Rainforests Of Borneo Research Articles

Source attribution of Bornean air masses by back trajectory analysis during the OP3 project

Abstract. Atmospheric composition affects the radiative balance of the Earth through the creation of greenhouse gases and the formation of aerosols. The latter interact with incoming solar radiation, both directly and indirectly through their effects on cloud formation and lifetime. The tropics have a major influence on incoming sunlight however the tropical atmosphere is poorly characterised, especially outside Amazonia. The origins of air masses influencing a measurement site in a protected rainforest in Borneo, South East Asia, were assessed and the likely sources of a range of trace gases and particles were determined. This was conducted by interpreting in situ measurements made at the site in the context of ECMWF backwards air mass trajectories. Two different but complementary methods were employed to interpret the data: comparison of periods classified by cluster analysis of trajectories, and inspection of the dependence of mean measured values on geographical history of trajectories. Sources of aerosol particles, carbon monoxide and halocarbons were assessed. The likely source influences include: terrestrial organic biogenic emissions; long range transport of anthropogenic emissions; biomass burning; sulphurous emissions from marine phytoplankton, with a possible contribution from volcanoes; marine production of inorganic mineral aerosol; and marine production of halocarbons. Aerosol sub- and super-saturated water affinity was found to be dependent on source (and therefore composition), with more hygroscopic aerosol and higher numbers of cloud condensation nuclei measured in air masses of marine origin. The prevailing sector during the majority of measurements was south-easterly, which is from the direction of the coast closest to the site, with a significant influence inland from the south-west. This analysis shows that marine and terrestrial air masses have different dominant chemical sources. Comparison with the AMAZE-08 project in the Amazon basin shows Bornean composition to arise from a different, more complex mixture of sources. In particular sulphate loadings are much greater than in Amazonia which is likely to mainly be the result of the marine influence on the site. This suggests that the significant region of the tropics made up of island networks is not well represented by extrapolation from measurements made in the Amazon. In addition, it is likely that there were no periods where the site was influenced only by the rainforest, with even the most pristine inland periods showing some evidence of non-rainforest aerosol. This is in contrast to Amazonia which experienced periods dominated by rainforest emissions.

Quantifying the magnitude of a missing hydroxyl radical source in a tropical rainforest

Abstract. The lifetime of methane is controlled to a very large extent by the abundance of the OH radical. The tropics are a key region for methane removal, with oxidation in the lower tropical troposphere dominating the global methane removal budget (Bloss et al., 2005). In tropical forested environments where biogenic VOC emissions are high and NOx concentrations are low, OH concentrations are assumed to be low due to rapid reactions with sink species such as isoprene. New, simultaneous measurements of OH concentrations and OH reactivity, k'OH, in a Borneo rainforest are reported and show much higher OH than predicted, with mean peak concentrations of ~2.5×106 molecule cm−3 (10 min average) observed around solar noon. Whilst j(O1D) and humidity were high, low O3 concentrations limited the OH production from O3 photolysis. Measured OH reactivity was very high, peaking at a diurnal average of 29.1±8.5 s−1, corresponding to an OH lifetime of only 34 ms. To maintain the observed OH concentration given the measured OH reactivity requires a rate of OH production approximately 10 times greater than calculated using all measured OH sources. A test of our current understanding of the chemistry within a tropical rainforest was made using a detailed zero-dimensional model to compare with measurements. The model over-predicted the observed HO2 concentrations and significantly under-predicted OH concentrations. Inclusion of an additional OH source formed as a recycled product of OH initiated isoprene oxidation improved the modelled OH agreement but only served to worsen the HO2 model/measurement agreement. To replicate levels of both OH and HO2, a process that recycles HO2 to OH is required; equivalent to the OH recycling effect of 0.74 ppbv of NO. This recycling step increases OH concentrations by 88 % at noon and has wide implications, leading to much higher predicted OH over tropical forests, with a concomitant reduction in the CH4 lifetime and increase in the rate of VOC degradation.

