Seasonality in an evergreen tropical mountain rainforest in southern Ecuador

Resumen

More than 400 individuals of 12 tree species growing in an evergreen tropical mountain rainforest in the eastern cordillera of southern Ecuador were examined over a period of 3 to 4 years with respect to flowering and fruiting as phenological events. In spite of the perhumid climate, a high degree of synchronization of flowering and fructification was observed at the intraand interspecific levels. Except one species that flowered more or less continuously, two groups of trees could be distinguished, of which one flowered during the less humid months (starting September/October) while the second initiated flowering towards the end of that phase and flowered during the heavy rains. Fructification also showed synchronization, but, due to species-specific time-spans of seed maturation was less pronounced than flowering. Concomitantly with the phenological recordings, climate was monitored in detail at both the regional and the local scale. In contrast to seasonal tropical lowland forests, no unambiguous relationship between flowering and fructification and seasonal changes in the amounts of precipitation could be found, but changes in cloudiness, and especially in the ratio of direct to diffuse global radiation, coincided with the induction of flowering of both groups. Superimposed on the periodical synchronization by the light regime were episodic events. Periods of unusual cold or dryness affected incidence of flowering, fruit maturation, and the production of germinable seeds. Knowledge of the biology and timing of reproduction is a prerequisite for the establishment of tree nurseries to produce saplings of indigenous trees for reforestation purposes. Accepted 14 August 2006.