Swamp Forest Research Articles

Environmental management: a country-level evaluation of atmospheric particulate matter removal by the forests of India.

Particulate matter (PM) is a critical air pollutant, responsible for an array of ailments leading to premature mortality worldwide. Nature-based solutions for mitigation of PM and especially role of forests in mitigating PM from an ecosystem perspective are less explored. Forests provide a natural pollution abatement strategy by providing a surface area for the deposition of PM. Depending on their structure and composition, forests have varying capacities for PM adsorption, which is again less explored. Hence, in the present study, we evaluate the removal capacity of PM by the forest-type groups of India. Deposition flux and total PM removal across sixteen forest types were estimated based on the 2019 dataset of PM using Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) data. Externality values and PM removal costs by industrial equipment were used for associating an economic value to the air pollution abatement service by forests. The total PM2.5 removal by forests in 2019 was estimated to be 1361.28 tons and PM10 was estimated to be 303,658.27 tons. Deposition of PM was found to be high in littoral and swamp forests, tropical semi-evergreen forests, tropical moist deciduous forests, and sub-tropical pine forests. Tropical dry deciduous forests had the highest net weight % removal of PM with 39% removal for PM2.5 and 39% removal for PM10. The air pollution abatement service by forests for PM removal was 188 M US dollars (USD) with externality-based removal service by forests of 2009 M USD. The net PM removed by all forests of India was estimated to be approximately worth ₹ 470-648 Crore (59-81 million dollars) for PM2.5 and worth ₹56,746-1,22,617 Crore (7093-15,327 million dollars) for PM10 based on valuation using value transfer method. The study concludes that forests can be a significant contributor to PM reduction at a global level. Especially for India's National Clean Air Programme and further research and policy considerations, the findings would be extremely useful.

A faunistic study and taxonomic account of species of pygmy grasshoppers (Orthoptera: Tetrigidae) from Singapore's last freshwater swamp forest

We surveyed the pygmy grasshoppers (Tetrigidae) of Nee Soon Swamp Forest (NSSF), the last substantial freshwater swamp habitat in Singapore, and found nine species from seven genera, including new locality records for Potua coronata Bolívar, 1887 and Thoradonta nodulosa (Stål, 1861). Overall, four subfamilies were represented: Cladonotinae, Metrodorinae, Tetriginae, and Scelimeninae. Here, we document the diversity and describe the intra-specific variation in Loxilobus insidiosus (Bolívar, 1887), Thoradonta nodulosa (Stål, 1861), and Coptotettix spp. as well as report natural history observations of these species related to their behavior in the semi-aquatic environment). We also provide a key to the species of Tetrigidae from NSSF.

A RETROSPECTIVE ANALYSIS OF MORBIDITY AND MORTALITY IN THE CAPTIVE LEADBEATER'S POSSUM (GYMNOBELIDEUS LEADBEATERI) POPULATION FROM 1970 TO 2021.

The Leadbeater's possum (Gymnobelideus leadbeateri) is a critically endangered nocturnal marsupial with a restricted range in the Central Highlands of Victoria, Australia. There are two genetically distinct populations divided by location: highland and lowland. Lowland possums exist in one remnant swamp forest and entered captivity in 2012 when ∼60 individuals remained. Today, with less than 20 lowland individuals remaining, any information that informs the yet-unsuccessful breeding program is critical. This study encompasses a retrospective analysis of the causes of mortality and significant histological lesions in captive highland and lowland individuals across seven institutions internationally from 1970 to 2021. During this time, 245 possums lived in captivity. Postmortem records exist for 99 animals, including 349 histopathology diagnoses from 80 reports and 264 gross necropsy diagnoses from 78 reports. Diagnoses were assigned into two categories based on the importance to the individual (causing death or morbidity to a single animal [n = 194]), or importance to the wider population (causing death or morbidity to more than one animal or was related to reproduction [n = 155]). Individual animals had multiple diagnoses, which were tallied as individual data points. Renal disease was diagnosed 57 times; the most common finding was chronic nephropathy (43/57). Cardiovascular disease was diagnosed 33 times; atherosclerosis associated with obesity was common (n = 10/33). Both categories suggest causal association with captive husbandry but elicit no comment on the lack of success of the breeding program. Reproductive disease was diagnosed 36 times in 24 animals (14 females and 10 males). In females, 11 cases of uterine inflammation and associated clinical signs were associated with ascending infection or neoplasia. Of the seven lowland male possums with mortality data, five were infertile (azoospermia or testicular atrophy). More investigation into the reproductive health of this population is indicated to understand the lack of success in the current breeding program.

