North Selangor Peat Swamp Forest Research Articles

Remote Sensing for Restoration Change Monitoring in Tropical Peat Swamp Forests in Malaysia

Effective planning and management strategies for restoring and conserving tropical peat swamp ecosystems require accurate and timely estimates of aboveground biomass (AGB), especially when monitoring the impacts of restoration interventions. The aim of this research is to assess changes in AGB and evaluate the effectiveness of restoration efforts in the North Selangor Peat Swamp Forest (NSPSF), one of the largest remaining peat swamp forests in Peninsular Malaysia, using advanced remote sensing techniques. A Random Forest machine learning method was employed to upscale AGB estimates, derived from a ‘LiDAR AGB model’, to larger landscape-scale areas with Sentinel-2 spectral and textural variables. The time period under investigation (2015–2018) marked a concentrated phase of restoration and regeneration efforts in NSPSF. The results demonstrate an overall increase in tropical peat swamp AGB during these years, where the total amount of estimated AGB stored in NSPSF increased from 19.3 Tg in 2015 to an estimated 19.8 Tg in 2018. The research found that a tailored variable selection approach improved predictions of AGB, with optimised input variables (n = 62) and parameter adjustments producing a good plausible result (R2 = 0.80; RMSE = 55.2 Mg/ha). This paper concludes by emphasizing the importance of long-term studies (>5 years) for analyzing the success of tropical peat swamp restoration methods, with a potential for integrating remote sensing technology.

Potential of APSIS-InSAR for measuring surface oscillations of tropical peatlands.

Tropical peatland across Southeast Asia is drained extensively for production of pulpwood, palm oil and other food crops. Associated increases in peat decomposition have led to widespread subsidence, deterioration of peat condition and CO2 emissions. However, quantification of subsidence and peat condition from these processes is challenging due to the scale and inaccessibility of dense tropical peat swamp forests. The development of satellite interferometric synthetic aperture radar (InSAR) has the potential to solve this problem. The Advanced Pixel System using Intermittent Baseline Subset (APSIS, formerly ISBAS) modelling technique provides improved coverage across almost all land surfaces irrespective of ground cover, enabling derivation of a time series of tropical peatland surface oscillations across whole catchments. This study aimed to establish the extent to which APSIS-InSAR can monitor seasonal patterns of tropical peat surface oscillations at North Selangor Peat Swamp Forest, Peninsular Malaysia. Results showed that C-band SAR could penetrate the forest canopy over tropical peat swamp forests intermittently and was applicable to a range of land covers. Therefore the APSIS technique has the potential for monitoring peat surface oscillations under tropical forest canopy using regularly acquired C-band Sentinel-1 InSAR data, enabling continuous monitoring of tropical peatland surface motion at a spatial resolution of 20 m.

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.

Detecting tropical peatland degradation: Combining remote sensing and organic geochemistry.

Tropical peatlands are important carbon stores that are vulnerable to drainage and conversion to agriculture. Protection and restoration of peatlands are increasingly recognised as key nature based solutions that can be implemented as part of climate change mitigation. Identification of peatland areas that are important for protection and restauration with regards to the state of their carbon stocks, are therefore vital for policy makers. In this paper we combined organic geochemical analysis by Rock-Eval (6) pyrolysis of peat collected from sites with different land management history and optical remote sensing products to assess if remotely sensed data could be used to predict peat conditions and carbon storage. The study used the North Selangor Peat Swamp forest, Malaysia, as the model system. Across the sampling sites the carbon stocks in the below ground peat was ca 12 times higher than the forest (median carbon stock held in ground vegetation 114.70 Mg ha-1 and peat soil 1401.51 Mg ha-1). Peat core sub-samples and litter collected from Fire Affected, Disturbed Forest, and Managed Recovery locations (i.e. disturbed sites) had different decomposition profiles than Central Forest sites. The Rock-Eval pyrolysis of the upper peat profiles showed that surface peat layers at Fire Affected, Disturbed Forest, and Managed Recovery locations had lower immature organic matter index (I-index) values (average I-index range in upper section 0.15 to -0.06) and higher refractory organic matter index (R -index) (average R-index range in upper section 0.51 to 0.65) compared to Central Forest sites indicating enhanced decomposition of the surface peat. In the top 50 cm section of the peat profile, carbon stocks were negatively related to the normalised burns ratio (NBR) (a satellite derived parameter) (Spearman's rho = -0.664, S = 366, p-value = <0.05) while there was a positive relationship between the hydrogen index and the normalised burns ratio profile (Spearman's rho = 0.7, S = 66, p-value = <0.05) suggesting that this remotely sensed product is able to detect degradation of peat in the upper peat profile. We conclude that the NBR can be used to identify degraded peatland areas and to support identification of areas for conversation and restoration.

