Forests Of Borneo Research Articles

Jumping in the Night: An Investigation of the Leaping Activity of the Western Tarsier (Cephalopachus bancanus borneanus) Using Accelerometers

Accelerometers enable scientists to quantify the activity of free-living animals whose direct observation is difficult or demanding due to their elusive nature or nocturnal habits. However, the deployment of accelerometers on small-bodied animals and, in particular, on primates has been little explored. Here we show the first application of accelerometers on the western tarsier (Cephalopachus bancanus borneanus), a nocturnal, small-bodied primate endemic to the forests of Borneo. The fieldwork was carried out in the Lower Kinabatangan Wildlife Sanctuary, Sabah, Malaysian Borneo. We provide guidelines for the deployment of accelerometers on tarsiers that might also be applied to other primate species. Our collected data on 2 females show levels of leaping activity comparable to those previously described using direct observation of wild or captive individuals. The 2 females showed different patterns of leaping activity, which calls for work to explore individual differences further. Our work demonstrates that accelerometers can be deployed on small primates to acquire body motion data that would otherwise be demanding to collect using classic field observations. Future work will be focused on using accelerometer data to discriminate in more detail the different behaviours tarsiers can display and to address the causes and consequences of individual variations in activity.

Forest structure and carbon dynamics of an intact lowland mixed dipterocarp forest in Brunei Darussalam

Tropical forests play a critical role in mitigating climate change because they account for large amount of terrestrial carbon storage and productivity. However, there are many uncertainties associated with the estimation of carbon dynamics. We estimated forest structure and carbon dynamics along a slope (17.3°–42.8°) and to assess the relations between forest structures, carbon dynamics, and slopes in an intact lowland mixed dipterocarp forest, in Kuala Belalong, Brunei Darussalam. Living biomass, basal area, stand density, crown properties, and tree family composition were measured for forest structure. Growth rate, litter production, and litter decomposition rates were also measured for carbon dynamics. The crown form index and the crown position index were used to assess crown properties, which we categorized into five stages, from very poor to perfect. The living biomass, basal area and stand density were 261.5–940.7 Mg ha−1, 43.6–63.6 m2 ha−1 and 6,675–8400 tree ha−1, respectively. The average crown form and position index were 4, which means that the crown are mostly symmetrical and sufficiently exposed for photosynthesis. The mean biomass growth rate, litter production, litter decomposition rate were estimated as 11.9, 11.6 Mg ha−1 a−1, and 7.2 g a−1, respectively. Biomass growth rate was significantly correlated with living biomass, basal area, and crown form. Crown form appeared to strongly influence living biomass, basal area and biomass growth rate in terms of light acquisition. However, basal area, stand density, crown properties, and biomass growth rate did not vary by slope or tree family composition. The results indicate that carbon accumulation by tree growth in an intact lowland mixed dipterocarp forest depends on crown properties. Absence of any effect of tree family composition on carbon accumulation suggests that the main driver of biomass accumulation in old-growth forests of Borneo is not species-specific characteristics of tree species.

