Displaying publications 1 - 20 of 97 in total

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  1. Complex pollination of a tropical Asian rainforest canopy tree by flower-feeding thrips and thrips-feeding predators
    Kondo T, Nishimura S, Tani N, Ng KK, Lee SL, Muhammad N, et al.
    Am J Bot, 2016 Nov;103(11):1912-1920.
    PMID: 27797714
    PREMISE OF THE STUDY: In tropical rainforests of Southeast Asia, a highly fecund thrips (Thrips spp.) responds rapidly to the mass flowering at multiple-year intervals characteristic of certain species such as the canopy tree studied here, Shorea acuminata, by feeding on flower resources. However, past DNA analyses of pollen adherent to thrips bodies revealed that the thrips promoted a very high level of self-pollination. Here, we identified the pollinator that contributes to cross-pollination and discuss ways that the pollination system has adapted to mass flowering.

    METHODS: By comparing the patterns of floral visitation and levels of genetic diversity in adherent pollen loads among floral visitors, we evaluated the contribution of each flower visitor to pollination.

    KEY RESULTS: The big-eyed bug, Geocoris sp., a major thrips predator, was an inadvertent pollinator, and importantly contributed to cross-pollination. The total outcross pollen adhering to thrips was approximately 30% that on the big-eyed bugs. Similarly, 63% of alleles examined in S. acuminata seeds and seedlings occurred in pollen adhering to big-eyed bugs; about 30% was shared with pollen from thrips.

    CONCLUSIONS: During mass flowering, big-eyed bugs likely travel among flowering S. acuminata trees, attracted by the abundant thrips. Floral visitation patterns of big-eyed bugs vs. other insects suggest that these bugs can maintain their population size between flowering by preying upon another thrips (Haplothrips sp.) that inhabits stipules of S. acuminata throughout the year and quickly respond to mass flowering. Thus, thrips and big-eyed bugs are essential components in the pollination of S. acuminata.

    Matched MeSH terms: Rainforest
  2. Fulltext Panthera tigris jacksoni Population Crash and Impending Extinction due to Environmental Perturbation and Human-Wildlife Conflict
    Ten DCY, Jani R, Hashim NH, Saaban S, Abu Hashim AK, Abdullah MT
    Animals (Basel), 2021 Apr 06;11(4).
    PMID: 33917373 DOI: 10.3390/ani11041032
    The critically endangered Malayan tiger (Panthera tigris jacksoni), with an estimated population of less than 200 individuals left in isolated rainforest habitats in Malaysia, is in an intermediate population crash leading to extinction in the next decade. The population has decreased significantly by illegal poaching, environmental perturbation, roadkill, and being captured during human-wildlife conflicts. Forty-five or more individuals were extracted from the wild (four animals captured due to conflict, one death due to canine distemper, one roadkilled, and 39 poached) in the 12 years between 2008-2019. The Malayan tigers are the first wildlife species to test positive for COVID-19 and are subject to the Canine Distemper Virus. These anthropogenic disturbances (poaching and human-tiger conflict) and environmental perturbation (decreasing habitat coverage and quality) have long been identified as impending extinction factors. Roadkill and infectious diseases have emerged recently as new confounding factors threatening Malayan tiger extinction in the near future. Peninsular Malaysia has an existing Malayan tiger conservation management plan; however, to enhance the protection and conservation of Malayan tigers from potential extinction, the authority should reassess the existing legislation, regulation, and management plan and realign them to prevent further population decline, and to better enable preparedness and readiness for the ongoing pandemic and future threats.
    Matched MeSH terms: Rainforest
  3. Shifts in foraging behaviour of heterospecific flocking birds in a lowland Malaysian rainforest
    Mansor MS, Nor SM, Ramli R
    Behav Processes, 2020 Nov;180:104229.