Ground Water Table Monitoring in North Selangor Peat Swamp Forest, Selangor, Peninsular Malaysia

Monitoring of ground water table in North Selangor Peat Swamp Forest was undertaken for 3 years period from December 2013 to December 2016. This is part of the initiative to monitor GWL in a peat swamp forest under different vegetation i.e., logged over forest, degraded open peatland as well as other land use such as smallholder oil palm. The effect of drainage on the GWT is also analyzed. The result showed that GWT fluctuates throughout the year, often correlate with rainfalls. 2014 is the dry year comparatively and it was reflected in the lowest GWT recorded in all transects. Forested area showed highest GWT whereas oil palm smallholder cultivation area had the lowest GWT; relatively higher GWT recorded in degraded open area most likely due to loss of peat surface caused by repeated fire in the past. Drained canals that were located within the peat swamp forest negatively affected the GWT. Overall, GWT recorded in NSPSF show negative value in most of the months except for November and December, a typical result for a peat swamp forest which had been drained.

Putative roles of bacteria in the carbon and nitrogen cycles in a tropical peat swamp forest

Tropical peat swamp forests are waterlogged, acidic, anoxic and oligotrophic ecosystems. They are important terrestrial carbon pools that help mitigating global warming through carbon sequestration in peat. This study aimed at investigating putative roles of bacteria in the carbon and nitrogen cycles in North Selangor peat swamp forest, Malaysia. Whole-genome sequencing was performed on four bacterial isolates using Illumina NextSeq 500 to decipher their genetic information while Gen III Microplate (Biolog) was applied to verify carbon source utilization. The isolates were identified as Dyella sp. strain C9, Dyella sp. strain C11, Klebsiella sp. strain C31 and Paraburkholderia sp. strain C35. Both Dyella spp. and Paraburkholderia sp. strain C35 were likely novel species while Klebsiella sp. strain C31 was a different strain of the type species, Klebsiella pneumoniae. Both genomic and bioassay results suggested the involvement of the isolates in the degradation of lignocellulose, carbohydrates, sugar alcohols, organic acids and aromatic compounds. The isolates could potentially perform methanotrophy, which helps to mitigate methane emissions from tropical peatlands. In addition, the isolates also contained genes encoding enzymes for nitrite, nitrate and nitric oxide reduction, as well as dissimilatory nitrate reduction to ammonium, which retains the nitrogen in the ecosystems. The results generated insights into potential functions of bacteria in the energy production and nutrient cycling of tropical peatlands, which are essential for the sustainability of high biomass and biodiversity in these ecosystems.

Peat swamp forest conservation withstands pervasive land conversion to oil palm plantation in North Selangor, Malaysia

ABSTRACTTropical deforestation remains one of the major global challenges of the twenty-first century driven to a large extent by the conversion of land for agricultural purposes, such as palm oil production. Malaysia is one of the world’s largest palm oil producers and has seen widespread conversion to oil palm from primary forest, including peat swamp forest (PSF). This study investigates the rate and extent of pervasive oil palm expansion in and around North Selangor Peat Swamp Forest (NSPSF) over the last three decades, exploring how land conversion has affected the region’s tropical forests, and assessing the relative success of PSF conservation measures. Time-series Landsat imagery was used to assess thematic land cover change and improvement in vegetation condition since NSPSF was given protected status in 1990. The results show a near tripling in oil palm cover throughout North Selangor, from 24,930 ha in 1989 to 70,070 ha in 2016; while at the same time tropical forest cover shrank from 145,570 ha to 88,400 ha. Despite concerns over the sustainability and environmental impact of such rapid oil palm conversion at a regional level, at the local scale, NSPSF represents a relative conservation success story. Effective land stewardship by government and non-governmental organization (NGO) management actors has limited illegal encroachment of oil palm around the reserve boundary. PSF rehabilitation measures have also markedly improved vegetation condition in NSPFS’s interior. These findings have broad significance for how oil palm agriculture is managed and especially for PSF stewardship and conservation, and the approaches described here may be usefully adopted elsewhere in Southeast Asia and around the world.