Phytochemistry and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia

Mangifera pajang Kostermans of the mango family (Anacardiaceae) is endemic to the lowland rain forests of Borneo. Although growing wild in the forest, trees of are planted in orchards and home gardens due to increasing demand for the fruits which are among the largest of the genus. Fruits are oval in shape, and have a characteristic rough and brown skin. In Sabah, M. pajang or bambangan has ethno-cultural significance, and has become an iconic fruit among the Kadazan-Dusun people, who have developed various traditional cuisines using fresh and preserved fruits. Phytochemical investigations on the edible fruit pulp, peel and kernel of M. pajang showed that they are rich in flavonoids and phenolic acids. From the edible pulp, flavonoids (daidzein, genis-tein, hesperidin, kaempferol, naringin, luteolin and quercetin), phenolic acids (caffeic acid, chlorogenic acid and p-coumaric acid), carotenoids (α-carotene and β-carotene), and xanthophylls (cryptoxanthin and cis-cryptoxanthin) have been reported. Pharmacological properties of bam-bangan fruits include antioxidant, antibacterial, anticancer and cytopro-tective activities. A clinical trial at Universiti Putra Malaysia (UPM) has demonstrated the health benefits of regular consumption of bambangan fruit juice. Treated subjects showed significant improvement in cer-tain cardiovascular biochemical parameters that can safeguard against cardiovascular diseases. Traditional and functional food products from bambangan fruits are being developed in Sabah How to Cite this Article Pubmed Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. SRP. 2017; 8(1): 86-91. doi:10.5530/srp.2017.1.15 Web Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. http://www.sysrevpharm.org/?mno=302644570 [Access: March 28, 2021]. doi:10.5530/srp.2017.1.15 AMA (American Medical Association) Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. SRP. 2017; 8(1): 86-91. doi:10.5530/srp.2017.1.15 Vancouver/ICMJE Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. SRP. (2017), [cited March 28, 2021]; 8(1): 86-91. doi:10.5530/srp.2017.1.15 Harvard Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan (2017) and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. SRP, 8 (1), 86-91. doi:10.5530/srp.2017.1.15 Turabian Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. 2017. and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Reviews in Pharmacy, 8 (1), 86-91. doi:10.5530/srp.2017.1.15 Chicago Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. Phytochemistry and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. Systematic Reviews in Pharmacy 8 (2017), 86-91. doi:10.5530/srp.2017.1.15 MLA (The Modern Language Association) Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan. Phytochemistry and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Malaysia. Systematic Reviews in Pharmacy 8.1 (2017), 86-91. Print. doi:10.5530/srp.2017.1.15 APA (American Psychological Association) Style Joseph Tangah, Fidelis Edwin Bajau, Werfred Jilimin, Hung Tuck Chan, Siu Kuin Wong, Eric Wei Chiang Chan (2017) and Pharmacology of Mangifera pajang: An Iconic Fruit of Sabah, Reviews in Pharmacy, 8 (1), 86-91. doi:10.5530/srp.2017.1.15

Plant–soil feedbacks and the dominance of conifers in a tropical montane forest in Borneo

AbstractWe investigated consequences of plant–soil feedbacks (PSFs) in a tropical montane forest on Mt. Kinabalu in Borneo by measurements of light and soil conditions, ecophysiological analyses of tree seedlings, a long‐term adult and seedling census, and a simple simulation model. The study plot (2.74 ha) is in a mixed conifer–broadleaf forest with 24% relative basal area of conifers. First, we investigated light and soil conditions beneath two dominant species, a conifer Dacrydium gracilis (Podocarpaceae, arbuscular mycorrhizal tree) and a broadleaf Lithocaprus clementianus (Fagaceae, ectomycorrhizal tree). The relative light intensity was marginally higher beneath Dacrydium tree crown than beneath Lithocarpus tree crown. The concentrations of inorganic nitrogen and labile phosphorus, and the nitrogen mineralization rate, were lower beneath Dacrydium than beneath Lithocarpus, suggesting that soils beneath Dacrydium were more nutrient deficient. Microscopic observations confirmed that conifer seedlings (including Dacrydium) harbored arbuscular mycorrhizal fungi. In addition, a molecular analysis showed that root‐associated mycorrhizal fungal communities were clearly different between conifer and broadleaf seedlings, and consequently, nutrient acquisition capacity of seedlings may be different between them. Indeed, stable isotopic evidence suggested that Dacrydium seedlings are more efficient in inorganic nitrogen acquisition than Lithocarpus seedlings. These results predicted that the conifer seedlings would out‐compete broadleaf seedlings and have a greater advantage beneath the conifer canopy. To test the possible advantage of conifer seedlings in performance, we developed hierarchical Bayesian models and estimated growth and mortality rates using the seedling census data during 2006–2012. We found that conifer seedlings performed better than broadleaf seedlings beneath Dacrydium canopy. On the other hand, broadleaf seedlings performed better than conifer seedlings beneath Lithocarpus canopy. The consequences of the PSFs for the tree community composition were investigated by developing a simple simulation model, and were compared with the results of a model without PSFs. After a 10 000‐year simulation, the relative abundance of conifers with PSFs converged to 22%, which was consistent with the actual abundance; the model without effects of PSFs predicted a relative abundance of only ~10%. The results suggested that PSFs contributed to the maintenance of the conifer dominance in the tropical montane forest.

