Treesearch

Urban expansion is accelerating in the tropics, and may promote the spread of introduced plant species into urban-proximate forests. For example, soil disturbance can deplete the naturally high soil nitrogen pools in wet tropical soils, favoring introduced species with nitrogen-fixing capabilities. Also, forest fragmentation and canopy disturbance are likely to favor high-light species over shade-adapted rainforest species. We measured understory woody diversity, the abundance of introduced species, and soil nitrogen and carbon in urban, suburban, and rural secondary forests in Puerto Rico...

The Cerrado, the savanna biome in central Brazil, mostly comprised of woodland savanna, is experiencing intense and fast land use changes. To understand the changes in Cerrado carbon stocks, we present an overview of biomass distribution in different Cerrado vegetation types (i.e., grasslands, shrublands and forestlands). We surveyed 26 studies including 170 Cerrado sites. The grasslands presented mean total biomass of 24 Mg/ha, with 70 percent allocated in the belowground portion. In shrublands, the mean total biomass was 58 Mg/ha being 58 percent in the belowground portion. Finally, in...

The objective of this study was to test the use of repeat flight, airborne laser scanning data (lidar) for estimating changes associated with low-impact selective logging (approx. 10-15 m3 ha−1 = 5-7% of total standing volume harvested) in natural tropical forests in the Western Brazilian Amazon. Specifically, we investigated change in area impacted by selective logging, change in tall canopy (30 m+) area, change in lidar canopy structuremetrics, and change in above ground biomass (AGB) using a model-based statistical framework. Ground plot measurements were only available from the time of...

Aim: Non-destructive methods for quantifying above-ground plant biomass are important tools in many ecological studies and management endeavours, but estimation methods can be labour intensive and particularly difficult in structurally diverse vegetation types. We aimed to develop a low-cost, but reasonably accurate, estimation technique within early-successional Bahamian broadleaf shrub vegetation. Location: Eleuthera, The Bahamas. Methods: Our biomass estimation technique was based on a visual obstruction method originally developed for use in grassland vegetation, but modified to suit...

Distribution of nonbreeding migrant birds in relation to variation in food availability has been hypothesized to result from the interaction of dominance hierarchies and variable movement responses, which together may have sex- and age-specific consequences. We predicted that site fidelity, movements, and abundance of Kirtland’s Warblers (Setophaga kirtlandii) wintering on the island of Eleuthera in the Commonwealth of the Bahamas (hereafter “The Bahamas”) would be correlated with food abundance but vary by sex and age. We found that the species’ food resources (fruits and arthropods)...

Background: The dynamics of gaps plays a role in the regimes of tree mortality, production of coarse woody debris (CWD) and the variability of light in the forest understory. Aims: To quantify the area affected by, and the carbon fluxes associated with, natural gap-phase disturbances in a tropical lowland evergreen rain forest by use of ground measurements and high-resolution satellite images. Methods:We surveyed two large forest inventory plots of 114 and 53 ha of the Tapajós National Forest (TNF) in the Brazilian Amazon during 2008 and 2009, respectively. We mapped all gaps and collected...

La Reserva Natural Datanlí-El Diablo, es un complejo mosaico de hábitats dentro de la zona de vida del bosque nuboso, ubicado en Jinotega. Datanlí, es un vocablo de la lengua indígena “Matagalpa”, y significa por donde bajan las aguas, expresión más que correcta para definir el complejo de riachuelos y ríos que nacen en esta zona, y que desembocan en el lago artificial de Apanás, una de las principales fuentes de generación de energía eléctrica en Nicaragua, y además de esto, forma parte de la cuenca 69 o cuenca del Río San Juan, lo cual nos da una idea de la importancia de estos bosques...

This paper has three objectives: 1) to provide a synopsis of the content of the reports, documents, data, and arguments used by the Corps to justify the channelization of the Rio Piedras; 2) to evaluate the accuracy of predictions and assumptions used by the Corps to reach conclusions that justify the channelization of the Rio Piedras; and 3) to make a case for the need to reassess the flooding problems in the San Juan Metropolitan Area with an eye to identifying solutions that are both effective and adaptable to evolving social and ecological conditions in the city. Our intent is not to...