TY - JOUR
T1 - Relationships among precipitation regime, nutrient availability, and carbon turnover in tropical rain forests
AU - Posada, Juan M.
AU - Schuur, Edward A.G.
N1 - Funding Information:
Acknowledgments This research was funded by a grant from the Andrew W. Mellon Foundation to E.A.G.S. We thank Alfredo Navas, Estebana Ortiz, Yan Ramos and Lou Santiago for their help in the field. We are grateful to Grace Crummer, Lauren Thorton, Kate Welch, Koushik Dutta and Melanie DesRochers for their help in different phases of this study. Jason Vogel gave valuable insights during the analysis of the data. We thank Deborah and David Clark (Organization for Tropical Studies, La Selva), Alicia Ríos and Yan Ramos (Universidad Tecnológica del Chocó), José Sinisterra (Min-isterio de Ambiente, Vivienda y Desarrollo) and the Smithsonian Tropical Research Institute for logistical support. The meteorological data for Colombia were obtained from the Institute of Hidrology, Meteorology and Environmental Studies of Colombia (IDEAM) thanks to a cooperative agreement with the International Center for Physics (Convenio CIF-IDEAM). This study comply with the laws of the countries at the time in which sampling took place. This manuscript benefited from comments by Deborah Clark, Amy Austin and three anonymous reviewers.
PY - 2011/3
Y1 - 2011/3
N2 - The effect of high precipitation regime in tropical forests is poorly known despite indications of its potentially negative effects on nutrient availability and carbon (C) cycling. Our goal was to determine if there was an effect of high rainfall on nitrogen (N) and phosphorous (P) availability and indexes of C cycling in lowland tropical rain forests exposed to a broad range of mean annual precipitation (MAP). We predicted that C turnover time would increase with MAP while the availability of N and P would decrease. We studied seven Neotropical lowland forests covering a MAP range between 2,700 and 9,500 mm. We used radiocarbon ({increment}14C) from the atmosphere and respired from soil organic matter to estimate residence time of C in plants and soils. We also used C, N, and P concentrations and the stable isotope ratio of N (δ15N) in live and dead plant tissues and in soils as proxies for nutrient availability. Negative δ15N values indicated that the wettest forests had N cycles that did not exhibit isotope-fractionating losses and were potentially N-limited. Element ratios (N:P and C:P) in senescent leaves, litter, and live roots showed that P resorption increased considerably with MAP, which points towards increasing P-limitation under high MAP regimes. Soil C content increased with MAP but C turnover time only showed a weak relationship with MAP, probably due to variations in soil parent material and age along the MAP gradient. In contrast, comparing C turnover directly to nutrient availability showed strong relationships between C turnover time, N availability (δ15N), and P availability (N:P) in senescent leaves and litter. Thus, an effect of MAP on carbon cycling appeared to be indirectly mediated by nutrient availability. Our results suggest that soil nutrient availability plays a central role in the dynamic of C cycling in tropical rain forests.
AB - The effect of high precipitation regime in tropical forests is poorly known despite indications of its potentially negative effects on nutrient availability and carbon (C) cycling. Our goal was to determine if there was an effect of high rainfall on nitrogen (N) and phosphorous (P) availability and indexes of C cycling in lowland tropical rain forests exposed to a broad range of mean annual precipitation (MAP). We predicted that C turnover time would increase with MAP while the availability of N and P would decrease. We studied seven Neotropical lowland forests covering a MAP range between 2,700 and 9,500 mm. We used radiocarbon ({increment}14C) from the atmosphere and respired from soil organic matter to estimate residence time of C in plants and soils. We also used C, N, and P concentrations and the stable isotope ratio of N (δ15N) in live and dead plant tissues and in soils as proxies for nutrient availability. Negative δ15N values indicated that the wettest forests had N cycles that did not exhibit isotope-fractionating losses and were potentially N-limited. Element ratios (N:P and C:P) in senescent leaves, litter, and live roots showed that P resorption increased considerably with MAP, which points towards increasing P-limitation under high MAP regimes. Soil C content increased with MAP but C turnover time only showed a weak relationship with MAP, probably due to variations in soil parent material and age along the MAP gradient. In contrast, comparing C turnover directly to nutrient availability showed strong relationships between C turnover time, N availability (δ15N), and P availability (N:P) in senescent leaves and litter. Thus, an effect of MAP on carbon cycling appeared to be indirectly mediated by nutrient availability. Our results suggest that soil nutrient availability plays a central role in the dynamic of C cycling in tropical rain forests.
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U2 - 10.1007/s00442-010-1881-0
DO - 10.1007/s00442-010-1881-0
M3 - Research Article
C2 - 21207233
AN - SCOPUS:79951551595
SN - 0029-8549
VL - 165
SP - 783
EP - 795
JO - Oecologia
JF - Oecologia
IS - 3
ER -