SUSTAINABLE DEVELOPMENT: THE NEXUS OF ENVIRONMENTAL SUSTAINABILITY, VALUES, AND ETHICS

The paper seeks to redesign the disciplines of sustainable development by establishing a new ethical-ecological order based on value pluralism and environmental ethics. The argument begins with identifying the failure of the Brundtland Report in addressing the fundamental premise for sustainability which is the need to adopt non-anthropocentric attitudes towards nature. It then moves for restoring an ethical human relationship with the non-human natural world. Citing empirical evidence from research conducted in the forests of Borneo, the paper concludes that for sustainable development to be a useful concept, it must embrace the ethical dimension of sustainability rather than merely targeting its classical aim of meeting “the needs of the present without compromising the ability of future generations to meet their own needs”. Key words: Brundtland Report, intergenerational equity, environmental sustainability, environmental ethics

The impact of logging roads on dung beetle assemblages in a tropical rainforest reserve

The demand for timber products is facilitating the degradation and opening up of large areas of intact habitats rich in biodiversity. Logging creates an extensive network of access roads within the forest, yet these are commonly ignored or excluded when assessing impacts of logging on forest biodiversity. Here we determine the impact of these roads on the overall condition of selectively logged forests in Borneo, Southeast Asia. Focusing on dung beetles along >40km logging roads we determine: (i) the magnitude and extent of edge effects alongside logging roads; (ii) whether vegetation characteristics can explain patterns in dung beetle communities, and; (iii) how the inclusion of road edge forest impacts dung beetle assemblages within the overall logged landscape. We found that while vegetation structure was significantly affected up to 34m from the road edge, impacts on dung beetle communities penetrated much further and were discernible up to 170m into the forest interior. We found larger species and particularly tunnelling species responded more than other functional groups which were also influenced by micro-habitat variation. We provide important new insights into the long-term ecological impacts of tropical logging. We also support calls for improved logging road design both during and after timber extraction to conserve more effectively biodiversity in production forests, for instance, by considering the minimum volume of timber, per unit length of logging road needed to justify road construction. In particular, we suggest that governments and certification bodies need to highlight more clearly the biodiversity and environmental impacts of logging roads.

ANALISIS PROKSIMAT, SENYAWA FENOLIK, SIFAT ANTIOKSIDAN DAN ANTIBAKTERI KULIT BUAH Lepisanthes alata

Bengalun (Lepisanthes alata) is a rare and under-reported fruit native from the forests of Borneo. This fruit is non-seasonal with a thick skin and crimson color, therefore shows potential to be used as raw material for herbal tea. This research was conducted in three phases, namely: (1) to report proximate portions of seed, flesh and skin of the fruit, (2) to find the best combination of time and temperature of fruit skin drying, and (3) to explore the potential antioxidant and antibacterial capacity of fruit skin extracts produced in step (2). Proximate analysis carried out following oven-drying (60 ° C, 12 hours) and sun-drying (8 hours). Combination of oven temperature (40, 50, 60 ° C) and time (8,10,12 hours) was given to find the best drying treatment in terms of vitamin C, total phenols and anthocyanins. Anthocyanins levels approached qualitatively by red color absorbance ( l =545 nm). The antioxidative capacity was approached with DPPH assay. Inhibition zones were measured against Staphylococcus aureus and Escherichia coli. Best drying treatment was at 60 ° C for 8 hours with moisture content of 6.73 ± 0.18%, vitamin C of 76.9±3 mg/100 g, total phenols of 1112±8 mg GAE/kg, and red color absorbance of 0.259 ± 0.060. The average IC 50 antioxidant activity for the fruit skin extracts was 252.83 ± 1.38 ppm. Ethanolic extract produced inhibition zones from 10.76% (1.0 mg extract/50 m L) to 22.77% (1.5 mg extract/50 m L), when compared to the positive control. Aquadest extract produced inhibition zones ranging from 7.99% (0.5 mg/50 m L) to 11.00% (1.5 mg/50 m L). N-hexane extracts showed no antibacterial activity.

