Peatland Drainage Research Articles

Pemodelan Tinggi Muka Air Gambut Berdasarkan Sifat Fisik Lahan Gambut

Lahan gambut di Indonesia cukup luas yaitu sekitar 7% dari luas daratan Indonesia. Beberapa tantangan terutama berkaitan dengan perubahan penggunaan lahan dialami oleh gambut di Indonesia. Pemanfaatan lahan gambut berdasarkan peraturan dapat dilakukan pada ekosistem gambut berfungsi budidaya yang biasanya disertai dengan pembangunan kanal untuk menurunkan tinggi muka air (TMA). Oleh karena itu pengamatan TMA harus dilakukan untuk meminimalkan dampak pemanfaatan lahan gambut. Untuk menghemat waktu dan biaya maka perlu adanya suatu model yang dapat menduga kedalaman muka air gambut berdasarkan sifat-sifat fisik gambut. Tujuan penelitian ini yaitu mencari model estimasi TMA dengan menggunakan sifat fisik lahan gambut sebagai upaya pencegahan terjadinya kebakaran gambut. Model aproksimasi terbaik dipilih dengan menggunakan Kriteria Informasi Akaike dengan koreksi sampel kecil (AICc). Studi ini memperoleh satu confidence set of model yang terdiri dari empat model dengan bobot isi (0-50 cm), kadar serat (50-100 cm) and kedalaman gambut sebagai predictor model. Hasil model juga menunjukkan kesesuaian dengan data pengukuran TMA di lapangan yang ditunjukkan oleh RMSE sebesar 16.2 cm dan R2=81%. Dari penelitian ini, tinggi muka air tanah gambut kritis untuk deteksi dini kebakaran hutan adalah pada kedalaman 74 cm. Oleh karena itu, kondisi TMA gambut harus dijaga lebih dangkal dari kedalaman kritis, jika tidak kebakaran gambut akan lebih mudah terjadi.

The full carbon balance of a rewetted cropland fen and a conservation-managed fen

On a global scale, the release of greenhouse gases (GHG) from peatland drainage and cultivation are believed to account for ∼5% of estimated anthropogenic GHG emissions. Drainage generally leads to peat subsidence and extensive soil loss, resulting in a diminishing store of soil carbon (C). This is a challenge for maintaining drainage-based agriculture, as such practices will eventually lead to the loss of organic soils that arable cultivation depends on. The conversion of croplands on peat to semi-natural grasslands, alongside raising water tables, is one possible way to reduce the loss of these valuable C stores. Here, we report the net ecosystem carbon balances (NECB) of two lowland peatlands in East Anglia, south-east UK. One site is a relic conservation-managed fen on deep peat, subject to active hydrological management to maintain water levels, and dominated by Cladium and Phragmites sedge and reed beds, whilst the other is a former cropland that has been converted to seasonally-inundated grazed grassland. Despite occasionally experiencing severe water table drawdown, the conservation-managed fen was a strong C sink of -104 g C m−2 yr−1. In contrast, the grassland was a C source of 133 g C m−2 yr−1, with gaseous carbon dioxide (CO2) emissions being the main loss pathway, due to low water tables exposing the soil profile in summer. At each site, ditch emissions of CO2 were moderately large (22 and 37 g C m−2 yr−1), whilst ditch methane (CH4) emissions (0.2 and 1.8 g C m−2 yr−1) made a negligible contribution to the NECB, but are important when considering the ecosystem GHG balance in terms of CO2 equivalents. Excluding dissolved inorganic carbon (DIC), fluvial C losses were 6 g C m−2 yr−1 for the conservation-managed fen and 12 g C m−2 yr−1 for the former cropland, and were dominated by dissolved organic carbon (DOC). The small fluvial C loss is the result of both sites being hydrologically isolated from the surrounding agricultural landscapes. Although the partially re-wetted cropland was still acting as a net C source, our estimates suggest that seasonal rewetting has reduced net annual C losses to ∼20% of their former cropland values. Maintaining high water tables year round would potentially further reduce C losses, and shallow inundation might allow the return of wetland species such as Phragmites and Typha, perhaps as floating rafts.

