Distribution of tree species along a gallery forest-savanna gradient: Patterns, overlaps and ecological thresholds
Savannas intermingled with gallery forests are dynamic habitats typical in Africa. This study aims to determine if differences in species traits lead to non-overlapping distribution of gallery-forest and savanna species and abrupt transition between gallery forest and savanna. Tree species densities were measured in 375 plots of 1500 m2 covering a total sample area of 56.25 ha along forty 3-km transects located at right angles to a riverbed with gallery forest into surrounding savanna. Location, vegetation type, soil physical properties, erosion and fire occurrence were recorded as site factors. Data analysis included the quantification of co-occurrence patterns, threshold indicator taxa analysis and fuzzy set ordination. The gallery forest-savanna gradient predicted floristic composition of plots with a correlation of 0.595 but its accuracy was locally modified by the occurrence of fire and the physical properties of soil that coveredmore than 30% of the range of residuals. The distribution of gallery-forest and savanna tree species did not overlap. Along the gallery forest-savanna gradient, savanna species gradually increased in density while gallery-forest species showed a community threshold at 120 m from the river beyond the width of gallery forest. The forest species driving this trend should play an important role in the dynamics of gallery forest-savanna boundaries.
| Main Authors: | , , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | K01 - Foresterie - Considérations générales, F70 - Taxonomie végétale et phytogéographie, F40 - Écologie végétale, arbre forestier, espèce, savane, distribution spatiale, espacement, inventaire forestier, écologie forestière, http://aims.fao.org/aos/agrovoc/c_3052, http://aims.fao.org/aos/agrovoc/c_7280, http://aims.fao.org/aos/agrovoc/c_6825, http://aims.fao.org/aos/agrovoc/c_36230, http://aims.fao.org/aos/agrovoc/c_7272, http://aims.fao.org/aos/agrovoc/c_24174, http://aims.fao.org/aos/agrovoc/c_3044, http://aims.fao.org/aos/agrovoc/c_875, |
| Online Access: | http://agritrop.cirad.fr/567602/ http://agritrop.cirad.fr/567602/1/document_567602.pdf |
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