge is to help sustain wildspecies in the human-dominated portion of nature thatmakes up 93% of the planetary ecological “cake”The other problem is that setting aside funds andrefuges and passing laws to protect endangered andthreatened species are essentially desperate attempts tosave species that are in deep trouble. This can help a fewspecies, but the real challenge is learning how to keepspecies from getting to such a point in the first place.Rosenzweig suggests that we develop a new formof conservation biology called reconciliation ecology.It is the science of inventing, establishing, and maintainingnew habitats to conserve species diversity inhttp://biology.brookscole.com/miller14247