Tropical islands are highly vulnerable to climate change or changes in land cover. Forest clearing for agriculture or urban development can disturb relatively large proportions of the small extents of the various ecosystems present. Maps of land use, vegetation type and land-cover change help guide sound land management decisions. Three recent studies describe new maps of land cover and forest type for several Caribbean islands that are based on satellite imagery. These raster data, as well as some maps, are downloadable here and include the following: Puerto Rico and its outlying islands of Vieques, Culebra, and Mona; the U.S. and British Virgin Islands; and five islands of the Lesser Antilles: St. Kitts, Nevis, St. Eustatius, Grenada and Barbados. Most of the maps are based on Landsat imagery and are the first satellite image-based maps to show detailed forest types of several Caribbean islands with a consistent classification scheme.
The Puerto Rico and Virgin Islands maps were produced by scientists from the USDA Forest Service International Institute of Tropical Forestry (IITF) and Colorado State University (CSU), in cooperation with the IITF State and Private Forestry program and the USFS Forest Inventory and Analysis Program (FIA).
The data for Puerto Rico are the basis for the National Land Cover Dataset (NLCD) for Puerto Rico. They were produced for research on how historical landscape structure impacts forest tree species composition and diversity, and for a study aimed at learning more about the tropical forest that is cleared for land development. The study found that most of the forest cleared for land development is younger, but that more species-rich older forests, like forests on karst lands, are still vulnerable to development if close to urban centers and unprotected. The data for the Virgin Islands came from a study that also used LiDAR data to map forest height for the islands of St. John and St. Thomas. Data from FIA were used to calibrate the relationship between the LiDAR data and forest height.
The study that produced the five maps for the Lesser Antilles also compared land use in the new maps with estimates made by the British forester and ecologist J. S. Beard during work with the Forestry Division of Trinidad and Tobago in the 1940s. The authors found that land cover in lowland areas has changed dramatically over the second half of the 20th century. Cultivated land areas on the islands declined 60 to 100 percent from about 1945 to 2000. Meanwhile, forest cover increased by 50 to 950%. They concluded that this trend will likely continue on islands where sugar production has dominated in the past, because growing sugar cane for sugar is no longer profitable on Caribbean islands. The study also concluded that former agricultural lands in lowland areas could provide lands for new reserves of the drier forest types that have re-established in some areas. Authors of the study included scientists from IITF, the US Geological Survey, The University of the West Indies, The Nature Conservancy, and CSU.
