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Peatlands and carbon
... One of the biological problems of peatland is the loss of C and N due to organic mineralization [3]. In a reductive peat environment, the rate of decomposition of peat is somewhat slow and a lot of toxic organic acids are produced, including CO2 and CH4 [4]. CH4 and CO2 are the main gases that determine the greenhouse effect or global warming [5]. ...
Toba highlands is unique and covers a large area. Peat plays an important role as a carbon sink, and is currently utilized for agricultural purposes, use as firewood, and left to degrade. The use of peatlands will impact the maturity of peat, and the emission of carbon dioxides and other gases caused by the decomposition process of microbes. A brief transformation of organic carbon from peat into carbon dioxide negatively impacts the environment, especially in increasing the greenhouse gas emissions. C-organic and C-microbial biomass was observed in peatlands of the Toba Highlands in Humbang Hasundutan, employing the Walkey and Black method, and fumigation and extraction methods to calculate the microbial population involved in the decomposition process or called C-microbial biomass. Moreover, descriptive method were used to map their distribution in the peat areas. The results showed that the highest C-organic was found in barren land at 22.05% and soil C-microbial biomass population was 3.24 µg g ⁻¹ soil, whereas the least C-Organic was found in peatland transferred to coffee fields, at 5.23% while the least C-microbial biomass was in peatland transferred to onion fields at 0.28 µg g ⁻¹ soil. There was a relatively small amount of organic matter and C-microbial biomass in paddy field, shallots, and grasses. Therefore, the results indicated that converting peatland into agricultural land would likely change the value of organic matter and C-biomass population.
... Data on tropical peatlands is limited and often of poor quality, and some peatlands like the Cuvette Centrale peatland complex in the Congo Basin (Dargie et al., 2017) were only recently described. Comparison of the estimated C storage in various biomes suggests that tropical peatlands are among the most C-dense terrestrial ecosystems on Earth (Joosten & Couwenberg, 2008): upland forests in the Amazon Basin store about 250-300 Mg C ha −1 (split about equally above-and belowground; Coronado et al., 2021;Draper et al., 2014), boreal peatlands store about 1,350 Mg C ha −1 (Yu et al., 2010), and, depending on the peatland type, tropical peatlands store between 685 (41 aboveground: 644 belowground) Mg C ha −1 and 1,752 (108 aboveground: 1,644 belowground) Mg C ha −1 (Coronado et al., 2021;Draper et al., 2014;Murdiyarso et al., 2009;Saragi-Sasmito et al., 2019). ...
Tropical peatlands are among the most carbon-dense ecosystems on Earth, and their water storage dynamics strongly control these carbon stocks. The hydrological functioning of tropical peatlands differs from that of northern peatlands, which has not yet been accounted for in global land surface models (LSMs). Here, we integrated tropical peat-specific hydrology modules into a global LSM for the first time, by utilizing the peatland-specific model structure adaptation (PEATCLSM) of the NASA Catchment Land Surface Model (CLSM). We developed literature-based parameter sets for natural (PEATCLSM Trop,Nat) and drained (PEATCLSM Trop,Drain) tropical peatlands. Simulations with PEATCLSM Trop,Nat were compared against those with the default CLSM version and the northern version of PEATCLSM (PEATCLSM North,Nat) with tropical vegetation input. All simulations were forced with global meteorological reanalysis input data for the major tropical peatland regions in Central and South America, the Congo Basin, and Southeast Asia. The evaluation against a unique and extensive data set of in situ water level and eddy covariance-derived evapotranspiration showed an overall improvement in bias and correlation compared to the default CLSM version. Over Southeast Asia, an additional simulation with PEATCLSM Trop,Drain was run to address the large fraction of drained tropical peatlands in this region. PEATCLSM Trop,Drain outperformed CLSM, PEATCLSM North,Nat and PEATCLSM Trop,Nat over drained sites. Despite the overall improvements of PEATCLSM Trop,Nat over CLSM, there are strong differences in performance between the three study regions. We attribute these performance differences to regional differences in accuracy of meteorological forcing data, and differences in peatland hydrologic response that are not yet captured by our model.
