Sanctuaries and Artificial Habitats

Sanctuaries and human-made habitats represent a proactive approach to land preservation, and they protect either specific wildlife or biodiversity in general, as in Costa Rica. The role of both sanctuaries and artificial habitats is to provide a setting that allows a species to enjoy health and follow their normal behavior.

As the word implies, a sanctuary is a “safe haven.” Wildlife sanctuaries usually operate under the guidance of private, nonprofit organizations that rely on donations for the sanctuary’s upkeep. Sanctuaries with healthy funding can accept a larger number of species, accommodate more individuals of a single species, or provide larger habitats containing an
animal’s natural vegetation and terrain. Many sanctuaries have recently begun specializing in animals that have been abused in captivity, injured in the wild, harmed by poaching, or orphaned. Sanctuaries worldwide give home to almost every animal from butterflies to elephants.

Artificial habitats consist of structures that serve one of two purposes: to provide habitat for species in which their habitat is severely threatened, or to provide habitat for certain species whose presence restores an ecosystem. Rebuilt coral reefs offer a good example of the first purpose. Coral reefs are among the most threatened ecosystems on Earth and the most threatened of all marine ecosystems; more than 65 percent of the world’s corals may already be dead or near death. Major reasons for the poor status of coral reefs are the following: rising ocean temperatures leading to bleaching, dynamite fishing, cyanide fishing, dredging, eutrophication,

Oil-drilling platforms have been blamed for ruining marine habitats, but they might
also support new habitats for plant and animal life. The underwater structures of
platforms provide shelter and artificial habitat for plant life, seaweed, invertebrates, and
fish. (Siemens Corporation)

disease, and physical damage and removal. Marine scientists have devised artificial reefs as substitute ecosystems for the life that depends on these unique structures. Some of the experimental approaches to artificial coral reef habitat are listed below:

• precipitating calcium carbonate by applying an electric charge to the surrounding sea water; causes calcium carbonate to form and bind to existing coral
• concrete structures
• scrap steel from bridge construction and shipbuilding
• scuttled military and other steel-hulled ships
• retired airplanes

Early attempts at building artificial reefs involved dumping old tires or discarded appliances into the ocean in the hope they would provide strong, permanent structures for sea life. Reefs must provide a stable place for attachment by corals, sponges, barnacles, clams, and other invertebrates. Once these foundation species establish themselves on a reef structure, the structure soon attracts small fish that use the reef’s nooks and crannies to feed, hide, and rest. Larger predators such as barracuda, grouper, and snapper then move in to complete the food web. Unfortunately, early attempts at building artificial reefs did not offer a habitat that would allow each phase to happen. In 1972 biologists began putting old tires into the ocean a mile (1.6 km) off the Ft. Lauderdale, Florida, coast. Years passed and aquatic species showed little interest in the tires. The tires began breaking loose and drifting away, sometimes landing on natural healthy corals. Ray McAllister, professor of ocean engineering at Florida Atlantic University, admitted in 2007, “The really good idea was to provide habitat for marine critters so we could double or triple marine life in the area. It just didn’t work that way. I look back now and see it was a bad idea.” The salvage operation to remove millions of dumped tires from the ocean may last beyond 2010 at a cost of more
than $3 million.

Oil companies have considered another type of artificial marine habitat: abandoned offshore oil rigs. After all of the oil has been removed from an undersea oilfield, oil companies prefer to leave their empty rigs at sea rather than dismantling them. Many environmentalists agree
with this decision, known as the rigs-to-reefs method of making artificial habitat. The Coalition for Enhanced Marine Resources described the benefits of the rigs-to-reef projects off California’s shore in its 2006 newsletter Reef Source: “California stands to benefit from the thriving habitat through increased tourism, diving and recreational fishing opportunities. For the petroleum industry, this program provides an alternative to full platform removal that is economical and less disruptive to the environment. Demolishing these platforms will literally kill 100 miles (161 km) of creatures and habitat.” Companies may also try an alternative to rigs-to-reefs in which demolition workers chop up the steel platform and sink the structure to the ocean bottom, where it then serves as a building block for coral attachment. Oceanographer Sylvia Earle has reported (to the Orange County Register in California in 2007) from her dives near the rigs, “You’ve got a cross-section of life in the sea.

Its diversity is greater than most rain forests.” But Linda Krop, counsel for the Environmental Defense Center, countered, “We see birds on telephone polls, seagulls at landfills. . . . Just because there are animals there, that doesn’t mean it’s a good habitat.” Plainly, rigs-to-reefs holds potential promise for further study but, like many conservation plans, it will produce a variety of opinions.

Artificial habitats on land also restore ecosystems by remaking conditions as close as possible to the original habitat. For example, constructed wetlands act as artificial habitats when newly planted natural vegetation establishes a slow and natural flow of water. If constructed properly, the mature wetland soon attracts fish, aquatic invertebrates, migrating birds, ducks, raccoons and fox, and rodents, and supports the regrowth of more plants.

Orchard and vineyard owners have begun to create artificial habitats that control pests without using pesticides. In some instances grassy areas, certain trees, or shrubbery can be planted near the areas to attract birds that eat ground insects and flying insects. Landowners also construct bat houses near crops; bats then eat several different types of moths that prey on crops. The mere presence of bats in an area drives away insects. Small mammals such as rabbits usually enter the cultivated area, and they attract larger predators like hawks, foxes, and coyotes. The predators help control rodents and gophers. In time the orchard or vineyard operates almost as a natural ecosystem.

Zoos and aquariums are a specialized type of sanctuary and artificial habitat in the same location. The sidebar “Zoos and Aquariums” describes how they play a role in wildlife preservation.