Impacts of agricultural drainage on the quantity and quality of tropical peat soil organic matter in different types of forests

Tropical peatlands serve as huge carbon (C) pools in the global C balance, and degradation due to agricultural use is a major concern. The objective of the present study was to examine the relationship between the C loss rate in agriculturally drained tropical peat soils in relation to groundwater level (GWL) and the chemical structure of the resulting soil organic matter (SOM). Soil mesocosms containing three peat soils collected from three forest types in Malaysia, Mixed peat swamp (MPS), Alan Batu (ABt), and Alan Bunga (ABg) forests, which are classified based on dominant plant species, species diversity, and forest structure, were buried in an oil palm plantation for a period of five years. Soil samples packed in the top layer (0–20 cm depth) and the bottom (60–80 cm depth) layer were then analyzed and the results were compared with the initial values for these soils. Weight loss, total C and N contents, ash content, and pyrophosphate solubility index (PSI; an index of the degree of humification) were measured. Changes in the chemical structure of the SOC were investigated using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy with phase-adjusted spinning side bands and thermally assisted hydrolysis and methylation-gas chromatography/mass spectrometry (THM-GC/MS). The C loss in the MPS forest soil, 2–12%, was smaller than that in the ABt and ABg forest soils, 20–37%, especially in the bottom layer. The higher C loss in the ABt and ABg soils, without significant difference between the top and bottom layers, can be attributed to the greater accumulation of less decomposed plant components as evidenced by the larger yields of lignin-derived phenols and polysaccharide-related compounds in THM-GC/MS analysis. The C composition as estimated by 13C NMR did not vary during incubation of the ABt and ABg soils while the yields of lignin-derived and other phenols as well as polysaccharide-related compounds in THM-GC/MS were decreased, especially in the top layer. These findings suggest that plant components with a low degree of decomposition are susceptible to drainage regardless of their structure. The progression of the oxidative degradation of lignin in the top layer of all soils was also suggested by the increases in PSI and the vanillic acid/vanillin ratio. The % O-alkyl C and % alkyl C may control the rate of C loss positively and negatively, respectively. PSI also appears to be useful for roughly estimating the decomposability of tropical peat SOM in various GWLs.

Revegetation of Tropical Peat Swamp Forest of Former Fires Using Local Tree Species in South Sumatra (Indonesia)

Revegetation of tropical peat swamp forests (PSF) from former fires with local tree species has strategic value for the recovery of PSF, which has been largely lost and severely degraded by logging, conversion, drainage, and repetitive fires. The PSF recovery will be followed by increased forest cover, CO2 sequestration, O2 production, and peat ecosystem biodiversity. The method of revegetation that guarantees successful planting is still very lacking and has not been widely publicized. The study aimed to analyze the growth of revegetated plants on PSF of former fires. It used a field experiment design with four types of local peat plants, namely ramin (Gonystylus bancanus), punak (Tetramerista glabra), tembesu (Fragraea fragrans), and pulai (Alstonia pneumatophora). The results of the study showed that until the age of 2 years, the survival rate of revegetated plants ranged from 92.56%–94.69%, with growth of 32.53–44.94 cm/year and diameter growth of 0.87–1.21 cm/year. The growth of revegetated plants still accelerated in observations until the age of 3 years. This study provides optimism that PSF revegetation degraded by the fires could be carried out with satisfactory results.

Moscow region’s swamp forests mapping for inventory of CH4 and CO2 fluxes.

Moscow region’s swamp forests mapping for inventory of CH4 and CO2 fluxes.

