Lopez T. M.

Mapping the Forest Type and Land Cover of Puerto Rico, a Component of the Caribbean Biodiversity Hotspot

ELMER,E. H.; RAMOS, O.; LÓPEZ, T. DEL M.; QUIÑONES, M.; DIAZ, W. 2002. Mapping the Forest Type and Land Cover of Puerto Rico, a Component of the Caribbean Biodiversity Hotspot. Caribbean Journal of Science, Vol. 38, No. 3-4, 165-183, .

Abstract: 
The Caribbean is one of the world’s centers of biodiversity and endemism. As in similar regions, many of its islands have complex topography, climate and soils, and ecological zones change over small areas. A segmented, supervised classification approach using Landsat TM imagery enabled us to develop the most detailed island-wide map of Puerto Rico’s extremely complex natural vegetation cover. Many Caribbean forest formations that are not spectrally distinct had distributions approximately separable using climatic zone, geology, elevation, and rainfall. Classification accuracy of 26 land cover and woody vegetation classes was 71 % overall and 83 % after combining forest successional stages within image mapping zones. In 1991-92, Puerto Rico had about 364,000 ha of closed forest, which covered 41.6 % of the main island. Unlike previous island-wide mapping, this map better identifies the spatial distributions of forest formations where certain groups of endemic species occur. Approximately 5 % of Puerto Rico’s forest area is under protection, but the reserve system grossly underrepresents lowland moist, seasonal evergreen forests.

The Effect of Land Use on Soil Erosion in the Guadiana Watershed in Puerto Rico

LÓPEZ, TANIA DEL MAR; AIDE, T. MITCHELL; SCATENA F. N. 1998. The Effect of Land Use on Soil Erosion in the Guadiana Watershed in Puerto Rico. Caribbean Journal of Science, Vol. 34, No. 3-4, 298-307, 1998.

Abstract: 
The Revised Universal Soil Loss Equation (RUSLE) was used in conjunction with a Geographic Information System to determine the influence of land use and other environmental factors on soil erosion in the Guadiana watershed in Puerto Rico. Mean annual erosion, suspended sediment discharge, and the rainfall-erosion factor of the RUSLE increased with annual rainfall. Median soil erosion rates varied among the seven land uses: bare soil (534 Mg ha-1 yr-1), open canopy forest (26 Mg ha-1 yr-1), agriculture (22 Mgha-1 yr -1), pasture (17 Mg ha -1 yr -1), less dense urban (15 Mg ha-1 yr -1), closed canopy forest (7 Mg ha -1 yr -1), and dense urban (1 Mg ha-1 yr -1). The differences between open canopy forest, agriculture, pasture, and less dense urban were not significantly different but median values for open canopy forests were slightly greater because they occurred on steep slopes. The five-year average sediment delivery ratio for the basin was 0.17, which is comparable to delivery ratios estimated for watersheds of similar size. Simulations of different land use configurations indicate that reforestation of 5% of the watershed with the highest erosion rates would decrease basin wide erosion by 20%. If the entire watershed was reforested, soil erosion would be reduced by 37%.
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