The conservation of species involves the use of strategies and techniques that can be classified into three broad approaches: in the wild, in captivity, and in-vitro (germ cells). Knowledge of these approaches is essential to understanding how conservation management practices conserve biodiversity in real life applications.
In the wild, or in-situ, conservation is defined by the Convention for Biological Diversity (1992) as "the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings, and in the case of domesticated or cultivated species, in the surroundings where they have developed their distinctive properties." Essentially, this definition translates to conserving species in their natural environments so that they can exist naturally. The understanding of the biological, ecological, and social underpinnings of in-situ conservation is one of the active research areas of conservation biology.
For common or nonthreatened species, in-situ conservation management practices may require little active effort other than monitoring species' populations and maintaining them at viable levels in their natural habitats (self-sustaining populations). This adaptive style of conservation management involves managing populations with little interference unless a problem (threat) develops, or potentially can develop. Such management practices are typical of how state and federal natural resource agencies in the United States manage most game species, notably fish, birds, and mammals. For vulnerable, threatened, and endangered species, more active, interventionist, in-situ conservation strategies and techniques are required. For example, the black rhino (Diceros bicornis) is one of the most endangered species in the world, numbering fewer than 2,400 individuals in the wild. This rhino has declined precipitously on account of poaching for its horn for the traditional medicine market. Today, the remaining rhinos have been translocated to secure natural parks and private game reserves, where they are tracked and protected by armed wardens twenty-four hours a day.
The creation and management of multipleuse biological reserves, nature reserves, protected areas, and national parks are the cornerstone of in-situ conservation efforts. They address the loss and degradation of species' habitats. These areas are created to protect species and their habitats and, thereby, to hinder their extinction in the wild. Initially, the creation of such natural resource areas focused on protecting habitat for keystone species, such as caribou (Rangifer tarandus) in the Arctic tundra, or particularly charismatic vertebrate species such as elephants (Lox-odonta africana), gorillas (Gorilla gorilla), and the large cats—and thereby, provide protection for the smaller, lesser-known plant and animal species coexisting in these habitats. Today, the creation of biological reserves increasingly focuses on management and protection of ecosystems and maintaining the ecological integrity of such systems. Landscape approaches are employed, and international intergovernmental cooperation is fostered to protect such reserves that cross country borders—for example, the management of the Serengeti Plains ecosystem involves national parks and reserves that are managed by Kenya and Tanzania.
Although such in-situ techniques have focused largely on terrestrial species and habitats, these concepts and methods are now being used to address the conservation of marine species and ecosystems. The Commonwealth of the Bahamas, in addition to its pioneering efforts in establishing land and sea national parks, recently initiated one of the world's first marine reserve networks. The Center of Biodiversity and Conservation at the American Museum of Natural History is supporting Bahamian marine conservation through two innovative research projects: a regional-scale initiative to study complex factors affecting marine reserve networks; and a local habitat-mapping project at Andros Island, site of the third largest barrier reef in the world. These in-situ conservation measures are attempting to understand the function of marine reserve networks through an interdisciplinary approach that involves physical, biological, and social scientists as well as representatives from the government of the Bahamas, local fishing communities, and conservation organizations.
Professional natural resource managers and conservationists recognized that in-situ conservation strategies need to involve local communities and to become more community-based. In-situ conservation practices routinely include outreach efforts to local com
munities to build a support base. One novel approach for heightening public awareness that is highly successful involves the designation of an endangered or endemic (native) species as a symbol of national pride. RARE Center for Tropical Conservation (based in Arlington, Virginia) pioneered this approach in its conservation efforts throughout the Caribbean region. The islands of St. Vincent, St. Lucia, and Dominica adopted national conservation strategies through the promotion of their endemic parrots as ambassadors for habitat protection and forestry reforms (Butler, 1992).
Local communities will increasingly play a vital role in conserving animal and plant species within their local environments. Because of biological, social, and financial constraints, species can not be protected only in reserves and park areas. Wildlife and plant species exist outside reserve boundaries, and these populations will need to be managed too or their genetic diversity will be lost. Many species are migratory and pass through habitats where they may come into conflict with man. Corridors and multiple-use areas are in-situ conservation methods employed to address such concerns. Where local communities at one time exploited species for hunting and harvesting, today they are involved in the management and protection of these same species. Locals are actively involved as park wardens, tourist guides, and resource biologists.
For example, the U.S.-AID funded "Camp-fire" (Communal Areas Management Programme for Indigenous Resources) program in Zimbabwe involves local, rural communities in the management of African big game species, such as leopard (Panthera pardus) and Cape Buffalo (Syncerus caffer), on their tribal lands. These rural communities directly profit from the hunting revenue generated, and such revenue provides support for schools and medical clinics. In return, it creates more habitat for the wildlife populations that coexist with human populations outside national park boundaries. In Argentina's grasslands, or "Chaco" region, local governments and communities are involved in an in-situ attempt to sustainably manage blue-fronted Amazon parrot (Amazona aestiva) and tortoise populations in their natural habitats. Under a strictly regulated harvesting program, local communities harvest a limited quota of parrots for international export as pet birds. The sales revenue from these parrots returns to the local community and funds a local, provincial university to biologically monitor this species. In addition, an incentive program exists to conserve the natural habitat for these species and to discourage the use of these natural areas for domestic species, such as cattle. Prior to the establishment of this model-harvesting program, Argentina exported more than 80,000 blue-fronted Amazons from 1985 to 1990 (CITES, 2002). This large-scale exploitation was unsustainable and threatened the species. Today, only 800 to 1,000 parrots are exported annually.
