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| Titel |
Contrasting photosynthetic characteristics of forest vs. savanna species (Far North Queensland, Australia) |
| VerfasserIn |
K. J. Bloomfield, T. F. Domingues, G. Saiz, M. I. Bird, D. M. Crayn, A. Ford, D. J. Metcalfe, G. D. Farquhar, 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 ; 11, no. 24 ; Nr. 11, no. 24 (2014-12-19), S.7331-7347 |
| Datensatznummer |
250117751
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| Publikation (Nr.) |
 copernicus.org/bg-11-7331-2014.pdf |
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| Zusammenfassung |
| Forest and savanna are the two dominant vegetation types of the tropical
regions with very few tree species common to both. At a broad scale, it has
long been recognised that the distributions of these two biomes are
principally governed by precipitation and its seasonality, but with soil
physical and chemical properties also potentially important. For tree species
drawn from a range of forest and savanna sites in tropical Far North
Queensland, Australia, we compared leaf traits of photosynthetic capacity,
structure and nutrient concentrations. Area-based photosynthetic capacity was
higher for the savanna species with a steeper slope to the photosynthesis ↔ nitrogen
(N) relationship compared with the forest group.
Higher leaf mass per unit leaf area for the savanna trees derived from denser
rather than thicker leaves and did not appear to restrict rates of
light-saturated photosynthesis when expressed on either an area or
mass basis. Median ratios of foliar N to phosphorus (P) were relatively high
(>20) at all sites, but we found no evidence for a dominant P limitation
of photosynthesis for either forest or savanna trees. A parsimonious
mixed-effects model of area-based photosynthetic capacity retained vegetation
type and both N and P as explanatory terms. Resulting model-fitted
predictions suggested a good fit to the observed data (R2 = 0.82). The
model's random component found variation in area-based photosynthetic
response to be much greater among species (71% of response variance)
than across sites (9%). These results suggest that, on a leaf-area basis, savanna trees of Far North Queensland, Australia, are capable of
photosynthetically outperforming forest species at their common boundaries. |
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