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| Titel |
Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate |
| VerfasserIn |
C. A. Quesada, O. L. Phillips, M. Schwarz, C. I. Czimczik, T. R. Baker, S. Patiño, N. M. Fyllas, M. G. Hodnett, R. Herrera, S. Almeida, E. Alvarez Dávila, A. Arneth, L. Arroyo, K. J. Chao, N. Dezzeo, T. Erwin, A. Fiore, N. Higuchi, E. Honorio Coronado, E. M. Jimenez, T. Killeen, A. T. Lezama, G. Lloyd, G. López-González, F. J. Luizão, Y. Malhi, A. Monteagudo, D. A. Neill, P. Núñez Vargas, R. Paiva, J. Peacock, M. C. Peñuela, A. Peña Cruz, N. Pitman, N. Priante Filho, A. Prieto, H. Ramírez, A. Rudas, R. Salomão, A. J. B. Santos, J. Schmerler, N. Silva, M. Silveira, R. Vásquez, I. Vieira, J. Terborgh, J. Lloyd |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 6 ; Nr. 9, no. 6 (2012-06-22), S.2203-2246 |
| Datensatznummer |
250007127
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| Publikation (Nr.) |
 copernicus.org/bg-9-2203-2012.pdf |
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| Zusammenfassung |
Forest structure and dynamics vary across the Amazon Basin in an east-west
gradient coincident with variations in soil fertility and
geology. This has resulted in the hypothesis that soil fertility may play an
important role in explaining Basin-wide variations in forest biomass, growth
and stem turnover rates.
Soil samples were collected in a total of 59 different forest plots across
the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and
pH, with several phosphorus fractions of likely different plant availability
also quantified. Physical properties were additionally examined and an index
of soil physical quality developed. Bivariate relationships of
soil and climatic properties with above-ground wood productivity,
stand-level tree turnover rates, above-ground wood biomass and wood density
were first examined with multivariate regression models then applied. Both forms of
analysis were undertaken with and without considerations regarding the
underlying spatial structure of the dataset.
Despite the presence of autocorrelated spatial structures complicating many
analyses, forest structure and dynamics were found to be strongly and
quantitatively related to edaphic as well as climatic conditions. Basin-wide
differences in stand-level turnover rates are mostly influenced by soil
physical properties with variations in rates of coarse wood production mostly
related to soil phosphorus status. Total soil P was a better predictor of
wood production rates than any of the fractionated organic- or inorganic-P
pools. This suggests that it is not only the immediately available P forms, but
probably the entire soil phosphorus pool that is interacting with forest growth on longer
timescales.
A role for soil potassium in modulating Amazon forest dynamics through its
effects on stand-level wood density was also detected. Taking this into account,
otherwise enigmatic variations in stand-level biomass
across the Basin were then accounted for through the interacting effects of
soil physical and chemical properties with climate. A hypothesis of
self-maintaining forest dynamic feedback mechanisms initiated by edaphic
conditions is proposed. It is further suggested that this is a major factor
determining endogenous disturbance levels, species composition, and forest
productivity across the Amazon Basin. |
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