heat dissipation sensors of variable length for the measurement of sap flow in trees with deep sapwood.robust thermal dissipation sensors of variable length (3 to 30 cm) were developed to overcome limitations to the measurement of radial profiles of sap flow in large-diameter tropical trees with deep sapwood. the effective measuring length of the custom-made sensors was reduced to 1 cm at the tip of a thermally nonconducting shaft, thereby minimizing the influence of nonuniform sap flux density profiles across the sapwood. sap flow was measured at different depths and circumferential positions in ...200211874724
study on natural breeding sites of sand flies (diptera: phlebotominae) in areas of leishmania transmission in colombia.the location of the microhabitats where immature phlebotomine sand flies of the genus lutzomyia develop is one of the least-known aspects of this group of medically important insects. for this reason strategies of source reduction approach for their control have not been possible in contrast to other insect vectors (such as mosquitoes), because their juvenile stages in terrestrial microhabitats is difficult to detect.201525888915
linking fruit traits to variation in predispersal vertebrate seed predation, insect seed predation, and pathogen attack.the importance of vertebrates, invertebrates, and pathogens for plant communities has long been recognized, but their absolute and relative importance in early recruitment of multiple coexisting tropical plant species has not been quantified. further, little is known about the relationship of fruit traits to seed mortality due to natural enemies in tropical plants. to investigate the influences of vertebrates, invertebrates, and pathogens on reproduction of seven canopy plant species varying in ...201122164837
hydraulic architecture of two species differing in wood density: opposing strategies in co-occurring tropical pioneer species often have different strategies for tolerating daily cycles of water stress. one underlying parameter that can link together the suite of traits that enables a given strategy is wood density. here we compare hydraulic traits of two pioneer species from a tropical forest in panama that differ in wood density: miconia argentea and anacardium excelsum. as hypothesized, the higher wood density of miconia was associated with smaller diameter vessels and fibres, more water stress- ...201221895699
differential seed and seedling predation by crabs: impacts on tropical coastal forest composition.recently, the importance of seed predation by crabs on mangrove species distributions and densities has been established by several studies. in a tropical coastal terrestrial forest in costa rica, we investigated the relative importance of predation by land crabs, gecarcinus quadratus, and hermit crabs, coenobita compressus, on measured forest composition through a series of seed removal and seedling establishment experiments. we also used natural light-gaps and adjacent non-gap sites to test ho ...200415349766
axial and radial water transport and internal water storage in tropical forest canopy trees.heat and stable isotope tracers were used to study axial and radial water transport in relation to sapwood anatomical characteristics and internal water storage in four canopy tree species of a seasonally dry tropical forest in panama. anatomical characteristics of the wood and radial profiles of sap flow were measured at the base, upper trunk, and crown of a single individual of anacardium excelsum, ficus insipida, schefflera morototoni, and cordia alliodora during two consecutive dry seasons. ...200312647177
sudden exposure to solar uv-b radiation reduces net co(2) uptake and photosystem i efficiency in shade-acclimated tropical tree seedlings.tree seedlings developing in the understory of the tropical forest have to endure short periods of high-light stress when tree-fall gaps are formed, and direct solar radiation, including substantial uv light, reaches the leaves. in experiments simulating the opening of a tree-fall gap, the response of photosynthesis in leaves of shade-acclimated seedlings (anacardium excelsum, virola surinamensis, and calophyllum longifolium) to exposure to direct sunlight (for 20-50 min) was investigated in pan ...200312586898
leaf carbohydrate responses to co2 enrichment at the top of a tropical forest.the accumulation of non-structural leaf carbohydrates is one of the most consistent plant responses to elevated co2. it has been found in both fast-and slow-growing plants and is largely independent of the duration of exposure. changes in leaf quality are thus to be expected, irrespective of other plant responses to atmospheric co2 enrichment. however, there is no experimental evidence from tropical forests, the biome with the largest biomass carbon pool. here we report in situ mesophyll respons ...199828308524
regulation of water flux through trunks, branches, and leaves in trees of a lowland tropical forest.we studied regulation of whole-tree water use in individuals of five diverse canopy tree species growing in a panamanian seasonal forest. a construction crane equipped with a gondola was used to access the upper crowns and points along the branches and trunks of the study trees for making concurrent measurements of sap flow at the whole-tree and branch levels, and vapor phase conductances and water status at the leaf level. these measurements were integrated to assess physiological regulation of ...199828308265
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