The reversed fortunes of sago and rice, Oryza sativa, in the rainforests of Sarawak, Borneo

Domesticated rice, Oryza sativa, is the main carbohydrate staple for most peoples in Sarawak; its dispersal putatively linked to the origins of agriculture and spread of the Neolithic in the region. Currently it is argued that domesticated rice is an introduction from mainland Southeast Asia, following either a sea-borne route into Borneo from the north via Taiwan or west via the mainland sometime during the mid Holocene. The purpose of this paper is to reappraise the model and suggest that while rice might have been introduced during the mid Holocene, it was not successful, and in fact might not have been widely adopted until the historic period. Rice appears to be an illogical crop choice in the rainforests of Borneo; it is difficult to grow, prone to failure and often low-yielding. By contrast, people had access to many other high yielding plants, particularly the sago palms which appear to have been widely cultivated in the recent historic past. As a crop, rice, in a vegecultural world of sago and taro, may not have been adopted to reduce the ’risk’ of going hungry, but because its successful cultivation is inherently ’risky’ and prone to failure, and thus uniquely, was attractive as a playing piece in games of social competition between individuals.

Continuous bioaerosol monitoring in a tropical environment using a UV fluorescence particle spectrometer

AbstractAn instrument designed to continuously monitor ambient bioaerosol concentrations is presented. The instrument is a compact, relatively low‐cost, UV aerosol spectrometer that monitors and classifies individual airborne particles by simultaneously recording both fluorescence excitation‐emission data and multi‐angle spatial elastic scattering data from each particle. The former can indicate the possible presence of specific biological fluorophores within the particle while the latter provides an assessment of particle size and shape. These parameters can facilitate discrimination between biological and non‐biological particles and potentially allow classification of biological particle types. Example measurements are given, illustrating data from the Borneo rain forest. Copyright © 2011 Royal Meteorological Society

Eusideroxylon zwageri (Ulin) as Key Species in Two Zones of Sangkima Rain Forest, Kutai National Park, East Kalimantan

Aim of this research was to study trees' diversity quality in primary and intensively used forest of Sangkima area in Kutai National Park (TNK), East Kalimantan (Borneo). Field observation was carried out by vegetation analysis using 17 sampling plots of 25x25 m2. Community structure of each forest was determined by calculating trees' density, basal area, frequency, important value and stratification of species. While trees diversity was estimated by taxa richness, Shannon-Wiener diversity index, and rate of endemism. Both forests were compared by Morisita community similarity index. Data were tabulated by Microsoft Excel 2007 and statistically analyzed by PCA method and supported by hierarchical cluster analysis in SPSS 15.00 for windows. The result showed that diversity quality in primary and intensively used forest of Sangkima TNK was high, indicated by similar stratification. The forests were composed by A stratum trees of > 30 m high to ground cover plants, but they were dominated by B stratum trees of 20-30m high. Primary forest's formation was Eusideroxylon zwageri-Mixed Dipterocarpaceae, while intensively used forest's formation was E. zwageri. Taxa richness of both forests was not different significantly. In the primary forest was found 34 species, 25 families and 16 orders, while intensively used forest was found 36 species, 20 families and 13 orders. Diversity Index of primary forest (H=4.57) was slightly higher than secondary forest (H=4.28). Rate of endemism of both forests reached 100%. Eusideroxylon zwageri and Cananga odorata were co-dominant in the Borneo rain forest. Tree of E. zwageri showed a biggest trunk and largest canopy. Cananga odorata showed a high density in both zones. Luxurious jungle performed A to E strata, but B stratum was dominant. Based on those five characters, trees' diversity quality in Sangkima was still high. Bi plot analysis showed that trees' community structure of both forests composed by three groups. In secondary forest, E. zwageri was a key species and characterized by high important value, while species C. odorata, Dyospiros borneensis and Dillenia beccariana found in a high distribution, otherwise other trees were classified into the 3rd group. Comparing to the secondary forest, even though E. zwageri was also as dominant tree, but the virgin one showed more species growing in a better density, distribution and dominance.Keywords: Tree, Borneo, rain forest, community structure, quality diversity, Kutai National Park

