The effect of tropical peat land-use changes on plant diversity and soil properties

Abstract

Alterations in land use of a million hectares of peatlands in Central Kalimantan and other regions, without an understanding of the characteristics of tropical peatlands, have led to land degradation. This study aimed to determine the effect of land-use changes on plant diversity and soil characteristics of peatlands in Central Kalimantan, Indonesia. The conversion of secondary forests to critically degraded land, acacia forest, agroforestry land, rubber gardens, and palm oil plantations by clear-cutting and fire converted organic materials to available nutrients and increased soil pH at the soil surface. However, the nutrients are easily leached by high rainfall intensity thus resulted in a more degraded land at long-term periods. Land-use change resulted in high humic acid levels, aromatic area, hydrophobic surface area, but low water storage capability. This condition made it easily burn during the dry season and is prone to flooding during the rainy season. The Shannon indexes for all tropical peatland land uses at all levels of plant growth categorized plant diversity and number of individuals as low to moderate due to waterlogging, low pH, low soil fertility, high metal toxicity, and fire. Land with oil-, sap- and litter-producing plants, which resist decomposition, and monoculture plantations tended to contain higher amounts of humic acid, hydrophilic areas, aromatic areas, and bulk density than naturally regenerated forests, although these land uses had lower organic C, available N, and water-holding capacity. Closed cycles of organic matter, carbon, water, nutrient, energy, production, and crops should be maintained for rehabilitation of peatland.