Peat swamp forest types and their regeneration in Giam Siak Kecil-Bukit Batu Biosphere Reserve, Riau, East Sumatra, Indonesia

Although the ecology of tropical peat swamp forests is only now becoming understood, they are already under severe threat of conversion and degradation. Based on studies of the peat swamp forest of the Giam Siak Kecil-Bukit Batu Biosphere Reserve carried out between 2009 and 2010, this paper discusses forest types and regeneration processes in terms of promoting biodiversity conservation and sustainable management of the remaining peat swamp forest. Permanent plots covering a total area of three hectares were established in natural and disturbed forest areas. Within these plots, 135 tree species belonging to 34 families were identified. Mixed peat swamp forest and bintangur forest, which have different dominant species, were identified as the main forest types. The greatest species richness was in logged-over forest, with 82 species and a density of 2,492 stems ha(-1). The success of regeneration varied between typical main species in the logged-over forest and in forest disturbed by wind and fire. All of the forest stands had high densities of trees with diameters at breast height (DBH) of 3-10 cm, which are a potential source of recruitment to ensure the sustained regeneration of the forest remaining in the Biosphere Reserve. Regeneration is very important for improving the condition of disturbed peat swamp forest areas in the reserve, but natural regeneration will not be sufficient to restore the forest vegetation and conserve the associated biodiversity. Some form of human-assisted accelerated regeneration will be needed, such as enrichment planting of typical canopy species that have problems with establishment. It is important for the remaining natural peat swamp forests to be conserved because of their unique forest-type formations which have distinct dominant species, floristic composition, diversity and local environment characteristics. Improved management of secondary forest must be achieved through rehabilitation, halted forest conversion, and reducing the impact of disturbance by wind and fire.