Testing the importance of a common ectomycorrhizal network for dipterocarp seedling growth and survival in tropical forests of Borneo

Background: Connections between mature trees and seedlings via ectomycorrhizal (EcM) hyphal networks existing in dipterocarp-dominated tropical rain forests of South-east Asia could have strong implications for seedling growth and survival and the maintenance of high diversity in such forests.Aim: To test whether EcM hyphal network connections are important for the growth and survival of dipterocarp seedlings.Methods: We conducted four independent experiments that prevented contact of experimental seedlings with an EcM network by using a series of fine meshes and/or plastic barriers. We measured the growth and survival (and foliar δ13C in one experiment) of seedlings of six dipterocarp species over intervals ranging from 11 to 29 months.Results: Seedling growth (diameter, height or leaf number) was unaffected by exclusion from the EcM network in three experiments and there were no differences in foliar δ13C values in the fourth. Seedling survival was reduced following exclusion from the EcM network in one experiment. Our results give little support to the hypothesis that dipterocarp seedlings growing in the shaded forest understorey benefit from being connected, through a common EcM network, to surrounding trees.Conclusions: We suggest that our negative results, in contrast to studies conducted in low diversity boreo-temperate or tropical forests, are due to these high diversity forests lacking host species-specific EcM fungi and therefore providing little opportunity for adaptive support of seedlings via hyphal networks.

Supervised logging and climber cutting improves stand development: 18 years of post-logging data in a tropical rain forest in Borneo

We analyzed 18yearsof post-logging data from Sabah, Borneo to evaluate the impact of two selective logging methods – Supervised logging (SL) including pre-aligned skid trails and directional felling, and conventional logging (CL), where trees were felled before the crawler tractor was called in for skidding and the fellers had no formal training in felling techniques – on net standing volume recovery, survivor growth, ingrowth and mortality of trees (⩾10cmDBH). The logging treatments were either combined with- (CC) or without (NCC) pre-harvest climber cutting in a randomized 2×2 factorial design consisting 16 one-hectare treatment plots. We investigated the effect on the complete stand including all trees (⩾10cmDBH) regardless of species, but also distinguished between the effects on the commercially interesting species of dipterocarps (Dipterocarpaceae family) and pioneer species (mainly Macaranga species). Supervised logging in combination with climber cutting was in many ways beneficial to stand development and these effects were mainly expressed at higher harvest intensities. For example, supervised logging reduced the ingrowth and survivor growth of pioneer Macaranga spp.; at high harvest intensities approximately 50% fewer pioneers grew in when SL was used in comparision to CL. In addition, climber cutting increased the ingrowth as well as decreased the mortality of highly valuable dipterocarp species with increasing harvest intensity. These effects appeared also to have stand level consequences as forests treated with the combination of supervised logging and climber cutting also exhibited faster recovery in standing volume of high value dipterocarps compared to any other combination of treatments. We conclude that, with improved ingrowth of dipterocarps, reduced overall mortality and generally better stand volume recovery; supervised logging (SL) in combination with climber cutting (CC) could be an attractive forest management system in mixed dipterocarp forests.

