Treesearch

Necromass is an important stock of carbon in tropical forests. We estimated volume, density, and mass of fallen and standing necromass in undisturbed and selectively logged forests at Juruena, Mato Grosso, Brazil (10.488S, 58.478W). We also measured standing dead trees at the Tapajos National Forest, Para, Brazil (3.088S, 54.948W) complementing our earlier study there on fallen necromass.We compared forest that was selectively logged using reduced-impact logging methods and undisturbed forest.We estimated necromass density accounting for void volume for necromass greater than 10 cm...

Selective logging is an extensive land-use practice in South America. Governments in the region have enacted policies to promote the establishment and maintenance of economically productive and sustainable forest industries.However, both biological and policy constraints threaten to limit the viability of the industry over the long term.Biological constraints, such as slow tree growth rates, can be overcome somewhat by management practices. In order to improve the likelihood of success for sustainable management, it is important to accept that forests change over time and that managed...

The northern karst of Puerto Rico is a unique formation that contains one of the island’s largest remaining forested tracts. The region is under ever-increasing human pressure, but large portions of it are being considered for conservation. Forest classification of the region is at a coarse scale, such that it is considered one vegetation type. We asked whether there were distinct tree assemblages which would necessitate targeted conservation strategies to ensure their protection. We examined tree species and communities across the region at three different major topographic positions...

Volcanic eruptions are an important and natural source of catastrophic disturbance to ecological communities. However, opportunities to study them are relatively rare. Here we report on the effects of the eruption of the Soufrière Hills volcano on the forest bird community of the Lesser Antillean island of Montserrat. The island’s species-poor avifauna includes 11 restricted-range species, including the Critically Endangered endemic Montserrat Oriole Icterus oberi. Analysis of monitoring data from 1997 to 2005 indicates that counts of most species were substantially lower following major...

Nutrient fluxes in rainfall and throughfall were measured weekly in a mature subtropical wet forest in NE Puerto Rico over a 15-year period that included the effects of 10 named tropical storms, several prolonged dry periods, and volcanic activity in the region. Mean annual rainfall and throughfall were 3482 and 2131 mm yr1, respectively. Average annual rainfall and throughfall fluxes of K, Ca, Mg, Cl, Na, and SO4–S were similar but somewhat larger than those reported for most tropical forests. Rainfall inputs of nitrogen were comparatively low and reflect the relative isolation of the...

Timber harvest is one of the main causes of degradation of Amazonian tropical forests, where bats represent important components of biodiversity. In addition, bats may represent keystone taxa in the Neotropics, as they are primary agents of pollination and seed dispersal for many pioneer plants. We assessed the impact of low harvest (18m3/ha), reduced impact logging (RIL) on population and community characteristics of phyllostomid bats in Amazonian terra firme forest of Brazil at 20.42 months post-harvest. Based on 103,680 net-meter-hours of netting in Tapajós National Forest, 2341...

Because the winter season is potentially limiting for migratory birds, understanding their nonbreeding distributional patterns is essential. At a given site, patterns of species occurrence and abundance may vary over time and, within a species, wintering strategies may vary with regard to the degree that individuals are site-faithful both within and between winters. We examined long-term patterns in the composition of a winter resident bird community to determine how long a site must be studied to understand the wintering community. Over a 34-yr period of constant-effort mist netting at a...

In this study, we describe earthworm communities along an elevation gradient of eight forest types in Northeastern Puerto Rico, and determine whether their abundance, biomass and/or diversity is related to climatic, soil physical/chemical and/or biotic characteristics. We found that the density, biomass, and diversity of worms varied significantly among forest types. The density of earthworms was highest in the Pterocarpus forest. In terms of biomass, both elfin and the Pterocarpus forests had the highest values. The number of earthworm species significantly increased as elevation and...

On the Caribbean island of Puerto Rico, forest, urban/built-up, and pasture lands have replaced most formerly cultivated lands. The extent and age distribution of each forest type that undergoes land development, however, is unknown. This study assembles a time series of four land cover maps for Puerto Rico. The time series includes two digitized paper maps of land cover in 1951 and 1978 that are based on photo interpretation. The other two maps are of forest type and land cover and are based on decision tree classification of Landsat image mosaics dated 1991 and 2000. With the map time...

Pterocarpus officinalis L. is a dominant tree of freshwater coastal wetlands in the Caribbean and the Guiana regions. It is frequently associated with mangroves in areas with high rainfall and/or surface run-off. We hypothesized that P. officinalis is a freshwater swamp species that when occurring in association with mangroves occupies low-salinity soil microsites, or alternatively that it possesses mechanisms preventing accumulation of salt in photosynthetic tissues. To test this we compared the mineral composition of soils and leaves of several species in two Pterocarpus forests in...