Streptomyces silvisoli sp. nov., a polyene producer, and Streptomyces tropicalis sp. nov., two novel actinobacterial species from peat swamp forests in Thailand.

Two novel actinobacterial strains, designated RB6PN23T and K1PA1T, were isolated from peat swamp soil samples in Thailand and characterized using a polyphasic taxonomic approach. The strains were filamentous Gram-stain-positive bacteria containing ll-diaminopimelic acid in their whole-cell hydrolysates. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strain RB6PN23T was most closely related to Streptomyces rubrisoli (99.1 % sequence similarity) and Streptomyces ferralitis (98.5%), while strain K1PA1T showed 98.8 and 98.7% sequence similarities to Streptomyces coacervatus and Streptomyces griseoruber, respectively. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were below the species-level thresholds (95-96 % ANI and 70 % dDDH). The genomes of strains RB6PN23T and K1PA1T were estimated to be 7.88 Mbp and 7.39 Mbp in size, respectively, with DNA G+C contents of 70.2 and 73.2 mol%. Moreover, strains RB6PN23T and K1PA1T encode 37 and 24 putative biosynthetic gene clusters, respectively, and in silico analysis revealed that these new species have a high potential to produce unique natural products. Genotypic and phenotypic characteristics confirmed that strains RB6PN23T and K1PA1T represented two novel species in the genus Streptomyces. The names proposed for these strains are Streptomyces silvisoli sp. nov. (type strain RB6PN23T=TBRC 17040T=NBRC 116113T) and Streptomyces tropicalis sp. nov. (type strain K1PA1T=TBRC 17041T=NBRC 116114T). Additionally, a giant linear polyene compound, neotetrafibricin A, exhibiting antifungal activity in strain RB6PN23T, was identified through HPLC and quadrupole time-of-flight MS analysis. The crude extract from the culture broth of strain RB6PN23T exhibited strong antifungal activity against Fusarium verticillioides, Fusarium fujikuroi and Bipolaris zeicola. This finding suggests that strain RB6PN23T could be a promising candidate for biological control of fungal diseases.

Streptomyces rugosispiralis sp. nov., a Novel Actinobacterium Isolated from Peat Swamp Forest Soil That Produces Ansamycin Derivatives and Nocardamines.

Actinomycetes, especially the genus Streptomyces, are one of the most promising sources of bioactive natural products. In this study, a novel Streptomyces strain, RCU-064T, was isolated from a soil sample collected from a peat swamp forest in Thailand. Strain RCU-064T showed the highest 16S rRNA gene sequence similarity (99.06%) with Streptomyces malaysiensis NBRC 16446T. Based on a polyphasic approach, strain RCU-064T represents a novel species of the genus Streptomyces, for which the name Streptomyces rugosispiralis sp. nov. is proposed. The chemical isolation of the crude ethyl acetate extracts of the strain led to the isolation of six compounds: (1) geldanamycin, (2) 17-O-demethylgeldanamycin, (3) reblastatin, (4) 17-demethoxyreblastatin, (5) nocardamine, and (6) dehydroxynocardamine. These compounds were evaluated for their biological activities. All compounds showed no antimicrobial activity against tested microorganisms used in this study. Compounds (1)-(4) displayed cytotoxic activity against the NCI-H187 cell line, with IC50 values ranging from 0.045-4.250 µg/mL. Cytotoxicity against the MCF-7 cell line was found in compounds (1) and (3) with IC50 values of 3.51 and 1.27 µg/mL, respectively. Compounds (5) and (6) exhibited cytotoxicity only against Vero cells (IC50 of 16.57 µg/mL) and NCI-H187 cells (IC50 of 13.96 µg/mL), respectively. These results indicate that peat swamp forest soil remains a promising reservoir of novel actinomycetes capable of producing bioactive natural products.

