Online ISSN : 1882-5729
Print ISSN : 0917-415X
ISSN-L : 0917-415X
Regular papers
Topography-dependent Spatial Pattern and Habitat Segregation of Sympatric Scaphium Species in a Tropical Rain Forest at Lambir, Sarawak.
Toshihiro YAMADATakuo YAMAKURAMamoru KANZAKIAkira ITOHTatsuhiro OHKUBOKazuhiko OGINOErnest CHAI O.K.Hua Seng LEEPeter Show ASHTON
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1997 Volume 7 Issue 1+2 Pages 57-66


The spatial distribution of sympatric Scaphium species (Sterculiaceae), Scaphium borneense, S. Iongipetiolatum, and S. macropodum was analyzed with reference to topography in a permanent plot of 52 ha in Lambir, Sarawak, East Malaysia. These are large, deciduous trees. The total numbers of S. borneense, S. Iongipetiolatum, and S macropodum larger than 1 cm DBH in the plot were 1135, 63, and 122, respectively. All Scaphium species showed clear clump distribution in the plot, and their distribution was associated with topography. The index of spatial association supports the existence of strong habitat segregation among the three Scaphium species in a small spatial scale (smaller than ca. 1250 m2), and between S. borneense and S. Iongipetielatzam in a large spatial scale larger than 2.5 ha). S. borneense and S macropodum mainly occurred in sites higher than and lower than 180 m in altitude in the plot, respectively. S. longipetiolatum was completely restricted to sites lower than 140 m in altitude. The differences in height within plot correlated with soil texture and water conditions. The lower part of the plot had clayish and wet soil. The higher part was covered by sandy and dry soil, We can thus conclude that the sympatric Scaphium species have divergent habitats and coexisted by segregating their habitats with respect to topography and/or soil.

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© 1997 The Japan Society of Tropical Ecology
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