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Seedling Dynamics of a Tropical Tree: Impacts of Herbivory and Meristem Damage

Clark, David B., Clark, Deborah A.
Ecology 1985 v.66 no.6 pp. 1884-1892
Dipteryx oleifera, adults, apical meristems, autocorrelation, forest trees, germination, herbivores, leaf area, leaves, longevity, rain, seedlings, survival rate, Costa Rica
The effects of herbivory and apical meristem damage on seedlings of the tropical wet forest tree Dipteryx panamensis (Leguminosae; Papilionoideae) were evaluated for natural and transplanted seedlings at the la Selva Biological Station, Costa Rica. Original seedling leaves were long lived, up to 21 mo, and new leaf production was slow. Damage to the original leaves was gradual and continued to accumulate well after the leaves matured. The amount of leaf area lost was serially correlated between census periods for individual seedlings. Seedling longevity was highly correlated with the percentage of original leaf area present at 1 mo after germination, and with the number of leaves present at 7 mo of age. Leaf damage and terminal meristem damage were positively related to seedling density. Onset of herbivory was earlier for seedlings in a dense natural population than for seedlings transplanted to sites with no conspecific seedlings within 10 m. In a 1—ha population, the number of leaves on 7—mo—old seedlings was negatively correlated with the number of seedling neighbors within 10 m. Incidence of terminal meristem damage was positively correlated with seedling density. Leaf number and meristem damage were also correlated with distance from the nearest Dipteryx adult. Only 19% of the seedlings survived the 1st yr without losing at least 1 apical meristem. Meristem damage was highly correlated with amount of rainfall in the preceding 60 d. We detected no effect of meristem damage on seedling survivorship. Processes acting on very young seedlings can have major effects on tree regeneration. Herbivory on the first seedling leaves may be one such important process.