Increase size of protected area
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Large protected areas may be better able to support viable populations of mammals than are smaller areas. However, protected area effectiveness may also be linked to sites being surrounded by similar habitat, having strong public support, effective law enforcement, low human population densities and sufficient financial resources (Struhsaker et al. 2005). Where these are not in place, factors such as activities of surrounding human populations may have a greater impact on species survival (Parks & Harcourt 2002).
Parks S.A, & Harcourt A.H. (2002) Reserve size, local human density, and mammalian extinctions in U.S. protected areas. Conservation Biology, 16, 800–808.
Struhsaker T.T., Struhsaker P.J. & Siex K.S. (2005) Conserving Africa’s rain forests: problems in protected areas and possible solutions. Biological Conservation, 123, 45–54.
Supporting evidence from individual studies
A before-and-after study in 2000–2001 at a primarily savanna site in South Africa (Druce et al. 2004) found that expanding a fenced reserve resulted in the home range of a reintroduced group of lions Panthera leo becoming larger but the core range becoming smaller. Following fence removal, the home range was larger (74 km2) than prior to fence removal (38 km2). The opposite was true for the core range (after fence removal: 2 km2; before fence removal: 11 km2). In December 1994, a pride of five lions was reintroduced to the fenced Greater Makalali Conservancy, where lions had previously become extinct. Two male lions were subsequently removed and replaced by two new males in 1999. In October 2000, the fenced area was enlarged from 11,089 ha to 13,600 ha, by removing a fence between the conservancy and a neighbouring game reserve. Lions were monitored through visual observations for six months before and six months after fence removal. The home range was defined as the smallest area containing 95% of the distribution used and the core range was the smallest area containing 50% of distribution used.Study and other actions tested