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1. One way in which dams affect ecosystem function is by altering the distribution and abundance of aquatic species. 2. Previous studies indicate that migratory shrimps have significant effects on ecosystem processes in Puerto Rican streams, but are vulnerable to impediments to upstream or downstream passage, such as dams and associated water intakes where stream water is withdrawn for human water supplies. Ecological effects of dams and water withdrawals from streams depend on spatial context and temporal variability of flow in relation to the amount of water withdrawn. 3. This paper...

Predator damage and shell size on the diadromous snail Neritina virginea (Gastropoda: Neritidae) in the Mameyes River, Puerto Rico. We compared predators’ damage with shell size in live individuals and empty shells (n=5066) of the snail Neritina virginea in the Mameyes River (Puerto Rico, Greater Antilles). According to the literature and direct observations, damages on empty shells were attributed to predation by aquatic birds (e.g. Gallinula chloropus) and decapods (e.g. Macrobrachium spp.), while damages on live individuals were due to rasping by co-specifics and erosion. Predation by...

In the wake of widespread loss of old-growth forests throughout the tropics, secondary forests will likely play a growing role in the conservation of forest biodiversity. We considered a complex hierarchy of factors that interact in space and time to determine the conservation potential of tropical secondary forests. Beyond the characteristics of local forest patches, spatial and temporal landscape dynamics influence the establishment, species composition, and persistence of secondary forests. Prospects for conservation of oldgrowth species in secondary forests are maximized in regions...

Because global timber demands continue to threaten tropical rain forests, identification of sustainable use forest management protocols that meet human needs while preserving biodiversity is critical. Reduced-impact logging (RIL) protocols are increasingly common in the tropics and may be a viable option for sustainable forest use; however, few studies have documented faunal responses to RIL. Moreover, evaluations of abundance or diversity may not be sufficient for a comprehensive understanding of faunal responses to human activities, especially in the short-term. We assessed the effects...

The main purpose of this paper is to summarize information about the Cabo Rojo and Laguna Cartagena National Wildlife Refuges in southwestern Puerto Rico. The Cabo Rojo (Headquarters and Salinas tracts) and Laguna Cartagena (Lagoon and Tinaja tracts) occupy 1174 ha and are part of the 10 231-ha Caribbean system of nine refuges. Their major geologic and physiographic features are Sierra Bermeja, the oldest mountain range in Puerto Rico, and the floodplains of the Lajas Valley. Together, the refuges combined contain 9 geologic features and 26 soils’ types. Rainfall averages about 1000...

This data set reports the results of an experiment that tested the short-term effects of root mortality on the soil-atmosphere fluxes of nitrous oxide, nitric oxide, methane, and carbon dioxide in a tropical evergreen forest. Weekly trace gas fluxes are provided for treatment and control plots on sand and clay tropical forest soils in two comma separated ASCII files. The study site in the Tapajos National Forest (TNF) is near km 83 on the Santarem-Cuiaba Highway south of Santarem, Para, Brazil. Root mortality was induced by isolating blocks of land to 1 m depth using trenching and root...

Measurements of the soil-atmosphere flux of CO2 were made at the km 67 flux tower site in the Tapajos National Forest, Santarem, Para, Brazil. Eight chambers were set up to measure trace gas exchange between the soil and atmosphere about 5 times a day (during daylight and night) at this undisturbed forest site from April 2001 to April 2003. CO2 soil efflux data are reported in one ASCII comma separated file. The automated chamber system consisted of 8 automatically opening and closing aluminum chambers with an infrared gas analyzer. The chambers were installed in a 0.5 ha area close to the...

St. John, U.S. Virgin Islands, is one of the most forested islands in the West Indies and provides an opportunity to conserve both resident birds and wintering neotropical migrants.We conducted double-observer point counts of landbirds in December 2005 and 2006 in Forest Inventory and Analysis (FIA) plots and National] Park Service (NPS) trails in Virgin Islands National Park (VINP) to assess population trends of birds in subtropical dry and moist forests. We recorded 2,270 individual birds representing 35 species at 150 point count stations in 2005, and 3,092 individuals of 32 species at...

Humid tropical forests are dynamic ecosystems that experience multiple and overlapping disturbance events that vary in frequency, intensity, and spatial extent. Here we report the results of a 10-year study investigating the effects of forest clearing and multiple hurricanes on ecosystem carbon reservoirs, nutrient pools and vegetation. The aboveground plant community was most heavily affected by multiple disturbances, with the 9-year-old stands showing high rates of hurricane-induced mortality relative to surrounding forest. Belowground pools were less affected. Live fine root biomass...

Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapaj´os National...