Eusideroxylon zwageri (Ulin) as Key Species in Two Zones of Sangkima Rain Forest, Kutai National Park, East Kalimantan

Aim of this research was to study trees' diversity quality in primary and intensively used forest of Sangkima area in Kutai National Park (TNK), East Kalimantan (Borneo). Field observation was carried out by vegetation analysis using 17 sampling plots of 25x25 m2. Community structure of each forest was determined by calculating trees' density, basal area, frequency, important value and stratification of species. While trees diversity was estimated by taxa richness, Shannon-Wiener diversity index, and rate of endemism. Both forests were compared by Morisita community similarity index. Data were tabulated by Microsoft Excel 2007 and statistically analyzed by PCA method and supported by hierarchical cluster analysis in SPSS 15.00 for windows. The result showed that diversity quality in primary and intensively used forest of Sangkima TNK was high, indicated by similar stratification. The forests were composed by A stratum trees of > 30 m high to ground cover plants, but they were dominated by B stratum trees of 20-30m high. Primary forest's formation was Eusideroxylon zwageri-Mixed Dipterocarpaceae, while intensively used forest's formation was E. zwageri. Taxa richness of both forests was not different significantly. In the primary forest was found 34 species, 25 families and 16 orders, while intensively used forest was found 36 species, 20 families and 13 orders. Diversity Index of primary forest (H=4.57) was slightly higher than secondary forest (H=4.28). Rate of endemism of both forests reached 100%. Eusideroxylon zwageri and Cananga odorata were co-dominant in the Borneo rain forest. Tree of E. zwageri showed a biggest trunk and largest canopy. Cananga odorata showed a high density in both zones. Luxurious jungle performed A to E strata, but B stratum was dominant. Based on those five characters, trees' diversity quality in Sangkima was still high. Bi plot analysis showed that trees' community structure of both forests composed by three groups. In secondary forest, E. zwageri was a key species and characterized by high important value, while species C. odorata, Dyospiros borneensis and Dillenia beccariana found in a high distribution, otherwise other trees were classified into the 3rd group. Comparing to the secondary forest, even though E. zwageri was also as dominant tree, but the virgin one showed more species growing in a better density, distribution and dominance. Keywords: Tree, Borneo, rain forest, community structure, quality diversity, Kutai National Park

Remote sensing of the tropical rain forest boundary layer using pulsed Doppler lidar

Abstract. Within the framework of the Natural Environment Research Council (NERC) Oxidant and Particle Photochemical Processes (OP3) project, a pulsed Doppler lidar was deployed for a 3 month period in the tropical rain forest of Borneo to remotely monitor vertical and horizontal transport, aerosol distributions and clouds in the lower levels of the atmosphere. The Doppler velocity measurements reported here directly observe the mixing process and it is suggested that this is the most appropriate methodology to use in analysing the dispersion of canopy sourced species into the lower atmosphere. These data are presented with a view to elucidating the scales and structures of the transport processes, which effect the chemical and particulate concentrations in and above the forest canopy, for applications in the parameterisation of climate models.

Parabiotic associations between tropical ants: equal partnership or parasitic exploitation?

