Treesearch

1 The controls over above-ground primary productivity following hurricane damage were investigated in a lowland subtropical wet forest (350–500 m altitude) and a lower montane elfin forest (1050 m) in Puerto Rico. Responses of understorey and canopy vegetation to addition of a complete nutrient fertilizer (both altitudes) or hurricane debris removal (lowland only) were monitored for 47–50 months. Treatments were initiated 1–6 months after Hurricane Hugo severely damaged both forests (18 September 1989). 2 Fertilization stimulated leaf litter production in both forests, but the recovery to...

The impact of severe habitat disturbance on plants and animals is often dramatically negative, but across species and guilds there is considerable variance. The effects of hurricane damage exemplify this phenomenon. When most organisms are adversely affected, it is expected that the dynamics of their inter actions will also be altered. The consequences of a direct hit by Hurricane Hugo, a category 4 storm, on a plant-pollinator interaction was investigated by comparing pre-hurricane (1981–1985) with post-hurricane data (1989-1990). The nectarless, self-compatible Epidendrum ciliare L....

Remnant population of the critically endangered Puerto Rican Parrot (Amazona vittata) survives in the Luquillo Mountains of northeastern Puerto Rico (Snyder et al. 1987). During the last three decades, intensive research and management have reversed a precipitous population decline to one of continual population growth (Wiley 1980, Snyder et al. 1987, Lindsey et al. 1989, Lindsey 1992). Prior to Hurricane Hugo in 1989, the wild population had grown from 14 birds during the mid-1970s to 47 (Meyers 1995). The hurricane reduced the population to about 22-24 birds; however, by early 1994, the...

In contrast to other ants in the genus Monomorium that produce cyclic amines, extracts of Monomorium floricola contain (Z)-7-tetradecenylamine (1) and (Z)-9-tetradecenylamine (2). The structures of these compounds were established from their spectral data and by comparison with synthetic 2.

A number of 15-carbon alkaloids have been identified in venoma extracts of four Puerto Rican species of ants in the genus Solenopsis (Diplorhoptrum). Workers of a species from El Verde produced the cis and trans isomers of 2-methyl-6-nonylpiperidine with the latter isomer predominating. The same compounds were identified in queens of a species from Rio Grande, hut in this species no alkaloids were detected in worker extracts. Workers of a Diplorhoptrum species collected on Mona Island produced primarily a trans-2-methyl-6-(Z-4-nonenyl)piperidine, 3, with smaller amounts of the cis isomer,...

This paper provides an overview of agricultural and forestry development in the Amazon basin, and presents and discusses the main land use systems in evidence today in that region. These are logging, shifting-cultivation and ranching. The issue of sustainability is addressed, and current Amazonian land use is interpreted in light of ecological impacts and long-run viability. Also considered are the ecological notions of criticality, endangerment, impoverishment and resilience. After addressing the threats of land use encroachment to the forest resource base, the paper identifies sufficient...

we compared forest structure over a 12 yr period. 1982-1994 that include measurements before and after a servere hurricaine in two forests: a 64 yr old swietenia macrophylla tree plantantion and a paired natural forest of similar age in a subtropical wet forests

We compared patterns of earthworms abundance and species composition in tree plantation and secondary forest of Puerto Rico. Tree plantations included pine (Pinus caribea Morelet) and mahogany (Swietenia macrophylla King) established in the 1930's; 1960's; and 1970's; secondary forests were naturally regenerated in areas adjacent to these plantations. We found that (1) earthworm density and fresh weight in the secondary forests were twice those in either of the tree plantations, and didn't differ between the plantations, and (2) the exotic earthworm species, Pontoscolex corethrurus Muller,...

This paper addresses the relationship between property regimes and land degradation outcomes, in the context of peasant agriculture. We consider explicitly whether private property provides for superior soil resource conservation, as compared to common property and open access. To assess this we implement optimization algorithms on a supercomputer to address resource decision-making of individual households. We find that conditions exist under which private property does not lead to the best environmental outcome. Access to farming technology and off-farm employment opportunities are key...