Use of remote sensing to analyse peatland changes after drainage for peat extraction

AbstractLarge‐scale peat extraction, in Finland and elsewhere, typically takes place on rather small extraction sites but has major impacts on surrounding aquatic and terrestrial ecosystems. The environmental conditions prior to drainage (baseline conditions) must be quantified in a statutory environmental impact assessment (EIA), but this is generally difficult due to lack of historical data. In this study, we developed and tested a method for EIA based on a reference area approach and remote sensing. The method calculates the normalized difference vegetation index in preextraction and postextraction periods using Landsat images of affected areas and reference surrounding areas. In a case study, we applied the method to assess changes after peat extraction at a site in northern Finland. The peat extraction area showed significant transformation from peatland vegetation to bare soil. Adjacent areas downstream and upstream were also affected by extraction. These results indicate that our method is a useful tool for EIA of peatland drainage.

Dampak Dinamika Muka Air Tanah pada Besaran Dan Laju Emisi Carbon Di Lahan Rawa Gambut Tropika

Pembukaan lahan gambut yang didahului dengan pembuatan saluran?saluran (drainase) akan menyebabkan turunnya muka air tanah, hal ini akan memacu laju dekomposisi bahan organik dan padaakhirnya gambut menjadi rentan terbakar dan teremisi. Oleh karena itu pengetahuan laju emisi carbon sangat penting untuk perencanaan sistem drainase, dalam rangka memelihara kelestarian gambut. Metode ilmiah yang digunakan meliputi: perhitungan sebaran ketebalan/kedalaman gambut, volume gambut kering, volume gambut teroksidasi, berat C gambut kering dan CO2 equivalent. Laju emisi karbon (C) dihitung berdasarkan emisi karbon (C) dan waktu subsiden. Selanjutnya laju emisi C (Mton CO2/tahun) dihitung berdasarkan 4 (empat) buah konsep pemodelan/skenario, yaitu: kondisi aktual/eksisting, perkebunan, bendung (canal blocking), bendung (canal blocking) dan dengan penghutanan kembali. Kegiatan ini dilakukan di Sei Ahas, Kapuas, Kalimantan Tengah dan Sungai Buluh, Tanjung Jabung Timur, Jambi. Berdasarkan hasil penelitian didapatkan bahwa perubahan tata guna lahan akan sangat berpengaruh terhadap perubahan elevasi muka air tanah gambut yang turut serta memacu peningkatan emisi C ke atmosfer.

Persistent carbon sink at a boreal drained bog forest

Abstract. Drainage of peatlands is expected to turn these ecosystems into carbon sources to the atmosphere. We measured carbon dynamics of a drained forested peatland in southern Finland over 4 years, including one with severe drought during growing season. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured with the eddy covariance method from a mast above the forest. Soil and forest floor CO2 and methane (CH4) fluxes were measured from the strips and from ditches with closed chambers. Biomass and litter production were sampled, and soil subsidence was measured by repeated levellings of the soil surface. The drained peatland ecosystem was a strong sink of carbon dioxide in all studied years. Soil CO2 balance was estimated by subtracting the carbon sink of the growing tree stand from NEE, and it showed that the soil itself was a carbon sink as well. A drought period in one summer significantly decreased the sink through decreased gross primary production. Drought also decreased ecosystem respiration. The site was a small sink for CH4, even when emissions from ditches were taken into account. Despite the continuous carbon sink, peat surface subsided slightly during the 10-year measurement period, which was probably mainly due to compaction of peat. It is concluded that even 50 years after drainage this peatland site acted as a soil C sink due to relatively small changes in the water table and in plant community structure compared to similar undrained sites, and the significantly increased tree stand growth and litter production. Although the site is currently a soil C sink, simulation studies with process models are needed to test whether such sites could remain C sinks when managed for forestry over several tree-stand rotations.

