Dynamics of Tropical Deforestation Around National Parks: Remote Sensing of Forest Change on the Osa Peninsula of Costa Rica

National parks and biological reserves play an important role in counteracting the effects of tropical deforestation in mountainous environments, a leading cause of biodiversity loss worldwide. Unfortunately, information is sparse on the nature, dynamics, and spatial dimension of land use and land cover change processes that contribute to park vulnerability. This article assesses the current state of landscape fragmentation and structure on the Osa Peninsula, Costa Rica, using Landsat Multispectral Scanner and Thematic Mapper satellite scenes between 1979 and 1997. The Osa Peninsula hosts the Corcovado National Park, which contains the only protected region of Tropical Wet forest on the Pacific slopes of Mesoamerica, including a significant number of species that are endemic, threatened, or new to science. The level of isolation of the Corcovado National Park is based on the degree of ecosystem degradation produced by frontal deforestation processes. Our results indicate that the proportion of the Osa Peninsula covered by forest declined from 97% in 1979 to 91% in 1987 and to 89% by 1997. Total forest area declined from 977 km2 in 1979 to 896 km2 by 1997. These results pose significant questions regarding the effectiveness of current conservation efforts in this mountain biodiversity-rich area of Mesoamerica.