Southern Borneo Research Articles

Gastrointestinal parasites of wild Bornean orang-utans (Pongo pygmaeus) in a habitat affected by wildfire smoke

Wildfires are becoming increasingly frequent and severe in the tropical peatlands of Southern Borneo, with major consequences for both wildlife and people that inhabit them. Burning peat releases vast amounts of toxic smoke that, when inhaled, can cause a plethora of health-related issues. With some of the largest remaining populations of Bornean orang-utans (Pongo pygmaeus) being found in peatland forests, wildfires are becoming one of the greatest threats to this Critically Endangered ape, yet the effects of the toxic smoke on their health are unknown. Wildfire has long been known to influence wildlife disease by reducing populations of free-living parasites in the environment (thus altering host exposure), and there is a growing body of evidence to suggest that smoke may affect host susceptibility to such parasites by diminishing physiological condition and immune function. In this study, we investigated parasitic nematode infections in wild Bornean orang-utans inhabiting a drained peatland forest prone to fire and smoke. We identified four gastrointestinal nematode taxa that varied significantly in their prevalence and intensity. Overall prevalence of nematode infection was high, but intensity was relatively low. We present some evidence for an increase the prevalence and intensity of certain nematode taxa after the wildfire smoke event. Namely, an increase in the prevalence of Enterobius spp. and Trichuris spp., and an increase in the intensity of hookworm infections, after the smoke period. We identify the need for multi-year, multi-fire event research to increase sample sizes, along with measuring endocrinological markers of physiological condition, in tandem with parasitological monitoring, to gain a more comprehensive understanding of the impacts of environmental changes on orang-utan health.

Expansion of winter ENSO‐associated rainfall affected area in Southeast Asia under warmer climate

AbstractThis paper examines the changes of El Niño–Southern Oscillation (ENSO) associated winter rainfall relationship in Southeast Asia (SEA) in the historical period (1981–2010) and future period (2071–2100) based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) models simulations. Twenty general circulation models (GCMs) are chosen from the Scenario Model Intercomparison Project (ScenarioMIP) highest emission scenario—Shared Socioeconomic Pathway (SSP) 5‐8.5. This study focuses only on the GCMs that have been able to replicate the consistent associated patterns observed, referred to as “teleconnection‐consistent models” (TCMs). During historical period, ENSO has significant negative association with SEA winter rainfall, particularly over Indochina mainland, Maritime Continent (MC) and northern Borneo. The significant negative‐associated teleconnection affected area has increased under future climate, particularly over southern part of South China Sea (SCS). The weakening of south westerlies at Western North Pacific (WNP) centred near 20°N reduces the moisture transport from Indochina into south of China, increase the negative correlated affected area in the SEA regions above equator. The northeasterlies/easterlies that prevailed from the WNP anticyclone (AC) brings significant moisture flux into southern Borneo, causing increment of significant positive‐associated moisture flux convergence to that region. The weakening of upward motion in TCM results in less warm and moist air rising over SEA MC, reducing the rainfall availability. The 1° eastward expansion of WC downward branch eastern edge leads to suppression of convective activities, increasing the dry affected area. The results suggest that the ENSO has a larger influence on the negative‐associated SEA rainfall and atmospheric circulation in the December–January–February (DJF) late‐21st century when compared to the 1980–2010.

The Kuching Formation: A deep marine equivalent of the Sadong Formation, and its implications for the Early Mesozoic tectonic evolution of western and southern Borneo

