Treesearch

Fine root dynamics were evaluated at four sites in a subtropical wet forest in PuertoRico over a period of 13 months followindisturbance by Hurricane Hugo in September 1989. Live fine root standing stocks(to a depth of 10cm) declined to zero over a three month period after the hurricanand fluctuated greatly thereafter. Maximum fine root biomass (49 g/m2) occurred in June 1990. Dead root standing s ocks( mean 423 g/m2) were relatively constant through the study period. Recovery of fine roots following the initial hurricane-related mortality appears to be a slow process,regulated at least...

Hurricane Hugo caused low to moderate damage to a flood plain forest that was partially protected by its topographic position. Treefalls and the location of damage suggested N to NW wind direction during the storm. Thirty percent of the trees, or 693 trees/ha, had some damage and 84 percent of the damage was to the canopy. Most of the damage to trees was caused by direct wind impact (83%) as opposed to secondary effects (16%). Over 80 percent of the snapped, leaning, and uprooted trees were dicotyledonous. Tree mortality was only 1 percent, and most of the damage to the sierra palm...

The forests and soils at Luquillo Experimental Forest(LEF), Puerto Rico, are frequently disturbed by hurricanes occurring at various frequencies and intensities.We have derived a forest version of the Century soil organic matter model to examine the impact of hurricanes on soil nutrienat avilability and pool sizes, and forest productivity in the tabonuco forest at Luquillo. The model adequately predicted aboveground plant production, soil carbon, and soil nitrogen levels for forest conditions existing before Hurricane Hugo. Simulations of Hurricane Hugo and of an historical sequence of...

Little is known about ecosystem-level responses to multiple, climatic disturbance events. In the subtropical forests of Puerto Rico, the major natural disturbances are hurricanes and droughts. We tested the ecosystem-level effects of these disturbances in sites with different land use histories. From 1989 to 1992, data were collected to determine the effects of Hurricane Hugo and two droughts on litterfall inputs, fine-root biomass, and decomposition rates in three topographic locations (stream, riparian, upslope) within two watersheds. From 1994 to 1998, we added a third watershed and an...

HURRICANE HUGO, A CATEGORY 4 hurricane with sustained winds of 140-150 miles per hour and gusts over 180 miles per hour, was perhaps the most violent storm ever to hit islands of the eastern Caribbean. The hurricane passedirectly over or near Puerto Rico, Montserrat, Guadeloupe, and Dominica. Each of these islands harbor endangered, threatened, or otherwise vulnerable species of endemic forest birds. We report on Hurricane Hugo's initial impacts to and consequences for some West Indian birds following the storm's landfalls during mid-September 1989 in the eastern Caribbean. We summarize...

We evaluated the accuracy of a portable radio teIemetry system in an insular tropical rain forest in preparation for a long-term radio telemetry study of the critically endangered Puerto Rican parrot (Amazona vittafa). No significant differences were found among error biases when comparing receiver systems, transmitter heights, distances, and topographical inclinations. Error of bearings to transmitters placed at distances of 100 m and 200 m from receivers at ground and canopy levels averaged –1.12°. Error polygons ranged from 0.5 ha to 2.0 ha (at 100 m and 200 m distances, respectively)....

We studied home range and movements of 15 radio-marked, juvenile Puerto Rican parrots (Amazona vittata) fledging from wild nests during summer and fall, 1985-87. When juvenile parrots remained in the nest valley, home ranges during 1986 (x̄ = 32 ± 10 [SE] ha, n = 4) were larger (P = 0.0079) than during 1987 (x̄ = 13 ± 6 ha, n = 5). After radio-marked parrots integrated into adult flocks, home ranges during 1986 (x̄ = 1,075 ± 135 ha, n = 3) were similar (P = 0.10) to 1987 (x̄ = 416 ± 62 ha, n = 2). Juvenile parrots restricted their movements to nest valleys an average of 58 ± 29 days...