Forests Of Southeast Asia Research Articles

Effects of climate change and land cover on the distributions of a critical tree family in the Philippines

Southeast Asian forests are dominated by the tree family Dipterocarpaceae, whose abundance and diversity are key to maintaining the structure and function of tropical forests. Like most biodiversity, dipterocarps are threatened by deforestation and climate change, so it is crucial to understand the potential impacts of these threats on current and future dipterocarp distributions. We developed species distribution models (SDMs) for 19 species of dipterocarps in the Philippines, which were projected onto current and two 2070 representative concentration pathway (RCP) climate scenarios, RCP 4.5 and 8.5. Current land cover was incorporated as a post-hoc correction to restrict projections onto intact habitats. Land cover correction alone reduced current species distributions by a median 67%, and within protected areas by 37%. After land cover correction, climate change reduced distributions by a median 16% (RCP 4.5) and 27% (RCP 8.5) at the national level, with similar losses in protected areas. There was a detectable upward elevation shift of species distributions, consisting of suitable habitat losses below 300 m and gains above 600 m. Species-rich stable areas of continued habitat suitability (i.e., climate macrorefugia) fell largely outside current delineations of protected areas, indicating a need to improve protected area planning. This study highlights how SDMs can provide projections that can inform protected area planning in the tropics.

Links between bushmeat species occupancy and indigenous hunting: a pilot study from Royal Belum State Park, Peninsula Malaysia

Indigenous communities have been hunting bushmeat species in the tropical forests of South East Asia for over 40,000 years. Today however, many bushmeat species are threatened by unsustainable hunting compounded by the pressures of decreasing forest area and growing human populations. This pilot study aimed to investigate the relationship between the Jahai, an indigenous hunter gatherer tribe and the mammal bushmeat species which they hunt in Royal Belum State Park (RBSP), peninsula Malaysia. A wildlife triggered camera survey was conducted between early May and late June 2018, from which data was used to calculate occupancy predictions for observed Jahai hunters and bushmeat species. Four mammal species occupancy were found to be associated with Jahai hunting pressure, all of which were preferred species among Jahai communities. Species richness of bushmeat species was also found to increase with Jahai occupancy while species diversity index declined, suggesting that Jahai hunting pressure was concentrated on a select few species, even when bushmeat species richness was high. Vegetation cover and the presence of saltlicks were significant drivers of species occupancy. Based on these findings, Jahai hunting pressure should not be disregarded as a threat to bushmeat species in RBSP.