The pre-Cretaceous history of Borneo remains relatively poorly studied. Limited exposures of Palaeozoic and lower Mesozoic rocks are located in NW Kalimantan and in West Sarawak, an area interpreted as the West Borneo basement. Lower Mesozoic sedimentary rocks in West Sarawak were analysed to study their depositional environments and implications for the tectonic evolution. Upper Triassic turbidites in West Sarawak, exposed in the northern part of Kuching city, informally named the Kuching Formation, are the deep marine equivalent to the more widespread, shallow marine Sadong Formation. The Kuching Formation comprises thinly-bedded stacked turbidites, consisting of incomplete Bouma sequences, with multiple, erosive channel sandstone bodies deposited under upper flow regime waning flows. Thin debrites with abundant coaly-material are interbedded with the channel sandstones. The Kuching and Sadong formations both contain volcaniclastic detritus that was derived from the westward-subducting Palaeo-Pacific plate, forming a Triassic Andean-type arc which extended from West Borneo in the south to southern China, Taiwan and Japan in the north. Palaeoproterozoic to Archean detrital zircons in the Kuching and Sadong formations reveal a Cathaysian basement source, providing insights into the nature of the West Borneo basement. Quartz-mica schists (Kerait Schist, Tuang Formation) in fault-contact with the two sedimentary successions may have formed during accretion.

Drought Potential in Borneo Based on the RCP 4.5 Scenario

One of the impacts of climate change is an increase in the frequency and intensity of hydrometeorological disasters such as prolonged droughts. Borneo is one of the areas threatened by drought due to climate change. Therefore, it is important to identify and implement appropriate mitigation and adaptation measures. This study used the dynamical downscaling method by the Conformal Cubic Atmospheric Model (CCAM) to evaluate the potential for drought events in Borneo based on the RCP 4.5 scenario. The annual rainfall in Borneo for 2021-2050 is projected to increase compared to 1991-2020. However, the increase in annual rainfall does not free Borneo from the possibility of drought events in the future. This study’s results indicate that areas in southern Borneo, such as Banjarmasin, Pangkalan Bun, and Pontianak, will have a higher frequency of meteorological drought events and are also expected to experience longer periods of consecutive dry days between 2021-2050 compared to 1991-2020.

Odonata (Insecta) Communities in a Lowland Mixed Mosaic Forest in Central Kalimantan, Indonesia

Assessing a taxon’s response to change in environmental variables is fundamental knowledge to understanding trends in species diversity, abundance, and distribution patterns. This is particularly needed on Borneo, where knowledge on Odonata populations in different habitats is poor. To address this gap, we present the first study investigating the relationship between morphology and species distribution of Odonata communities in a heath (kerangas)-dominated mixed-mosaic-lowland forest in southern Borneo. We sampled 250-m line transects in three habitat types: mixed peatcswamp, kerangas, and low-pole peatcswamp, with weekly surveys from December 2019 to February 2020. A total of 309 individuals were detected from 25 species. Anisoptera and Zygoptera diversity was the highest in mixed peatcswamp and lowest in low pole, while abundance was the highest in low pole and lowest in kerangas; with kerangas notably harboring a very small sample size. Odonata community assemblages differed most between mixed peat swamp and low pole. Morphological data were compared between suborders and habitats. Anisoptera showed significantly larger thoraces, hindwings, and hindwing-to-body ratio than Zygoptera. Anisoptera in low pole were significantly smaller in body, thorax, and hindwing compared to both kerangas and mixed peat swamp. Anisoptera showed a strong association with pools and Zygoptera with flowing water. Heterogeneity, habitat characteristics, presence of specialists, body size, and the interaction between species’ morphological traits and habitat characteristics likely explained the trends observed.

'Annoying Requests': The Missionary Johann Michael Carl Hupe's Collecting In Borneo (1842-1847)