Water Quality Influences Fish Occurrence in Peat Swamp Forest and Its Converted Areas in North Selangor, Malaysia

Tropical peat swamp forest (PSF) is one of the most endangered ecosystems in the world. However, the impacts of anthropogenic activities in PSF and its conversion area towards fish biodiversity are less understood. This study investigates the influences of water physico-chemical parameters on fish occurrences in peat swamp, paddy field and oil palm plantation in the North Selangor peat swamp forest (NSPSF), Selangor, Malaysia. Fish and water samples were collected from four sites located in the peat swamps, while two sites were located in the paddy field and oil palm plantation areas. Multivariate analyses were used to determine the associations between water qualities and fish occurrences in the three habitats. A total of 1,382 individual fish, belonging to 10 families, 15 genera and 20 species were collected. The family Cyprinidae had the highest representatives, followed by Bagridae and Osphronemidae. The most abundant species was Barbonymus schwanefeldii (Bleeker 1854), while the least abundant was Wallago leerii Bleeker, 1851. The paddy field and oil palm plantation area recorded significantly higher fish diversity and richness relative to peat swamp (p 0.05), but was significantly different from the peat swamp (p<0.05). However, no water quality parameter was consistently observed to be associated with fish occurrences in all of the three habitats, but water temperature, NH3-N, Cl2, SO4, and EC were at least associated with fish occurrences in two habitats studied. This study confirmed that each habitat possess different water quality parameters associated with fish occurrences. Understanding all these ecological aspects could help future management and conservation of NSPSF.

Draft Genome Sequence of Klebsiella sp. Strain C31 Isolated from a Malaysian Tropical Peat Swamp Forest.

ABSTRACTWe report here the draft genome of Klebsiella sp. strain C31, a bacterial isolate from the North Selangor peat swamp forest in Malaysia. The putative genes for the biogeochemical processes of the genome were annotated and investigated.

Tropical Peatland Vegetation Structure and Biomass: Optimal Exploitation of Airborne Laser Scanning

Accurate estimation of above ground biomass (AGB) is required to better understand the variability and dynamics of tropical peat swamp forest (PSF) ecosystem function and resilience to disturbance events. The objective of this work is to examine the relationship between tropical PSF AGB and small-footprint airborne Light Detection and Ranging (LiDAR) discrete return (DR) and full waveform (FW) derived metrics, with a view to establishing the optimal use of this technology in this environment. The study was undertaken in North Selangor peat swamp forest (NSPSF) reserve, Peninsular Malaysia. Plot-based multiple regression analysis was performed to established the strongest predictive models of PSF AGB using DR metrics (only), FW metrics (only), and a combination of DR and FW metrics. Overall, the results demonstrate that a Combination-model, coupling the benefits derived from both DR and FW metrics, had the best performance in modelling AGB for tropical PSF (R2 = 0.77, RMSE = 36.4, rRMSE = 10.8%); however, no statistical difference was found between the rRMSE of this model and the best models using only DR and FW metrics. We conclude that the optimal approach to using airborne LiDAR for the estimation of PSF AGB is to use LiDAR metrics that relate to the description of the mid-canopy. This should inform the use of remote sensing in this ecosystem and how innovation in LiDAR-based technology could be usefully deployed.

Effects of peat swamp logging and agricultural expansion on species richness of native mammals in Peninsular Malaysia

The biodiversity inhabiting tropical peat swamp forests in Southeast Asia is currently threatened by commercial logging and agricultural expansion. The occurrence of mammals in such forests is often poorly known and the factors influencing their occurrence in these ecosystems have rarely been quantified. We aim to determine the key habitat and landscape drivers of mammal species richness in fragmented peat swamp reserves. We conducted camera trap surveys in the North Selangor Peat Swamp Forest (NSPSF), the last remaining area of peat swamp forest on the west coast of Peninsular Malaysia. We also measured vegetation structure and landscape metrics to investigate the relationship between these factors and mammal richness. We recorded a total of 16 mammal species from 45 sampling sites using camera traps located in peat swamp forest reserves. Mammal species richness increased with the abundance of large trees and distance away from roads. Species richness decreased significantly with canopy cover and height, the abundance of fallen trees, the abundance of forest palms and saplings, distance away from rivers, and a measure of landscape compositional heterogeneity. Our findings underscore the high conservation value of logged peat swamp forests and the urgent need to halt further deforestation. We recommend: (1) protecting riparian habitat; (2) avoiding further forest conversion particularly areas supporting large trees into oil palm plantations; and (3) limiting road development within and around the NSPSF.