Identification of Tropical Peatland Using ALOS 2 Palsar

In Indonesia, a huge amount of peat has accumulated under peat swamp forest over millennia. However, a repeatable large-scale fire as a result of land clearing has rapidly devastated these tropical peatlands. These disturbances (e.g. climate change, deforestation, peatland drainage, forest and peatland fires, and land conversion) change the ecosystem respiration and resulting a high carbon emitted to the atmosphere. To restore the peatland ecosystem, Indonesia government makes a special force by using three activities, namely rewetting, replantation, and communal empowerment. These activities need an accurate peatland monitoring. However, accessing the spatial variation of the peatland is quite limited, difficult and laborious. Therefore, we investigated the existence of tropical peatland in Siak, Riau Province, Indonesia. We measured soil moisture at four different types of land cover (namely; forest, oil palm, shrubs, and agriculture) a long with two types of peat conditions. We estimated the Constanta Dielectric (ε) values obtained from a fully polarimetry for ALOS 2/PALSAR. Results indicated that the 8 of oil palm was lower in non-peat area than in peat area, whereas the decrease in 8 probably in peat area resulted from the rapid growth of oil palm.

Groundwater contamination and land drainage induce divergent responses in boreal spring ecosystems

Degradation of freshwater ecosystems has engendered legislative mandates for the protection and management of surface waters while groundwater-dependent ecosystems (GDEs) have received much less attention. This is so despite biodiversity and functioning of GDEs are currently threatened by several anthropogenic stressors, particularly intensified land use and groundwater contamination. We assessed the impacts of land drainage (increased input of dissolved organic carbon, DOC, from peatland drainage) and impaired groundwater chemical quality (NO3−-N enrichment from agricultural or urban land use) on biodiversity and ecosystem functioning in 20 southern Finnish cold-water springs using several taxonomic and functional measures. Groundwater contamination decreased macroinvertebrate and bacterial diversity and altered their community composition. Changes in macroinvertebrate and bacterial communities along the gradient of water-quality impairment were caused by the replacement of native with new taxa rather than by mere disappearance of some of the original taxa. Also species richness of habitat specialist (but not headwater generalist) bryophytes decreased due to impaired groundwater quality. Periphyton accrual rate showed a subsidy-stress response to elevated nitrate concentrations, with peak values at around 2500 μg L−1, while drainage-induced spring water brownification (increased DOC) reduced both periphyton accrual and leaf decomposition rates already at very low concentrations. Our results highlight the underutilized potential of ecosystem-level functional measures in GDE bioassessment as they seem to respond to the first signs of spring ecosystem impairment, at least for the anthropogenic stressors studied by us.

A Review of Techniques for Effective Tropical Peatland Restoration

Indonesia’s peatlands have been subject to extensive deforestation and degradation resulting from logging, drainage, fires and conversion to other land uses. A number of restoration initiatives have been attempted to address this degradation yet, to date, there has been little coherent or rigorous reflection on the effectiveness of these interventions. This paper examines the barriers to peatland restoration in Indonesia and reviews the techniques so far used to restore degraded peatland in the tropics. Direct barriers to peatland restoration in Indonesia include altered peat topography, peatland drainage, the presence of invasive ferns and shrub species, repeated fires, and flooding risks. Indirect barriers include climate change, inconsistent land-use policy and lack of alternative livelihood options. We highlight that most restoration activities carried out to date have been small-scale trials and the restoration techniques used have included canal blocking, seedling transplantation, and promotion of seed dispersal. We suggest that successful peatland restoration in Indonesia is as much dependent on meaningful land use policy and governance reform as it is on the technical effectiveness of specific restoration methods.

Greenhouse Gas Emissions Under Different Drainage and Flooding Regimes of Cultivated Peatlands