Equatorial Forests Display Distinct Trends in Phenological Variation: A Time-Series Analysis of Vegetation Index Data from Three Continents

Recent studies have questioned the applicability of satellite-derived vegetation indices (VIs) for evaluating phenological variation in tropical forests, due to potential artifacts caused by the bidirectional reflectance distribution function (BRDF). For nadir-normalized data, BRDF will be driven principally by intraannual variation in solar elevation. Where areas lying on the same latitude are under similar solar elevation “regimes,” if the observed variation in VIs is indeed driven by BRDF, then different regions at the same latitude should display identical VI variations. That hypothesis was tested by comparing VI data for tropical evergreen forests in three zones north of the equator (the Guianas, central Africa, and northern Borneo). Enhanced vegetation index, the fraction of green vegetation cover, and leaf area index (LAI) from MODIS and SPOT VEGETATION ultimately showed that VI trends for the regions differ greatly. The trend for Borneo's forests is generally flat over the 12 years studied, while data for the Guianas and central Africa both exhibit strong but distinct seasonal patterns. Correlation analyses indicate that the VI trends between zones are neither strongly correlated to each other nor to variation in solar elevation (except in central Africa), suggesting that the observed variation in the VIs is not driven by BRDF. In contrast, regression analysis indicated that for the Guianas and central Africa, VI variation was most explained by variation in environmental factors, but not atmospheric effects, suggesting seasonally driven phenology.

Response of tree species diversity to disturbance in humid tropical forests of Borneo

AbstractQuestionsThe intermediate disturbance hypothesis (IDH) predicts that the highest species diversity occurs at an intermediate level of disturbance. The validity of the IDH remains contentious in tropical forests because the IDH has been supported in tropical dry forests but often not in humid tropical forests. We addressed the following questions: (1) is the IDH valid in humid tropical forests of Borneo; (2) how does the disturbance index (DI) influence conformity to the IDH; and (3) does the rainfall regime influence conformity to the IDH within the tropical biome?LocationHumid tropical forests of northern Borneo.MethodsWe established approximately 50 20‐m radius circular plots across primary to highly degraded forests in each of three logging concessions. Species richness was regressed against the following four DIs: above‐ground biomass (AGB), relative number (RNO) of pioneer trees, average wood density, and the principal component analysis (PCA) axis 1 score for the three DIs. For studies that examined the IDH in tropical forests, the relationship between total and dry season precipitation and the percentage reduction in species diversity from a unimodal maximum to the lowest disturbance level was examined.ResultsSpecies richness peaked at intermediate disturbance levels when average wood density and PCA 1 score, but not AGB and pioneer RNO, were used as DIs. The peaks were relatively flat, with 8–11% reduction in species richness from a unimodal maximum to the lowest disturbance level. The percentage reduction in species richness from a unimodal maximum to the lowest disturbance level increased with decreasing total and dry season precipitation within the tropical biome.ConclusionSpecies richness showed a unimodal response to disturbance, but conformity to the IDH varied with DI because different DIs may have different biological meanings. Species richness changed little from a moderately disturbed to the least disturbed stand in humid tropical forests compared with tropical dry forests, indicating that IDH is dependent on rainfall regime.

Leaf litter decomposition rates in degraded and fragmented tropical rain forests of Borneo

AbstractPreviously extensive tracts of primary rain forest have been degraded by human activities, and we examined how the effects of forest disturbance arising from habitat fragmentation and commercial selective logging affected ecosystem functioning in these habitats by studying leaf litter decomposition rates in litter bags placed on the forest floor. The rain forests of Borneo are dominated by trees from the family Dipterocarpaceae, and we compared leaf litter decomposition rates of three dipterocarp species at eight forest fragment sites (area 3–3529 ha) that had different histories of disturbance pre‐fragmentation: four fragments had been selectively logged prior to fragmentation and four had been formed from previously undisturbed forest. We compared these logged and unlogged forest fragments with sites in continuous forest that had been selectively logged (two sites) and fully protected and undisturbed (two sites). After 120 d, undisturbed continuous forest sites had the fastest rates of decomposition (52% mass loss). Forest fragments formed from unlogged forest (32% mass loss) had faster decomposition rates than logged forest fragments (28% mass loss), but slower rates than continuous logged forest (39% mass loss). Leaves of a light‐demanding species (Parashorea malaanonan) decomposed faster than those of a shade‐tolerant species (Hopea nervosa), but decomposition of all three dipterocarp species that we studied responded similarly to logging and fragmentation effects. Reduced decomposition rates in logged and fragmented forest sites may affect nutrient cycling and thus have detrimental consequences for forest regeneration. Conservation management to improve forest quality should be a priority, particularly in logged forest fragments.