1. The huge diversity of symbiotic associations among animals and/or plants comprises both mutualisms and parasitisms. Most symbioses between social insect species, however, involve social parasites, while mutual benefits have been only suspected for some parabiotic associations - two colonies that share a nest. 2. In the rainforest of Borneo, we studied parabiotic associations between the ants Crematogaster modiglianii and Camponotus rufifemur. Parabiotic nests were regularly found inside hollow tree trunks, most likely initiated by Cr. modiglianii. This species frequently nested without its partner, whereas we never found non-parabiotic Ca. rufifemur nests. We experimentally investigated potential benefits, potential interference competition for food (as a probable cost), and foraging niches of both species. 3. The two species never showed aggressive interactions and amicably shared food resources. However, Cr. modiglianii had a wider temporal and spatial foraging range than Ca. rufifemur, always found baits before Ca. rufifemur and recruited more efficiently. Camponotus rufifemur probably benefited from following pheromone trails of Cr. modiglianii. In turn, Ca. rufifemur was significantly more successful in defending the nest against alien ants. Crematogaster modiglianii hence may profit from its partner's defensive abilities. 4. In neotropical parabioses, epiphytes grown in 'ant-gardens' play a crucial role in the association, e.g. by stabilization of nests. Hemiepiphytic Poikilospermum cordifolium (Cecropiaceae) seedlings and saplings frequently grew in the entrances of parabiotic nests in Borneo, obviously dispersed by the ants. In cafeteria experiments, both parabiotic ants carried its elaiosome-bearing seeds into the nest. However, P. cordifolium does not provide additional nest space, contrasting with neotropical ant-gardens. 5. The parabiotic association appears beneficial for both ant species, the main benefits being nest initiation by Cr. modiglianii and interspecific trail-following (for Ca. rufifemur), and, in turn, nest defence by Ca. rufifemur (for Cr. modiglianii). However, Ca. rufifemur seems to be more dependent on its partner than vice versa.

The Social Landscape of Rice within Vegecultural Systems in Borneo

The papers by Hayden (2009, in this issue) and Pearsall (2009, in this issue) highlight the importance of our understanding, to quote Pearsall, of the social landscapes in which early agriculture and intensive agriculture occurred and, it could be added, of contexts (e.g., Australia) in which agriculture did not occur. While the enormous transformations of societies that adopted agriculture are obvious, the actual nature of those transformations remains poorly understood, and at a global scale we must consider that the trajectories toward seed-based systems of plant food production and those associated with vegecultural practices in the tropics of Africa, Southeast Asia, Melanesia, and the Neotropics may have been very different. This response is an attempt to think about both social and economic motivations behind the manipulation of plants and food production. In particular, I want to consider the circumstances under which a rice-based system of agriculture might have been adopted in tropical Southeast Asia by hunter-gatherers already engaged in some form of plant management or vegeculture. Pearsall notes that the Neotropics might be the ideal place to investigate agricultural origins through human-environment relationships on a landscape scale. Paleoenvironmental records there include deep sedimentary cores from periods predating human occupation and include good proxies of human-induced disturbance such as long-term fire records and pollen and phytolith sequences. Similar claims might also be made for the tropics of Southeast Asia. Human occupation of the rainforests of Borneo is now dated to at least 45,000 years ago (Barker et al. 2007; Higham et al. 2009), and fire records may indicate a human presence as early as 60,000 years ago in southern Indonesia (Dam, van der Kaars, and Kershaw 2001). Southeast Asia also provides a rather unique context in which to hypothesize about the long-term consequences of people-plant interactions; the emergence of vegeculture and possible independent domestication of a wide variety of tubers, rhizomes, and trees (Barton and Denham, forthcoming; Barton and Paz 2007; Denham and Barton 2006); and the hypothesized rapid introduction of a completely novel mode of plant food production based on the freproduction of a short-lived annual, rice (see Bellwood 2009, in this issue). For example, it is still argued that agriculture did not occur in Island Southeast Asia until after the expansion of rice-farming peoples into the region during the midHolocene (Bellwood 2009). However, this seems increasingly harder to support in light of the archaeological and genetic evidence that shows that the earlier foraging groups may have been actively engaged in the manipulation of several species through vegecultural systems of plant propagation (Barton and Denham, forthcoming; Denham and Barton 2006). It seems likely that rice and its associated systems of propagation were adopted by peoples already heavily engaged in their own systems of plant management, some of which may have already produced domesticates such as the greater yam Dioscorea alata, taro Colocasia esculenta, and bananas Musa spp. (Carreel et al. 2002; De Langhe and de Maret 1999; Lebot et al. 2004). It also seems likely that the transition toward the reliance of rice as a food staple after its mid-Holocene introduction was still occurring in recent prehistory. Even as late as the early twentieth century in parts of Southeast Asia where rice held center stage as a plant of social preeminence, this did not necessarily reflect its role in daily subsistence. Among many groups in interior Borneo, rice remained a relatively minor crop—supplementing other starchy staples, frequently roots that could be grown in greater quantity and that were considered more reliable come harvest (Harrisson 1949, 142). Among the Dusun of North Borneo, though rice was planted by all tribes, it was considered supplementary to a diet of taro and imported South American cultivars such as cassava, sugar cane, and maize (Rutter 1929, 75). Wild fruits and sago were also considerably important, though the latter more so in the swampy lowlands (Rutter 1929, 96), suggesting that it may be the introduced swamp sago Metroxylon sagu Rott. (the timing of this introduction remains unknown, but the original range of this palm was not westward of the Molluccas; Flach 1997). Root crops and