Sarawak’s first missionary was Johann Michael Carl Hupe (1818–1861), from the German town of Halle. After working in southern Borneo for several months, Hupe eventually travelled overland from the west to the north coast of Borneo, where he tried to establish a mission school in Kuching. It is hardly known that he was collecting cultural artefacts and natural science specimens of various types in the Pulopetak region (at present, the region about fifteen kilometres northeast of Kuala Kapuas, Kalimantan Tengah) and in Sarawak this early. Today, only a signboard at the old Courthouse in Kuching memorializes him and the site of his mission house. This paper attempts to highlight Hupe’s role as a source for European knowledge and images about Borneo drawing on archival material from the Francke Foundations in Halle. The focal point of the paper will be on the objects Hupe collected and dispatched to Halle. Many of them can still be found in the Kunst-und Naturalienkammer or Cabinet of Artefacts and Natural Curiosities, the museum collection of the Francke Foundations. Others were circulated and passed on in different ways within existing networks. By examining the collecting project of Hupe, it will be demonstrated that, even in the first half of the nineteenth century, interest in Borneo and knowledge of this remote island in European circles was substantial, which connected the island to scientific and cultural circuits, and even into Protestant homes, with the traffic of its objects.

Data to the Malaysian Liverwort Flora, III: New Lejeuneaceae Records from Sabah and Peninsular Malaysia

New Malaysian records from the family Lejeuneaceae are presented, including four species new to Malaysia and seven new to Peninsular Malaysia (Kelantan or Terengganu). The new records include Lejeunea convexiloba M.L.So & R.L.Zhu, which was only known from China and Radula grandilobula Promma & Chantanaorr. , which was only known from its type from southern Thailand and Borneo. All species are illustrated, their diagnostic characteristics and morphological comparison between their allies are provided and discussed, habitat and distribution are given.

Rumah Bulat Sebagai Markas Perjuangan Pemuda Bakumpai Marabahan Borneo Bagian Selatan (1929-1946)

The stage of Indonesian history, especially southern Borneo (Kalimantan), in the first decade of the 20th century was marked by the growth and development of nationalism. The main actors are the youngsters. From 1929-1942, there were many movement organizations with various characteristics. The organization is generally based in one headquarters. Among them are Bakumpai’s youth organizations such as the Marabahan Youth Association (PPM), the Marabahan Branch of Sarekat Islam up to the Taman Siswa School which is headquartered in Round House, Marabahan. Historical studies of the existence of round houses are still not enough. Spatial aspects (place of events) still get a small portion in local historiography. This study aims to describe the existence of Round House as the headquarters for the Marabahan Youngsters (Bakumpai) in Marabahan, Southern Borneo, in 1929 -1946. This research used a historical method with heuristics, criticism, interpretation and historiography stages. The results of the research showed that Round House is a symbolic name for the determination of the Bakumpai youngsters to fight through the organization. Originally named the Joglo Cap Crown House, as a symbol of the glory of the Bakumpai Merchant. The Cap Crown house later changed its name to Round House after becoming the headquarters of the Marabahan Youth Association and the Marabahan Branch of Islamic Sarekat in 1929. This house was also the location of the Sarekat Borneo (Kalimantan) Congress in 1930. Round House also became the school area for PHIS-Taman Siswa Branch in 1931. Due to its important position, Round House became the Headquarters of Indonesian People's Rebellion Front (BPRI) before the return of NICA to southern Borneo in 1945. This building has the status of a cultural heritage building in 2011. However, unfortunately, it is still minimally functioning as a learning resource, place or learning facility for students.

South Borneo as an ancient Sprachbund area

In South and Central Kalimantan (southern Borneo) there are some unusual linguistic features shared among languages which are adjacent but do not belong to the same genetic linguistic subgroups. These languages are predominantly Banjar Malay (a Malayic language), Ngaju (a West Barito language), and Ma’anyan (a Southeast Barito language). The same features also appear to some degree in Malagasy, a Southeast Barito language in East Africa. The shared linguistic features are the following ones: a grammaticalized form of the originally Malay noun buah ‘fruit’ expressing affectedness, nasal spreading in which N - not only nasalizes the onset of the first syllable but also a *y in the next syllable, a non-volitional marker derived from the Banjar Malay prefix combination ta-pa- (related to Indonesian t ə r - + p ə r -), and the change from Proto Malayo-Polynesian *s to h (or Malagasy Ø). These features have their origins in the various members of the language configuration outlined above and form a Sprachbund or “Linguistic Area”. The concept of Linguistic Area is weak and difficult to define. Lyle Campbell (2002) considers it little else than borrowing or diffusion and writes it off as “no more than [a] post hoc attempt [..] to impose geographical order on varied conglomerations of [….] borrowings”. While mindful of its shortcomings, the current author still uses the concept as a useful tool to distinguish between inherited and borrowed commonalities. In the configuration of languages currently under discussion it also provides a better understanding of the linguistic situation in South Borneo at a time prior to the Malagasy migrations to East Africa (some thirteen centuries ago).