Forest surveys extend the range of the Krau woolly bat (Kerivoula krauensis) in the Malay-Thai Peninsula, Borneo and Sumatra

Abstract Kerivoula krauensis was formally described in 2007 and until recently was only known from tropical forest in central peninsular Malaysia. We report four new records, which, together with recent published collections, extend the known range for this species to peatswamps, lowland and montane forests in Borneo and Sumatra (Brunei and Indonesia), and further north on the Malay peninsula, including Thailand. External body measurements and cranial data match well with those from the type locality, although echolocation call parameters differ – most likely due to technological improvements in recording devices. The species remains patchily distributed and rarely encountered, despite substantial sampling effort.

Life after logging in tropical forests of Borneo: A meta-analysis

Selectively logged tropical forests retain high species richness and functional diversity, but species composition changes after logging, suggesting that some species are more vulnerable to logging than others. We did a meta-analysis to summarise the effect of logging on the abundance of individual bird and mammal species in tropical forests of Borneo, which have suffered some of the most intense selective logging in the tropics. We found that species classified by the International Union for Conservation of Nature (IUCN) as ‘vulnerable’ or ‘near-threatened’ are generally less abundant in logged tropical forests than those classified as ‘least concern’. However, the effect of logging within each IUCN category is variable, indicating that logging is not the only or main cause of decline in abundance. While our results show that closely related species responded similarly to logging, in birds there was significant variation between responses of some closely related species. Bigger species were significantly more susceptible to logging than smaller species in both birds and mammals. We also found that cavity-nesting birds suffered more from logging than did other species. Our results highlight the importance of identifying which factors lead individual species to flourish or suffer in logged tropical forests.

Movement Behavior of Native and Invasive Small Mammals Shows Logging May Facilitate Invasion in a Tropical Rain Forest

AbstractInvasive species pose one of the greatest threats to biodiversity. This study investigates the extent to which human disturbance to natural ecosystems facilitates the spread of non‐native species, focusing on a small mammal community in selectively logged rain forest, Sabah, Borneo. The microhabitat preferences of the invasive Rattus rattus and three native species of small mammal were examined in three‐dimensional space by combining the spool‐and‐line technique with a novel method for quantifying fine‐scale habitat selection. These methods allowed the detection of significant differences for each species between the microhabitats used compared with alternative, available microhabitats that were avoided. Rattus rattus showed the greatest preference for heavily disturbed habitats, and in contrast to two native small mammals of the genus Maxomys, R. rattus showed high levels of arboreal behavior, frequently leaving the forest floor and traveling through the understory and midstory forest strata. This behavior may enable R. rattus to effectively utilize the complex three‐dimensional space of the lower strata in degraded forests, which is characterized by dense vegetation. The behavioral flexibility of R. rattus to operate in both terrestrial and arboreal space may facilitate its invasion into degraded forests. Human activities that generate heavily disturbed habitats preferred by R. rattus may promote the establishment of this invasive species in tropical forests in Borneo, and possibly elsewhere. We present this as an example of a synergistic effect, whereby forest disturbance directly threatens biodiversity and indirectly increases the threat posed by invasive species, creating habitat conditions that facilitate the establishment of non‐native fauna.

