Treesearch

Tropical soils and vegetation represent globally significant sources of a range of atmospheric gases, including CO2, CO, N20, NO, CH4, and volatile organic compounds. Conversion of tropical forests to agriculture and other uses, and intensification of agricultural practices in both forest and savanna areas are occurring very rapidly; yet the impacts of these land use practices on biogeochemical cycles, trace gas emissions, and atmospheric chemistry are not well understood. We present early results of IGAC's Biosphere-Atmosphere Trace Gas Exchange in the Tropics (BATGE) Activity that...

Point counts and mist nets were used to survey the distribution of nearctic migrant landbirds wintering in 15 habitat types on the islands of Andros, New Providence, and Great Inagua in the Bahamas, and in western Cuba, Jamaica, Dominican Republic, Puerto Rico, and St. John in the Greater Antilles. Of 150 species detected, 23% were overwintering nearctic migrants. Migrants were found at l-7 1% of the points in natural or disturbed habitat (mean = 25%). Distance from North America and island size contributed only 9% of the variation in total migrant abundance among all habitats, reflecting...

Cyclonic storms, variously called typhoons, cyclones, or hurricanes (henceforth, hurricanes), are common in many parts of the world, where their frequent occurrence can have both direct and indirect effects on bird populations. Direct effects of hurricanes include mortality from exposure to hurricane winds, rains, and storm surges, and geographic displacement of individuals by storm winds. Indirect effects become apparent in the storm's aftermath and include loss of food supplies or foraging substrates; loss of nests and nest or roost sites; increased vulnerability to predation; microclimat...

The biomass and nutrient content of two steepland watersheds were estimated using allometric equations and nutrient concentrations derived from a subsample of the vegetation. Prior to the passage of Hurricane Hugo in September 1989, the watersheds had a total vegetative biomass of 301 tons/ha, 75 percent of which was aboveground. The total nutrient content of this vegetation was 907, 49, 644, 653, and 192 kg/ha for N, P, K, Ca, and Mg, respectively and varied with topographic setting. Concentrations per unit dry weight of P (0.16), K (2.49), Ca (2.13), and Mg (0.62) in aboveground vegetatio...