Degradation of Southeast Asian tropical peatlands and integrated strategies for their better management and restoration

Abstract

1. About half of the world's tropical peatlands occur in Southeast (SE) Asia, where they serve as a major carbon (C) sink. Nearly 80% of natural peatlands in this region have been deforested and drained, with the majority under plantations and agriculture. This conversion increases peat oxidation which contributes to rapid C loss to the atmosphere as greenhouse gas emissions and increases their vulnerability to fires which generate regional smoke haze that has severe impacts on human health. Attempts at restoring these systems to mitigate environmental problems have had limited success.2. We review the current understanding of intact and degraded peatlands in SE Asia to help develop a way forward in restoring these ecosystems. As such, we critically examine them in terms of their biodiversity, C storage, hydrology and nutrients, paying attention to both above-ground and below-ground subsystems.3. We then propose an approach for better management and restoration of degraded peatlands that involves explicit consideration of multiple interacting ecological factors and the involvement of local communities who rely on converted peatlands for their livelihood. 4. We make the case that as processes leading to peatland development involve modification of both above-ground and below-ground subsystems, an integrated approach that explicitly recognizes both subsystems and their interactions is key to successful tropical peatland management and restoration. Synthesis and applications.Gaining a better understanding of not just carbon stores and their changes during peat degradation, but also an in-depth understanding of the biota, nutrient dynamics, hydrology and biotic and abiotic feedbacks, is key to developing better solutions for the management and restoration of peatlands in Southeast Asia. Through the application of science-and nature-based solutions | 1371

Tree species that ‘live slow, die older’ enhance tropical peat swamp restoration: Evidence from a systematic review

“…In our review, mycorrhizal inoculation enhanced TPSF seedling survival, but not half‐life or RGR. A promising avenue for further research would be investigations into the nutrient acquisition strategies of TPSF species, for example, mycorrhizal symbiosis (Mishra et al, 2021) to develop alternative strategies to the application of artificial fertilisers.…”

“…Intact TPSF have poor drainage, permanent waterlogging and anaerobic conditions that slow decomposition and lead to the formation of peat, that is, partially decomposed organic matter. Conversion and drainage cause peat oxidation and elevated CO 2 emissions, subsidence (lowering of the peat surface) and flooding, increased risk of fires (particularly during drier El Niño conditions), and a surface vegetation primarily comprised of a dense thicket of sedges and ferns that competes with naturally recolonising trees and planted seedlings (Blackham et al, 2014; Miettinen et al, 2017; Mishra et al, 2021; Page et al, 2009).…”

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

“…Some of the important challenges which affect efforts to restore degraded peatlands are increasing the groundwater level on drained peatlands and the development of economically competitive crop species suitable for paludiculture (Wosten et al 2008;Wichtmann et al 2010;Uda et al 2017;Uda et al 2017;Evans et al 2019;Tan et al 2021). Damage to the peat ecosystem causes disturbance to this diversity (Mishra et al 2021). Tropical peatland degradation generally begins after converting PSF into a nonforest area for agriculture, smallholder plantations, and industrial forest plantations, which is usually accompanied by drainage channel construction.…”

Mapping the Restoration of Degraded Peatland as a Field of Research Area: A Scientometric Review

“…Many studies have indicated huge amounts of carbon emissions into the atmosphere due to peatland deforestation and degradation, draining, and repeated res (Jaenicke et al, 2010;Hooijer et al, 2014;Ballhorn et al, 2009). The removal of above-and below-ground biomass, peat decomposition and oxidation caused by drainage, and peat combustion are all major sources of carbon loss and CO 2 emissions into the atmosphere while the application of N fertilisers on degraded peatland acts as a source of N 2 O emission especially when nitrogen fertilisers have been added to promote agricultural productivity (Mishra et al, 2021;. Tree harvesting by clear-cutting on drained peatland has also been reported to enhance the leaching of dissolved organic C (DOC), dissolved organic N (DON), and mineral N to surface waters and the nearest catchment in a boreal peatland (Könönen et al, 2018).…”