    PMID: 32866554 DOI: 10.1016/j.beproc.2020.104229
    Mixed-species flocks (MSFs) serve important roles in bird communities, especially in tropical forests. Although structure of mixed-species bird flocks and its benefits has been intensively studied globally, the foraging plasticity of a species when joining MSFs has rarely been evaluated. The present study examines foraging strategies of the Rufous-crowned Babbler (Malacopteron magnum), Chestnut-winged Babbler (Cyanoderma erythropterum) and Black-naped Monarch (Hypothymis azurea) when participating in MSFs in the Krau Wildlife Reserve, central Peninsular Malaysia. These species exhibit active foraging shifts in utilisation of vertical strata, foraging substrate, attack manoeuvres and foliage density, when foraging in MSFs, compared to when foraging outside MSFs. While the Rufous-crowned Babbler and Chestnut-winged Babbler commonly used gleaning and stretching (to completely extend the legs or neck to reach the food items) manoeuvres when foraging outside MSFs, respectively, they adopted probing manoeuvre and frequently used higher strata upon joining MSFs. The Chestnut-winged Babbler tended to forage on the underside of leaves and the Black-naped Monarch frequently utilised branches when joining MSFs, while they exclusively used aerial leaf litter and live green leaves, respectively, when foraging with conspecifics. The monarch also adopted the hovering manoeuvre and frequently foraged within denser foliage cover when joining MSFs. This study demonstrated that flock members exhibits foraging plasticity either through an expansion or active shift in foraging niches when participating in MSFs, thus suggesting the occurrence of possible foraging improvement and/or reductions in predation risk.
    Matched MeSH terms: Rainforest*
  4. Niche separation in flycatcher-like species in the lowland rainforests of Malaysia
    Mansor MS, Ramli R
    Behav Processes, 2017 Jul;140:121-126.
    PMID: 28438691 DOI: 10.1016/j.beproc.2017.04.010
    Niche theory suggests that sympatric species reduce interspecific competition through segregation of shared resources by adopting different attack manoeuvres. However, the fact that flycatcher-like bird species exclusively use the sally manoeuvre may thus challenge this view. We studied the foraging ecology of three flycatcher-like species (i.e. Paradise-flycatcher Terpsiphone sp., Black-naped Monarch Hypothymis azurea, and Rufous-winged Philentoma Philentoma pyrhoptera) in the Krau Wildlife Reserve in central Peninsular Malaysia. We investigated foraging preferences of each bird species and the potential niche partitioning via spatial or behavioural segregation. Foraging substrate was important parameter that effectively divided paradise-flycatcher from Black-naped Monarch and Rufous-winged Philentoma, where monarch and philentoma foraged mainly on live green leaves, while paradise-flycatcher foraged on the air. They also exhibited different foraging height preferences. Paradise-flycatcher, for instance, preferred the highest studied strata, while Black-naped Monarch foraged mostly in lower strata, and Rufous-winged Philentoma made use of the lowest strata. This study indicates that niche segregation occurs among sympatric species through foraging substrate and attack manoeuvres selection.
    Matched MeSH terms: Rainforest*
  5. Fulltext The antiacetylcholinesterase and antileishmanial activities of Canarium patentinervium Miq
    Mogana R, Adhikari A, Debnath S, Hazra S, Hazra B, Teng-Jin K, et al.
    Biomed Res Int, 2014;2014:903529.
    PMID: 24949478 DOI: 10.1155/2014/903529
    In continuation of our natural and medicinal research programme on tropical rainforest plants, a bioassay guided fractionation of ethanolic extract of leaves of Canarium patentinervium Miq. (Burseraceae Kunth.) led to the isolation of scopoletin (1), scoparone (2), (+)-catechin (3), vomifoliol (4), lioxin (5), and syringic acid (6). All the compounds exhibited antiacetylcholinesterase activity with syringic acid, a phenolic acid exhibiting good AChE inhibition (IC50 29.53 ± 0.19 μ g/mL). All compounds displayed moderate antileishmanial activity with scopoletin having the highest antileishmanial activity (IC50 163.30 ± 0.32 μ g/mL). Given the aforementioned evidence, it is tempting to speculate that Canarium patentinervium Miq. represents an exciting scaffold from which to develop leads for treatment of neurodegenerative and parasitic diseases.
    Matched MeSH terms: Rainforest
  6. Biodiversity characterization in Malaysia through biology and genetics
    Tan, Soon Guan
    Buletin Persatuan Genetik Malaysia, 2009;14(1):3-7.