‘Random‐flight’ dispersal in tropical fruit‐feeding butterflies? High mobility, long lifespans and no home ranges

1. Tropical fruit‐feeding Nymphalidae butterflies are widely used in research, monitoring, and conservation projects, but to date a key aspect of their behaviour – dispersal – remains poorly understood. They have anecdotally been described as ‘relatively sedentary’ based on movement vectors from mark‐recapture studies, but this may be inaccurate because plot‐based studies in small sampling areas often underrepresent long‐distance movements.2. Based on data from a peat‐swamp forest in Borneo, it was found that these butterflies may be much more mobile than previously thought, as they frequently moved distances of 1–2 km between sampling plots. Median daily movements were approximately 200–250 m, and over lifespans of one or more months these movements may sum to total life‐time dispersals of several kilometres.3. Recapture rates for long‐distance movements between sampling plots were between 28.2% and 41.6% of the re‐encounter rates that would be predicted by a random‐walk approximation/Brownian motion (without accounting for survival rates), supporting the hypothesis that it is a suitable model of dispersal in this group, although further research is needed to confirm this.4. There was no evidence that butterflies occupied permanent home ranges, and it is suggested that a permanent home range or territorial behaviour would be maladaptive in this group. Pseudo‐replication caused by ‘trap‐happy’ behaviour was not found to be widespread, and some recommendations are provided regarding the treatment of recapture data in trap‐based studies.5. These findings substantially increase the spatial parameters for future research and conservation projects in this group and are also applicable to theoretical modelling studies.An abstract for this article in Bahasa Indonesia is included in the online supporting information File S1.

Assessment of Above-Ground Biomass of Borneo Forests through a New Data-Fusion Approach Combining Two Pan-Tropical Biomass Maps

This study investigates how two existing pan-tropical above-ground biomass (AGB) maps (Saatchi 2011, Baccini 2012) can be combined to derive forest ecosystem specific carbon estimates. Several data-fusion models which combine these AGB maps according to their local correlations with independent datasets such as the spectral bands of SPOT VEGETATION imagery are analyzed. Indeed these spectral bands convey information about vegetation type and structure which can be related to biomass values. Our study area is the island of Borneo. The data-fusion models are evaluated against a reference AGB map available for two forest concessions in Sabah. The highest accuracy was achieved by a model which combines the AGB maps according to the mean of the local correlation coefficients calculated over different kernel sizes. Combining the resulting AGB map with a new Borneo land cover map (whose overall accuracy has been estimated at 86.5%) leads to average AGB estimates of 279.8 t/ha and 233.1 t/ha for forests and degraded forests respectively. Lowland dipterocarp and mangrove forests have the highest and lowest AGB values (305.8 t/ha and 136.5 t/ha respectively). The AGB of all natural forests amounts to 10.8 Gt mainly stemming from lowland dipterocarp (66.4%), upper dipterocarp (10.9%) and peat swamp forests (10.2%). Degraded forests account for another 2.1 Gt of AGB. One main advantage of our approach is that, once the best fitting data-fusion model is selected, no further AGB reference dataset is required for implementing the data-fusion process. Furthermore, the local harmonization of AGB datasets leads to more spatially precise maps. This approach can easily be extended to other areas in Southeast Asia which are dominated by lowland dipterocarp forest, and can be repeated when newer or more accurate AGB maps become available.

Negative Correlation between Ant and Spider Abundances in the Canopy of a Bornean Tropical Rain Forest

AbstractIn tropical rain forests, high canopy trees have diverse and abundant populations of ants and spiders. However, accessing high trees and their fauna remains difficult; thus, how ants and spiders interact in the canopy remains unclear. To better understand the interspecific interactions between these two dominant arthropod groups, we investigated their spatial distributions at the canopy surface in a tropical rain forest in Borneo. We sampled ants and spiders six times between 2009 and 2011 by sweeping with an insect net at the tree crown surfaces of 190 emergent or tall (≥20 m in height) trees. We collected 438 ant individuals belonging to 94 species and 1850 spider individuals (1630 juveniles and 220 adults) belonging to 142 morphospecies (adults only) from a total of 976 samples. The fact that we collected four times more spider individuals than ant individuals suggests that fewer ants forage at the tree crown surface than previously thought. The number of spider individuals negatively correlated with the number of ant individuals and the number of ant species, indicating significant exclusivity between ant and spider spatial distributions at the tree crown surface. Niche‐overlap between the two taxa confirmed this observation. Although our data do not address the causes of these spatial distributions, antagonistic interspecific interactions such as interference behaviors and intra‐guild predation are ecological mechanisms that give rise to exclusive spatial distributions.

