Leaf Decomposition in a Dry Season Irrigation Experiment in Eastern Amazonian Forest Regrowth

• Published in: Biotropica Vol. 39; no. 5; pp. 593 - 600
• Main Authors: Vasconcelos, Steel Silva, Zarin, Daniel Jacob, da Rosa, Maria Beatriz Silva, de Assis Oliveira, Francisco, de Carvalho, Cláudio José Reis
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.09.2007; Blackwell Publishing; Blackwell
• Subjects: Animal, plant and microbial ecology; Annona; Annona paludosa; Applied ecology; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Dry seasons; Forest ecosystems; Forest litter; Forest regeneration; Forest soils; Forestry; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Lacistema pubescens; Leaves; litter quality; litterbag; Ocotea; Ocotea guianensis; Plant litter; Regrowth; Stryphnodendron pulcherrimum; Tropical Biology; Tropical forests; Tropical rain forests; tropical secondary forest; Vismia; Vismia guianensis; South America; America; Amazon Basin; South America, Amazonia; South America, Amazon R; Irrigation; Tropical zone; Ocotea guianensis; Decomposition; Vismia guianensis; Climatic zone; litter quality; Dicotyledones; Angiospermae; Secondary forest; Water engineering; Annonaceae; litterbag; Litter; Stryphnodendron pulcherrimum; Tropical rain forest; Regrowth; Natural forest regeneration; Plant leaf; Tropical forest; Dry season; Spermatophyta; Annona paludosa; Lacistema pubescens; tropical secondary forest
• ISSN: 0006-3606; 1744-7429
• DOI: 10.1111/j.1744-7429.2007.00313.x

Leaf-litter decomposition is a major component of carbon and nutrient dynamics in tropical forest ecosystems, and moisture availability is widely considered to be a major influence on decomposition rates. Here, we report the results of a study of leaf-litter decomposition of five tree species in response to dry-season irrigation in a tropical forest regrowth stand in the Brazilian Amazon; three experiments differing in the timing of installation and duration allowed for an improved resolution of irrigation effects on decomposition. We hypothesized that decomposition rates would be faster under higher moisture availability in the wet season and during dry-season irrigation periods in the treatment plots, and that decomposition rates would be faster for species with higher quality leaves, independent of treatment. The rates of decomposition (k) were up to 2.4 times higher in irrigated plots than in control plots. The highest k values were shown by Annona paludosa (0.97 to 1.26/yr) while Ocotea guianensis (0.73 to 0.85/yr) had the lowest values; intermediate rates were found for Lacistema pubescens (0.91 to 1.02/yr) and Vismia guianensis (0.91 to 1.08/yr). These four tree species differed significantly in leaf-litter quality parameters (nitrogen, phosphorus, lignin, and cellulose concentrations, as well as lignin:nitrogen and carbon:nitrogen ratios), but differences in decomposition rates among tree species were not strictly correlated with leaf-litter quality. Overall, our results show that dry-season moisture deficits limit decomposition in Amazonian forest regrowth.