Forest swamp succession alters organic carbon composition and survival strategies of soil microbial communities

Forest swamp ecosystems plays crucial role in the global carbon cycle. However, the effects of forest swamp succession on soil organic matter (SOM) and microbial community structure remain unclear. To determine the drivers of SOM change and soil microbial communities in forest swamp succession, a ‘space instead of time’ approach was used. Soil samples from 0 to 40 cm were collected along forest swamp (early stage), dried-up forest swamp (middle stage), and forest (late stage) ecosystems. Our findings reveal that as succession progresses, the relative content of aromatics decreases and SOM undergoes a transition towards a more readily degradable form. These changes affect soil carbon sequestration and nutrient availability. Bacterial diversity was significantly influenced by succession and changes in soil depth, with fungi exhibiting higher resilience. Soil properties and environmental conditions exert influence over the structure and function of microorganisms. As succession occurred, microbial interactions shifted from cooperation to competition, with bacteria displaying a deterministic distribution pattern and fungi exhibiting a random distribution pattern. SOM quality plays a key role in shaping microbial communities and influencing their growth strategies. Microorganisms are the major drivers of soil respiration, with K-strategist dominated communities in early succession exhibiting slower degradation rates, whereas r-strategists dominated in later stages, leading to faster decomposition.

Variation of carbon source and sink along the environmental gradient from lakeside to highlands in Yuanchi swamp wetlands, Changbai Mountains, China.

Lacustrine wetlands have long-term carbon storage capacity and contribute significantly to regional carbon cycle, but it is unclear how its carbon sinks respond to climate change. We measured soil heterotrophic respiration carbon emissions (CO2 and CH4), vegetation carbon sequestration, and related environmental factors (temperature, water level, etc.) of five kinds of natural swamps (Phragmites marsh-L, Carex schmidtii marsh-C, Rhododendron capitatum swamp-D, Betula fruticose swamp-H, Larix olgensis swamp-LT)by using static chamber gas chromatography and relative growth equation methods, along the water environmental gradients from lakeside to highlands in Yuanchi of Changbai Mountains. We quantified the carbon source/sink function (CSS) and global warming potential (GWP) of various swamp types by estimating ecosystem net carbon balance, and revealed the variation patterns and formation mechanisms of CSS and GWP along the environmental gradients, aiming to explore the response of carbon source/sink of lakeside wetland in high altitude area to climate change. The results showed that marshes (L and C) were weak sources (-1.018 and -0.090 t C·hm-1·a-1) at the lower habitats of the water environment gradient, shrub swamps (D and H) were strong or weak sinks (1.956 and 0.239 t C·hm-1·a-1) at the middle habitats, forest swamp (LT) was strong source (-3.214 t C·hm-1·a-1) at the upper habitat. The spatial changes were promoted by water level and suppressed by soil temperature. For GWP, strong thermal radiation for marshes (from 44.682 to 59.282 t CO2·hm-1·a-1), cold radiation for shrub swamps (from -0.920 to -7.008 t CO2·hm-1·a-1), and weak thermal radiation for forest swamp (11.668 t CO2·hm-1·a-1), and their GWP was only promoted by soil temperature. Under current climate change background, marshes and forest swamp at both ends of the water environment gradient from lakeside to highlands played a positive feedback effect due to the increases of CH4 or CO2 emissions, while the middle shrub swamp still maintained a negative feedback effect in Yuanchi located the high-altitude area of the temperate Changbai Mountains.

Mapping spatial patterns in Tinondo Swamp, East Kolaka Regency to increase land productivity

The development of land use activities in the Tinondo Swamp promotes the acceleration of spatial planning to ensure sustainability. This research aimed to evaluate land use in Tinondo Swamp and to provide alternative areas in the spatial plan of the east Kolaka regency. Primary and secondary data were collected using survey methods. The research used qualitative and quantitative methods to analyze the deepening and scanning of autopilot aircraft, the environmental carrying capacity, linkages and existence of linkages with the community, the needs of facilities and infrastructure, and spatial analysis. The results showed that the survey area of the Tinondo Swamp was 5,699.41 hectares, consisting of 11 land-use types. There are swamps with an area of 1,999.34 hectares (35.08%), settlements of 133.41 hectares (2.34%), the company’s Base Camp of 0.94 acres, the forest of 104.65 hectares (1.84%), swamp forests of 178.02 hectares (3.12%), roads of 26.22 hectares (0.46%), canals of 51.59 hectares (0.91%), mixed gardens of 489.88 hectares (8.60%), oil palm plantations of 1,178,298 hectares (20.67%), rice fields of 1,536,096 hectares (26.95%), and open land of 0.96 hectares. Furthermore, the total survey area that is available and planned for was 1,999.34 hectares.

