Abstract
A plot census for trees over 5 cm in diameter at breast height was conducted in tropical wetlands to understand the effects of distance from river and peat depth on the development of communities, using 14 50 m_50 m plots in Central Kalimantan, Indonesia. There are 294 taxa of woody species were recorded. Combretocarpus rotundatus, Palaquium leiocarpum, Stemonurus scorpioides and Tristania whittiana are the common species. In the 14 plots, Stem density and cumulative basal diameter ranged from 1612-3088/ha, and 18.5-44.6 m2//ha, respectively. Species richness (S) ranged from 41 to 87. Diversity index (H’) and evenness (J’) varied from 1.29 to 1.68 and 0.771 to 0.910, respectively. Stem density was positively related to distance from river but not to peat depth. Geographical differences were also related to the stem density. H' was related to distance from river, but S and J' were not explained by any environmental factors examined. Plot distribution patterns were examined by detrended canonical correspondence analysis (DCCA). DCCA ordination indicated that distance from river, and hence the intensity and/or frequency of flooding more adequately explained plant community distribution patterns than peat depth. Geographical differences also significantly affected the distribution patterns. Therefore, the distance from river is a suitable parameter to use to investigate plant community distribution in tropical wetland forests, even if peat thickness differs greatly.
