TY  - JOUR
A1  - Germer, Sonja
A1  - Zimmermann, Alexander
A1  - Neill, Christopher
A1  - Krusche, Alex V.
A1  - Elsenbeer, Helmut
T1  - Disproportionate single-species contribution to canopy-soil nutrient flux in an Amazonian rainforest
JF  - Forest ecology and management
N2  - Rainfall, throughfall and stemflow were monitored on an event basis in an undisturbed open tropical rainforest with a large number of palm trees located in the southwestern Amazon basin of Brazil. Stemflow samples were collected from 24 trees with a diameter at breast height (DBH) > 5 cm, as well as eight young and four full-grown babassu palms (Attalea speciosa Mart.) for 5 weeks during the peak of the wet season. We calculated rainfall, throughfall and stemflow concentrations and fluxes of Na+, K+, Ca2+, Mg2+,, Cl-, SO42-, NO3- and H+ and stemflow volume-weighted mean concentrations and fluxes for three size classes of broadleaf trees and three size classes of palms. The concentrations of most solutes were higher in stemflow than in rainfall and increased with increasing tree and palm size. Concentration enrichments from rainfall to stemflow and throughfall were particularly high (81-fold) for NO3-. Stemflow fluxes of NO3- and H+ exceeded throughfall fluxes but stemflow fluxes of other solutes were less than throughfall fluxes. Stemflow solute fluxes to the forest soil were dominated by fluxes on babassu palms, which represented only 4% of total stem number and 10% of total basal area. For NO3-, stemflow contributed 51% of the total mass of nitrogen delivered to the forest floor (stemflow + throughfall) and represented more than a 2000-fold increase in NO3- flux compared what would have been delivered by rainfall alone on the equivalent area. Because these highly localized fluxes of both water and NO3- persist in time and space, they have the potential to affect patterns of soil moisture, microbial populations and other features of soil biogeochemistry conducive to the creation of hotspots for nitrogen leaching and denitrification, which could amount to an important fraction of total ecosystem fluxes. Because these hotspots occur over very small areas, they have likely gone undetected in previous studies and need to be considered as an important feature of the biogeochemistry of palm-rich tropical forest.
KW  - Stemflow
KW  - Throughfall
KW  - DBH
KW  - Open tropical rain forest
KW  - Babassu palm (Attalea speciosa Mart. synonym: Orbignya phalerata Mart.)
KW  - Amazonia
Y1  - 2012
U6  - https://doi.org/10.1016/j.foreco.2011.11.041
SN  - 0378-1127
VL  - 267
IS  - 2
SP  - 40
EP  - 49
PB  - Elsevier
CY  - Amsterdam
ER  -