Anthropogenic disturbance modifies tree functional traits in the only remnant swamp forest of Bangladesh

The relationship between ecosystem functions and plant functional traits has been well documented and is considered to be one of the most vital topics in ecology. However, the correlation between anthropogenic disturbance and tree functional trait diversity remains largely unclear. The present study investigates the role of anthropogenic disturbance on selected tree functional traits in Ratargul Swamp Forest (RSF) – the only remnant tropical freshwater swamp forest ecosystem in Bangladesh. We established 50 plots and collected six plant traits, i.e., tree height, specific leaf area (SLA), wood density (WD), leaf dry matter content (LDMC), seed mass, and bark thickness. A two-way analysis of variance (ANOVA) was carried out to test the interaction between plant functional traits and anthropogenic disturbance in RSF. Our study found that anthropogenic disturbance has a significant (p< 0.05) influence on deciduous swamp forest tree species’ functional traits but none on evergreen tree species’ functional traits. For deciduous trees, disturbance has a significant positive effect on CWM.SLA (p< 0.05) and CWM.Height (p< 0.05) and a negative impact on CWM.Bark-thickness and CWM.Seed-mass (p< 0.05). There were no significant effects of disturbance on CWM.WD and CWM.LDMC. We believe the present study will contribute toward improving our understanding of the effect of disturbances on tree functional trait diversity in tropical human-dominated landscapes where anthropogenic pressure is increasing at an unprecedented rate. It will also function as an essential conservation for related decision-making of Ratargul Swamp Forest in northeastern Bangladesh and elsewhere in the tropics with a similar context.

Variations in abundance of Imbrasia epimethea (Lepidoptera: Saturniidea) on Petersianthus macrocarpus in different forest types in Central Cameroon

Edible caterpillars are of vital importance to rural communities in developing countries providing high protein values and income. However, their ecology particularly seasonal fluctuations in their numbers is still poorly understood. With the ongoing climate change and increasing deforestation, their survival is a crucial issue. The aim of this study was to assess the structural characteristics of Petersianthus macrocarpus (Lecythidaceae) on the abundance of edible caterpillars of Imbrasia epimethea (Saturniidea). The forest area on the outskirts of Yaoundé is an important production basin for edible caterpillars making a perfect medium to answer questions on the variations in the abundance of caterpillars of I. epimethea in relation to the forest type of P. macrocarpus. Concerning biometric parameters, the [20-30[ cm diameter class in agroforest had more edible caterpillars (31.1 %). In the secondary forest and swamp forest, it was the [50-60[ cm diameter class with respectively 34 % and 27.4 %. In terms of height, the [30-40[ m height class contained more edible caterpillars (68.50 %), whereas the [60-70[ m height class represented the stratum with the least edible caterpillars (5.10 %). In different forest types, the abundance of caterpillars of I. epimethea according to the social status of P. macrocarpus individuals showed that caterpillars are found in abundance preferentially on dominant individuals (52.7 % in swamp forest, 49.7 % in secondary forest and 45.6 % in agroforest). The mean abundance of I. epimethea caterpillars was higher in secondary forest (563 ± 62 caterpillars) compared to agroforest and swamp forest. In contrast, swamp forest had the lowest mean abundance of edible caterpillars (375 ± 24 caterpillars) according to the social status of P. macrocarpus. These results point way to a better understanding of the use and management of an economically important NTFP.