Within‐tree distribution of nest sites and foraging areas of ants on canopy trees in a tropical rainforest in Borneo

AbstractIt has been argued that canopy trees in tropical rainforests harbor species‐rich ant assemblages; however, how ants partition the space on trees has not been adequately elucidated. Therefore, we investigated within‐tree distributions of nest sites and foraging areas of individual ant colonies on canopy trees in a tropical lowland rainforest in Southeast Asia. The species diversity and colony abundance of ants were both significantly greater in crowns than on trunks. The concentration of ant species and colonies in the tree crown seemed to be associated with greater variation in nest cavity type in the crown, compared to the trunk. For ants nesting on canopy trees, the numbers of colonies and species were both higher for ants foraging only during the daytime than for those foraging at night. Similarly, for ants foraging on canopy trees, both values were higher for ants foraging only during the daytime than for those foraging at night. For most ant colonies nesting on canopy trees, foraging areas were limited to nearby nests and within the same type of microhabitat (within‐tree position). All ants foraging on canopy trees in the daytime nested on canopy trees, whereas some ants foraging on the canopy trees at night nested on the ground. These results suggest that spatial partitioning by ant assemblages on canopy trees in tropical rainforests is affected by microenvironmental heterogeneity generated by three‐dimensional structures (e.g., trees, epiphytes, lianas, and aerial soils) in the crowns of canopy trees. Furthermore, ant diversity appears to be enriched by both temporal (diel) and fine‐scale spatial partitioning of foraging activity.

Anti‐herbivore effects of an ant species, Crematogaster difformis, inhabiting myrmecophytic epiphytes in the canopy of a tropical lowland rainforest in Borneo

AbstractAnts are believed to regulate herbivorous insects in the canopy of tropical rainforests, but few studies have empirically investigated the anti‐herbivore effects of the ants there. We examined the anti‐herbivore effects of the ant species Crematogaster difformis, which territorializes a large area of the crown of emergent canopy trees and inhabits the myrmecophytic epiphytes, Lecanopteris sp. and Platycerium sp., which grow in the crown, by performing an ant‐exclusion experiment in the field. The average proportion of leaf area loss, the proportion of damaged leaves, and the proportion of leaves with ≥50% leaf area loss were all significantly higher on experimentally ant‐excluded branches than on ant‐attended branches at 3 months from the beginning of the ant‐exclusion treatment. These results suggest that C. difformis regulates not only herbivorous insects that potentially feed on its host epiphytes but also those that could feed on leaves of emergent canopy trees that harbor the epiphytes.