The Cinematic Forest and Southeast Asian Cinema

The Cinematic Forest and Southeast Asian Cinema Graiwoot Chulphongsathorn (bio) As a cinephile and a film scholar, when I think of Southeast Asian Cinema, I think of the forest. I think of a mysterious jungle where humans encounter animistic animals, spirits, and forces in the cinema of Apichatpong Weerasethakul; a vast forested landscape, shot in black-and-white long takes in the films of Lav Diaz; a deep, dense, precolonial jungle in the work of Filipino auteur Raya Martin; a haunted rainforest on the Malaysian-Singaporean border in a film installation by Boo Junfeng; the woods, as a transitional space between realistic and speculative worlds in the work of Pimpaka Towira.1 In this contemporary art cinema, the forest is not simply a mere background for human stories. Instead, through specific aesthetic choices, the forest in these films becomes a powerful and complex cinematic assemblage. As a recurring presence, or representative space, within Southeast Asian cinema, the forest has received far less scholarly attention than studies of film form, auteurism, political histories, and transnational reception. While discussions of regional cinemas often draw from these kinds of national cinema frameworks, what these studies can miss is an attention to the specific, material, and topological nature of the region. In what follows, I propose an alternative cartography or framework shaped by the cinematic forests of Southeast Asia. [End Page 182] “It was the most beautiful tropical landscape unfolding before my eyes with a rich variety of fine undergrowth palms of different sizes, some as thin as sticks,” wrote an Austrian painter, Eugen von Ransonnet, the first time he saw Singapore in 1876.2 This description evokes a striking image of the rich ecosystem of the forest, which covered the majority of Southeast Asia in the nineteenth century. The present state of the forest, however, offers a stark contrast. In 2019, the journal Nature Communications indicated that while Southeast Asian forests “are home to nearly 15% of the world’s tropical forest” and are habitats for “nearly two-thirds of the world’s floral and faunal diversity,” they are also a “hotspot” for deforestation.3 By 2100, without protection, more than 40 percent of the region’s biodiversity will be disappeared completely.4 Between the colonial era and the current ecological crisis, histories of the region’s forests consist of multilayered and entangled narratives of conflict and exploitation. During the colonial period, the forests of Southeast Asia were perceived by the Imperial imagination as a bountiful resource, resulting in conflict between the colonizers and the nationalists. The Cold War era saw widespread exploitation and commercialization under the dictatorial regimes of many Southeast Asian countries.5 The forest continues to be embedded within national discourses and is managed as a part of national projects.6 It can also be viewed as a site for national religious practices.7 Beyond processes of modernization and nation-building, however, the forest is also a space where premodern cosmologies and beliefs still exist and is thus a place that carries “different notions of boundaries to those formalized in the colonial period.”8 One important theoretical framework we can draw from to understand the forest in Southeast Asian film is the Zomia. First coined by historian Willem van Schendel to describe a vast area of forested land that stretches across parts of South, Southeast, and East Asia, the designation Zomia was popularized by James C. Scott in The Art of Not Being Governed: An Anarchist History of Upland Southeast Asia (2009), where he uses it to map a geographical area that resists state borders.9 The Zomia, as imagined by Scott, emphasizes narratives [End Page 183] of the forests that are excluded from national histories of the region. In what follows, I will show how Southeast Asian cinema responds to these historically and ecologically entwined narratives through its depiction of the forest in the Zomia region. However, instead of adopting already-established regional theoretical frameworks to understand the Southeast Asian cinematic forest, I propose that we need to think in reverse by starting with the forest and letting it guide us to imagine the possibilities of what “Southeast Asian cinema” might mean. What is a cinematic forest? As an...

Towards better estimates of carbon stocks in Borneo's logged-over Dipterocarp forests

Tropical forests are a major reservoir of biodiversity and carbon (C), playing a pivotal role in global ecosystem function and climate regulation. However, most tropical forests, especially Borneo's forests in Southeast Asia, are under intense pressure and threatened by human activities such as logging, mining, agriculture and conversion to industrial plantations. Selective logging is known to reduce both above- and below-ground biomass by removing selected large trees, while increasing deadwood stocks through collateral logging damage and creating large gaps in the canopy. The extent of incidental damage, canopy opening and the rate of C recovery were shown to be primarily related to logging intensity. This thesis assesses the long-term effects of logging intensity on five main C pools in Dipterocarp forests in northern Borneo (Malinau District, North Kalimantan) along a logging intensity gradient ranging from 0 to 57% of initial biomass removed in 1999/2000. Our results showed that total C stocks 16 years after logging ranged from 218-554 Mg C/ha with an average of 314 Mg C/ha. A difference of 95 Mg C/ha was found between low logging intensity (< 2.1% of initial biomass lost) and high logging intensity (> 19%). Most C (approx. 77%) was found in living trees, followed by soil (15%), deadwood (6%) and a small fraction in litter (1%). The imprint of logging intensity was still detectable 16 years after logging. Logging intensity was thus shown to be the main driver explaining the reduction of AGC>20, BGC>20, in deadwood and total C stocks and an increase in deadwood. Our results quantify the long-term effects of logging on forest C stocks, especially in AGC and deadwood. High logging intensity (50% reduction of initial biomass) reduced total C stocks by 27%. AGC recovery was lower in high logging intensity plots, suggesting lowered forest resilience to logging. Our study showed that keeping logging intensity below 20% of the initial biomass can limit the long-term effects of logging on AGC and deadwood stocks.

