Treesearch

Premise of the study: Flowering phenology is a crucial determinant of reproductive success and offspring genetic diversity in plants. We measure the fl owering phenology of big-leaf mahogany ( Swietenia macrophylla , Meliaceae), a widely distributed neotropical tree, and explore how disturbance from logging impacts its reproductive biology. • Methods: We use a crown scoring system to estimate the timing and duration of population-level fl owering at three forest sites in the Brazilian Amazon over a fi ve-year period. We combine this information with data on population structure and spatial...

En este mapa de investigacion describimos las areas protegidas terrestres de Puerto Rico basado en elementos naturales y antropogenicos del paisaje. Utilizamos datos geoespaciales para calcular la extension y representatividad de elementos del paisaje dentro de las areas protegidas de Puerto Rico, i.e., cobertura del terreno (Gould et al. 2007), asentamientos urbanos, suburbanos y rurales (Martinuzzi et al. 2008), y fisiografia general. Las graficas circulares y de barra muestran la distribucion y el nivel de proteccion de cada uno de los elementos analizados. En adicion, analizamos el...

Given the importance of biological corridors, it is necessary to evaluate their fauna especially those species are bioindicators of habitat quality, to determine patterns and extent of community diversity and how such factors reflect the level of conservation within and among green corridors in general. We investigated how selected landscape features within the Paso del Istmo, located in the Department of Rivas, Nicaragua, are influencing avian diversity and how key groups are providing clues to habitat quality. We recorded 8703 detections of 168 avian species using fixed-radius point...

Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m2), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflux from a humid tropical forest in Puerto Rico. We measured hourly soil CO2 efflux, temperature and moisture in control and exclusion plots (n = 6) for 6-months. The variance of each time series was...

Ridges within the lower montane rain forests (sensu Beard) of the Caribbean Basin are dominated by Dacryodes excelsa, a tree species known as tabonuco in Puerto Rico and gommier in the Lesser Antilles. Periodially, hurricanes traverse the islands causing changes in structure, species composition, and dynamics of forests. The chronology of post-hurricane vegetation change from 1946 to 2010 on a 0.4 ha ridge plot approximately 380 m in elevation in the Luquillo Experimental Forest of northeastern Puerto Rico showed: (1) defoliation, breakage, and uprooting by wind accompanied by immediate...

Tropical plantations are considered a viable option to sequester carbon on abandoned agricultural lands, but implications of tree species selection for overall greenhouse gas budgets on plantations have been little studied. During three wet seasons, we investigated the influence of nine tree species on soil pH, temperature (ST), bulk density (BD), moisture content water filled pore space (WFPS), and greenhouse gas fluxes in diverse forest sites and monoculture plantation plots. All sites were on clay-rich soils of the Barreiras formation, in east-central Amaz^onia, Brazil. We found that ST...

This research map describes Puerto Rico's terrestrial protected areas based on natural and anthropogenic elements of the landscape. We used geospatial data, i.e., land cover (Gould et al. 2007); urban, suburban, and rural settlements (Martinuzzi et al. 2008); and physiography to illustrate landscape elements and analyze what and how much is protected in Puerto Rico. Pie and bar charts convey statistics about each landscape element's distribution and level of protection. We also analyzed the landscape context of the protected areas by classifying each one as coastal, forested, herbaceous,...

Entre Ríos province is an important center of Eucalyptus spp. plantations in Argentina. It was hypothesized that fine root biomass and litter mass increased with age increasing in plantations. Five, seven and seventeen year old stands of Eucalyptus grandis were sampled. All of them were first rotation stands. We estimated the mass of litter and fine roots (< 5 mm) in the top 30 cm of the soil profile. We determined: carbon, nitrogen, phosphorus, potassium, calcium and magnesium concentrations in living fine roots and litter. Their mineral content was calculated. ANOVA was used for compariso...

Four new species of Coenogonium are described from the Caribbean island of Puerto Rico—C. aurantiacum Mercado-Díaz & Lucking, C. borinquense Mercado-Díaz & Lucking, C. dimorphicum Mercado-Díaz & Lucking and C. portoricense Mercado-Díaz & Lucking. All were discovered in small and highly fragmented forest remnants of relatively rare Puerto Rican forest ecosystems, Pterocarpus wetlands and noncalcareous dry forests. The discoveries are discussed relative to the conservation status of these threatened ecosystems, the need to catalogue biodiversity before it vanishes, and the notion that...