Treesearch

Stratified sampling by topography in the dwarf cloud forest of the Luquillo Experimental Forest indicated that many common tree species showed topographic preferences, favoring either ravines or slopes and ridges. Delayed post-hurricane mortality (≥1.3 and ≤6.3 yrs) on permanent plots established after the passage of Hurricane Hugo in September 1989 reduced the number of stems on Pico del Este by 21%, most notably impacting the smallest dbh and height classes in ridges. Mortality varied by species, with the palm Prestoea montana (R. Grah.) Nichols showing the best survival and the tree...

This slide program highlights the natural resources of the area known as Las Cabezas de San Juan Reserve on the northeastern tip of Puerto Rico. The visual tour includes: (I) the scenic shorelines, wind-swept promontories, and lagoons; (2) points of historic, cultural, and human interest; (3) the fauna and flora in their natural habitat; and (4) the role of the Puerto Rican Conservation Trust in furthering conservation and environmental education of the island.

The first fifty years (1959-1989) of the Tropical Forestry Experiment Station, which has evolved into the International Institute of Tropical Forestry, are reviewed through pictures, narrative, summaries of accomplishments, and a selected bibliography. Plans and projections for the future are also discussed. Appendices describe the people of the Institute in the past and up to the 50th anniversary, and contain the texts of two speeches given at the celebration, one by USDA Forest Service Chief F. Dale Robertson and the other by Congressman Bruce F. Vento.

The Montserrat Oriole Icterus oberi is endemic to the Caribbean island of Montserrat where, prior to 1995, it was widely distributed across the island's three main interior mountain ranges: the Centre, Soufriere and South Soufriere Hills. In July 1995, a long-dormant volcano on Chances Peak in the Soufriere Hills began to erupt. Since then the forest habitat of the oriole on the Soufriere and South Soufriere Hills has been devastated by pyroclastic flows and surges, heavy ash eruptions and rock falls. The Montserrat Oriole populations that inhabited these two mountain ranges have probably...

The Puerto Rican Vireo (Vireo Zatimeri), a Puerto Rican endemic, is declining in at least one forest reserve as the result of pressures from introduced nest predators and an introduced brood parasite. We collected data on adult survival, adult longevity, and juvenile survival from a long-term mist netting study (1973-1999) and a demographic study of color-marked birds (1990-1993) in Guanica Forest, Puerto Rico. Of the adult birds banded in the first three years of the demographic study, 24 of 32 males (75%) and 6 of 7 females (86%) were known to survive until June of the year following...

Megalomyrmex is an exclusively Neotropical ant genus allied to Nothidris, Tranopelta, and others currently placed in the tribe Solenopsidini (Ettershank, 1966; Bolton, 1994). In a recent revision of the genus, Brandao (1990) recognized 31 species and four species groups. The distribution of Megalomyrmex extends from tropical Mexico to southern Brazil. Recently, saturated nitrogen heterocycles, similar to those found in Monomorium and Solenopsis species, have been reported in four Megalomyrmex species (Jones et al., 1991a, l991b). In Monomorium and Solenopsis these venom components are...

Structures for 2,5-disubstituted decahydroquinolines (DHQs) are reported for the two diastereomeric pairs cis-275B (14) and cis-275B' (15) and 5-epi-trans-269AB (18) and trans-269AB (19), all isolated from skin extracts of dendrobatid frogs, and for 5-epi-cis-275B' (16) and 5-epi-trans-275B (17) found in the extracts of virgin queens of a myrmicine ant [Solenopsis (Diplorhoptrum) azteca]. Detection of such DHQs in an ant, their first reported occurrence, strengthens a dietary hypothesis for the origin of the approximately 30 DHQs that have been detected in extracts of frog skin. NMR data...

La especie Pseudomethoca argyrocephala fue descrita muy brevemente a partir de una hembra colectada en St. John, Islas Vfrgenes (Gerstaecker, 1874). Su presencia, inadvertida por la ausencia de ejemplares en las principales colecciones y la deposicion del holotipo en algun museo de Alemania, posiblemente motivo la omision en una clave para las especies antillanas (Schuster, 1945) y en el catalogo para la region Neotropical (Nonveiller, 1990). El gran dimorfismo sexual de los mutilidos impide la identificacion correcta de los sexos cuando no se colectan juntos. En pocas especies antillanas...

The cephalic extracts of the ant Anochetus kempfi were found to contain 2,5-dimethyl-3-isoamylpyrazine (1) and 3-methyl-4-phenylpyrrole (2). The structures of these compounds were established from their spectral data and by comparison with synthetic samples. This is the first report of a phenylpyrrole found in an insect and only the third report of a pyrrole from ants.

Arguments against active tropical management are analyzed in light of available data and new research that shows tropical forests to be more resilient after disturbances than previously thought. Tropical forest management involves a diverse array of human activity embedded in a complex social and natural environment. Within this milieu, forest structure and composition adjust to change and reflect the human and natural economy of regions. Critics of active forest management overestimate problems and underestimate human capacity to solve them. They isolate parts of a complex issue, i.e. the...