AbstractGlobally, approximately 10–20% of peatlands have been drained for agricultural purposes. A strategy to protect peatlands and mitigate carbon dioxide (CO2) emissions, while continuing agricultural production, is the use of intermittent flooding and drainage. A potential drawback of this strategy could be increases in methane (CH4) and nitrous oxide (N2O) emissions. The objective of this study was to compare greenhouse gas (GHG) emissions from peatlands under various flooding–drainage cycles. A laboratory study was performed using intact soil cores subjected to different durations of flooding and drainage for 6 months. Average daily emissions of CO2 and N2O were significantly higher (P < 0.001) under drained (667 ± 37 mg CO2–C m−2 d−1 and 135 ± 19 μg N2O–N m−2 d−1) than flooded conditions (86 ± 6 mg CO2–C m−2 d−1 and 48 ± 2 μg N2O–N m−2 d−1). Methane emissions were not influenced by drained/flooded conditions, with an average rate of 116 ± 11 μg CH4–C m−2 d−1. Peaks of CH4 and N2O emissions were observed after flooding events and lasted less than 24 h. The peak emissions were approximately 8 and 19 times higher than the mean CH4 and N2O emissions, respectively. Carbon dioxide was the dominant component of GHGs, irrespective of hydrologic regime, accounting for more than 92% of overall global warming potential. Global warming potential was inversely proportional to the flooding period, indicating that prolonging the flooding period of peatlands would help mitigate soil oxidation and GHG emissions and enhance sustainability of these agricultural peatlands.

Will CO2 Emissions from Drained Tropical Peatlands Decline Over Time? Links Between Soil Organic Matter Quality, Nutrients, and C Mineralization Rates

Conversion, drainage, and cultivation of tropical peatlands can change soil conditions, shifting the C balance of these systems, which is important for the global C cycle. We examined the effect of soil organic matter (SOM) quality and nutrients on CO2 production from peat decomposition using laboratory incubations of Indonesian peat soils from undrained forest in Kalimantan and drained oil palm plantations in Kalimantan and Sumatra. We found that oil palm soils had higher C/N and lower SOM quality than forest soils. Higher substrate quality and nutrient availability, particularly lower ratios of aromatic/aliphatic carbon and C/N, rather than total SOM or carbon, explained the higher rate of CO2 production by forest soils (10.80 ± 0.23 µg CO2–C g C h−1) compared to oil palm soils (5.34 ± 0.26 µg CO2–C g C h−1) from Kalimantan. These factors also explained lower rates in Sumatran oil palm (3.90 ± 0.25 µg CO2–C g C h−1). We amended peat with nitrogen (N), phosphorus (P), and glucose to further investigate observed substrate and nutrient constraints across the range of observed peat quality. Available N limited CO2 production, in unamended and amended soils. P addition raised CO2 production when substrate quality was high and initial P state was low. Glucose addition raised CO2 production in the presence of added N and P. Our results suggest that decline in SOM quality and nutrients associated with conversion may decrease substrate-driven rates of CO2 production from peat decomposition over time.

Anthropogenic habitat disturbance induces a major biodiversity change in habitat specialist bryophytes of boreal springs

Land-use is a major driver of global biodiversity loss. Despite much evidence of land-use impacts on freshwater biodiversity, long-term changes to groundwater-dependent ecosystems, and their post-disturbance recovery, remain largely unknown. We examined long-term changes of bryophyte communities in 34 boreal springs from 1987 to 2015. In 1987, all the study springs were in near-pristine condition, but 29 of them were disturbed by peatland drainage in the late 1980s and early 1990s. Five sites retained their natural status throughout the study and were used as reference sites. We aimed to assess whether bryophyte vegetation, particularly spring specialist bryophytes, showed gradual recovery toward near-pristine conditions or whether the drainage-induced habitat degradation had caused delayed extinctions of specialists, leading to dominance by generalist taxa. Bryophyte diversity showed no signs of recovery about 20years since the initial disturbance. In disturbed springs, the abundance of specialists first decreased, then remained relatively stable. Specialist richness decreased steadily and their community composition shifted gradually from the pre-disturbance state. Abundance of habitat generalists did not change but generalist richness also decreased with a time lag. At the same time, both groups remained unaltered in undisturbed springs. We conclude that without restoration measures that improve groundwater hydrology the self-recovery potential of springs is very low. As little is currently known about the effectiveness of spring restoration in halting spring biodiversity loss, the safest management strategy is to refrain from land use within broad buffers around springs.