Limited contributions of plant pathogens to density-dependent seedling mortality of mast fruiting Bornean trees.

Fungal pathogens are implicated in driving tropical plant diversity by facilitating strong, negative density‐dependent mortality of conspecific seedlings (C‐NDD). Assessment of the role of fungal pathogens in mediating coexistence derives from relatively few tree species and predominantly the Neotropics, limiting our understanding of their role in maintaining hyper‐diversity in many tropical forests. A key question is whether fungal pathogen‐mediated C‐NDD seedling mortality is ubiquitous across diverse plant communities. Using a manipulative shadehouse experiment, we tested the role of fungal pathogens in mediating C‐NDD seedling mortality of eight mast fruiting Bornean trees, typical of the species‐rich forests of South East Asia. We demonstrate species‐specific responses of seedlings to fungicide and density treatments, generating weak negative density‐dependent mortality. Overall seedling mortality was low and likely insufficient to promote overall community diversity. Although conducted in the same way as previous studies, we find little evidence that fungal pathogens play a substantial role in determining patterns of seedling mortality in a SE Asian mast fruiting forest, questioning our understanding of how Janzen‐Connell mechanisms structure the plant communities of this globally important forest type.

Integrated analysis of the transcriptome, metabolome and analgesic effect provide insight into potential applications of different parts of Lindera aggregata

Lindera aggregata(L. aggregata) is a wild shrub growing in the forests of Southeast Asia, whose main bioactive constituents are isoquinoline alkaloids. They are widely used in food and pharmaceutical industries. The studies on the metabolites and biosynthesis pathways inL. aggregata remain poorly understood. Nine isoquinoline alkaloid compounds were identified by UPLC Triple TOF-MS/MS in this study. Except for N-methyllaurotetanine, most isoquinoline alkaloid compounds were widely distributed in various parts ofL. aggregata and accumulated preferentially in roots than in leaves. Transcriptome data showed that several isoquinoline alkaloid biosynthetic genes, such as TyrAT, PPO, TDC, and SOMT, were identified to play important roles in generating differential metabolites in roots and leaves ofL. aggregata. Concentration-dependent analgesic effects and toxic effects of them were demonstrated in zebrafish experiments, and the overall ranking was JRAL > TRAL > LAL. The results of this study would provide useful information for the synthesis mechanisms of isoquinoline alkaloids inL. aggregata, and provide valuable information for the application of traditional non-medicinal parts ofL. aggregata in food and pharmaceutical industries.

On the systematic status of Calliophis macclellandi nigriventer Wall, 1908 (Reptilia: Serpentes: Elapidae).

Sinomicrurus macclellandi (Reinhardt, 1844) is a species of coral snakes distributed across the forests of Southeast Asia and the Himalayas. The species exhibits distinct forms across its range, and it has been classified into four subspecies. Calliophis macclellandi nigriventer Wall, 1908 a population from Western Himalayas, which was described as a variety, has not been attended to until now. Our study of a recently collected specimen from near Solan, Himachal Pradesh, India and existing museum material has allowed us to assess the validity of this population based on molecular and morphological data and has given us enough evidence to suggest its elevation to a species rank. Sinomicrurus nigriventer comb. nov. was found to be embedded within a clade comprising S. peinani, but not S. macclellandi s. l., with a genetic distance of 7-16% from its congeners. Morphologically, it differs from its congeners in having a reddish brown dorsum and a mid-dorsal black vertebral strip extending from the nape to the vent and with three thin bands on the tail, belly white with black smear up to the vent, tail dorsum with a few band-like blotches, and males with 230-235 ventral scales.

