Conspecific density dependence in seedlings varies with species shade tolerance in a wet tropical forest

• Published in: Ecology letters 2011-05, Vol.14 (5), p.503-510
• Main Authors: Kobe, Richard K., Vriesendorp, Corine F.
• Format: Article
• Language: English
• Subjects: Abundance; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Community compensatory trend; Costa Rica; Density; density dependence; Forestry; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; irradiance; Janzen-Connell hypothesis; Light; Models, Biological; Population Density; Rainforests; resource partitioning; seedling mortality; seedlings; Seedlings - physiology; Seedlings - radiation effects; Seeds; shade tolerance; species coexistence; species richness; Species Specificity; Trees - physiology; Trees - radiation effects; Tropical Climate; wet tropical forest
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/j.1461-0248.2011.01612.x

Ecology Letters (2011) 14: 503–510 Density‐dependent seedling mortality could increase with a species relative abundance, thereby promoting species coexistence. Differences among species in light‐dependent mortality also could enhance coexistence via resource partitioning. These compatible ideas rarely have been considered simultaneously. We developed models of mortality as functions of irradiance and local conspecific density (LCD) for seedlings of 53 tropical woody species. Species varied in mortality responses to these factors, but mortality consistently increased with shading and LCD. Across species, density‐dependent mortality on a per‐neighbour basis was inversely related to species community abundance, but higher LCD in more common species resulted in a weak relationship between species abundance and density‐dependent mortality scaled to species maximum LCD. Species mortality responses to shading and maximum LCD were strongly and positively correlated. Our results suggest that species differences in density‐dependent mortality are more strongly related to physiologically based life‐history traits than biotic feedbacks related to community abundance.