Treesearch

I studied ant coexistence in adjacent areas of upland tropical forest, grassland, and agricultural land in San Lorenzo, Puerto Rico. Data on food utilization, daily activity, nesting sites, microhabitat utilization and interspecific aggression were collected. Ants' tolerance to 45 degree C was determined in the laboratory. Agricultural and grassland ants eat grain, liquid food or insects, or grow fungus; only liquid drinking and insectivorous ants occurred in the forest. Some species within food groups in the agricultural and grassland ants differed in size of food consumed or daily...

I studied ants in upland tropical forest, grassland and agricultural land in San Lorenzo, Puerto Rico, to uncover factors responsible for the distribution and number of species in these communities. Observations, laboratory studies and field experiments were used. Microclimate influenced the distributions of Pheidole fallax, Solenopsis geminata and Monomorium ebeninum; forest ants had lower tolerance to high temperatures than ants from non-forest areas. In addition, Ponerinae ants did not tolerate high temperatures as well as ants in the Formicinae, Myrmicinae and Dolichoderinae. The...

Puerto Rico and the Virgin Islands together have about 551 species of native trees, of which 539 are found in Puerto Rico. More than one-fourth, or 142, are known only from these islands (endemic). Only about 13 rare endemic tree species need additional protection and have been proposed as endangered. Also, 22 are to be watched or monitored and have been proposed as threatened. About 100 others listed as rare are native also beyond (nonendemic). The economic possibilities of endemic tree species merit special attention.

Measurements over approximately a 30-year period in a Dacryodes-Sloanea forest indicate two distinctive phases in stand development. Secondary species were common in the early stand (1940's), and rapid accumulations of biomass and basal area were measured. Many new species entered the stand, and the number of stems increased. In contrast, the stand of the 1970's approached steady-state for biomass and basal area accumulations, and, relative to earlier measurements, fewer stems and fewer species were recorded in the plot. This apparent dichotomy can be correlated to the periodic disturbance...

Buck Island is located in the Caribbean Sea only 1 2/3 miles north of the eastern part of St. Croix and about 5 miles northeast of Christiansted, United States Virgin Islands (map, figure 1, and figure 2). This "beautiful little uninhabited island" scarcely 1 mile long and less than half as wide supports a rich and representative land flora of the seasonal or relatively dry forest, tropical zone, totaling 228 listed species of seed plants but no ferns. A major objective of this study was to obtain records at Buck Island Reef National Monument for the 2-volume illustrated reference on the...

The trees of Puerto Rico and the Virgin Islands, both United States and British, are described and illustrated in two volumes, of which this is the second (volume 2). "Common Trees of Puerto Rico and the Virgin Islands" by Little and Wadsworth (52, 53), the first, is cited here as volume l. The first volume contains on facing pages the descriptions and drawings of 250 common tree species, both native and introduced. This second volume similarly treats 460 additional species and briefly describes 40 others, a total of 500. Thus, the two volumes together contain the text of 750 species and...

Most of the neotropical nations except Mexico and Brazil are mapped according to the Moldridge system of ecological life zones. In order to have comparability with these areas, Puerto Rico and the U.S. Virgin Islands were mapped and a discussion and a description of each life zone were written. The manuscript in English offers water balances, a description of the Holdridge theory of biotemperature, and greater detail in general. The shortened version in Spanish is intended as a field manual to be used with the map. Six life zones are present on these islands and are present also in South...

Forestry has been less studied in tropical than in temperate climate. In the tropics information is needed in many phases of forestry work. In Puerto Rico, reforestation had not been carried on an isalnd-wide scale until the Civilian Conservation Corps and the Puerto Rico Reconstruction Administration initiated a forestry program in Federal and Insular forests during 1934 and 1935.Pratically no research and little plantation establishment had een done previously. Formal research was not organized until 1939.