Revision of generic concepts in Schoeneae subtribe Tricostulariinae (Cyperaceae) with a new genus Ammothryon and new species of Tricostularia

The Tricostularia Nees ex Lehm. group of genera is reviewed and formally recognised as Cyperaceae tribe Schoeneae subtribe Tricostulariinae R.L.Barrett, K.L.Wilson & J.J.Bruhl. Molecular data based on plastid trnL–F and nuclear ITS and ETS regions are combined with a novel assessment of morphological characters to support our new classification. Six genera are included: a new genus, Ammothryon R.L.Barrett, K.L.Wilson & J.J.Bruhl, and the named genera Chaetospora R.Br., Morelotia Gaudich., Tetraria P.Beauv., Tricostularia, and Xyroschoenus Larridon. Ammothryon, Chaetospora and Tricostularia are all endemic to southern Australia. Morelotia has one species each in Hawaii, French Polynesia and New Zealand, and three species in south-west Western Australia. Tetraria has a disjunct distribution in Southern Africa, Borneo, New Guinea and New Caledonia. Xyroschoenus is endemic to the Seychelles. Tetrariopsis C.B.Clarke (based on Tetrariopsis octandra (Nees) C.B.Clarke) is included under an expanded concept of Morelotia, which also includes Tetraria australiensis C.B.Clarke and Tetraria microcarpa S.T.Blake from south-west Western Australia. Tricostularia davisii R.L.Barrett & K.L.Wilson and Tricostularia sandifordiana R.L.Barrett & K.L.Wilson are described as new species from south-west Western Australia. The following new combinations are made: Ammothryon grandiflorum (Nees) R.L.Barrett, K.L.Wilson & J.J.Bruhl, Morelotia australiensis (C.B.Clarke) R.L.Barrett & K.L.Wilson, Morelotia microcarpa (S.T.Blake) R.L.Barrett & K.L.Wilson, Morelotia octandra (Nees) R.L.Barrett & J.J.Bruhl and Tricostularia drummondii (Steud.) R.L.Barrett & K.L.Wilson. Tricostularia drummondii is reinstated from synonomy, having previously been confused with T. exsul. Lectotypes are selected for Chaetospora flexuosa var. β gracilis Boeckeler, Discopodium drummondii Steud., Elynanthus grandiflorus Nees ex Lehm., Lampocarya affinis Brongn., Lepidosperma exsul C.B.Clarke, Morelotia gahniiformis Gaudich. var. minor A.Rich., Tetraria australiensis C.B.Clarke, Tetraria capillacea var. intercedens Kük., Tricostularia compressa Nees ex Lehm. and Tricostularia neesii Lehm.

Shifting Valuations of Sociality and the Riverine Environment in Central Kalimantan, Indonesia

ABSTRACT This article explores how changing environmental conditions and practices connect with shifting forms and valuations of sociality in a Ngaju Dayak village in the radically transformed peatlands of southern Borneo. It proposes that the production of values and social relations is indivisible from the production of a livelihood through material means and dwelling in the local environment. The article describes how changing Ngaju orientations to social life and the riverscape have been interlinked with fluctuations in the local valuescape. The focus is on two distinct but overlapping forms of organising sociality and labour in the riverine environment, and how they have influenced and been influenced by the dialectically conjoined Ngaju values of solidarity and autonomy, and, more recently, by emerging economic value. It is argued that the valuation of sociality crucially reflects the changing valuation of land and nature and related politics of value within the local riverscape. Finally, the article shows that the radically transformed riverine environment sets limits on (imagining) environmental practices, forms of sociality, and how they are valued.