On the detection of dynamic responses in a drought-perturbed tropical rainforest in Borneo

The dynamics of aseasonal lowland dipterocarp forest in Borneo is influenced by perturbation from droughts. These events might be increasing in frequency and intensity in the future. This paper describes drought-affected dynamics between 1986 and 2001 in Sabah, Malaysia, and considers how it is possible, reliably and accurately, to measure both coarse- and fine-scale responses of the forest. Some fundamental concerns about methodology and data analysis emerge. In two plots forming 8 ha, mortality, recruitment, and stem growth rates of trees ≥10 cm gbh (girth at breast height) were measured in a ‘pre-drought’ period (1986–1996), and in a period (1996–2001) including the 1997–1998 ENSO-drought. For 2.56 ha of subplots, mortality and growth rates of small trees (10–<50 cm gbh) were found also for two sub-periods (1996–1999, 1999–2001). A total of c. 19 K trees were recorded. Mortality rate increased by 25% while both recruitment and relative growth rates increased by 12% for all trees at the coarse scale. For small trees, at the fine scale, mortality increased by 6% and 9% from pre-drought to drought and on to ‘post-drought’ sub-periods. Relative growth rates correspondingly decreased by 38% and increased by 98%. Tree size and topography interacted in a complex manner with between-plot differences. The forest appears to have been sustained by off-setting elevated tree mortality by highly resilient stem growth. This last is seen as the key integrating tree variable which links the external driver (drought causing water stress) and population dynamics recorded as mortality and recruitment. Suitably sound measurements of stem girth, leading to valid growth rates, are needed to understand and model tree dynamic responses to perturbations. The proportion of sound data, however, is in part determined by the drought itself.

Tropical parabiotic ants: Highly unusual cuticular substances and low interspecific discrimination

BackgroundAssociations between animal species require that at least one of the species recognizes its partner. Parabioses are associations of two ant species which co-inhabit the same nest. Ants usually possess an elaborate nestmate recognition system, which is based on cuticular hydrocarbons and allows them to distinguish nestmates from non-nestmates through quantitative or qualitative differences in the hydrocarbon composition. Hence, living in a parabiotic association probably necessitates changes of the nestmate recognition system in both species, since heterospecific ants have to be accepted as nestmates.ResultsIn the present study we report highly unusual cuticular profiles in the parabiotic species Crematogaster modiglianii and Camponotus rufifemur from the tropical rainforest of Borneo. The cuticle of both species is covered by a set of steroids, which are highly unusual surface compounds. They also occur in the Dufour gland of Crematogaster modiglianii in high quantities. The composition of these steroids differed between colonies but was highly similar among the two species of a parabiotic nest. In contrast, hydrocarbon composition of Cr. modiglianii and Ca. rufifemur differed strongly and only overlapped in three regularly occurring and three trace compounds. The hydrocarbon profile of Camponotus rufifemur consisted almost exclusively of methyl-branched alkenes of unusually high chain lengths (up to C49). This species occurred in two sympatric, chemically distinct varieties with almost no hydrocarbons in common. Cr. modiglianii discriminated between these two varieties. It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others. However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety.ConclusionWe conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur. Ca. rufifemur actively or passively acquires cuticular steroids from its Cr. modiglianii partner, while the latter acquires at least two cuticular hydrocarbons from Ca. rufifemur. The cuticular substances of both species are highly unusual regarding both substance classes and chain lengths, which may cause the apparent inability of Cr. modiglianii to discriminate Ca. rufifemur nestmates from allocolonial Ca. rufifemur workers of the same chemical variety.