    MyJurnal
    The world’s biodiversity is not distributed uniformly throughout the globe. Some areas such as the tropical rainforests, seas and coral reefs teem with the varieties of life whereas others such as some deserts and polar regions are almost devoid of them (Gaston, 2000). Malaysia, with her tropical jungles and seas, is rich with biodiversity. She is fortunate to have had eminent pioneers such as Ridley (1967), Corner (1972), Soepadmo (1972) and Whitmore (1983) to study her flora and Medway (1968) and Lim (1991) to study her fauna taxonomy. Other pioneers in Malaysian biology included Berry, Dhaliwal and Mohsin. These pioneers are then ably followed by workers such as Latiff, Kiew, Go, Khoo, Davidson, Saberi, Omar, Jambari, Idris, Zekri, Teo, Marziah, Tan, Mukherjee, Shapor, Yusoff, Azmi and many others studying the various subdisciplines of biology. In addition to the more obvious large plants and animals, microorganisms and aquatic organisms had not been neglected either. Workers such as Nawawi, Verghese, Ho and Faridah are known
    for their work on fungi while Fatimah, Phang, Japar and Anton had studied algae, seaweeds, diatoms and seagrasses. However, some of these workers have now either retired or are soon going to attain retirement age and the worrying part is that there are not many younger
    workers keen to pursue research in taxonomy and biosystematics, a prerequisite to further studies in ecology, genetics, biotechnology which in turn are prerequisites for rational conservation, management and sustainable utilization of our rich biological resources. With each passing day species are becoming extinct sometimes without us even knowing that they had ever existed. Even in a developed country such as the USA, one third of her plant and animal species are at risk of extinction (McCann, 2000). Hence, taxonomic and biosystematic studies of our plants, animals and microbes whether terrestrial or aquatic, freshwater and marine, should be priority areas. So should studies on their reproductive biology, life cycles, physiology, feeding habits, migration patterns, predators and their sensitivities to environmental changes.
    Matched MeSH terms: Rainforest
  7. Building a discovery partnership with Sarawak Biodiversity Centre: a gateway to access natural products from the rainforests
    Yeo TC, Naming M, Manurung R
    Comb Chem High Throughput Screen, 2014 Mar;17(3):192-200.
    PMID: 24409959
    The Sarawak Biodiversity Centre (SBC) is a state government agency which regulates research and promotes the sustainable use of biodiversity. It has a program on documentation of traditional knowledge (TK) and is well-equipped with facilities for natural product research. SBC maintains a Natural Product Library (NPL) consisting of local plant and microbial extracts for bioprospecting. The NPL is a core discovery platform for screening of bioactive compounds by researchers through a formal agreement with clear benefit sharing obligations. SBC aims to develop partnerships with leading institutions and the industries to explore the benefits of biodiversity.
    Matched MeSH terms: Rainforest
  8. Fulltext The genome of Shorea leprosula (Dipterocarpaceae) highlights the ecological relevance of drought in aseasonal tropical rainforests
    Ng KKS, Kobayashi MJ, Fawcett JA, Hatakeyama M, Paape T, Ng CH, et al.
    Commun Biol, 2021 Oct 07;4(1):1166.
    PMID: 34620991 DOI: 10.1038/s42003-021-02682-1
    Hyperdiverse tropical rainforests, such as the aseasonal forests in Southeast Asia, are supported by high annual rainfall. Its canopy is dominated by the species-rich tree family of Dipterocarpaceae (Asian dipterocarps), which has both ecological (e.g., supports flora and fauna) and economical (e.g., timber production) importance. Recent ecological studies suggested that rare irregular drought events may be an environmental stress and signal for the tropical trees. We assembled the genome of a widespread but near threatened dipterocarp, Shorea leprosula, and analyzed the transcriptome sequences of ten dipterocarp species representing seven genera. Comparative genomic and molecular dating analyses suggested a whole-genome duplication close to the Cretaceous-Paleogene extinction event followed by the diversification of major dipterocarp lineages (i.e. Dipterocarpoideae). Interestingly, the retained duplicated genes were enriched for genes upregulated by no-irrigation treatment. These findings provide molecular support for the relevance of drought for tropical trees despite the lack of an annual dry season.
    Matched MeSH terms: Rainforest*
  9. Correlation and persistence of hunting and logging impacts on tropical rainforest mammals
    Brodie JF, Giordano AJ, Zipkin EF, Bernard H, Mohd-Azlan J, Ambu L
    Conserv Biol, 2015 Feb;29(1):110-21.
