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Hurricane effects on forest ecosytems in the Caribbean
| Author: |
Tanner, E. V. J.; Kapos, V.; Healey, J. R. |
| Date: |
1991 |
| Periodical: |
Biotropica |
| Abstract: |
Hurricanes are common, potentially catastrophic events for ecosystems in the Caribbean. We synthesize the work reported in this issue, together with the existing literature, to discuss effects of hurricanes on Caribbean ecosystems and to highlight priorities for future work. Comparisons of the impacts of hurricanes on different ecosystems are made difficult by the lack of detailed meteorological data, lack of pre-hurricane ecological data and differences between studies in types and timing of measurements made. <br>
Effects of recent hurricanes on Caribbean forest ecosystems include: defoliation, ranging from complete in lowland wet forest in Nicaragua after Hurricane Joan to negligible in parts of Jamaican montane forest after Hurricane Gilbert; felling of trees by uprooting and snapping (80% in Nicaragua to 14% in Jamaica); and tree mortality, which is rarely recorded and generally low (13% in the Yucatan following Hurricane Gilbert to 3% in Puerto Rican montane forests following Hurricane Hugo). Damage to individual trees varies with topographic location, stand characteristics, tree size (large ones uprooting and small ones snapping in Dominica during Hurricane David, but not in Jamaica), and species characteristics (such as wood density), but it is difficult to generalize about these factors.<br>
Effects on animal populations are both direct and through reductions in food supplies. Frugivorous and nectarivorous birds were more severely affected than insectivorous species in the Virgin Islands and Jamaica. There is little information about hurricane effects on insect populations, but populations of two species of walking sticks in Puerto Rico declined sharply after Hurricane Hugo. Numbers of adults of one frog species in Puerto Rico quadrupled after Hurricane Hugo, but numbers of juveniles were severely reduced by the storm.<br>
Effects of hurricanes on the physical environment include modified microclimates due to increased light penetration through defoliated canopies and landslides triggered by rainfall. Increased litterfall led to increases in some soil nutrients, and fine root biomass was drastically reduced in a Puerto Rican montane forest. Recovery of forest ecosystems from hurricanes depends on a combination of seedling growth and resprouting of canopy trees. In several studies, seed germination was promoted by higher light and/or higher temperature, but seedling mortality also increased. The relative importance of newly germinated seedlings, advance regeneration, and regrowth of damaged adults has not been studied. The few long-term studies of adult trees show the expected decline in the proportion of pioneer and intolerant species with time after disturbance. Hurricanes may be the most important factor controlling species composition and some aspects of ecosystem dynamics in the Caribbean; there is much still to be learned, and we suggest some priorities for future research. |
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