Farmers’ perceptions and attitudes toward forest watershed conservation of the North Selangor Peat Swamp Forest

ABSTRACTOver the past several decades, the management of forest ecosystem functions through policies such as “command and control” has not been successful, largely because existing policies and legislation for natural resource management are inadequate and often formulated without consulting local communities such as farmers. However, farmers’ decisions to participate in natural resource conservation or watershed conservation more particularly are generally influenced by their knowledge of the problems and perceived benefits of conservation. This study focuses on farmers’ perceptions and attitudes toward forest watershed conservation in the North West Selangor Peat Swamp forest of Malaysia. A survey questionnaire was administered to 380 paddy farmers at the North West Selangor irrigation scheme. Dates were analyzed using exploratory factor analysis (EFA) and the theory of value and social psychology constructs. The study concludes that farmers have generally positive attitudes toward forest watershed conservation. Therefore, we recommend farmers’ involvement in the conservation and management of the North Selangor Peat Swamp Forest (NSPSF).

Depauperate Avifauna in Tropical Peat Swamp Forests Following Logging and Conversion to Oil Palm Agriculture: Evidence from Mist-netting Data

Increased demand for oil palms has led to a massive expansion of logging and conversion of peat swamp forests in Southeast Asia. Although palm oil is a primary driver of economic growth, the unsustainable expansion of the oil palm industry has led to the widespread degradation of peat swamp forests. Birds have been studied to determine their responses to landscape changes in the North Selangor Peat Swamp Forest (NSPSF). We captured 1045 birds from 72 species of the NSPSF and 168 individual birds from 13 species in oil palm plantations using mist-netting. Our results show that peat swamp forest supports more bird species than the oil palm areas. Non-metric Multidimensional Scaling revealed that both vegetation types had an influence on bird species composition. SIMPER analysis also showed that the percentage of the assemblage similarity within the oil palm areas was 51.30 %, while it was 31.32 % in the peat swamp. We found that the populations of frugivores, insectivores, and omnivores were significantly higher in the peat swamp forest, whereas there was no significant difference in the granivores between the two sites. To conserve peat swamp forests, stakeholders should implement habitat restoration, maintain landscape connectivity, and retain a forest area network.

Habitat occupancy patterns and activity rate of native mammals in tropical fragmented peat swamp reserves in Peninsular Malaysia

Intensive land use plays a major role in tropical peat swamp deforestation in Southeast Asia. In Peninsular Malaysia, the North Selangor Peat Swamp Forest (NSPSF) is the second largest remaining peatland ecosystem. Although the NSPSF is recognized as a biodiversity hotspot area in the region, this peat swamp forest is rapidly shrinking because of the expansion of commercial oil palm agriculture. More than 87% of the NSPSF has been designated as reserves, but in reality, this is not comparable to protected area status. The NSPSF is under constant threats from forest conversions, forest fires, and road constructions. Faunal biodiversity loss is likely to occur in the NSPSF unless immediate action is taken by stakeholders. To determine the habitat occupancy and activity rate of native mammals, we conducted camera-trap survey at 45 sites located within the NSPSF. From a total survey effort of 2565 trap nights in an area of 778km2, 16 mammal species were recorded. Our data provide vital information on the occupancy of high conservation value species in the NSPSF. However, we did not record Sumatran rhinoceros (Dicerorhinus sumatrensis) and Malayan tiger (Panthera tigris), nor did we find any indirect evidence such as footprints, indicating that these species are extirpated from this region. We found that mammal activity rate responded differently to in situ habitat quality and landscape factors according to feeding guild. Government stakeholders should focus on prohibiting further forest conversion and prioritize the upgrading NSPSF’s conservation status from reserve to protected area.