Late Holocene riparian vegetation dynamics, environmental changes, and human impact in the Harapan forest of Sumatra, Indonesia

Riparian wetland ecosystems provide important ecological services but are also vulnerable to climate change and human activities. To understand the influence of natural factors (e.g. climate change, flooding, drought) and human activities (e.g. agriculture) as well as to support management strategies, reconstructions of past vegetation and environmental changes are needed. To achieve this, we conducted a multi-proxy paleoecological analysis, including pollen and spores, macro-charcoal and radiocarbon dating, on a sediment core taken from a riparian area in the Harapan forest of Sumatra. Three distinct periods were identified: i) AD 1100 – 1400: Upland and swamp forest with riparian and herbaceous vegetation, possibly part of a riparian buffer zone (e.g. riverbank), was present in the study area under a stronger dry season regime; ii) AD 1400 – 1870: freshwater swamps expanded to the study site; iii) later, from AD 1870 to present, upland forests dominated in the study area with a strong dry season. The presence of cereal cultivation from AD 1300 – 1450, and oil palm (Elaeis guineensis) since the mid-19th century AD indicates the presence of small-scale agriculture in the study area. This study of riparian vegetation dynamics and environmental changes in the Harapan forest of Sumatra shows the development from a riparian forest to a freshwater swamp and upland forest under the impact of climate change and human activities.

GC-MS and LC-MS/MS Analysis of Secondary Metabolites in the Methanolic Extract of Uncaria callophylla Blume ex Korth. Stems

Uncaria callophylla Blume ex Korth. is a wild plant species belonging to the Rubiaceae family. These plants thrive in the peat swamp forest of Kalimantan, Indonesia. The stems of Uncaria callophylla have been used by the Dayak Ngaju tribe to treat various diseases and to restore stamina while they work in the forest. The present study was conducted to identify the secondary metabolites in the methanolic extract of Uncaria callohylla stems to increase the knowledge about this plant and its potential in medicinal applications and drug discovery. The analysis was conducted using GC-MS and LC-MS/MS. GC-MS analysis was performed with the Agilent Technologies 7890 Gas Chromatography equipped with an Auto Sampler and 5975 Mass Selective Detector. The LC-MS analysis was carried out in the C18 column of the Waters Acquity UPLC system. MS analysis was performed with an electrospray ionization source (ESI) in positive and negative ion modes, and the compounds were identified using a UNIFI data processor with a mass spectrum library of natural active substances from the Waters Traditional Medical Scientific Library database based on UPLC/QTof MSE Data Acquisition. GC-MS analysis revealed the presence of 24 peaks, and nine of them showed quality 90% or higher, namely n-Hexadecanoic acid (16.63%), 1,3,7-Trimethyl-3,7-Dihydro-1H-Purine-2,6-Dione (13.07%), Hexadecanoic Acid, Methyl Ester; 1,2-Benzenedicarboxylic Acid, Diethyl Ester; 9,12-Octadecadienoic Acid, Methyl Ester; Methyl 14-Methylheptadecanoate; (9E,12E)-9,12-Octadecadienoic Acid; Z, E-3,13-Octadecadien-1-o1; and 2,6,10,14,18,22-Tetracosahexaene, 2,6,10,15,19,23-hexanethyl-, (all-E)-. LC-MS/MS analysis revealed the presence of five compounds, namely Arecatannin A1, Sweroside_2, Uncarine A, Epianhydrobelachinal, and Betulonic acid. All the secondary metabolites identified from GC-MS and LC-MS/MS analysis have biological activity, which indicates their medicinal potencies. From the result, it can be concluded that Uncaria callophylla stem methanolic extract contains various bioactive compounds justifies its traditional use, and therefore it can be developed further for new drug discovery.

Developing biomass allometric equations for small trees in mixed-species forests of tropical rainforest ecozone