Predation on Multiple Prey Types Across a Disturbance Gradient in Tropical Montane Forests of Peninsular Malaysia

Predation plays a critical role in animal and plant survivorship, and can be highly sensitive to habitat loss and disturbance. Tropical montane forests in Southeast Asia are being modified rapidly by land-use change, and the consequences of this on predation likelihood are poorly understood. In Peninsular Malaysia, we conducted predation experiments at eight tropical montane forest sites along a disturbance gradient. We investigated whether (1) predation pressure in primary forests differs between different mountains; (2) predation probability is linked to habitat degradation; and (3) vegetation variables explain predation occurrence. At each forest site, we placed artificial nests with real and model quail eggs, dishes with real and artificial seeds of the cempedak (Artocarpus champeden), models resembling four-lined tree frogs (Polypedetes leucomystax) and models of the late instar caterpillar of the common Mormon (Papilio polytes) at points 100 m apart for three nights. Using Bayesian binomial simulations, we showed that predation likelihood in primary forests from different mountains can vary (e.g., probability of the difference in predation rate of artificial caterpillars between two primary forests was estimated at 82%–100%). We also found that higher predation was not linked to habitat degradation for all artificial prey and seeds (e.g., comparing forests of varying degrees of disturbance from the same mountain, the probability that predation of an artificial caterpillar is lower at the primary forest was estimated at 2%–20% only). Model selection and hierarchical partitioning showed that vegetation variables can explain predation occurrence, suggesting microhabitat characteristics may be influential. Conducting predation experiments by using artificial prey and seeds is useful for comparing predation likelihood at different sites, making ecological comparisons, and for informing conservation decisions. This novel approach of using multiple prey items also showed that predation for each can vary and thus caution against deploying a single prey type to draw broad inferences of predation in degraded systems.

Quaternary land bridges have not been universal conduits of gene flow.

Quaternary climate oscillations are a well-known driver of animal diversification, but their effects are most well studied in areas where glaciations lead to habitat fragmentation. In large areas of the planet, however, glaciations have had the opposite effect, but here their impacts are much less well understood. This is especially true in Southeast Asia, where cyclical changes in land distribution have generated enormous land expansions during glacial periods. In this study, we selected a panel of five songbird species complexes covering a range of ecological specificities to investigate the effects Quaternary land bridges have had on the connectivity of Southeast Asian forest biota. Specifically, we combined morphological and bioacoustic analysis with an arsenal of population genomic and modelling approaches applied to thousands of genome-wide DNA markers across a total of more than 100 individuals. Our analyses show that species dependent on forest understorey exhibit deep differentiation between Borneo and western Sundaland, with no evidence of gene flow during the land bridges accompanying the last 1-2 ice ages. In contrast, dispersive canopy species and habitat generalists have experienced more recent gene flow. Our results argue that there remains much cryptic species-level diversity to be discovered in Southeast Asia even in well-known animal groups such as birds, especially in nondispersive forest understorey inhabitants. We also demonstrate that Quaternary land bridges have not been equally suitable conduits of gene flow for all species complexes and that life history is a major factor in predicting relative population divergence time across Quaternary climate fluctuations.

Development and application of a new mangrove vegetation index (MVI) for rapid and accurate mangrove mapping

Advancement in Remote Sensing allows rapid mangrove mapping without the need for data-intensive methodologies, complex classifiers, and skill-dependent classification techniques. This study proposes a new index, the Mangrove Vegetation Index (MVI), to rapidly and accurately map mangroves extent from remotely-sensed imageries. The MVI utilizes three Sentinel-2 bands green, Near Infrared (NIR) and Shortwave Infrared (SWIR) in the form |NIR-Green|/|SWIR-Green| to discriminate the distinct greenness and moisture of mangroves from terrestrial vegetation and other land cover. Spectral band analysis shows that the |NIR-Green| part of MVI captures the differences of greenness between mangrove forests and terrestrial vegetation. The |SWIR-Green| part of the index expresses the distinct moisture of mangroves without the need for additional intertidal data and water indices. The MVI value increases with the increasing probability of a pixel being classified as mangroves. Eleven mangrove forests in the Philippines and one mangrove park in Japan were then mapped using MVI. Accuracy assessment was done using field inventory data and high-resolution drone orthophotos. MVI have successfully separated the mangroves from other cover especially terrestrial vegetation, with an overall index accuracy of 92%. The MVI was applied to Landsat 8 images using the equivalent bands to test the universality of the index. Comparable MVI mangrove maps were produced between Sentinel-2 and Landsat images, with an optimal minimum threshold of 4.5 and 4.6, respectively. MVI can effectively highlight the greenness and moisture information in mangroves as reflected by its moderate to high correlation value (r = 0.63 and 0.84, α = 0.05) with the Sentinel-derived chlorophyll-a (Ca) and canopy water (Cw) biophysical products. This study developed and implemented two automated platforms: an offline IDL-based ‘MVI Mapper’ and an online Google Earth Engine-based MVI mapping interface. The MVI implemented in Google Earth Engine was used in generating the latest mangrove extent map of the Philippines. Additionally, the application of MVI were tested to four additional mangrove forests in Southeast Asia: Thailand, Vietnam, Indonesia and Cambodia; and to selected mangroves forests in South America, Africa and Australia.