Substantial decline of Northern European peatland bird populations: Consequences of drainage

Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peatland species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habitat preferences of peatland bird species, hence helping to target conservation to the most relevant habitat types. There was a general decline of 40% in Northern European peatland bird population sizes in 1981–2014 (speed of decline 1.5%/year) largely driven by Finland, where populations declined almost 50% (2.0% annual decline). In Sweden and Norway, peatland bird populations declined by 20% during 1997–2014 (1.0% annual decline). In contrast, southern populations in Estonia and Latvia, where the majority of open peatlands are protected, showed a 40% increase during 1981–2014 (1.0% annual increase). The most important habitat characteristics preferred by common peatland species in Finland were openness and low tree height, while wetness proved to be an important feature for waders. Drainage of peatlands had clear negative effects on the densities of many species, with the only exception of rustic bunting, which specializes on edge habitats. Our findings call for more effective conservation actions in Northern European peatland habitats, especially in Finland where peatland drainage represents a major threat to biodiversity.

Perceptions across scales of governance and the Indonesian peatland fires

Across leading environmental challenges—fire management, climate change, deforestation – there is growing awareness of the need to better account for diverse stakeholder perceptions across complex, multi-level governance arrangements. Perceptions often condition behavior, compliance and engagement in ways that impact environmental outcomes. We illustrate the importance of, and approaches to, examining perceptions across scales of governance (e.g. international, national, local) and sectors (e.g. civil society, government, corporate) through the example of Indonesian peatland fires. Peatlands are crucial global carbon stocks threatened by land use change and fire and subject to a range of policy interventions that affect many different stakeholder groups. Peatland drainage and conversion to plantation agriculture has been associated with severe, uncontrolled peat fires that present significant climate, public health and economic risks. Peatland fire management has become a domestic and international priority, spurring intensely contentious debates, policies and legal proceedings. Previous fire management interventions (FMI) are numerous yet have suffered widespread implementation failures. Against this backdrop, our manuscript provides a thematically and methodologically novel analysis of how diverse stakeholders, from local farmers to international policy makers, perceive peatland fires in terms of, i) how they prioritize the associated benefits and burdens, and ii) the perceived effectiveness of FMI. We adopt an innovative application of Q method to provide needed insights that serve to quantify the areas of contention and consensus that exist among the stakeholders and their multi-dimensional perspectives. We show that many of the contemporary FMI were perceived as among the most effective interventions overall, but were also the most controversial between groups. Clear consensus areas were related to the shared concerns for the local health impacts and the potential of government support for fire-free alternatives as a solution pathway. Improved understanding of stakeholder perceptions has potential to: give voice to marginalized communities; enable transparent mediation of diverse priorities; inform public education campaigns, and shape future policy and governance arrangements.

Factors affecting oxidative peat decomposition due to land use in tropical peat swamp forests in Indonesia

The increasing frequency of fire due to drainage of tropical peatland has become a major environmental problem in Southeast Asia. To clarify the effects of changes in land use on carbon dioxide emissions, we measured oxidative peat decomposition (PD) at different stages of disturbance at three sites in Central Kalimantan, Indonesia: an undrained peat swamp forest (UF), a heavily drained peat swamp forest (DF), and a drained and burned ex-forest (DB).PD exhibited seasonality, being less in the wet season and greater in the dry season. From February 2014 to December 2015, mean PD (±SE) were 1.90±0.19, 2.30±0.33, and 1.97±0.25μmolm−2s−1 at UF, DF, and DB, respectively. The groundwater level (GWL) was a major controlling factor of PD at all sites. At UF and DF, PD and GWL showed significant quadratic relationships. At DB, PD and GWL showed significant positive and negative relationships during the dry and wet seasons, respectively. Using these relationships, we estimated annual PD from GWL data for 2014 and 2015 as 698 and 745gCm−2yr−1 at UF (mean GWL: −0.23 and −0.39m), 775 and 825gCm−2yr−1 at DF (−0.55 and −0.59m), and 646 and 748gCm−2yr−1 at DB (−0.22 and −0.62m), respectively. The annual PD was significantly higher in DF than in UF or DB, in both years. Despite the very dry conditions, the annual PD values at these sites were much lower than those reported for tropical peat at plantations (e.g., oil palm, rubber, and acacia). The differences in the relationship between PD and GWL indicate that separate estimations are required for each type of land. Moreover, our results suggest that PD can be enhanced by drainage both in forests and at burned sites.