Identification of dust transport pathways from Lake Eyre, Australia using Hysplit

The HYbrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT_4) is used to create seasonal climatologies (1980–2000) of air parcel trajectories from the Southern Hemisphere's most active dust source Lake Eyre, Australia. Daily trajectories were computed forward for eight days from an origin centered over Lake Eyre at 500 m above the ground surface. Trajectory density maps were then created within a GIS for five levels; 0–500 m agl., 500–1000 m agl., 1000–1500 m agl., 1500–2000 m agl. and 2000–5000 m agl. These show that air parcel trajectories originating from Lake Eyre can affect regions many thousands of kilometers from the Australian continent in a relatively short period of time. Importantly, under favourable atmospheric conditions these air parcels have the potential to transport dust and other aerosols. During the austral winter, trajectories extended north to the southern Philippines highlighting the potential for dust from central Australia to affect most of Indonesia. This includes the tropical rainforests of Borneo and New Guinea, and the coral reefs of northern Australia and the Indonesian archipelago. We also show the potential for transport of dust from Lake Eyre to the Antarctic and much of the South Pacific and Southern Oceans. Accordingly, dust from Lake Eyre may affect biogeochemical cycles, sediment budgets, atmospheric processes and a wide range of ecosystems over a region much larger than previously thought. This highlights the need for further research to confirm the deposition of dust in the areas mapped by the present study.

Another Threat to Borneo's Rainforests?

![Figure][1] CREDIT: LOUISE MURRAY/ROBERT HARDING WORLD IMAGERY/CORBIS I welcome the recent initiative by the governments of Brunei, Indonesia, and Malaysia to commit to conserve the highly diverse forests on the island of Borneo through the “Heart of Borneo” initiative (“Last-gasp effort to save Borneo's tropical rainforests,” News Focus, 13 July, p. [192][2]). This is timely and hopefully will lead toward improved conservation efforts and more sustainable land use in this beleaguered biodiversity hotspot. However, large areas of Borneo are already under threat from a nonsustainable land use—that of open-cast coal mining. The mining giant BHP Billiton plans to develop a number of coal-mining areas directly within the Heart of Borneo ([1][3]). If these vast surface mines are allowed to proceed, it may lead to a catastrophic destruction of pristine rainforest and associated loss of plant and animal species. If efforts to allow countries with tropical forests to obtain carbon credits from avoided deforestation come to fruition ([2][4]), the forests of Borneo will have value in a different currency, that of their forest-carbon stocks rather than the coal buried beneath them. 1. 1.[↵][5] 1. C. Rewcastle, 2. J. Ungoed-Thomas , “Mining giant to raze apes' forest home,” Sunday Times, 20 (15 July 2007). 2. 2.[↵][6] 1. W. F. Laurance , Biotropica 39, 20 (2007). [OpenUrl][7][CrossRef][8][Web of Science][9] [1]: pending:yes [2]: /lookup/doi/10.1126/science.317.5835.192 [3]: #ref-1 [4]: #ref-2 [5]: #xref-ref-1-1 View reference 1. in text [6]: #xref-ref-2-1 View reference 2. in text [7]: {openurl}?query=rft.jtitle%253DBiotropica%26rft.volume%253D39%26rft.spage%253D20%26rft_id%253Dinfo%253Adoi%252F10.1111%252Fj.1744-7429.2006.00229.x%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: /lookup/external-ref?access_num=10.1111/j.1744-7429.2006.00229.x&link_type=DOI [9]: /lookup/external-ref?access_num=000243294500002&link_type=ISI

Reproductive phenology over a 10‐year period in a lowland evergreen rain forest of central Borneo