Carbon storage capacity of tropical peatlands in natural and artificial drainage networks

Tropical peatlands store over 75 gigatons of carbon as organic matter that is protected from decomposition and fire by waterlogging if left undrained. Over millennia, this organic matter builds up between channels or rivers into gently mounded shapes called peat domes. Measurements of peat accumulation and water flow suggest that tropical peat domes approach a steady state in which the peat surface morphology is described by a uniform curvature, setting a limit on the carbon that a peatland can store. We explored the maximum amount of carbon that can accumulate as water-saturated peat in natural and artificial drainage networks of northwest and southern Borneo. We find that the maximum volume of peat accumulation in a channel-bounded parcel is proportional to the square of the parcel area times a scale-independent factor describing the shape of the parcel boundary. Thus, carbon capacity per area scales roughly with mean parcel area in the peatland. Our analysis provides a tool that can be used to predict the long-term impacts of artificial drainage, and to devise optimal strategies for arresting fires and greenhouse gas emissions in tropical peatlands.

Carbon dioxide flux in the Java Sea estimated from satellite measurements

The oceans play a pivotal role in the carbon cycle due to its dynamics to act as a carbon source or sink to the atmosphere. Previous studies showed that the Java Sea acts as a carbon dioxide (CO2) source. However, their analysis was only based on the observation data which was limited in time and coverage. In the present study, we utilize the advantage of satellite measurements which have wide coverage and continues monitoring. Sea surface temperature, chlorophyll-a, sea surface salinity, surface wind speed, tropospheric mole fraction of CO2 and sea level pressure were analyzed to calculate CO2 gas transfer velocity, CO2 solubility, CO2 pressure in the sea water and atmosphere to estimate CO2 flux in the Java Sea. We found that the Java Sea acts as a CO2 source. However, during May 2015 and August 2016 small areas along the southern Borneo Island become the sink areas of CO2. The influence of CO2 gas transfer velocity and CO2 solubility is stronger than the difference of CO2 pressure between sea and atmosphere to determine CO2 flux in the Java Sea. Therefore, wind speed and sea surface salinity play important role to determine the variability of CO2 flux in the Java Sea. El Niño condition tends to amplify the release of CO2 to the atmosphere since CO2 gas transfer velocity, CO2 solubility and the difference of CO2 pressure between sea and atmosphere increases during El Niño.

A new, uniquely patterned spiny eel (Teleostei: Mastacembelidae) from southern Borneo, Kalimantan Tengah, Indonesia.

A new species of Macrognathus of the M. aculeatus species group is described from the Kahayan River drainage in southern Borneo, Kalimantan Tengah, Indonesia. Macrognathus kris, new species, is distinguished from all Asian congeners in having the following unique combination of characters: rim of anterior nostril with two fimbriae and two fimbrules; 43-45 rostral tooth plates; 24-25 dorsal spines; 46-55 dorsal-fin rays; 51-59 anal-fin rays; 20-23 principal caudal-fin rays; 76-78 total vertebrae; body depth at anus 11.8-15.9% SL; color pattern consisting of light brown stripe on dorsum and 11-14 irregular pentagonal dark brown blotches on sides of body.