Allometric equations for the small trees that dominate many forests recovering from disturbance, such as fire, are relatively rare, increasing the uncertainty of aboveground biomass (AGB) estimates in young regrowth forests. In this study we sampled 516 small trees (diameter <5 cm at 1.3 m height) from 105 species within Indonesian mixed forests to develop multispecies biomass allometric models and root to shoot ratio. Small trees were sampled across three ecosystems: peat swamp forests, heath forests and dryland forests. Several combinations of weighted log-linear regression analyses of tree diameter (D) and tree height (H) versus tree biomass were applied to identify the best model for estimating AGB. The allometric models developed in this study used a power function with diameter (D) and diameter and height (D2H) as predictors and ecosystem as an additional predictor in the D model. Seemingly unrelated regression (SUR) was used to generate equations of biomass components incorporating additivity. For the additive biomass equation components, the allocation of biomass for these small trees was stem > leaves > branches. AGB estimates based on allometric equations developed for larger trees, sourced from the literature, overestimated small tree biomass by up to 25% when compared with AGB estimates from equations developed in this study. The allometric models of small trees and the root-to-shoot ratio values obtained in this study will improve biomass estimates for young regrowth forests of Indonesia and the tropical region in general.

Insights for restoration: Reconstructing the drivers of long-term local fire events and vegetation turnover of a tropical peatland in Central Kalimantan

Fire events in tropical peatlands often relate to dry peat conditions associated with climate variability (drought) and anthropogenic-driven ecosystem degradation. However, drought is not the only driver of long-term fire events and peatland ecosystem changes. This study used palaeoecological and geochemical proxies to investigate the long-term drivers of charcoal influx to identify local fires and examine the associated responses to the tropical peatland ecosystem in Central Kalimantan, Indonesia. The results showed local fire events increased after 756 cal. yr BP, and possible drivers of charcoal influx include changes in sea level, increased frequency of El Niño events, increased biomass, and anthropogenically-driven ecosystem degradation. However, the vegetation composition showed changes since ∼2300 cal. yr BP from a mix of peat swamp forest (PSF) and open vegetation (OV) during the late Holocene (∼2300 to 1129 cal. yr BP), to predominantly PSF from 1128 to 375 cal. yr BP, dry lowland mixed with swamp forest (LMS) and open vegetation (OV) from 374 to 135 cal. yr BP, and predominantly OV and freshwater swamp forest (FSF) from 134 to −62 cal. yr BP. The possible drivers of the vegetation turnover were hydrological conditions and the availability of peat nutrients, while the vegetation turnover affected the accumulation and decomposition of recalcitrant organic matter in peat. The thresholds of the peatland ecosystems over longer-term timeframes provided the following restoration insights: 1) PSF species (i.e. Eurya and Ilex) showed high fire tolerance and increased in abundance up to charcoal influx threshold of ∼23 grains mm−2 cm−3 yr−1 while LMS and OV species increased up to a lower threshold of ∼13 grains mm−2 cm−3 yr−1before declining; 2) PSF species expanded during periods of wet conditions and high peat nutrients (i.e. TN - enriched); and 3) Future revegetation in the region can focus on tree taxa such as Euphorbiaceae, Arenga, Ficus, and Trema as they were historically able to thrive in fire events and dry hydrological conditions.

Tropical peat surface oscillations are a function of peat condition at North Selangor peat swamp forest, Malaysia

Tropical peatland condition across southeast Asia is deteriorating as a result of conversion to agriculture and urban zones. Conversion begins by lowering the water table, which leads to peat decomposition, subsidence and increased risk of large-scale forest fires. Associated changes in mechanical peat properties impact the magnitude and timing of changes in peatland surface motion, making them a potential proxy for peatland condition. However, such a relationship is yet to be observed in a tropical peatland setting. This study aimed to establish whether patterns of tropical peatland surface motion were a function of peat condition at North Selangor Peat Swamp Forest in Selangor, Malaysia. Results showed that subsidence was greatest at fire-affected scrubland sites, whilst the lowest mean water table levels were found at smallholder oil palm sites. Peat condition and magnitude of tropical peat surface oscillation were significantly different between peat condition classes, whilst peat condition differed with depth. More degraded tropical peats with high bulk density throughout the peat profile due to high surface loading and low mean water table levels showed greater surface oscillation magnitudes. The dominant peat surface oscillation mechanisms present at all sites were compression and shrinkage from changes in water table level. Mean water table level and subsidence rate were related to surface oscillation magnitude. However further work towards measuring surface and within-water table range bulk densities and surface loading is required to better understand the controls on surface oscillation magnitudes.

