Module 59 The Sixth Mass Extinction

Module 60 Causes of Declining Biodiversity

Module 61 The Conservation of Biodiversity

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The biodiversity of the world is currently declining at such a rapid rate that many scientists have declared that we are in the midst of a sixth mass extinction. There are many causes of this decline, but all are related to human activities ranging from habitat destruction to overharvesting plant and animal populations. In response to this crisis, there is growing interest in conserving biodiversity by setting aside areas that are protected from many human activities.

The conservation of biodiversity has a long history. The United States, for example, has been protecting habitats as national parks, national monuments, national forests, and wilderness areas for more than a century. Yellowstone National Park was the first national park in the United States, designated in 1872 by President Ulysses Grant. During the presidency of Theodore Roosevelt (1901–1909), nearly 93 million hectares (230 million acres) received federal protection. This included the creation of more than a hundred national forests, although much of this land was set aside to ensure a future supply of trees for lumber and therefore lacked complete protection.

In contrast to the long history of protecting terrestrial habitats, efforts to protect marine habitats are relatively recent. One of the most expansive efforts in the United States was made during the administration of George W. Bush. From 2006 to 2009, President Bush designated a total of 95 million hectares (215 million acres) of marine habitats as protected around the northwestern Hawaiian Islands and other U.S. Pacific islands. In the northwestern Hawaiian Islands, 36 million hectares (90 million acres) of these marine habitats were set aside as the Papahānaumokuākea Marine National Monument. This protected region is immense, covering an area about the size of California.

The marine ecosystem that surrounds the Hawaiian Islands contains a great deal of biodiversity—more than 7,000 marine species, approximately one-fourth of which are found nowhere else in the world. Unfortunately, in recent decades human activities have caused a decline in this diversity. The human causes of declining diversity are wide ranging. Although Hawaii has only 1.3 million residents, 7 million tourists visit each year. Individual anglers and commercial fishing operations have exploited marine life, including coral and fish. In addition to this exploitation, there are thousands of kilograms of old fishing equipment lying at the bottom of the ocean that sometimes wash up on shore, entangling wildlife in old fishing lines. Invasive species of algae also dominate some areas.

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The Papahānaumokuākea monument presents an opportunity for improving the Hawaiian marine environment. As a national monument, the area is protected from fishing, harvesting of coral, and the extraction of fossil fuels. Large amounts of solid waste debris are being removed from the shorelines and coral reefs, and efforts are under way to clean out much of the invasive algae. It is expected that the biodiversity of the area will quickly respond to these efforts. As the populations of organisms increase in the protected areas, individuals will disperse and add to the populations in the larger surrounding area. In this way, the protected area can serve as a constant supply of individuals to help neighboring areas maintain their diversity of species.

In the United States and the rest of the world, conserving the biodiversity of marine areas by creating marine reserves is a relatively new activity for governments, but the idea is gaining ground. In the Galápagos Islands, where Charles Darwin studied the evolution of finches, the nation of Ecuador recently designated a marine reserve that extends 64 km (40 miles) into the ocean from the islands and allows only limited fishing. Marine reserves have also been designated by Russia, the United Kingdom, Australia, Canada, and Belize.

Efforts to protect critical wildlife habitats continue today. For example, in 2009 the Obama administration set aside more than 484,000 km² (187,000 square miles) of Alaska coastline and waters as critical habitat for polar bears. Although this does not prevent activities such as gas and oil drilling, it does mean that potential impacts on polar bears must now be considered when such activities are proposed in this area. As more countries develop marine reserves, we have to make sure these areas are large enough to allow long-term protection of local species and we must consider how each new reserve is positioned relative to other reserves so that individuals are able to move among them. Furthermore, countries must decide what human activities will be allowed in each reserve, perhaps protecting a core area and allowing tourism, fishing, or extraction of fossil fuels to occur in more distant areas of the reserve. These are exciting times that demonstrate that there is a great potential for conserving biodiversity in the twenty-first century.

Sources: P. Thomas, President Bush to add marine reserves; not all are applauding, Los Angeles Times, January 6, 2009. http://latimesblogs.latimes.com/outposts/2009/01/news-flash-pres.html; U.S. government heads for row with big business after Obama sets aside land in Alaska for polar bear sanctuary, Daily Mail, November 25, 2010. http://www.dailymail.co.uk/news/article-1333008/Obama-sets-aside-land-Alaska-polar-bear-sanctuary.html.