Soil-Related Floristic Variation in a Hyperdiverse Dipterocarp Forest

Abstract

A 52 hectare permanent research plot was established in Lambir Hills National Park to enable long-term study of factors controlling the origin and maintenance of tree diversity. In this chapter we summarize some of our recent work on the relationships between floristic variation and edaphic heterogeneity in the Lambir forest. First, we provide a general description of the floristic composition of this hyperdiverse forest. Second, we use a detailed survey of soil chemistry to test whether floristic composition changes in relation to edaphic characteristics. We also assess the extent to which individual species have non-random distributions in the forest with respect to edaphic heterogeneity. Finally, to investigate the influence of habitat variation on floristic diversity we compare our results from the heterogeneous forest at Lambir Hills with a more homogeneous forest in Peninsular Malaysia.

Species–habitat associations in a Sri Lankan dipterocarp forest

“…Among the plots examined using comparable methods, Sinharaja stands among those with the highest percentage of species demonstrating significant habitat associations: the plot on Barro Colorado Island, Panama, has 33% of its species significantly associated with habitats, those at Mudumalai in India and Korup in Cameroon have 68% each (Anon. 2003, Harms et al 2001, but that at Lambir in Sarawak -also a topographically heterogeneous plot -has 86.8% of species significantly biased with respect to the habitat gradient of the plot (Davies et al 2005). This study may have underestimated the total percentage of habitat specialists at Sinharaja, however, by arbitrarily confining the analysis only to an elevational and topographic gradient.…”

Nitrogen uptake strategies of edaphically specialized Bornean tree species

“…Shale-derived soils are clay-rich ultisols generally lacking a humus layer and root mat and have greater nutrient and moisture retention (Baillie et al 2006). Four soil types have been described based on differences in soil chemistry (C, N and P and exchangeable K, Ca and Mg) and elevation (Davies et al 2005). Davies et al (2005) found that of the abundant species at Lambir, 73 % had distributions significantly aggregated on at least one of the four soil types.…”

“…Four soil types have been described based on differences in soil chemistry (C, N and P and exchangeable K, Ca and Mg) and elevation (Davies et al 2005). Davies et al (2005) found that of the abundant species at Lambir, 73 % had distributions significantly aggregated on at least one of the four soil types. Here we focus on two soil types, clay and sandy loam, at the extremes of this gradient that differ most in soil properties (Baillie et al 2006).…”

“…We sought to fill this gap by testing whether tree species in a Bornean rain forest display differential uptake of different chemical forms of N using both 15 N natural abundance (d 15 N) and a 15 N tracer experiment. In this forest, most tree species' distributions are tightly correlated with soil resources, causing forest composition to vary dramatically between soil types along an edaphic gradient, resulting in high b diversity (Davies et al 2005) that contributes to the exceptionally high species richness of this region (Ashton and Hall 1992). We focused on the two soil types at the extremes of the edaphic gradient, clay and sandy loam (Baillie et al 2006).…”

Spatial associations of humus, nutrients and soils in mixed dipterocarp forest at Lambir, Sarawak, Malaysian Borneo

“…Davies et al (2005) concluded that a substantial proportion of the plot's tree flora consists of edaphic specialists, and Russo et al (2005) showed that the forests on various soil types differ considerably in their demographic dynamics, with lower mortality and slower growth in sandstone-specialist species.…”