Soil nitrous oxide and methane fluxes from a land-use change transition of primary forest to oil palm in an Indonesian peatland

Despite the documented increase in greenhouse gas (GHG) emissions from Southeast Asian peat swamp forest degradation and conversion to oil palm over recent decades, reliable estimates of emissions of nitrous oxide (N2O) and methane (CH4) are lacking. We measured soil fluxes of N2O and CH4 and their environmental controls along a peatland transition from primary forest (PF) to degraded drained forest (DF) to oil palm plantation (OP) over 18 months in Jambi, Sumatra, Indonesia. Sampling was conducted monthly at all sites and more intensively following two fertilization events in the OP. Mean annual emissions of N2O (kg N ha−1 yr−1) were 1.7 ± 0.2 for the PF, 2.3 ± 0.2 for the DF and for the OP 8.1 ± 0.8 without drainage canals (DC) and 7.7 ± 0.7 including DC. High N2O emissions in the OP were driven by peat decomposition, not by N fertilizer addition. Mean CH4 annual fluxes (kg C ha−1 yr−1) were 8.2 ± 1.9 for the PF, 1.9 ± 0.4 for the DF, and 1.6 ± 0.3 for the OP with DC and 1.1 ± 0.2 without. Considering their 20-year global warming potentials (GWP), the combined non-CO2 GHG emission (Mg CO2-equivalent ha−1 yr−1) was 3.3 ± 0.6 for the PF and 1.6 ± 0.2 for the DF. The emission in the OP (3.8 ± 0.3 with or without DC) was similar to the PF because reductions in CH4 emissions offset N2O increases. However, considering 100-year GWP, the combined non-CO2 GHG emission was larger in the OP (3.4 ± 0.3 with DC and 3.5 ± 0.3 without) compared to both the PF and the DF (1.5 ± 0.2 and 1.2 ± 0.1, respectively). The increase in peat N2O emissions associated with the land-use change transition from primary forest to oil palm plantation at our sites provides further evidence of the urgent need to protect tropical peat swamp forests from drainage and conversion.

Evolution of the facies development of the Knurów deposit (USCB) based on the microlithotypes analysis

This paper presents the first attempt to reconstruct the facies development of the entire Carboniferous coal deposit with an area of 38.50 km2, in the western part of the Upper Silesian Coal Basin based on microscopic microlithotype analysis. For this purpose, eight coal seams in the Knurów deposit were sampled. Samples were taken from all stratigraphic series of exploited seams and exploratory boreholes. This paper reconstructs the transition of environments between eight coal seams extracted in the active Knurów coking coal mine in the Upper Silesian Coal Basin, using microlithotype analysis of the whole seam basis on the fifty coal samples. Facies diagrams proposed in the literature by other researchers were used to reconstruct the depositional environments. The dominant microlithotypes in the coking coal of the Knurów deposit are vitrite (in the range from 19.96 vol% for coal seam No. 504 to 42.96 vol% for coal seam No. 355) and duroclarite (in the range from 20,57 vol% for coal seam No. 410 to 33,65 vol% for coal seam No. 405/1). The distribution of the samples indicates two dominant peat-forming environments. These are telmatic reed moor rich in duroclarite and telmatic forest moor rich in vitrite. This indicates a transitional environment between forest swamp and herbaceous swamp. Thus, the deposit evolved from the paralic to limnic facies. The formation of the river delta caused the progradation of terrestrial environments into the sea and the formation of extensive mires fed mainly by groundwater connected to the river system. Over time, the deposit changed from a reed facies to a forest facies. Periodically, the mires were flooded with waters formed in the proximal lacustrine delta by rising water levels or delta subsidence. The remnants of this phenomenon are interbeds in coal seams resembling macroscopic sapropelic coal rich in the clay matters and gelinite. These are layers containing vitrite in the range of 52.99–59.06 vol% and mineral matter in the amount of 19.76–34.59 vol%. The evolution of the basin proceeded from the paralic to limnic stage. The main factor determining the evolution of the mire was the existing river system with periodically variable activity and intensity.