Treesearch

We used artificial nest experiments to study rates and patterns of egg predation in subtropical wet and lower montane wet forest on the island of Puerto Rico. Levels of depredation were higher for ground nests than for elevated nests, but we found no difference in rates of egg predation between forest edge (5-50 m) and forest interior (100--250 m) nests. We quantified 25 forest vegetation variables surrounding ground and elevated, forest interior nests, and correlated nest success with these vegetation parameters. Utilizing discriminant function analysis, nest success was correctly...

Bird populations in a subtropical wet forest were monitored every two to three weeks with mist nets and point counts beginning two weeks after the passage of Hurricane Hugo in September 1989. The results were compared with those of a pre-hurricane study in the same locations in which birds were sampled in forest understory and openings. Capture rates were initially higher than in the previous study, due to displaced canopy dwellers foraging in the understory. The shift of canopy dwellers may have obscured expected declines in nectarivores and fruit/seedeaters and contributed to increased...

The comparison of tropical birds having small clutches and long lifespans with temperate birds having large clutches and short lifespans is one of the cornerstones of theories dealing with avian reproductive strategies (Cody 1966, 1971, Stearns 1976, Ricklefs 1983, 1992, Murray 1985, Skutch 1985, Godfray et al. 1991). Karr et al. (1990) described the limited data supporting the assumption of long tropical lifespans and provided data for one sample of tropical birds--25 species from Panama--that did not show greater survivorship than a sample of temperate species (10 from Maryland). Their...

This book contains illustrations and descriptions, in English and Portuguese, of 172 tree species com­monly found in primary and secondary forests of the centrai Brazilian Amazon region, focussing on the Tapajos National Forest in western Para State. Photographic illustrations for each species include foliage (plus flowers and/or fruits for some species), seedling, bark, and trunk features that are intended to facilitate field identification. Written descriptions of each species include identification characteristics not apparent from illustrations, as well as information on wood and...

Relationships between landforms, soil nutrients, forest structure, and the relative importance of different disturbances were quantified in two subtropical wet steepland watersheds in Puerto Rico. Ridges had fewer landslides and treefall gaps, more above-ground biomass, older aged stands, and greater species richness than other landscape positions. Ridge soils had relatively low quantities of exchangeable bases but high soil organic matter, acidity and exchangeable iron. Valley sites had higher frequencies of disturbance, less biomass, younger aged stands, lower species richness and soils...

The tabonuco forest of Puerto Rico support a diverse population of tree species valued for timber, fuel, food, wildlife food and cover, and erosion control among other use. tree basal area growth data spanning 39 years are avaible on 15 species from eigth permanent plots in Luquillo Experimental Forest. The complexity of the rain forest challeges current forest standsmodeling techniques.

The development of the Hawaiian montane rainforest was investigated along a 4.1-million-year soil age gradient at 1200 m elevation under two levels of precipitation, the mesic (c. 2500 mm annual rainfall) vs. wet (> 4000 mm)age gradient. Earlier analyses suggested that soil fertility and foliar nutrient concentrations of common canopy species changed unimodally on the same gradients, with peak values at the 20,000-150,000 yr old sites, and that foliar concentrations were consistently lower under the wet than under the mesic conditions. Our objectives were to assay the influences of soil...