Linkage of root physiology and morphology as an adaptation to soil phosphorus impoverishment in tropical montane forests

Summary Tropical forests in Borneo maintain a high level of productivity/biomass even under phosphorus (P)‐limited conditions. The P‐acquisition properties of roots may be an important factor that contributes to forest productivity, but they have not been well evaluated compared with above‐ground properties of plants. In this study, we analysed root acid phosphatase activity and morphological properties (surface area, diameter and tissue density of roots) of dominant tree species in three tropical montane forests on Mt. Kinabalu, Borneo, to investigate changes in root properties along a soil P availability gradient. We found at the community level that root phosphatase activity and specific root surface area (root surface area per gram root biomass) increased, and root diameter decreased, with decreasing soil P availability at the community level, and the relationship was not changed in general even if we focused on a single‐tree species distributed across multiple study sites that differ in soil P availability. Root acid phosphatase was significantly positively correlated with specific root surface area, and negatively correlated with root diameter, suggesting that finer roots have higher phosphatase activities. Furthermore, we compared root acid phosphatase activity with leaf P concentration of a given tree species and found a significant negative correlation between them. The significant correlation suggested that root P‐acquisition properties could influence leaf P concentration, and/or vice versa. Below‐ground properties (i.e. root P‐acquisition properties) might be directly/indirectly linked to above‐ground properties (i.e. leaf P concentration) of a tree individual. In conclusion, the root physiological and morphological properties change along a gradient of soil P availability in the tropical montane forests. In addition, the changes in the root properties are coordinated with the changes in leaf P concentrations. The adaptive changes in the above‐ground and below‐ground properties along the soil P gradient could contribute to the maintenance of forest productivity in the tropical montane forest in Borneo.

Aboveground and belowground biomass in logged-over tropical rain forests under different soil conditions in Borneo

Although an estimation of forest biomass is essential for the development of a carbon storage baseline in the “Reducing Emissions from Deforestation and Degradation in Developing Countries” scheme, few have been conducted in logged-over rain forests of Southeast Asia. We measured the aboveground and belowground biomass in logged-over mixed dipterocarp forests growing on an infertile soil with bleached white sand (Sabal) and on a clay and nutrient-rich soil (Balai Ringin) in Sarawak, Malaysia. We established four 0.5-ha plots on each site and calculated the biomass. Basal area and stand density of large trees (diameter at breast height, DBH ≥ 10 cm) were relatively similar in Sabal (27.0 m2, 720 tree ha−1) and Balai Ringin (28.9 m2, 586 tree ha−1). However, the corresponding measurements for small trees (1 ≤ DBH < 10 cm) were twice as large in Sabal than in Balai Ringin. Aboveground biomass (AGB) in the forests was less than half of the value recorded for undisturbed forests in Borneo, even 20 years after logging. Although total AGB was 20 % smaller in Sabal (205 Mg ha−1) than in Balai Ringin (242 Mg ha−1), the total belowground biomass (TBGB) was 20 % greater in Sabal (59.6 Mg ha−1) than in Balai Ringin (44.6 Mg ha−1). The larger TBGB in Sabal was due to the larger amounts of small roots (diameter <5 mm) in Sabal (26.8 Mg ha−1) compared to Balai Ringin (5.8 Mg ha−1). This accumulation of small roots at Sabal may have contributed to rapid nutrient absorption from infertile soil.