SummaryThe aim of this study was to document patterns in tree reproductive phenology in a rain forest of central Borneo and examine relationships between phenology and climatic patterns.A 10‐year data set (1990–2000) of monthly observations of flowering and fruit production of 171 trees (including 39 members of the Dipterocarpaceae) at Barito Ulu, Central Kalimantan, Indonesia, showed that most trees (73%) underwent reproductive activity on a supra‐annual timescale.There were three general flowering (GF) events, in 1991, 1994 and 1997, which were preceded by major drought periods (30‐day sliding total rainfall of less than 100 mm for more than 10 days) in which at least 40% of dipterocarps and at least 18% of all other trees underwent synchronized reproductive activity; there was also a minor event in 1990. Around 1.3% of trees flowered and 3.8% produced fruit in months outside of these four events.At the community level, the strongest negative correlation was found between the percentage of flowering individuals and total rainfall in the preceding 150 days.Within three genera of dipterocarps examined in more detail (Dipterocarpus,ShoreaandVatica) there were clear and consistent patterns of sequential flowering with certain species flowering early in the GF events and others towards the end of these events.Our results confirm the importance of large‐scale climatic fluctuations (El Niño‐Southern Oscillation) on plant reproductive phenology in South‐east Asian tropical forests and indicate that drought may be a more important cue than low night‐time temperatures.

The importance of amino acids in the adult diet of male tropical rainforest butterflies

Adult diet is a major factor contributing to life history variation in the Lepidoptera. Amino acids derived from adult feeding, in particular, are suspected to be a major contribution to fitness, but this could be proven in only few species so far. Effects of amino acids in the diet of butterflies were experimentally investigated in 13 species from a Borneo rainforest community (using caged males without mating opportunity). Four species lived substantially longer when given a mix of amino acids additionally to water, sodium and sugar solutions. No significant phylogenetic pattern was found for effects of amino acid feeding, although none of six pierid species were among the taxa with significant effects. Species that do react to amino acids tend to be among the most long-lived taxa in the community, suggesting that amino acids are a key variable to attain long life spans. Weaker effects, or impacts on other fitness-related variables, cannot be excluded in the remaining taxa. Results indicate that adult amino acid intake may not be a rare strategy of few exotic taxa, but is, at least in non-seasonal tropical regions, a common life history trait in a substantial number of butterfly species.

Anthropology and Environmental Debate: Reflections on Science, Resource Nationalism, and News Reporting

Anthropology and Environmental Debate: Reflections on Science, Resource Nationalism, and News Reporting

Interaction between flowers, ants and pollinators: additional evidence for floral repellence against ants

AbstractIt has been commonly suggested that ants negatively affect plant pollination, particularly in the tropics. We studied ant–flower–pollinator interactions in a lowland rainforest in Borneo. Frequency and duration of pollinator visits were compared between flowers attended by ants and flowers from which ants were excluded. In all four plant species studied, the activity of ants decreased the rate and/or duration of the pollinators’ floral visits. For this and other reasons it is expected that plants repel ants from flowers during anthesis. We tested this prediction for a different set of plant species in which we observed the behaviour ofDolichoderus thoracicusants when encountering flowers. In eight out of 18 plant species studied, ants showed a significantly higher rejection rate when they encountered flowers than when they encountered controls. Our results are thus consistent with the hypothesis that ants may negatively affect plant fitness by reduced intensity of pollinator visits and that ants are repelled from flowers of many tropical plant species, although this repellence is clearly not ubiquitous.

MICROGEOGRAPHIC EVOLUTION OF SNAIL SHELL SHAPE AND PREDATOR BEHAVIOR

Genetic divergence in geographically isolated populations is a prerequisite for allopatric speciation, one of the most common modes of speciation. In ecologically equivalent populations existing within a small, environmentally homogeneous area, an important role for environmentally neutral divergence is often found or inferred. We studied a species complex of conspicuously shaped Opisthostoma land snails on scattered limestone outcrops within a small area of lowland rainforest in Borneo. We used shell morphometrics, mitochondrial and nuclear DNA sequences, and marks of predation to study the factors involved in allopatric divergence. We found that a striking geographic divergence exists in shell morphology, which is partly associated with neutral genetic divergence. We also found geographic differentiation in the behavior of the snails' invertebrate predator and evidence of an evolutionary interaction between aspects of shell shape and predator behavior. Our study shows that adaptation to biotic aspects of the environment may play a more important role in allopatric speciation than previously suspected, even on a geographically very small scale.