Simulating the long‐term impacts of drainage and restoration on the ecohydrology of peatlands

AbstractDrainage alters the carbon storage and accumulation functions of peatlands, but the long‐term effects of drainage ditches, and their restoration, on peatland development are poorly understood. Timescales of monitoring studies in ditch‐drained and restored peatlands are typically limited to a few years, and occasionally decades. In addition, experimental studies seldom monitor spatial changes in peat structure caused by ditches, despite such changes affecting water flow and water retention in peat. Ecosystem models offer an alternative to experimental studies and can help explain how complex systems such as peatlands may respond to external disturbances. Here we report on a 2‐D application of a peatland development model (DigiBog) to explore how contour‐parallel ditches, and their damming, affect the ecohydrology of peatlands over decades to centuries, using blanket peatlands as a case study. Drainage resulted in the rapid loss of peat due to increased oxic decay. The majority of these losses occurred in the first 100 years after the ditch was created, but water table dynamics were altered even centuries later. Restoration halted the loss of peat and encouraged net peat accumulation, although the amount lost in 100 years of drainage had not been replaced 200 years after the ditch was dammed. Restoration of ditches in sloping peatlands brought about more peat regrowth downslope of the restored ditch than further upslope. Our study demonstrates the potential for spatially distributed ecosystem‐scale models as tools to explore complex spatiotemporal responses to disturbance, and to support land managers in making decisions about peatland drainage and restoration.

How temporal patterns in rainfall determine the geomorphology and carbon fluxes of tropical peatlands

Tropical peatlands now emit hundreds of megatons of carbon dioxide per year because of human disruption of the feedbacks that link peat accumulation and groundwater hydrology. However, no quantitative theory has existed for how patterns of carbon storage and release accompanying growth and subsidence of tropical peatlands are affected by climate and disturbance. Using comprehensive data from a pristine peatland in Brunei Darussalam, we show how rainfall and groundwater flow determine a shape parameter (the Laplacian of the peat surface elevation) that specifies, under a given rainfall regime, the ultimate, stable morphology, and hence carbon storage, of a tropical peatland within a network of rivers or canals. We find that peatlands reach their ultimate shape first at the edges of peat domes where they are bounded by rivers, so that the rate of carbon uptake accompanying their growth is proportional to the area of the still-growing dome interior. We use this model to study how tropical peatland carbon storage and fluxes are controlled by changes in climate, sea level, and drainage networks. We find that fluctuations in net precipitation on timescales from hours to years can reduce long-term peat accumulation. Our mathematical and numerical models can be used to predict long-term effects of changes in temporal rainfall patterns and drainage networks on tropical peatland geomorphology and carbon storage.

DAMPAK PARIT DRAINASE TERHADAP TINGGI MUKA AIR, KONDISI TANAH DAN PERTUMBUHAN POHON DI HUTAN GAMBUT KALIMANTAN BARAT

Currently, tropical peatland forests are under considerable pressure because of increasing deforestation and degradation of forests. In Kalimantan, degradation and deforestation of peatland forests are driven primarily by industrial logging, expansion of agricultural activities through primarily conversion of forests to agricultural land and oil palm plantations. By the establishment of intensive drainage, it can induce wildfires in peatland. Unmanaged drainage ditches will alter water table levels within the site adjacent to the drainage including to surrounding peatland forest. Water table assessments were conducted before and after peatland drainage on 2007/2009 and 2012/2015 in Kubu Raya, West Kalimantan. This paper studies the effect of drainage ditches into the peatland water table. Results show the establishment of drainage ditches on this peatland landscape lowered the water table by more than 3 times from ~11.7 cm (SE = 1.5, n = 5) to ~37.3 cm (SE = 2.1 cm, n = 26). The effect on the water table was in drier months of July-August. Lowering the water table level altered worst the soil micro climate, peat temperature and peat water content. The results indicate the land use changes in peatland with the establishment of drainage affects peatland water table currently. In the area of less than 500 m from the drainage, the water level tends to lower toward the drainage feature. Therefore, recovery of peatland forests should be initiated by managing the landscape hydrology (i.e. water table) to restore the ecosystem and to protect the remaining peat swamp forest.