Forest, fire & monsoon: investigating the long-term threshold dynamics of south-east Asia’s seasonally dry tropical forests

Tropical forests are the most biodiverse terrestrial ecosystems on earth, yet are particularly susceptible to future climatic and human-induced change. Identifying tipping points at which tropical ecosystems will reorganise is therefore an important research goal. Limited research within the seasonally dry tropical forests of south-east Asia means that much uncertainty exists around the resilience of these systems to future global change. This is a critical research gap because these forests should – given their physiognomic attributes, current bioclimatic envelope and the range of stressors – be very sensitive to a stable-state shift to savanna. Here we adopt a palaeoecological approach to examine the interaction between key drivers of change (decreased precipitation and heightened fire activity) and forest response over ∼4700 years though interrogation of sediment-based proxies from volcanic crater lakes within north-east Cambodia – in the core range of southeast Asia’s tropical dry forests. Our results suggest that rapidly regenerating, secondary forest taxa are important for maintaining a forested state when the landscape is subject to moderate fire and climatic disturbance. However, when these stressors are amplified, recovery and resistance traits associated with key deciduous dipterocarp forest taxa appear critical for forest stability. Notably, shifts from more closed, seasonal evergreen forest formations to more open secondary/deciduous dipterocarp formations appear reversible when the stressors are removed, suggesting that these transitions are not analogous with the difficult-to-reverse, forest-to-savanna stable state shifts that occur elsewhere in Neotropical and Afrotropical settings. Our results indicate that the resilience of south-east Asian forests to climatic forcing appears contingent on the maintenance of secondary forest, deciduous forest, and seasonal evergreen dry forest mosaics across the ecoregion. This has implications for the conservation and wise-use of mainland south-east Asia’s lowland dry forests.

Forged in flames: indigeneity, forest fire and geographies of blame in the Philippines

ABSTRACT The forests of Southeast Asia are represented as increasingly ‘at-risk' to fire, constituting a regional fire politics concerned with the management and organisation of environmental blame. State governments often place culpability for this increasing flammability on histories of deforestation that disproportionately blame Indigenous peoples who now face a correspondingly large burden in conservation schemes. By tracing the history of fire management from the colonial period to the 1980s, this paper explores how the management of forests and fire in the Philippines has been shaped over time with imperatives to govern and economically exploit upland spaces. While these histories clearly point to a political economy of knowledge production, they also show how forest governance in the Philippines has worked to construct ethnic difference through policies and practices that naturalise livelihoods, spaces and qualities to essentialised ‘tribal' uplanders. To understand the contemporary geography of blame that surrounds forest fires and deforestation in the Philippines and Southeast Asia more broadly, we argue for a more nuanced examination of ‘the uplands’ as a post-colonial geography co-constituted with the historical production of indigeneity and environmental knowledge. We conclude by emphasising the historical role of colonial forest and land management institutions in fashioning lasting socio-spatial differences.

