Effect of Drainage Channels on Vegetation Diversity of Tropical Peatswamp Forest of Sebangau National Park, Indonesia

Abstract

Peat swamp forests are playing important role in climate change by carbon storage, biodiversity conservation, and crucial local livelihoods. The construction of drainage channels in Sebangau National Park, Indonesia negatively affects the Peatland ecosystem and degrades the vegetation diversity. This research aims to study the composition and vegetation diversity of secondary peat swamp forests in Sebangau National Park (SNP), especially around large and small drainage channels. For the observation of vegetation composition and diversity, each observation block consisted of 3 transects that were 300 m apart from each other, and perpendicular to the channel. For observations on small drainage channel blocks, transects are made to continue the previous transect at a distance of 500 m from the end of the large drainage channel. On each transect, 5 plots of vegetation were made using the plot line method with a distance of 50 m between each plot. A total of 15 plots of 30mx30m size were prepared for each drainage channel category. Observations were made on the growth rate of seedlings in a 2m x 2m plot, poles in a 5m x 5m plot, saplings in a 10m x 10m plot, and trees in a 20m x 20m plot. The results of the study showed that Shorea spp., Combretocarpus rotundatus, Cratoxylum arborencens, and Calophyllum sp. are the dominant plant species of the study area. Overall 92 species were reported from the Large Drainage Channel block and 86 species from the Small Drainage Channel block. Further, the Species Diversity ranged between 1.43 - 1.57 while Species Richness ranged from 16.80 – 23.03, and the Evenness Index ranged from 0.83 – 0.92 at all levels of vegetation growth. Results of the study can be concluded that the channel dimensions do not have any effect on species number, diversity index, species richness, and species evenness at all levels of vegetation growth. The Similarity Index of species at seedlings, saplings, and poles is more than 50%, while at the tree level it was reported less than 50%.