... Because wetlands are globally important carbon storage reservoirs and methane sources, their responses to climate change will probably feed back to further modulate climate (Bardgett et al., 2008;Davidson & Janssens, 2005;Zhang et al., 2017). This is a particularly important issue for carbon-accumulating wetlands (peatlands) which contain approximately one-third of Earth's soil carbon, more than twice the carbon stored above ground in Earth's tropical rain forests (Joosten & Couwenberg, 2008). Drier conditions in peatlands can alter carbon cycles and expose carbon formerly sequestered below the water table (WT) to aerobic microbial oxidation (Bragazza et al., 2013;Bridgham et al., 2008;Davidson & Janssens, 2005;Freeman et al., 2001;Kane et al., 2019). ...
Peatlands store one‐third of Earth’s soil carbon, the stability of which is uncertain due to climate change‐driven shifts in hydrology and vegetation, and consequent impacts on microbial communities that mediate decomposition. Peatland carbon cycling varies over steep physicochemical gradients characterizing vertical peat profiles. However, it is unclear how drought‐mediated changes in plant functional groups (PFGs) and water table (WT) levels affect microbial communities at different depths. We combined a multi‐year mesocosm experiment with community sequencing across a 70 cm depth gradient, to test the hypotheses that vascular PFGs (Ericaceae vs. sedges) and WT (high vs. low) structure peatland microbial communities in depth‐dependent ways. Several key results emerged. 1) Both fungal and prokaryote (bacteria and archaea) community structure shifted with WT and PFG manipulation, but fungi were much more sensitive to PFG whereas prokaryotes were much more sensitive to WT. 2) PFG effects were largely driven by Ericaceae, although sedge effects were evident in specific cases (e.g., methanotrophs). 3) Treatment effects varied with depth: the influence of PFG was strongest in shallow peat (0‐10, 10‐20 cm), whereas WT effects were strongest at the surface and middle depths (0‐10, 30‐40 cm), and all treatment effects waned in the deepest peat (60‐70 cm). Our results underscore the depth‐dependent and taxon‐specific ways that plant communities and hydrologic variability shape peatland microbial communities, pointing to the importance of understanding how these factors integrate across soil profiles when examining peatland responses to climate change.
... They are linked to Indonesia's nationally determined contribution (NDC) (Government of Indonesia, 2016) and other global pledges to reduce greenhouse gas emissions. Tropical peatland contains a significant amount of carbon (Joosten & Couwenberg, 2008) and is key to achieving Indonesia's NDC and other climate targets. However, in 2015, progress toward this was threatened by severe forest and land fires, which caused massive greenhouse gas emissions (Field et al., 2016). ...
Collective action is important when the activities and costs of restoration cannot all be internalized by the government or when urgent maintenance is required beyond the scope of the restoration project. Collective action can be influenced by social capital. In this study, we examine components of social capital and the factors that affect them. Using key informant interview, household survey, and participant observation, we also identify the extent to which social capital is related to collective action. We found that women farmer groups have high social capital, which has led to strong collective action. Social capital in Dompas’ women groups is characterized by the norms of trust and reciprocity. Strong trust and reciprocity are driven by shared culture and values and supported by kinship. Social capital arises from and is reflected in the interactions between individuals in the group. It is naturally embedded within the community, supported by strong motivation and commitment, primarily to improve the family welfare. The social capital established influenced and drove collective action, which contributes to successful management of the women farmer groups’ action arena. This paper highlights the evidence of social capital and its relation to collective action in a case from restoration in the Global South. We suggest that for a restoration action to successfully mobilize voluntary, active participation from the community, the intervention should be designed with an emphasis on establishing social capital.
... Peatlands are also a considerable store of carbon due to the permanently saturated conditions in which they form, resulting in suppressed decomposition of organic matter and therefore an accumulation of carbon, estimated globally at just below 100 Mt C/year (Joosten and Couwenberg, 2008). Whilst peatlands cover just 21% of total land area in Ireland, they hold over 75% of the soil carbon stock (1,566 Mt) (Renou-Wilson et al., 2011). ...
This report is part of a detailed scoping study to:
-Provide an in depth literature review of peatlands in Ireland covering the following topics: 1) rewetting degraded peatlands; 2) carbon sequestration; 3) social value of peatlands; 4) alternative management options.
-Provide strategic guidance and identify resources for future integrated management of peatlands.
