Tropical peat swamp forest is a unique ecosystem that is most extensive in Southeast Asia, where it is under enormous threat from logging, tire, and land conversion. Recent research has shown this ecosystem's significance as a global carbon store, but its value for biodiversity remains poorly understood. We review the current status and biological knowledge of tropical peat swamp forests, as well as the impacts of human disturbances. We demonstrate that these forests have distinct floral compositions, provide habitat for a considerable proportion of the region's fauna, and are important for the conservation of threatened taxa, particularly specialized freshwater fishes. However, we estimate that only 36% of the historical peat swamp forest area remains, with only 9% currently in designated protected areas. Given that peat swamp forests are more vulnerable to synergies between human disturbances than other forest ecosystems, their protection and restoration are conservation priorities that require urgent action.
Keywords: peat, Southeast Asia, blackwater, wetland, threatened
Peatlands are ecosystems characterized by the accumulation of partially decayed organic matter, called peat, which is formed from plant debris under waterlogged conditions (Andriesse 1988). In the tropics, peat and peaty soils (histosols) form in a variety of conditions, but the greatest peat depths--and thus carbon stores--occur in peat swamp forests situated at low altitudes in the river valley basins, watersheds, and subcoastal areas of Southeast Asia. Until recently, the inaccessibility of peat swamp forests and the belief that they support lower species diversity than dryland rainforests meant that they received relatively little attention from scientists (Prentice and Parish 1990, Yule 2008). Countries with extensive peat swamp forests have tended to regard them as wastelands that must be converted to more productive land use (e.g., Rijksen and Peerson 1991). Thus, they remain poorly understood, and their importance is underappreciated. Vast tracts of peat swamp forest have already been degraded, and remaining areas are quickly disappearing as a result of logging, tire, and conversion to agriculture and industry (Yule 2008, Hansen et al. 2009).
In the last decade, there has been increased interest in the role of peatlands in the global carbon cyde because of the large amount of carbon they store and can potentially release to the atmosphere (55 gigatons is estimated for Indonesia alone; Page et al. 2004, Jaenicke et al. 2008). The realization that carbon dioxide emissions from the clearance and burning of peat swamp forests in Southeast Asia may comprise as much as 3% of total global anthropogenic emissions (Ballhorn et al. 2009, van der Werf et al. 2009) has sparked an explosion of interest in their past, present, and future roles as carbon stores. However, the biological implications arising from the loss and degradation of peat swamp forests are not yet fully understood, and proper assessment is hampered by the la& of baseline data on their flora and fauna. In this article, we summarize current knowledge on (a) the development and biogeography of peat swamp forests in Southeast Asia, (b) their current geographic extent and conservation status, (c) peat...