Protected areas are generally seen as a triumph for the preservation of nature, yet the reality on the ground is more complex.
The world's largest protected areas encompass vast amounts of wilderness but do not extensively overlap the highest priority areas for conservation or include unusually large numbers of birds, amphibians, or mammals, according to an analysis published in the November issue of BioScience.
The study, by Lisette Cantú-Salazar and Kevin J. Gaston of the University of Sheffield, United Kingdom, nonetheless describes anecdotal evidence that some very large protected areas play an important conservation role, by preserving natural species assemblages and populations of regional concern.
Cantú-Salazar and Gaston examined in detail the 63 protected areas that each extend over 25,000 square kilometers or more (about the area of Vermont). These huge areas are found in all continents except Antarctica, and are preferentially found in areas where there are few people. The findings thus seem to support the idea that such areas are created in places where they will least inconvenience people, rather than where they would do the most for conservation.
Yet very large protected areas are also likely to include particular land-cover types, such as snow and ice, bare areas, and areas with sparse vegetation. Examination of individual cases reveals that several ecoregions of high conservation priority are partly included in very large protected areas, including the Guianan Highlands Moist Forests, the Tibetan Plateau Steppe, and the Eastern Himalayan Alpine Meadows. Their preservation is therefore important. And many of the largest protected areas are vulnerable, Cantú-Salazar and Gaston conclude. Some have inadequate management. Others are threatened by incursions for logging, fishing, grazing, and mining, and the effects of climate change and political instability.
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