In captivity, or "ex-situ," conservation is defined by the Convention on Biological Diversity (1992) as "the conservation of biological diversity outside their natural habitats." Essentially, this definition translates to conserving species outside their natural environments, usually in zoos, aquaria, botanical gardens and arboreta, and in gene banks. Often these ex-situ conservation facilities exist outside the range countries for these species, in Europe and the United States. Already a number of animal species are extinct in the wild but survive in captivity, such as Pere David's deer (Elaphurus davidianus) and Przewalski's horse (Equus caballus przewalski).
Captive breeding or propagation plays a key role in these ex-situ conservation efforts. The purpose for this captive propagation is varied and includes scientific research, mostly for physiological, nutritional, and behavioral studies; production of individuals for in-situ reintroduction programs; maintenance of genetic diversity; and production of self-sustaining (self-maintaining) populations in captivity so that no individuals are taken from the wild. Captive animals and plants also educate the public about the need to conserve species in the wild. In many developed countries, such as the United States, large populations reside in urban areas and never see wildlife in their natural environments. Yet their awareness and appreciation of wildlife is essential to building a support (policy and financial) basis for in-situ conservation efforts and the alteration of environmentally destructive practices, such as pollution.
Ex-situ conservation programs for animals are limited by the number of species that they can address, the amount of space they have for specimens, their focus on vertebrate species, their genetic variability, and their ability to represent only a fraction of the genetic diversity found in the wild. Such programs are also limited by the ability of captive populations to undergo genetic adaptation to artificial conditions and to withstand the loss of their survival skills and knowledge of their natural environments. To achieve their long-term goals, ex-situ conservation efforts require continuity with a large, continuing investment of funds and a steady institutional support policy. Only a few private institutions and some government-managed facilities can afford to make such far-ranging commitments. The American Zoo and Aquarium Association, whose membership includes 185 accredited zoos and aquariums throughout North America, helps to ensure the survival of targeted wildlife species through its Special Survival Plan (SSP) program. They currently administer ninety SSPs covering 119 individual species. Studbooks are fundamental to the successful operation of SSPs, as each contains the vital records of a captive population of a species, including births, deaths, transfers, and lineage.
Opponents of ex-situ conservation efforts argue that such efforts are too costly, too risky, do not address the threats to the species in their natural environments, and maintain the species under artificial conditions. However, conservation biologists are recognizing that for some endangered species, ex-situ conservation can complement in-situ conservation efforts and become part of an integrated conservation strategy. If the remnant wild population is too small or inbred, or if all the remaining individuals in the wild are outside of protected areas, in-situ conservation efforts by themselves may not be enough to avoid extinction. If part of a holistic conservation approach, captive breeding and propagation can play a role in helping these species to survive, but they should not be viewed as an overall cure for the threats to biodiversity.
Examples can best help illustrate this point: The California condor (Gymnogyps californi-anus) was rescued from extinction by an intense captive breeding program by the San Diego Zoological Society and the Los Angeles Zoo (Synder and Snyder, 2000). However, this captive effort was integrated into the U.S. Fish and Wildlife Service's overall recovery plan for the species. Key recovery plan actions addressed: the purchase of critical habitat for the species, the Bitter Creek National Wildlife Refuge; the removal of lead shot in the condor's habitat and supplemen tal, "lead-free" carcass feeding; reintroduction of captive, bred condors into the wild, initiated with the release of the first generation of captive-raised condors; and establishment of a second population in the wild and outside of California to protect it against the occurrence of a natural disaster—a population has been established in the Grand Canyon National Park, a former natural habitat. In Puerto Rico, the highly endangered Puerto Rican parrot (Amazona vittata), of which fewer than one hundred specimens exist in the wild, survives in its rain forest habitat through intensive in-situ management efforts that include the fostering into active nests in the wild of parrot chicks produced ex-situ, thereby increasing natural reproduction.
Similar reintroduction programs exist for endangered mammals and reptiles—the red wolf (Canis rufus), the Arabian oryx (Oryx leu-coryx), Przewalski's horse, the Cuban crocodile (Crocodylus rhombifer), the Jamaican inagua (Cyclura colleli), and the endemic plowshare tortoise (Geochelone yniphora) of Madagascar. In South Africa, captive-bred cheetahs (Aci-nonyx jubatis) are being released into natural populations to increase the genetic diversity of the wild populations. A key component to the success of the above ex-situ conservation efforts is that they have actively involved government natural resource agencies that are legally responsible for the conservation of these endangered species. It is far more difficult and complex to foster such efforts when all the remaining individuals held in captivity are in private collections. An example is the critically endangered Spix's macaw (Cyanop-sitta spixii). Despite suitable habitat in the wild, this Brazilian endemic parrot is extinct in the wild; the only successful captive breeding has occurred outside of Brazil in private collections, thus hindering reintroduction efforts. The International Union for the Conservation of Nature's Captive Breeding Specialist Group provides expertise for assessing the contribution that ex-situ captive breeding programs can provide and their inclusion in conservation efforts for a species.