Enhanced Primary Production in the Oligotrophic South China Sea Related to Southeast Asian Forest Fires

AbstractAtmospheric reactive nitrogen deposition is an important process in the nitrogen cycle of natural ecosystems, especially in oligotrophic oceans. Increased land‐based atmospheric nitrogen deposition over the ocean changes the stoichiometric balance of marine ecosystems; this causes changes in ecosystem functions and biogeochemical cycles. Current studies have shown that atmospheric reactive nitrogen is mainly derived from land‐based human activities, such as the use of fertilizers, combustion of fossil fuels, and forest fires. Forest fires can provide a vast amount of reactive nitrogen and other nutrients over short time scales and may greatly influence marine ecosystems. Here, we document a large change in nitrogen concentration and primary productivity in upper levels of the South China Sea (SCS), coincident with Indonesian forest fires between August and September of 2012. Using back trajectories, fire spot maps, geographical distributions of the smoke, vertical distributions of the depolarization ratio, and nitrogen isotope values of nitrate in rainwater, we found that the change in nitrogen could be attributed to the forest fires. Our results show that the SCS received about 180 Gg of N as wet deposition during the sampling period. This atmospheric nitrogen deposition caused high primary productivity (40.679 ± 15.852 mg C·m−2·hr−1) in the upper levels of the SCS, which tripled values recorded in other years. This suggests that high nitrogen levels as well as other nutrients derived from tropical Asian forest fires are of great importance to the marine ecosystem of the SCS and also likely affect global marine biogeochemical cycles.

Logging intensity drives variability in carbon stocks in lowland forests in Vietnam

Forest degradation in the tropics is generating large carbon (C) emissions. In tropical Asia, logging is the main driver of forest degradation. For effective implementation of REDD+ projects in logged forests in Southeast Asia, the impacts of logging on forest C stocks need to be assessed. Here, we assess C stocks in logged lowland forests in central Vietnam and explore correlations between logging intensity, soil, topography and living aboveground carbon (AGC) stocks. We present an approach to estimate historical logging intensities for the prevalent situation when complete records on logging history are unavailable. Landsat analysis and participatory mapping were used to quantify the density of historical disturbances, used as a proxy of logging intensities in the area. Carbon in AGC, dead wood, belowground carbon (BGC) and soil (SOC) was measured in twenty-four 0.25 ha plots that vary in logging intensity, and data on recent logging, soil properties, elevation and slope were also collected. Heavily logged forests stored only half the amount of AGC of stems ≥10 cm dbh as lightly logged forests, mainly due to a reduction in the number of large (≥60 cm dbh) trees. Carbon in AGC of small trees (5–10 cm dbh), dead wood and BGC comprised only small fractions of total C stocks, while SOC in the topsoil of 0–30 cm depth stored ~50% of total C stocks. Combining logging intensities with soil and topographic data showed that logging intensity was the main factor explaining the variability in AGC. Our research shows large reductions in AGC in medium and heavily logged forests. It highlights the critical importance of conserving big trees to maintain high forest C stocks and accounting for SOC in total C stock estimates.

Forest aboveground biomass stock and resilience in a tropical landscape of Thailand

