Treesearch

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...

Target 2 of the 2020 Global Strategy for Plant Conservation (GSPC) calls for a comprehensive list of the world’s threatened plant species. The lack of such a list is one of the greatest impediments to protecting the full complement of the world’s plant species, and work to achieve this has been slow. An efficient system for identifying those species that are at risk of extinction could help to achieve this goal in a timeframe sensitive to today’s conservation needs. Two systems that efficiently use available data to assess conservation status were tested against a provisional International...

Humid tropical forests play a dominant role in many global biogeochemical cycles, yet long-term records of tropical stream chemistry and its response to disturbance events such as severe storms and droughts are rare. Here we document the long-term variability in chemistry of two streams in the Luquillo Mountains, Puerto Rico over a period of 27 years. Our two focal study watersheds, the Rio Icacos and Quebrada Sonadora, both drain several hundred hectares of tropical wet forests, and each received direct hits from Hurricanes Hugo (1989) and Georges (1998). They differ primarily in lithology...

We now live in a world dominated by humans (the Anthropocene), whose activities on Earth are resulting in new habitats and new environmental conditions, including climate change. To many, the Anthropocene is an era of environmental doom that unless reversed, will result in catastrophic reductions in biodiversity. An alternate view is that the biota will adjust to the new environmental conditions and through processes of species mixing and self-organization will form sustainable novel communities of organisms. Using examples from Puerto Rico, I discuss the conditions that lead to novel...

Methylmercury, a potent neurotoxin, can damage health of humans and wildlife. In 2012, we collected 73 blood and feather samples from birds among diverse foraging guilds to assess mercury exposure in wetland habitats associated with Lakes Managua and Nicaragua. Blood levels (0.72 parts per million) in a piscivorous Neotropic Cormorant Phalacrocorax brasilianus from Lake Managua exceeded the United States Environmental Protection Agency recommended screening value for fish consumption of 0.3 ppm. Cormorants should be considered as an upper trophic level bioindicator of aquatic Hg toxicity....

Tropical forests account for approximately half of above-ground carbon stored in global vegetation. However, uncertainties in tropical forest carbon stocks remain high because it is costly and laborious to quantify standing carbon stocks. Carbon stocks of tropical forests are determined using allometric relations between tree stem diameter and height and biomass. Previous work has shown that the inclusion of height in biomass allometries, compared to the sole use of diameter, significantly improves biomass estimation accuracy. Here, we evaluate the effect of height measurement error on...

Although the Caribbean region is considered a biodiversity hotspot and a priority for ecological conservation efforts, little information exists on population trends of West Indian landbirds. We combined avian survey data collected from three studies spanning a 16-year period on a small island with a minimal human presence in the British Virgin Islands. Although abundances varied among surveys, the same species were detected with rare exceptions. Despite stability in species composition, the resident landbirds were variable in their individual detectabilities. Survey detections relatively...