The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests

• Published in: The New phytologist Vol. 189; no. 4; pp. 967 - 977
• Main Authors: Salinas, N., Malhi, Y., Meir, P., Silman, M., Cuesta, R. Roman, Huaman, J., Salinas, D., Huaman, V., Gibaja, A., Mamani, M., Farfan, F.
• Format: Journal Article
• Language: English
• Published: Oxford, UK John Wiley & Sons 01-03-2011; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: Altitude; Carbon cycle; Decay; Decay rate; Decomposition; elevational gradient; Environmental factors; Forest ecology; Forest litter; Forest soils; Geography; Humidity; Kinetics; Leaf litter; Leaves; Mineralization; Morphology; Nutrient cycles; Parameter sensitivity; Peru; Plant Leaves - physiology; Plant litter; Rain; Rainfall; Soil; Soil ecology; Soil moisture; Soil temperature; Soil temperature regimes; Soil water; Species; Species Specificity; Temperature; Thermal decomposition; Time Factors; Translocation; Trees - physiology; Tropical Climate; tropical forest; Tropical forests
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2010.03521.x

We present the results from a litter translocation experiment along a 2800-m elevation gradient in Peruvian tropical forests. The understanding of the environmental factors controlling litter decomposition is important in the description of the carbon and nutrient cycles of tropical ecosystems, and in predicting their response to long-term increases in temperature. Samples of litter from 15 species were transplanted across all five sites in the study, and decomposition was tracked over 448 d. Species' type had a large influence on the decomposition rate (k), most probably through its influence on leaf quality and morphology. When samples were pooled across species and elevations, soil temperature explained 95% of the variation in the decomposition rate, but no direct relationship was observed with either soil moisture or rainfall. The sensitivity of the decay rate to temperature (𝒦 T ) varied seven-fold across species, between 0.024 and 0.169°C⁻¹, with a mean value of 0.118 ± 0.009°C⁻¹ (SE). This is equivalent to a temperature sensitivity parameter (Q₁₀) for litter decay of 3.06 ± 0.28, higher than that frequently assumed for heterotrophic processes. Our results suggest that the warming of approx. 0.9°C experienced in the region in recent decades may have increased decomposition and nutrient mineralization rates by c. 10%.