Utilization of Dual Stable Isotope Markers (δ13C and δ15N) to Determine Trophic Structure in Aquatic Environment of Malaysian Peat Swamp Forest

This study was conducted to develop a preliminary food web model of aquatic environment at the North Selangor Peat Swamp Forest (NSPSF) using stable isotope markers (δ13C and δ15N). The samples were collected from two selected points of peat swamp area representing disturbed and undisturbed areas. Samples collected then underwent analytical procedures before being analysed using an Isotope Mass Ratio Spectrometry (IRMS). Results showed that there are differences in trends of the food web between disturbed and undisturbed area. A consumer in the higher trophic level had significantly higher δ13C and δ15N values compared to the lower consumer. Hemibagus nemurus has become the top predator in disturbed areas while Channa lucius becomes the top predator in undisturbed areas. Sampling throughout the year is highly recommended as different species are only available for a certain period of time due to the water input from the rainfall.

Leaf litter decomposition in a tropical peat swamp forest in Peninsular Malaysia

It has long been assumed that the peat underlying tropical peat swamp forests accumulates because the extreme conditions (water logged, nutrient poor, anaerobic and acidic—pH 2.9–3.5) impede microbial activity. Litterbag studies in a tropical Malaysian peat swamp (North Selangor peat swamp forest) showed that although the sclerophyllous, toxic leaves of endemic peat forest plants (Macaranga pruinosa, Campnosperma coriaceum, Pandanus atrocarpus, Stenochlaena palustris) were barely decomposed by bacteria and fungi (decay rates of only 0.0006–0.0016 k day−1), leaves of M. tanarius, a secondary forest species were almost completely decomposed (decay rates of 0.0047–0.005 k day−1) after 1 year. Thus it is intrinsic properties of the leaves (that are adaptations to deter herbivory in the nutrient poor environment) that impede microbial breakdown. The water of the peat swamp was very high in dissolved organic carbon (70–84 mg l−1 DOC). Laboratory studies revealed initial rapid leaching of DOC from leaves (up to 1,720 mg l−1 from 4 g of leaves in 7 days), but the DOC levels then fell rapidly. The leaching of DOC resulted in weight loss but the physical structure of the leaves remained intact. It is suggested that the DOC is used as a substrate for microbial growth hence lowering the concentration of DOC in the water and transferring energy from the leaves to other trophic levels. This would explain how nutrient poor tropical peatswamps support diverse, abundant flora and fauna despite low nutrient levels and lack of rapid litter cycling such as occurs in other types of tropical rainforests.

Diversity and conservation of blackwater fishes in Peninsular Malaysia, particularly in the North Selangor peat swamp forest

One of the most extreme freshwater habitats in Peninsular Malaysia is the peat swamp forest, with dark-coloured and highly acidic waters. Surprisingly, little is known about blackwater fishes in Peninsular Malaysia. Until 1968, only 26 fish species were known from blackwaters throughout Peninsular Malaysia, of which only one can be regarded as stenotopic. A recent intensive survey of part of the North Selangor peat swamp forest yielded 47 species, of which 14 are probably stenotopic taxa. These include four undescribed species and several new records for western Peninsular Malaysia. These discoveries are significant in that they include the family Chaudhuriidae which until 1985, was not reported from Sundaic Southeast Asia, and the rare genus Encheloclarias which had not been encountered for over 50 years. The rapid rate of destruction of the peat swamp forest owing to development, forestry and agricultural activities must be halted or slowed significantly to enable the proper zoological surveys and studies to be conducted. Conservation plans and environmental impact assessments based on inadequate sampling and knowledge of species present is acutely dangerous. There are no longer substantial undisturbed blackwater peat swamp forests left in most of Peninsular Malaysia. Conservation of the remaining blackwater biotopes is critically important if extinction of many species, here regarded as economically valuable renewable resources, is to be prevented.

The avifauna of the North Selangor peat-swamp forest, West Malaysia

SummaryThe North Selangor peat-swamp forest occupies an area of about 75,000 ha and has been extensively logged for timber. Of the six sites surveyed, three were located in regenerating or selectively logged areas and contained a higher proportion of forest-dependent species of birds than the other three, which had been extensively cleared by logging and for agriculture. The presence of the nearby Kuala Selangor Nature Park should not diminish the conservation value of the peat-swamp forest, at least where the avifauna is concerned, as their avifauna complement one another.