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| Titel |
Spatial distribution and functional significance of leaf lamina shape in Amazonian forest trees |
| VerfasserIn |
A. C. M. Malhado, R. J. Whittaker, Y. Malhi, R. J. Ladle, H. Steege, N. Butt, L. E. O. C. Aragão, C. A. Quesada, A. Murakami-Araujo, O. L. Phillips, J. Peacock, G. López-González, T. R. Baker, L. O. Anderson, L. Arroyo, S. Almeida, N. Higuchi, T. J. Killeen, A. Monteagudo, D. A. Neill, N. C. A. Pitman, A. Prieto, R. P. Salomão, R. Vásquez-M., W. F. Laurance, H. Ramírez A. |
| 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 ; 6, no. 8 ; Nr. 6, no. 8 (2009-08-10), S.1577-1590 |
| Datensatznummer |
250003948
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| Publikation (Nr.) |
 copernicus.org/bg-6-1577-2009.pdf |
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| Zusammenfassung |
| Leaves in tropical forests come in an enormous variety of sizes and shapes,
each of which can be ultimately viewed as an adaptation to the complex
problem of optimising the capture of light for photosynthesis. However, the
fact that many different shape "strategies" coexist within a habitat
demonstrate that there are many other intrinsic and extrinsic factors
involved, such as the differential investment in support tissues required
for different leaf lamina shapes. Here, we take a macrogeographic approach
to understanding the function of different lamina shape categories.
Specifically, we use 106 permanent plots spread across the Amazon rainforest
basin to: 1) describe the geographic distribution of some simple metrics of
lamina shape in plots from across Amazonia, and; 2) identify and quantify
relationships between key environmental parameters and lamina shape in
tropical forests. Because the plots are not randomly distributed across the
study area, achieving this latter objective requires the use of statistics
that can account for spatial auto-correlation. We found that between
60–70% of the 2791 species and 83 908 individual trees in the dataset
could be classified as having elliptic leaves (= the widest part of the leaf is on an axis
in the middle fifth of the long axis of the leaf). Furthermore, the average
Amazonian tree leaf is 2.5 times longer than it is wide and has an entire
margin. Contrary to theoretical expectations we found little support for the
hypothesis that narrow leaves are an adaptation to dry conditions. However,
we did find strong regional patterns in leaf lamina length-width ratios and
several significant correlations with precipitation variables suggesting
that water availability may be exerting an as yet unrecognised selective
pressure on leaf shape of rainforest trees. Some support was found for the
hypothesis that narrow leaves are an adaptation to low nutrient soils.
Furthermore, we found a strong correlation between the proportion of trees
with non-entire laminas (dissected, toothed, etc.) and mean annual
temperature once again supporting the well documented association that
provides a basis for reconstructing past temperature regimes. |
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