This project was produced for and funded by Fóram Uisce (The Irish Water Forum).
the report can also be found here: https://mail.thewaterforum.ie/app/uploads/2021/03/Peatlands_Full_Report_Final_Feb2021.pdf
... The aeration of naturally water saturated conditions leads to increased decomposition of soil organic matter (SOM) and greenhouse gas emissions, mainly in form of CO 2 . The conversion of pristine peatlands to arable and forested land accounts for 80% of the loss of peatlands worldwide (Joosten and Couwenberg, 2008). In Scotland, the majority of disturbed peat soils are affected by drainage and agricultural purposes, 17% of the deep peat soils (defined as > 40-50 cm depth; Vanguelova et al., 2018) are afforested while less than 10% of the lowland raised bogs are in a near-natural state (Artz et al., 2012;Vanguelova et al., 2018). ...
Peatlands comprise major global stocks of soil organic carbon (SOC). Many degraded peatlands are currently being restored, but little is known to which degree former disturbances leave a ‘legacy’ in such restored peatlands, and subsequently how this impacts their response to global change. Our aims were to investigate if after 20 years of restoration (i) carbon stability may still be affected by the former land use and if (ii) restored bogs are less susceptible to nutrient input but (iii) more sensitive to temperature. We sampled the top- and subsoil of a formerly drained, a previously drained and afforested part and an unmanaged control site of a Scottish bog. We incubated peat from each part for determination of potential basal respiration, nutrient limitation and temperature sensitivity (Q10) of aerobic peat degradation. Lowest respiration rates were identified at the afforested site while nutrient addition had no significant effect on topsoil organic matter decomposition at all sites. Q10 values were significantly higher in the topsoil (2.6 ± 0.3 to 2.8 ± 0.2) than in the subsoil. For the subsoil, the drained site (2.0 ± 0.0) showed significantly lower Q10 values than the afforested one (2.6 ± 0.6), while the control site had a Q10 of 2.1 ± 0.0, indicating contrasting temperature sensitivities of potential SOC losses following specific forms of disturbance. Overall, our data indicate that afforestation left a legacy on potential subsoil SOC losses with global warming. Such effects must be considered when integrating restored bogs into global data bases on peatlands’ responses to global change.
... Less well-known, but of equal concern, are losses of peat underneath tropical peat swamp forests. The largest tropical peat deposits are found in Indonesia, the Peruvian Amazon, and the Congo Basin, accounting for a total of approximately100 gigatons carbon (GtC), equal to 25% of the carbon stock stored globally in biomass [3][4][5]. For example, in degraded peat swamp forests in Indonesia, on average, approximately 0.4 GtC is lost annually because of oxidization and fires [6]. ...
The use of Sentinel-1 (S1) radar for wide-area, near-real-time (NRT) tropical-forest-change monitoring is discussed, with particular attention to forest degradation and deforestation. Since forest change can relate to processes ranging from high-impact, large-scale conversion to low-impact, selective logging, and can occur in sites having variable topographic and environmental properties such as mountain slopes and wetlands, a single approach is insufficient. The system introduced here combines time-series analysis of small objects identified in S1 data, i.e., segments containing linear features and apparent small-scale disturbances. A physical model is introduced for quantifying the size of small (upper-) canopy gaps. Deforestation detection was evaluated for several forest landscapes in the Amazon and Borneo. Using the default system settings, the false alarm rate (FAR) is very low (less than 1%), and the missed detection rate (MDR) varies between 1.9% ± 1.1% and 18.6% ± 1.0% (90% confidence level). For peatland landscapes, short radar detection delays up to several weeks due to high levels of soil moisture may occur, while, in comparison, for optical systems, detection delays up to 10 months were found due to cloud cover. In peat swamp forests, narrow linear canopy gaps (road and canal systems) could be detected with an overall accuracy of 85.5%, including many gaps barely visible on hi-res SPOT-6/7 images, which were used for validation. Compared to optical data, subtle degradation signals are easier to detect and are not quickly lost over time due to fast re-vegetation. Although it is possible to estimate an effective forest-cover loss, for example, due to selective logging, and results are spatiotemporally consistent with Sentinel-2 and TerraSAR-X reference data, quantitative validation without extensive field data and/or large hi-res radar datasets, such as TerraSAR-X, remains a challenge.
... Forest regeneration stabilizes hillsides and reduces 229 landslides (Robledo et al., 2004). 230 In terms of management of pollution, including acidification, UNEP and WMO (2011) and 247 (2010) and Joosten and Couwenberg (2008), though in some cases there could be an increase 248 in methane emissions after restoration (Jauhiainen et al. 2008; Table 5). 249 Mitigation potential from biodiversity conservation varies depending on the type of practice 250 and specific context. ...