Compounding impact of deforestation on Borneo’s climate during El Niño events

Both deforestation and El Niño events influence Borneo’s climate, but their interaction is not well understood. Borneo’s native forest cover decreased by 37.1% between 1980 and 2015 with large areas being replaced by oil palm and a mosaic of plantations and regrowth vegetation. The island is also affected by El Niño events, resulting in severe droughts and fires. Here, we used a high-resolution climate model to simulate and evaluate how deforestation and El Niño episodes interact during the 1980–2016 period. Simulations revealed that deforestation resulted in a warmer and drier climate with the most pronounced changes in the extensively deforested regions of eastern and southern Borneo. Deforestation-linked impacts were more pronounced under El Niño than neutral (non El Niño/La Niña) conditions. Changes in climate mainly corresponded with areas with the most deforestation. There was a significant increase in the frequency of hotter and drier climatic extremes, with the probability distribution of temperature, humidity and aridity shifting from narrow to a broadening distribution. For example, the frequency of 90th percentile of the hot temperatures (defined as average monthly temperatures >28.9 °C) during the dry season increased from 10% for neutral conditions for the 1980 forest cover to 22% for neutral conditions for the 2015 forest cover. For strong El Niño events, the frequency increased from 15.6% to 32.5%. Replacement of intact native forest with oil palm resulted in increased frequency of hot temperatures to 49% for neutral and 74% for El Niño conditions. Hotter and drier conditions are likely to increase tree mortality and forest flammability (and fire-driven deforestation). The continued reduction and fragmentation of Borneo’s forests diminishes the ability to moderate regional climate impacted by larger scale and other regional/local human climate forcings.

El Niño driven haze over the Southern Malaysian Peninsula and Borneo

The Southeast Asian (SEA) region is no stranger to forest fires - the region has been suffering from severe air pollution (known locally as ‘haze’) as a result of these fires, for decades. The fires in SEA region are caused by a combination of natural (the El Niño weather pattern) and manmade (slash-and-burn and land clearing for plantations) factors. These fires cause the emissions of toxic aerosols and pollutants that can affect millions of people in the region. Thus, this study aims to identify the impact of the SEA haze on the Southern region of the Malaysian Peninsula and Borneo region of East Malaysia using the entire air quality observation data at surface level in 2015. Overall, the concentration of PM10 was about two-fold higher during the haze period compared to non-haze period. The concentrations of CO, flux of CO and flux of BC were aligned with PM10 during the entire observation period. The wind field and cluster of trajectory indicated that the Southern Malaysian Peninsula and Borneo were influenced mainly from the wildfires and the combustion of peat soil in the Indonesian Borneo. This study finds that wildfires from Borneo impacted the Southern Malaysian Borneo more seriously than that from Sumatra region.

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

The symmetry of conjugate rifted margins is a first-order observable feature reflecting the geodynamic processes acting during and after continental rifting. The symmetry of the South China Sea (SCS) rifted margins can be deduced from comprehensive geophysical datasets on a continental-margin scale. Here, we combine three key approaches: (1) lateral fault distributions are delineated according to free-air gravity anomalies, (2) crustal stretching styles are mapped based on gravity inversion constrained by deep seismic profiles, and (3) total extension of conjugate margins is estimated according to margin restorations and tectonic settings. We infer a predominantly symmetric rifting style caused by pure shear extension, with only narrow domains of asymmetric deformation in continent-ocean transition (COT) regions that have undergone simple shear and where the lower crust of the highly thinned distal margin is embrittled before continental breakup. However, our analysis also suggests that this symmetry has been modified by post-rift geodynamic processes. Southward lower crustal flow, which occurred only on the southern margin due to the low viscosity of the lower crust and the slab pull induced by the subducting Proto-SCS plate during seafloor spreading, shifted the crustal stretching styles from symmetric to asymmetric. The collision between the southern margin and Borneo thickened the lower crust more than the upper crust at the southern end of the southern margin and shortened the southern margin. This event had a large impact on the SE margin but a small impact on the SW margin. We conclude that (1) for the SE and NE margins, the crustal stretching styles shifted from asymmetric to approximately symmetric, and the total extension shifted from symmetric to asymmetric; (2) for the SW and NW margins, the crustal stretching and total extension remained asymmetric and symmetric, respectively. • The total extensions are asymmetric in the eastern margins, but symmetric in the western margins. • The crustal stretching styles of the eastern margins are approximately symmetric, but asymmetric in the western margins. • Post-rifting lower crust flow and collision modified margin symmetry.

