Center for Large Landscape Conservation; Literature Review on Select Topics in Landscape Conservation; May 27, 2010
How much is enough? What is the minimum area required to ensure the maintenance of biodiversity in an area?
A 10 percent (or 12%) conservation target of land area in each nation (Myers 1979, Miller 1984, Soule and Sanjayan 1998) is frequently cited and has been recurrently used in setting policy, though with little biological support. Soule and Sanjayan (1998) interviewed a set of biologists and land managers about this target and most agreed that it was developed for political expediency and was too small to protect biodiversity. Based on published parameters for the species-area relationship, there would be a 50% decline in species with a 90% loss of area. A sample of conservation estimates from published studies with varying biodiversity objectives found that approximately 50% (range: 33 – 75%) of the land area needs to be protected (Soule and Sanjayan 1998).