There is a clear need for transformative change in the land management and food production sectors to address the global land challenges of climate change mitigation, climate change adaptation, combatting land‐degradation and desertification, and delivering food security (referred to hereafter as “land challenges”). We assess the potential for 40 practices to address these land challenges and find that: Nine options deliver medium to large benefits for all four land challenges. A further two options, have no global estimates for adaptation, but have medium to large benefits for all other land challenges. Five options have large mitigation potential (> 3 GtCO2e yr‐1) without adverse impacts on the other land challenges. Five options have moderate mitigation potential, with no adverse impacts on the other land challenges. Sixteen practices have large adaptation potential (>25 million people benefit), without adverse side‐effects on other land challenges. Most practices can be applied without competing for available land. However, seven options could result in competition for land. A large number of practices do not require dedicated land, including several land management options, all value chain options, and all risk management options. Four options could greatly increase competition for land if applied at a large scale, though the impact is scale and context specific, highlighting the need for safeguards to ensure that expansion of land for mitigation does not impact natural systems and food security. A number of practices such as increased food productivity, dietary change and reduced food loss and waste, can reduce demand for land conversion, thereby potentially freeing‐up land and creating opportunities for enhanced implementation of other practices, making them important components of portfolios of practices to address the combined land challenges.
... However, the temperate regions comprise a heterogeneous set of environmental conditions, resulting in contrasting ecosystems. Although covering only 3% of the terrestrial surface, with 18.5 Mha in the temperate zone (Leifeld and Menichetti 2018), peatlands store twice the amount of carbon as the whole biomass of all forests on earth (Joosten et al. 2008). Thus, peatlands are the most space efficient Cstorages of the terrestrial biogeosphere and highly climate relevant. ...
Start and end of the growing season determine important ecosystem processes, but their drivers may differ above-and belowground, between autumn and spring, and between ecosystems.Here, we compare above-and belowground spring and autumn phenology, and their abiotic drivers (temperature, water level, and soil moisture) in four temperate ecosystems (beech forest, alder carr, phragmites reed, and sedge reed).
Root growth was measured in-situ with minirhizotrons and compared with aboveground phenology assessed with dendrometer data and NDVI.
Synchrony of above- and belowground phenology depended on ecosystem.
Onset of root growth was later than shoot growth in all three peatlands (12–33 days), but similar in the beech forest. The growing season ended earlier belowground in the two forested ecosystems (beech forest: 27 days, understory of the alder carr: 55 days), but did not differ in the phragmites reed. Generally, root production was correlated with soil temperature (especially in spring) and water level in the peatlands, while abiotic factors were less correlated with leaf activity or root production in either spring or autumn in the beech forest.
Root production on organic soils was ten times higher compared to the zonal broadleaf deciduous forest on mineral soils, highlighting the importance of peatlands. Belowground phenology cannot be projected from aboveground phenology and measuring root phenology is crucial to understand temporal dynamics of production and carbon fluxes.
Peatlands are effective carbon sinks as more bio-mass is produced than decomposed under the prevalent anoxic conditions. Draining peatlands coupled with warming releases stored carbon, and subsequent rewetting may or may not restore the original carbon sink. Yet, patterns of plant production and decomposition in rewetted peatlands and how they compare to drained conditions remain largely unexplored. Here, we measured annual above-and belowground biomass production and decomposition in three different drained and rewetted peatland types: alder forest, percolation fen and coastal fen during an exceptionally dry year. We also used standard plant material to compare decomposition between the sites, regardless of the decomposability of the local plant material. Rewetted sites showed higher root and shoot production in the percolation fen and higher root production in the coastal fen, but similar root and leaf production in the alder forest. Decomposition rates were generally similar in drained and rewetted sites, only in the percolation fen and alder forest did aboveground litter decompose faster in the drained sites. The rewetted percolation fen and the two coastal sites had the highest projected potential for organic matter accumulation. Roots accounted for 23-66% of total biomass production, and belowground biomass, rather than above-ground biomass, was particularly important for organic matter accumulation in the coastal fens. This highlights the significance of roots as main peat-forming element in these graminoid-dominated fen peatlands and their crucial role in carbon cycling, and shows that high biomass production supported the peatlands' function as carbon sink even during a dry year.
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