Abstract. Half of Asian tropical forests were disturbed in the last century resulting in the dominance of secondary forests in Southeast Asia. However, the rate at which biomass accumulates during the recovery process in these forests is poorly understood. We studied a forest landscape located in Khao Yai National Park (Thailand) that experienced strong disturbances in the last century due to clearance by swidden farmers. Combining recent field and airborne laser scanning (ALS) data, we first built a high-resolution aboveground biomass (AGB) map of over 60 km2 of forest landscape. We then used the random forest algorithm and Landsat time series (LTS) data to classify landscape patches as non-forested versus forested on an almost annual basis from 1972 to 2017. The resulting chronosequence was then used in combination with the AGB map to estimate forest carbon recovery rates in secondary forest patches during the first 42 years of succession. The ALS-AGB model predicted AGB with an error of 14 % at 0.5 ha resolution (RMSE=45 Mg ha−1) using the mean top-of-canopy height as a single predictor. The mean AGB over the landscape was 291 Mg ha−1, showing a high level of carbon storage despite past disturbance history. We found that AGB recovery varies non-linearly in the first 42 years of the succession, with an increasing rate of accumulation through time. We predicted a mean AGB recovery rate of 6.9 Mgha-1yr-1, with a mean AGB gain of 143 and 273 Mg ha−1 after 20 and 40 years, respectively. This rate estimate is about 50 % larger than the rate prescribed for young secondary Asian tropical rainforests in the 2019 refinement of the 2006 IPCC guidelines for national greenhouse gas inventories. Our study hence suggests that the new IPCC rates, which were based on limited data from Asian tropical rainforests, strongly underestimate the carbon potential of forest regrowth in tropical Asia. Our recovery estimates are also within the range of those reported for the well-studied Latin American secondary forests under similar climatic conditions. This study illustrates the potential of ALS data not only for scaling up field AGB measurements but also for predicting AGB recovery dynamics when combined with long-term satellite data. It also illustrates that tropical forest landscapes that were disturbed in the past are of utmost importance for the regional carbon budget and thus for implementing international programs such as REDD+.

Hunting and Forest Modification Have Distinct Defaunation Impacts on Tropical Mammals and Birds

The mammalian and avian assemblages of intact tropical forests are among the most diverse vertebrate communities on Earth and influence the structure, composition and functioning of these forests in myriad ways. Over recent centuries, however, increasing human domination of the tropics has led to widespread defaunation, or the decline, local- or global extinction of tropical animal species. Defaunation is one of the defining features of the Anthropocene and is best documented for vertebrate species, especially mammals and birds. Defaunation is driven by several direct (e.g., hunting) and indirect (e.g., habitat alteration) anthropogenic threats, but how these threats differ in the nature and magnitude of their impacts on tropical mammal and bird species remains unclear. Using a meta-analysis of 82 studies on 254 mammal and 1640 bird species from across the tropics, we assess the effects of three major regional-scale drivers of tropical defaunation, namely hunting, forest degradation and forest conversion, on measures of abundance for tropical mammal and bird species belonging to different dietary guilds and IUCN conservation status groups. Mammal species across dietary guilds declined or did not vary, on average, in response to the three drivers, with hunting having the most consistent negative impacts on abundances of carnivores, frugivores, herbivores/granivores, large-bodied species, and species of high conservation importance. By contrast, bird species declined most strongly in response to forest conversion, with responses varying widely across different dietary and conservation importance groups, and not consistently related to body size. Our results reveal that hunting, forest degradation and conversion are associated with distinct types of defaunation of mammal and bird species, and are therefore likely to have distinct implications for animal-mediated interactions and processes, ecosystem functions, and conservation of tropical forests. Addressing major gaps in our empirical understanding of defaunation effects – e.g., hunting impacts on smaller-bodied mammals and birds, and responses of species in southeast Asian forests – is key to better understanding, predicting, and mitigating the impacts of this pervasive global threat.

Expansión de cultivos industriales en el sudeste asiático:El caso de la palma aceitera en Indonesia y Malasia

The oil palm or African palm (Elaeis guineensis) is a native plant of West Africa. In recent decades, approximately since the sixties, this crop has experienced significant growth in the tropical regions of the southern hemisphere, as a monoculture for the production of vegetable oils for export. Within a context in which oil palm cultivation is expanding into new regions of the world, such as Africa and Central America, research aims to identify the social and environmental problems that the development of industrial oil palm crops has had in the two main oil palm producing countries in the world: Indonesia and Malaysia. It is hypothesized that the expansion of industrial monoculture of oil palm is inserted in the current extractivist paradigm of appropriation of natural resources worldwide; also, that it is responsible for the massive deforestation of tropical forests in Southeast Asia; and that, therefore, it endangers the food sovereignty of the countries of Southeast Asia, by displacing family farming and traditional food crops. The methodology consisted in the survey of academic sources and reports of international organizations and NGOs.

