intermediate disturbance hypothesis applies to tropical forests, but disturbance contributes little to tree diversity

• Published in: Ecology letters Vol. 12; no. 8; pp. 798 - 805
• Main Authors: Bongers, Frans, Poorter, Lourens, Hawthorne, William D, Sheil, Douglas
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.08.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biodiversity; Biological and medical sciences; coexistence; Disturbance; dynamics; Ecology; Environment; Forestry; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Ghana; gradients; guild; intermediate disturbance hypothesis; mechanisms; Models, Biological; patterns; Plant populations; rain-forests; Rainforests; Regression Analysis; shade tolerance; species density; species diversity; species richness; Species Specificity; Trees; Tropical Climate; tropical forest; tropical forests; Ghana; Africa; Diversity; Tropical forest; Ghana; shade tolerance; Perturbation; Guild; Density; species density; Disturbance; Tree; intermediate disturbance hypothesis; Species richness; Sciaphyte
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/j.1461-0248.2009.01329.x

The intermediate disturbance hypothesis (IDH) predicts local species diversity to be maximal at an intermediate level of disturbance. Developed to explain species maintenance and diversity patterns in species-rich ecosystems such as tropical forests, tests of IDH in tropical forest remain scarce, small-scale and contentious. We use an unprecedented large-scale dataset (2504 one-hectare plots and 331 567 trees) to examine whether IDH explains tree diversity variation within wet, moist and dry tropical forests, and we analyse the underlying mechanism by determining responses within functional species groups. We find that disturbance explains more variation in diversity of dry than wet tropical forests. Pioneer species numbers increase with disturbance, shade-tolerant species decrease and intermediate species are indifferent. While diversity indeed peaks at intermediate disturbance levels little variation is explained outside dry forests, and disturbance is less important for species richness patterns in wet tropical rain forests than previously thought.