Journal of Tropical Ecology



Litterfall production and fluvial export in headwater catchments of the southern Amazon


Evandro Carlos Selva a1, Eduardo Guimarães Couto a1, Mark S. Johnson a2c1 and Johannes Lehmann a2
a1 Departamento de Solos, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, MT, Brazil
a2 Department of Crop and Soil Sciences, Cornell University, Ithaca, NY 14850, USA

Article author query
selva ec   [PubMed][Google Scholar] 
couto eg   [PubMed][Google Scholar] 
johnson ms   [PubMed][Google Scholar] 
lehmann j   [PubMed][Google Scholar] 

Abstract

Resolving the carbon (C) balance in the Amazonian forest depends on an improved quantification of production and losses of particulate C from forested landscapes via stream export. The main goal of this work was to quantify litterfall, the lateral movement of litter, and the export of coarse organic particulate matter (>2 mm) in four small watersheds (1–2 ha) under native forest in southern Amazonia near Juruena, Mato Grosso, Brazil (10°25′S, 58°46′W). Mean litterfall production was 11.8 Mg ha−1 y−1 (5.7 Mg C ha−1 y−1). Litterfall showed strong seasonality, with the highest deposition in the driest months of the year. About two times more C per month was deposited on the forest floor during the 6-mo dry season (0.65 Mg C ha−1 mo−1) compared with the rainy season (0.3 Mg C ha−1 mo−1). The measured C concentration of the litterfall samples was significantly greater in the dry season than in the rainy season (49% vs. 46%). The lateral movement of litter increased from the plateau (upper landscape position) towards the riparian zone. However, the trend in C concentration of laterally transported litter samples was the opposite, being highest on the plateau (44%) and lowest in the riparian zone (42%). Stream-water exports of particulate C were positively correlated with streamflow, increasing in the rainiest months. The export of particulate C in streamflow was found to be very small (less than 1%) in relation to the amount of litterfall produced.

(Accepted December 6 2006)


Key Words: Amazon basin; Brazil; lateral movement; litterfall; run-off; small watersheds; streams; tropical forest.

Correspondence:
c1 Corresponding author. Email: msj8@cornell.edu