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| Titel |
Spatial variation of water and element fluxes in throughfall of a tropical lowland forest, Panama |
| VerfasserIn |
Matthias Wiggenhauser, Tobias Messmer, Wolfgang Wilcke |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082628
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| Zusammenfassung |
| Quantity and chemical quality of throughfall fluxes are influenced by incident precipitation,
interception loss, dry deposition and canopy exchange processes. During the passage through
the canopy, water and nutrient fluxes are spatially redistributed resulting in a heterogeneous
input of water and dissolved nutrients into the soil. Furthermore, different tree species
influence the deposition of aerosols and canopy exchange processes differently. In this study,
we quantified (i) the spatial variation of throughfall water and element fluxes and (ii) the
influence of fig trees (Ficus insipida Willd.).
The study was conducted in a tropical lowland forest in Panama (Barro Colorado Island
9Ë 10 N and 79Ë 50’ W). Mean annual rainfall and temperature are 2600 mm and 27Ë C,
respectively. We sampled twelve pairs of plots, each involving a F. insipida plot (F) and a
reference plot without F. insipida (R). Each plot was equipped with nine throughfall
samplers, totalling 216 samplers, which were individually sampled in May, June and July
2012. We determined water volumes and concentrations of Ca, K, Mg, Na, NH4+, NO3-,
TN, Cl-, and organic C (TOC). Number of collectors needed to reach a standard error of
10% were calculated according to the methods of J.P Kimmins and B. Lawrence & I.J.
Fernandez.
The weekly average water was 87 mm and those of the studied elements 661 mg/m2
(TOC), K (545), Cl (367), TN (131), Na (111), Ca (98), NH4+ (77), Mg (48), NO3-(16).
The highest variation in throughfall fluxes occurred for NO3-(R) (coefficient of
variation, CV = 94%) and Ca(F)(80) and the lowest variation for H2O(F,R)(22) and
TN(R)(37). The largest difference in the spatial variation between F and R plots
occurred for NH4+ (CV(F) % - CV(R) % = 19), Ca (17), K (-7) and NO3- (-23).
To reach a standard error of the mean below 10%, most collectors are needed for
NO3-(R)(98),Ca(F)(77), K(R) (73), Mg(F) (72). Mean throughfall fluxes of Ca,
K and NO3-were significantly (p < 0.05) different between F and R plots. Figs
released more Ca and K than the remaining forest while they lost less or retained more
NO3- .
Our results demonstrate that (i) up to 16 and 98 throughfall samplers are required to
determine water volumes and element fluxes in a tropical lowland forest with a standard error
< 10% and (ii) individual tree species can have a significant influence on throughfall volumes
and chemical quality. |
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