A new species ofMegophrysKuhl amp; Van Hasselt (Amphibia: Megophryidae) from Borneo allied toM. nasuta (Schlegel, 1858).

Within Sundaland, the species diversity of the genus Megophrys is richest in Borneo, with some species restricted to the northern highlands of the island. On the basis of molecular, morphological and acoustic evidence, we describe a new species of large-sized Megophrys, once confused with M. nasuta. The new species Megophrys kalimantanensis sp. nov. can be differentiated from all its congeners by large genetic distance more than 6.11% in the mitochondrial 16S rRNA gene, much shorter rostral and orbital appendages, and unique advertisement call. This new species has been recorded from medium to high altitudes of mountain forest in southern and northernmost Borneo.

Antibacterial and Antispore Activities of Isolated Compounds from Piper cubeba L.

Piper cubeba L. is the berry of a shrub that is indigenous to Java, Southern Borneo, Sumatra, and other islands in the Indian Ocean. The plant is usually used in folk traditional medicine and is an important ingredient in cooking. The purpose of this study was to isolate and purify the bioactive compounds from P. cubeba L. fractions. In addition, the isolated compounds were tested for their antibacterial and antispore activities against vegetative cells and spores of Bacillus cereus ATCC33019, B. subtilis ATCC6633, B. pumilus ATCC14884, and B. megaterium ATCC14581. The phytochemical investigation of the DCM fraction yielded two known compounds: β-asarone (1), and asaronaldehyde (2) were successfully isolated and identified from the methanol extract and its fractions of P. cubeba L. Results showed that exposing the vegetative cells of Bacillus sp. to isolated compounds resulted in an inhibition zone with a large diameter ranging between 7.21 to 9.61 mm. The range of the minimum inhibitory concentration (MIC) was between 63.0 to 125.0 µg/mL and had minimum bactericidal concentration (MBC) at 250.0 to 500.0 µg/mL against Bacillus sp. Isolated compounds at a concentration of 0.05% inactivated more than 3-Log10 (90.99%) of the spores of Bacillus sp. after an incubation period of four hours, and all the spores were killed at a concentration of 0.1%. The structures were recognizably elucidated based on 1D and 2D-NMR analyses (1H, 13C, COSY, HSQC, and HMBC) and mass spectrometry data. Compounds 1, and 2 were isolated for the first time from this plant. In conclusion, the two compounds show a promising potential of antibacterial and sporicidal activities against Bacillus sp. and thus can be developed as an anti-Bacillus agent.

Savanna in equatorial Borneo during the late Pleistocene

Equatorial Southeast Asia is a key region for global climate change. Here, the Indo-Pacific Warm Pool (IPWP) is a critical driver of atmospheric convection that plays a dominant role in global atmospheric circulation. However, fluctuating sea-levels during the Pleistocene produced the most drastic land-sea area changes on Earth, with the now-drowned continent of Sundaland being exposed as a contiguous landmass for most of the past 2 million years. How vegetation responded to changes in rainfall that resulted from changing shelf exposure and glacial boundary conditions in Sundaland remains poorly understood. Here we use the stable carbon isotope composition (δ13C) of bat guano and High Molecular Weight n-alkanes, from Saleh Cave in southern Borneo to demonstrate that open vegetation existed during much the past 40,000 yrs BP. This location is at the southern equatorial end of a hypothesized ‘savanna corridor’ and the results provide the strongest evidence yet for its existence. The corridor would have operated as a barrier to east-west dispersal of rainforest species, and a conduit for north-south dispersal of savanna species at times of lowered sea level, explaining many modern biogeographic patterns. The Saleh Cave record also exhibits a strong correspondence with insolation and sea surface temperatures of the IPWP, suggesting a strong sensitivity of vegetation to tropical climate change on glacial/interglacial timeframes.