Elevational patterns of species richness and density of rattan palms (Arecaceae: Calamoideae) in Central Sulawesi, Indonesia

We studied species richness and density of rattan palms in 50 plots of 10 × 100 m² each between 250 m and 2420 m in eight sites in Lore Lindu National Park (LLNP), Central Sulawesi. Rattans were observed in all sample sites, representing three genera and 34 species. The elevational patterns for species richness and density were humped-shaped with maxima around 1000 m. Polynomial models of second order explained 59 and 32% of species richness and density with the factor elevation, respectively. A majority of rattan species (65%) overlapped between 1000 and 1100 m elevation, while a pronounced change in the rattan flora occurred above 1100 m. Commercially important rattan species (Calamus zollingeri, C. ornatus var. celebicus, Daemonorops macroptera) were not observed above 1250 m. The change of species assemblage was significantly related to elevation (56%), followed by geographical distance (47%) and precipitation (40%). Less than 10% of LLNP is lowland forests, much of which is threatened by agricultural intensification. In contrast, montane forests are well represented in the park and high elevation forests are not subject to agricultural conversion or intensive harvesting of rattan and other forest products.