Treesearch

Mist nets have been used to monitor site, composition, and survival rates of bird populations in the Guanica Forest of Puerto Rico every winter since 1972. Each line of nets consists of 16. 12-m nets erected end-to-end in a straight line and operated from dawn to dark for three consecutive days. Here we examine features of the netting protocol that could affect quality of results for population studies, including species sampled, length and frequency of netting sessions. and number of captures and recaptures. Point counts and mist-net samples gave very different results for relative...

There is a dichotomy between open- and cavity-nesting species in the quantitative and temporal aspects of most reproductive parameters. For example, parameters such as 1) breeding season commencement, length, and conclusion, 2) number of clutches per season, 3) length of recrudescence periods, and 4) incubation and nestling periods, usually reflect shorter times in open nesters. However, these parameters are not always comparable among species with a proclivity for similar nest placement strategies, nor are they mutually exclusive within a given species. The Pearly-eyed Thrasher (Margarops...

A discussion of the general characteristics of shrubs as a life form and their distribution within the United States is followed by 311 short monographs containing general descriptions, ranges, ecology, reproductive habits, growth and management, and benefits to humans, animals, and the environment.

WE ENDORSE THE ECOLOGICAL SOCIETY OF America’s (ESA) call to shift its primary focus from the study of undisturbed ecosystems to interdisciplinary studies of humaninfluenced ecosystems for the betterment of human societies (1, 2). At the 2004 annual meeting of the Association for Tropical Biology and Conservation (ATBC) in Miami, Florida, we released a report (“Beyond Paradise: Meeting the Challenges in Tropical Biology in the 21st Century”), which also makes a plea for an interdisciplinary, participatory, and socially relevant research agenda to study and conserve human-impacted as well...

Observations of foraging behavior of the Puerto Rican boa (Epicrates inornatus) were performed at a cave entrance beginning one hour before sunset until one hour after sunrise. Boas captured bats from 1745 h to 0600 h, but most captures were between 1900 and 2400 h. The most common preyed bats were Erophylla sezekorni, Mormoops blainivillii, Pteronotus quadridens and Monophyllus redmanii, while Brachyphylla cavernarum was rarely caught. The average prey handling time was 12.53 min. The Radiotelemetry was used to determine the home range, activity and movements of E. inornatus. Eleven...

Conversion of abandoned cattle pastures to secondary forests and plantations in the tropics has been proposed as a means to increase rates of carbon (C) sequestration from the atmosphere and enhance local biodiversity. We used a long-term tropical reforestation project (55–61 yr) to estimate rates of above- and belowground C sequestration and to investigate the impact of planted species on overall plant community structure. Thirteen tree species (nine native and four nonnative species) were planted as part of the reforestation effort in the mid to late 1930s. In 1992, there were 75 tree...

Various complementary techniques were used to investigate the stormflow generating processes in a small headwater catchment in northeastern Puerto Rico. Over 100 samples were taken of soil matrix water, macropore flow, streamflow and precipitation, mainly during two storms of contrasting magnitude, for the analysis of calcium, magnesium, silicon, potassium, sodium and chloride. These were combined with hydrometric information on streamflow, return flow, precipitation, throughfall and soil moisture to distinguish water following different flow paths. Geo-electric sounding was used to survey...

Egg color, size, and shape vary considerably within and among female Pearly-eyed Thrashers (Margarops fuscatus). Results of a 25-yr study (1979-2004) are presented to provide comparative data. In a sample of 4,128 eggs, typical shape was prolate spheroid; but several variations were observed, depending on the age, stature, and physiological condition of the female, as well as environmental influences such as the availability of essential nutrients. From a subset of 3,867 eggs measured between 1979 and 2000, a speciesspecific egg shape, or elongation index of 1.44 was derived (mean = 1.44;...

To evaluate the current status of instream flow practices in streams that drain into the Caribbean Basin, a voluntary survey of practising water resource managers was conducted. Responses were received from 70% of the potential continental countries, 100% of the islands in the Greater Antilles, and 56% of all the Caribbean island nations. Respondents identified ‘effluent discharges’, ‘downstream water quality’ and ‘existing extraction permits’ to be the most common sources of instream flow conflicts. In 75% of the countries, some type of ‘formal procedures’ exist for reviewing permit...