An assessment of the restoration efforts of degraded peatland in central Kalimantan, Indonesia

Abstract

Indonesia’s tropical peatlands are an ecosystem of global significance. They contain immense stores of carbon and play a key role in regional and global climate systems. They provide habitat for iconic species such as the orangutan and Sumatran tiger, and they sustain the livelihoods of thousands of local people. Despite these values, Indonesia’s peatland ecosystems have been subject to extensive deforestation and degradation during the past two decades. Recurrent peatland fires related to these land use activities have caused smoke pollution across the region, resulting in substantial public health issues and political controversy. More than 50% of the nation’s 21 Mha of peatland can be considered as degraded. There is an urgent need to slow the rate of peatland degradation in Indonesia and to effectively restore the vast areas already damaged. A key consideration in this challenge is that tropical peatland restoration is an emerging field of scientific inquiry and little research has been published on the factors that constitute and influence successful restoration of tropical peatland ecosystems. This thesis addresses this gap in the broader ecosystem restoration literature by focusing on a case study of the so-called “Ex-Mega Rice Project” area of Central Kalimantan (an area previously subject to extensive degradation) and examining how successful peatland restoration can be achieved in Indonesia by: (1) reviewing the drivers of peatland degradation in the country in order to better understand the competing interests and broader socioecological context in which restoration activities need to be carried out; (2) studying previous restoration initiatives in Indonesia to better understand the restoration techniques used and the factors influencing their relative effectiveness; (3) analysing the specific tropical peatland restoration technique of “re-wetting” to better understand which elements of the technique best support effective restoration outcomes; (4) analysing the specific issue of illegal oil palm development on Indonesian peatland, including a consideration of what sorts of interventions are required to halt illegal oil palm development and control the associated recurrent fires that have been shown to substantially constrain the effectiveness of restoration initiatives; and (5) presenting an overarching conceptual framework of the factors that influence effective peatland restoration, which can be used by policy makers to devise restoration interventions that should have a greater probability of success. The drivers of peatland degradation in Indonesia can be categorised as direct and indirect. Direct drivers include logging, oil palm development and recurrent fires (mostly caused by large- and small-scale land use activities). Indirect drivers include climate change, the poverty and employment needs of local people, and the ineffective and sometimes perversely counter-productive land use governance systems. Techniques previously used to restore peatlands in Indonesia include rewetting through canal blocking, re-forestation through seedling transplanting, the development of seed-based tree seedling nurseries, and measures that support natural regeneration such as the strategic planting of seed trees and additional seed dispersal. Previous restoration measures in the case study area were typically “small and pilot-based” and, as such, their impact were limited. That noted, of these techniques, rewetting appears to be the most common and the most likely to result in larger-scale successful peatland restoration. A detailed analysis of rewetting activities in the case study area revealed that effective rewetting and peatland restoration can be achieved with or without spillways on “dam box” designs, and if special design consideration is given to dam crest elevation and dam spacing, and if the materials used to construct dams were sufficiently durable and appropriate. The case analysis also showed that rewetting dams built for restoration were frequently damaged, apparently by loggers and fishermen opposed to the restoration intervention in the area. A detailed analysis of the extent of illegal oil palm development in the case study area is also included in this thesis. Spatial analysis and emissions modelling revealed that around 86,700 ha of palm oil plantations had been developed on “deep” peatland in the case study area (2004 to 2012) in direct contravention of a range of applicable laws, rules, decrees and ordinances aimed at conservation of deep peatland. Our modelling suggests that these oil palm plantations have directly resulted in between 3.73 MtCO2e (minimum) to 8.67 MtCO2e (maximum) of emissions annually between 2004 and 2012. Laws and government policies protecting peatlands must be properly enforced in Indonesia to not only halt the damage caused by this illegal development, but also to allow restoration activities to be enacted with a reasonable chance of success. The final part of this thesis presents an assessment framework for evaluating the likelihood of success of different peatland restoration interventions in the tropics. The assessment framework includes a hierarchal structure that covers principal aspects, attributes, success indicators, standards for comparison, and decision criteria. The framework can be used by policy makers to improve the probability of success of future peatland restoration initiatives in Indonesia.