In-vitro conservation is a special case of ex-situ conservation and involves the use of a species' cells and tissues, along with biotech-nological techniques in a laboratory environment, to assist species conservation. It can involve maintenance of germ (that is, eggs and sperm) and somatic (body) cells in a sterile, pathogen-free environment under artificial conditions. In-vitro techniques are most commonly used in the conservation of plants, and they are widely used for vegetatively propagated and recalcitrant-seeded species (species whose seeds can not be dried or frozen without lost of viability). This method provides an alternative to field gene banks and is a useful solution for recalcitrant, sterile, or clonally propagated plant species. The future for long-term in-vitro conservation efforts lies in the storage of frozen tissue cultures at very low temperatures—for example, in liquid nitro-gen-cryopreservation.
With the cloning of domestic species, such as Dolly the sheep, the use of in-vitro conservation techniques for wildlife species has recently attracted much research. Borrowing techniques from human fertility clinics and livestock breeding, reproductive technologies are playing an increasingly greater role in species conservation. These techniques include: artificial insemination for species that are difficult to breed in captivity, such as giant pandas (Ailuropoda melanoleuca); interspecies embryo transfers, such as producing the endangered mountain bongo antelope (Tragelaphus eurycerus) from embryo transfers to the more common eland (Taurotragus elands); and testtube fertilization.
One of the newest in-vitro techniques that has become available is interspecies (or "cross-species") nuclear transfer (Lanza et al., 2000). This cloning technique involves growing two kinds of cells in culture dishes: cells from the animal being cloned (somatic cells, such as skin tissue can be used) and recipient eggs from the species to which the surrogate mother belongs. Next, the nucleus of the egg is sucked out with a needle, and the whole cell from the future clone is injected into the enucleated (that is, emptied) egg. The egg is then given an electric shock to fuse the contents of the clone's cell with the cytoplasm of the egg. Through chemical stimulation, the fertilization event occurs and the egg divides to form new cells. This mass of cells is implanted in the uterus of the surrogate mother. In January 2001, a healthy baby gaur, Noah, was born to a cow named Bessie. Gaurs (Bos gaurus) are a threatened oxlike species that range from India to southeast Asia. The clone, Noah, was the first clone of a threatened species, and the first animal created from interspecies nuclear transfer. Frozen skin tissue from a deceased male gaur at the San Diego Zoo that had never reproduced in captivity, provided the cells for cloning.
Cloning faces the same opposing arguments that conventional ex-situ, captive breeding programs encounter: it is extremely expensive; it requires laborious efforts to produce a few successes; reintroduction with cloned animals will be no more successful than conventional ex-situ reintroduction programs; and it fails to address the conservation problems that endangered species face in the wild. Yet it does show the promise of increasing genetic diversity in captive populations, and if such efforts can be integrated with in-situ conservation efforts, they may help in the short term. They represent just another tool in the toolbox of conservation approaches. Cloning or the ability to resuscitate endangered populations from clones is not a justification for allowing further development or habitat loss. Ultimately, in-situ conservation efforts will always be more successful in the conservation and management of all species. However, ex-situ conservation approaches can provide some short-term relief for endangered species until in-situ conservation measures can be implemented and sustained. The recovery of the California condor attests to the success of such approaches.
See also: Conservation Biology; Endangered Species; Organizations in Biodiversity, The Role of; Preservation of Habitats; Sustainable Development; Sys-tematics
American Zoo and Aquarium Association, http://www.aza.org. This Website offers species fact sheets for the Species Survival Plan (SSP) species; Butler, Paul J. 1992. "Parrot, Pressures, People and Pride." In New World Parrots in Crisis: Solutions from Conservation Biology, edited by S. R. Beissinger and N. F. R. Snyder, pp. 25-46. Washington DC: Smithsonian Institution Press; Caughley, Graeme, and Anne Gunn. 1996. Conservation Biology in Theory and Practice. Cambridge, MA: Blackwell; Captive Breeding Specialist Group, http://www.cbsg.org; CITES (Convention on the International Trade in Endangered Species) Annual Flora and Fauna Reports, data compiled by World Conservation Monitoring Center. http://www.cites.org; Communal Areas Management Programme for Indigenous Resources, http://www.campfire-zimbabwe.org; Lanza, Robert P., Betsy L. Dresser, and Philip Damiani. 2000. "Cloning Noah's Ark." Scientific; American 283, no. 5:84-89; Primack, Richard B. 1998. Essentials of Conservation Biology. 2d ed. Sunderland, MA: Sinauer; RARE Center for Tropical Conservation, www.rarecenter.org; Snyder, Noel, and Helen Snyder. 2000. The California Condor: A Saga of Natural History and Conservation. New York: Academic.
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