Treesearch

Measurement of fish body-size distributions is increasingly used as a management tool to assess fishery status. However, the effects of gear selection on observed fish size structure has not received sufficient attention. Four different gear types (experimental gill nets, fine mesh bag seine, and two different sized mesh trap nets), which are commonly employed in the study area for fisheries surveys, were used to fish in five small (< 200 ha) lakes to evaluate differential catch in terms of species composition and assemblage size distributions. Kolmogorov–Smirnov tests revealed that, out...

An important element of the wise use of water-related ecosystem services provided by El Yunque National Forest, located in the Luquillo Mountains in northeastern Puerto Rico, is the facilitation of a clear understanding about the composition of land cover and its relation to water resources at different scales of analysis, management, and decision making. In this study we present the results of a site-specific analysis that identify and quantify the land cover of the watersheds of the main rivers that have their headwaters in El Yunque National Forest and relate land-cover data to three...

Summary 1. The impacts of selective harvesting in tropical forests on population recovery and future timber yields by high-value species remain largely unknown for lack of demographic data spanning all phases of life history, from seed to senescence. In this study, we use an individual- based model parameterized using 15 years of annual census data to simulate population dynamics of big-leaf mahogany Swietenia macrophylla King in southeast Amazonia in response to multiple harvests and in the absence of harvesting. 2. The model is based on regression equations of stem diameter growth,...

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project -- and avert -- future declines. We describe and assess a new database of more than...

Eugenia fragrans var.? fajardensis was described in 1895 and raised to species status in 1923 as E. fajardensis. In 1925, it was relegated to the synonymy of Anamomis fragrans (Myrcianthes fragrans). Since 2001, we have re-discovered wild plants and herbarium specimens, including a previously unidentified isotype of E. fajardensis, supporting the validity of this species. Here we designate a lectotype and an epitype for E. fajardensis. In addition, we provide: 1) an extended description for the species including the previously unknown flowers and fruits, an illustration, and photographs of...

Climate-induced disturbances such as hurricanes affect the structure and functioning of many ecosystems, especially those in the Caribbean Basin, where effects are well documented with regard to biodiversity and biogeochemical dynamics. Because climate change will likely alter the frequency or intensity of such storms, it is increasingly important to understand the mechanistic bases for ecosystem responses. However, this is particularly difficult to do in the absence of manipulative experiments that decouple confounded factors such as canopy opening and debris deposition. To address this...

We experimentally manipulated key components of severe hurricane disturbance, canopy openness and detritus deposition, to determine the independent and interactive effects of these components on tree recruitment, forest structure, and diversity in a wet tropical forest in the Luquillo Experimental Forest, Puerto Rico. Canopy openness was increased by trimming branches, and we manipulated debris by adding or subtracting the trimmed materials to the trimming treatments, in a 2  2 factorial design replicated in three blocks. Tree (stems P1 cm diameter at breast height) responses were...

El cuco hormiguero, Neomorphus geoffroyi, se registró en la Reserva de Biósfera de Bosawás y representa el primer gráfico de la especie para el Norte y para el país. Esta especie es rara y es sensible a la deforestación, se observó en compañía de bandadas mixtas, con su comportamiento característicos de saltos rápidos en busqueda o siguiendo a su presa. El área de Bosawás ha sido evaluada periódicamente por Wildlife Conservation Society (WCS) a través del uso de trampas cámara para registrar mamíferos grandes desde el año 2006 y ha sido hasta en marzo, abril y julio de 2013 que se obtuviero...

Water fluxes in tree plantations and other ecosystems carry dissolved organic carbon (DOC) provided by atmospheric inputs, autotrophic and heterotrophic metabolisms and from the lysis of dead material. These compounds may be colorless or provide a yellow-to-brown color to water and may also absorb visible light due to the presence of chromophores in the chemical structure. Concentration and composition of DOC and DOC annual flux in water pathways of a Eucalyptus grandis plantation were studied in Entre Ríos, Argentina. Samples of bulk precipitation, throughfall, stemflow, litter lixiviation...

Ferns are abundant in most rainforest understories yet their responses to hurricanes have not been well studied. Fern community structure, growth and spore production were monitored for two years before and five years after a large-scale experiment that simulated two key components of severe hurricane disturbance: canopy openness and debris deposition. The canopy was opened by cutting branches above 3 m and the fallen leaf and woody debris was either added to or removed from the forest floor resulting in four treatments that were replicated three times in a factorial design. Of the 16 fern...