EMISI METHANA (CH4) DARI SALURAN DRAINASE LAHAN GAMBUT DI KALIMANTAN TENGAH

<p>ABSTRACT</p><p>Peatland development is increasingly becoming a strategic, both in terms of aspects of agronomy, and environmental aspects. Information magnitude of GHG emissions from drainage canals are important in the management of peat sustainability. Its objective is to determine the amount of GHG emissions from peatland drainage channels that are used for traditional rubber plantation. Gas sampling is done in the secondary drainage channel with a channel width of 5 m and 3 m wide tertiary. Sampling was performed six times with five points by using the lid closed cylinder. Sample was analyzed by gas chromatography flame ionization detector incorporates detector (FID) for the determination of the concentration of CH4. CH4 fluxes in peatland drainage channel width of 5 m is relatively higher than in the drainage channel width of 3 m in Jabiren peatlands of Central Kalimantan. GHG emissions in the channel width of 5 m was 542,20 ± 258,57 kg CO2-e yr-1 and 379,14 ± 260,7 kg CO2-e yr-1 of the channel width of 3 m.</p>

Evaporation fractionation in a peatland drainage network affects stream water isotope composition

AbstractThere is increasing interest in improving understanding of evaporation within a catchment for an enhanced representation of dominant processes in hydrological models. We used a dual‐isotope approach within a nested experimental design in a boreal catchment in the Scottish Highlands (Bruntland Burn) to quantify the spatiotemporal dynamics of evaporation fractionation in a peatland drainage network and its effect on stream water isotopes. We conducted spatially distributed water sampling within the saturated peatland under different wetness conditions. We used the lc‐excess—which describes the offset of a water sample from the local meteoric water line in the dual‐isotope space—to understand the development of kinetic fractionation during runoff in a peatland network. The evaporation fractionation signal correlated positively with the potential evapotranspiration and negatively with the discharge. The variability of the isotopic enrichment within the peatland drainage network was higher with higher potential evapotranspiration and lower with higher discharge. We found an increased evaporation fractionation toward the center of the peatland, while groundwater seepage from minerogenic soils influenced the isotopic signal at the edge of the peatland. The evaporation signal was imprinted on the stream water, as the discharge from a peatland dominated subcatchment showed a more intense deviation from the local meteoric water line than the discharge from the Bruntland Burn. The findings underline that evaporation fractionation within peatland drainage networks affects the isotopic signal of headwater catchments, which questions the common assumption in hydrological modeling that the isotopic composition of stream waters did not undergo fractionation processes.

Hydrologic aspects of drained peatland renaturalization

The peatland drainage is one of the main man-made factors of the landscape water circulation and peatland ecosystems degradation. To return former sustainable ecological state of peatland it is necessary to carry out the renaturalization. The essence of renaturalization is renewal of water regime with following renewal of the peatland ecosystem like it was before drainage. Change of water runoff regime is effective mechanism of the peatland renaturalization – so called active protection. To renaturalize the Zalyvky peatland in the Roztochia Natural Reserve it is necessary to keep high groundwater level that will cause renewal of peat forming, stop succession processes, growing up by untypical for peatland plant species, reduce the risk of peat burning. Based on the results of natural conditions and recent ecological state of the Zalyvky peatland analysis the general scheme of renaturalization and hydrologic regime renewal has been worked out. With this aim, the series of measures are realized. They allow increasing the groundwater levels due to coming of water from the river streams and channels, making the runoff slower and renewing small water bodies. Small water bodies like ponds play not only water regulating role but also key ecological role for many bird species, ecological education, and tourist-recreation attractive. It is expected that keeping of higher ground water levels will be assisted by the beavers population with their natural dams. Key words: renaturalization, drainage melioration, peatland, water runoff regulating.