Department of Biology, Faculty of Sciences, Utrecht University
The importance of variation among individuals for tree population dynamics
日時 3月23日 15：00-
場所 生物地学共通講義室 （青葉山キャンパス理学部生物棟）
Trees in forest environments experience highly varying growing conditions. This is true for individual trees in the course of their lives: canopy openings, droughts, damage, etc. But there is also ample variation in growing conditions among trees, related to topography, nutrient availability and other conditions that vary over space. Variation in growing conditions can have major implications for the chance to reach reproductive size and the age at which this happens. This clearly has important implications for population dynamics and fitness. Trees of one species in a particular population that have experienced favourable conditions and reach reproductive size at young age have a boosting effect on population growth and therefore a higher fitness. In the study of tree population dynamics, surprisingly little attention has been paid to the implications of growth variation among individuals. Demographic studies have mainly used average growth rates, without accounting for the large degree of growth variation among individuals. I will show examples of persistent variation in growth among trees of tropical forest species at different sites. Then, I will show how new insights on the ecology of tropical forest trees can be obtained from demographic studies that explicitly account for growth variation among trees.