Protected areas and conservation of biodiversity in the tropics

We compared deforestation rates and the extent of fragmentation inside and outside protected areas in the Sarapiqui region of Costa Rica. We determined deforestation rates using remotely sensed images with supervised classification. We georeferenced the processes images and then transformed them to vector format for final mapping and parameter quantification. The deforestation rate in protected areas was low and declined sharply from 0.56% annually between 1976 and 1986 to 0.16% from 1991 to 1995. Outside the protected areas, the rate decreased from 3.6% in 1976-1986 to 2.8% in 1986-1991, but it increased again to 3.2% in 1991-1995. Fragmentation outside the protected areas increased considerably: the number of patches increased from 537 in 1976 to 1231 in 1996, while during the same period the average size of patches decreased from 0.95 to 0.25 km(2). Forest landscapes in the Sarapiqui region are likely to lose considerable biodiversity because of the past forest loss and fragmentation even without further increases in deforestation and fragmentation.