Dynamic and synergistic influences of air temperature and rainfall on general flowering in a Bornean lowland tropical forest

AbstractSupra‐annually synchronized flowering events occurring in tropical forests in Southeast Asia, known as general flowering (GF), are “spectacular and mysterious” forest events. Recently, studies that combined novel molecular techniques and model‐based theoretical approaches suggested that cool temperature and drought synergistically drove GF. Although these advanced our understanding of GF, it is still difficult to know whether the individual‐based molecular measurements and model‐based mathematical representations reasonably well capture the complex and dynamic GF processes at the community level. In the present study, we collected a 17‐year set of community‐wide phenology data from Lambir Hills National Park in Borneo, Malaysia, and analyzed it using a model‐free approach, empirical dynamic modeling (EDM), which does not rely on specific assumptions about the underlying mechanisms, to overcome and complement the previous limitations. We found that GF in the region is driven synergistically, not independently, by cool air temperature and drought, which is consistent with the previous studies. More importantly, our model‐free approach showed for the first time that effects of cumulative meteorological variables on GF changed over time. The time‐varying influences of meteorological variables on GF imply that the relationship between GF and meteorological variables might be influenced by other factors such as plant/soil nutrient resource dynamics. Our study provides a novel insight about the mechanism underlying the spectacular tropical forest event GF, and future studies integrating advanced mathematical/statistical frameworks, long‐term and large spatial scale ecosystem monitoring and molecular phenology data are promising for achieving better understanding and forecasting of GF events in Southeast Asia.

Discovery of Deep-Water Bamboo Coral Forest in the South China Sea

A deep-water coral forest, characterized by slender and whip-shaped bamboo corals has been discovered from water depths of 1200–1380 m at the western edge of the Xisha (Paracel Islands) area in the South China Sea. The bamboo corals are often accompanied by cold-water gorgonian “sea fan” corals: Anthogorgia sp. and Calyptrophora sp., as well as assemblages of sponges, cirrate octopuses, crinoids and other animals. The coral density increased toward the shallower areas from 24.8 to 220 colonies per 100 m2 from 1380 m to 1200 m water depth. This is the first set of observations of deep-water bamboo coral forests in Southeast Asia, opening a new frontier for systematic, ecological and conservation studies to understand the deep-coral ecosystem in the region.

Occurrence of blood‐feeding terrestrial leeches (Haemadipsidae) in a degraded forest ecosystem and their potential as ecological indicators

AbstractBlood‐feeding invertebrates are emerging model taxa in biodiversity assessments, both as indicators of mammal abundance and also as sources of mammal DNA for identification. Among these, terrestrial leeches arguably offer the greatest promise; they are abundant and widespread in the humid tropics, and their blood meals can be easily assayed to establish diet. Unfortunately, terrestrial leeches are understudied, with little known about their ecology and behavior. Such information is needed to evaluate their utility as ecological indicators and to account for potential sampling biases that might arise from habitat preferences. By combining occupancy modeling and thermal tolerance assays, we determined the factors affecting species occurrence in the related terrestrial brown (Haemadipsa sumatrana) and tiger leech (Haemadipsa picta), both of which are widespread in tropical forests in Southeast Asia. We sampled both species across a degraded forest landscape in Sabah, Borneo, in wet and dry seasons, associating occurrence with habitat‐level metrics. We found that, for both species, detection probability increased with canopy height regardless of season. Additionally, increased vegetation heterogeneity had a strong negative influence on brown leech occurrence in the dry season, implying an interaction between vegetation structure and climate. However, we found no difference in physiological thermal tolerance (CTMAX) between the two species. Finally, using a reduced dataset, we found a small improvement in brown leech model fit when including mammal abundance. Our results suggest that the presence of terrestrial leeches may act as useful ecological indicators of habitat quality and potentially mammalian abundance.Abstract in Indonesia is available with online material.