Treesearch

Carbon accounting, forest health monitoring and sustainable management of the subtropical dry forests of Puerto Rico and other Caribbean Islands require an accurate assessment of forest aboveground biomass (AGB) and stem volume. One means of improving assessment accuracy is the development of predictive equations derived from locally collected data. Forest inventory and analysis (FIA) measured tree diameter and height, and then destructively sampled 30 trees from 6 species at an upland deciduous dry forest site near Ponce, Puerto Rico. This data was used to develop best parsimonious...

This special issue is based on scientific contributions presented at the 2nd Latin American Symposium of Earthworm Ecology and Taxonomy (ELAETAO, for its Spanish acronym) held in San Juan, Puerto Rico November 14-18, 2005. The first of these symposia was organized by George G. Brown and Klaus D. Sautter and held at Londrina, Brazil from December 1-3, 2003.The objective of the first symposium was to summarize the state of knowledge on the ecology, biodiversity and distribution of earthworms in Latin America and of their usefulness as bio-indicators in various natural and agricultural...

Tree species assemblages described by landscape-scale forest inventory data both agreed and differed from those described by intensive, site specific studies in Puerto Rico’s highly disturbed northern karst belt. Species assemblages found on hill tops (typified by Tabebuia heterophylla or Bursera simaruba with Coccoloba diversifolia, Licaria parvifolia, and Drypetes alba), abandoned coffee shade (Guarea guidonia, Dendropanax arboreus, Inga vera, and Persea americana), early successional forest (Tetrazygia elaeagnoides with Bucida bursera), and reverting pasture (Spathodea campanulata and...

Diadromous faunas dominate most tropical coastal streams and rivers, but the factors controlling their distribution are not well understood. Our study documents abiotic variables controlling the distribution and abundance of the diadromous snail Neritina virginea (Gastropoda:Neritidae) in the Caribbean island of Puerto Rico. An intensive survey of N. virginea density and shell size, and channel substrate, velocity, and depth was conducted at microhabitat, habitat, and reach scales of a coastal plain reach of the Río Mameyes between August and December 2000. In addition, the inland extent...

We used a fluorescence technique to mark and re-count the invasive earthworm, Pontoscolex corethrurus from PVC tubes established in a forest and a recently abandoned pasture in Puerto Rico to test the effects of the labeling treatment on earthworm population survival over time. A fluorescent marker was injected into the earthworms in the middle third section of the body, between inside and outside walls. Five labeled juveniles and two unlabeled adults of P. corethrurus were incubated in the PVC tubes under field conditions and retrieved after 2, 4, 8, and 16 weeks (labeled population; four...

Extreme events (hurricanes, floods, and droughts) can influence upstream migration of macroinvertebrates and wash out benthic communities, thereby locally altering food webs and species interactions. We sampled palaemonid river shrimp (Macrobrachium spp.), dominant consumers in headwaters of the Luquillo Mountains of northeastern Puerto Rico, to determine their distributions along an elevational gradient (274–456 m asl) during a series of disturbances (Hurricane Hugo in 1989, a drought in 1994, and Hurricane Georges in 1998) that occurred over a 15-y period (1988
2002).We measured shrimp...

Populations of some native earthworm species are decreasing or disappearing due to human activities like habitat disturbance and introduction of exotic earthworms. Habitat disturbance can cause changes in soil physical structure and nutrient cycling, which may reduce native earthworm populations prior to the invasion of exotic earthworms. Our purpose was 1) to investigate habitat disturbance as a key process in the decline or extirpation of native earthworms, and 2) to measure the ability of native earthworms to re-colonize disturbed areas. We hypothesized that habitat disturbance will...

Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C allocation and the response of different C pools to nutrient addition in these forests remain poorly understood. We measured soil organic carbon (SOC), litterfall, root biomass, microbial biomass and soil physical and chemical properties in a wet tropical forest from May 1996 to July 1997 following a 7-year continuous fertilization. We found that although there was no significant difference in total SOC in the top 0–10cm of the soils between the fertilization plots (5.42
0.18 kgm2) and the control...

Post-logging seedling regeneration density by big-leaf mahogany (Swietenia macrophylla), a nonpioneer light-demanding timber species, is generally reported to be low to nonexistent. To investigate factors limiting seedling density following logging within the study region, we quantified seed production rates, germinability, dispersal patterns, and seed fates on the forest floor through germination and the first seedling growing season in southeastern Amazonia, Brazil. Fruit production rates were low by three logged and one unlogged populations compared to reports from other regions....

Question: What are the composition, conservation status, and structural and environmental characteristics of eight mature tropical forest plant communities that occur along an elevational gradient. Location: Northeastern Puerto Rico. Methods: We quantified the species composition, diversity, conservation status, and ecological attributes of eight mature tropical forest plant communities in replicated plots located to sample representative components of important forest types occurring along an elevational gradient. A suite of environmental and vegetation characteristics were sampled at...