    PMID: 25196079 DOI: 10.1111/cobi.12389
    Humans influence tropical rainforest animals directly via exploitation and indirectly via habitat disturbance. Bushmeat hunting and logging occur extensively in tropical forests and have large effects on particular species. But how they alter animal diversity across landscape scales and whether their impacts are correlated across species remain less known. We used spatially widespread measurements of mammal occurrence across Malaysian Borneo and recently developed multispecies hierarchical models to assess the species richness of medium- to large-bodied terrestrial mammals while accounting for imperfect detection of all species. Hunting was associated with 31% lower species richness. Moreover, hunting remained high even where richness was very low, highlighting that hunting pressure persisted even in chronically overhunted areas. Newly logged sites had 11% lower species richness than unlogged sites, but sites logged >10 years previously had richness levels similar to those in old-growth forest. Hunting was a more serious long-term threat than logging for 91% of primate and ungulate species. Hunting and logging impacts across species were not correlated across taxa. Negative impacts of hunting were the greatest for common mammalian species, but commonness versus rarity was not related to species-specific impacts of logging. Direct human impacts appeared highly persistent and lead to defaunation of certain areas. These impacts were particularly severe for species of ecological importance as seed dispersers and herbivores. Indirect impacts were also strong but appeared to attenuate more rapidly than previously thought. The lack of correlation between direct and indirect impacts across species highlights that multifaceted conservation strategies may be needed for mammal conservation in tropical rainforests, Earth's most biodiverse ecosystems.
    Matched MeSH terms: Rainforest
  10. Evaluating multispecies landscape connectivity in a threatened tropical mammal community
    Brodie JF, Giordano AJ, Dickson B, Hebblewhite M, Bernard H, Mohd-Azlan J, et al.
    Conserv Biol, 2015 Feb;29(1):122-32.
    PMID: 25065425 DOI: 10.1111/cobi.12337
    Habitat corridors are important tools for maintaining connectivity in increasingly fragmented landscapes, but generally they have been considered in single-species approaches. Corridors intended to facilitate the movement of multiple species could increase persistence of entire communities, but at the likely cost of being less efficient for any given species than a corridor intended specifically for that species. There have been few tests of the trade-offs between single- and multispecies corridor approaches. We assessed single-species and multispecies habitat corridors for 5 threatened mammal species in tropical forests of Borneo. We generated maps of the cost of movement across the landscape for each species based on the species' local abundance as estimated through hierarchical modeling of camera-trap data with biophysical and anthropogenic covariates. Elevation influenced local abundance of banded civets (Hemigalus derbyanus) and sun bears (Helarctos malayanus). Increased road density was associated with lower local abundance of Sunda clouded leopards (Neofelis diardi) and higher local abundance of sambar deer (Rusa unicolor). Pig-tailed macaque (Macaca nemestrina) local abundance was lower in recently logged areas. An all-species-combined connectivity scenario with least-cost paths and 1 km buffers generated total movement costs that were 27% and 23% higher for banded civets and clouded leopards, respectively, than the connectivity scenarios for those species individually. A carnivore multispecies connectivity scenario, however, increased movement cost by 2% for banded civets and clouded leopards. Likewise, an herbivore multispecies scenario provided more effective connectivity than the all-species-combined scenario for sambar and macaques. We suggest that multispecies habitat connectivity plans be tailored to groups of ecologically similar, disturbance-sensitive species to maximize their effectiveness.
    Matched MeSH terms: Rainforest
  11. Fulltext Hunter-Gatherer Olfaction Is Special
    Majid A, Kruspe N
    Curr Biol, 2018 02 05;28(3):409-413.e2.
    PMID: 29358070 DOI: 10.1016/j.cub.2017.12.014
    People struggle to name odors [1-4]. This has been attributed to a diminution of olfaction in trade-off to vision [5-10]. This presumption has been challenged recently by data from the hunter-gatherer Jahai who, unlike English speakers, find odors as easy to name as colors [4]. Is the superior olfactory performance among the Jahai because of their ecology (tropical rainforest), their language family (Aslian), or because of their subsistence (they are hunter-gatherers)? We provide novel evidence from the hunter-gatherer Semaq Beri and the non-hunter-gatherer (swidden-horticulturalist) Semelai that subsistence is the critical factor. Semaq Beri and Semelai speakers-who speak closely related languages and live in the tropical rainforest of the Malay Peninsula-took part in a controlled odor- and color-naming experiment. The swidden-horticulturalist Semelai found odors much more difficult to name than colors, replicating the typical Western finding. But for the hunter-gatherer Semaq Beri odor naming was as easy as color naming, suggesting that hunter-gatherer olfactory cognition is special.
    Matched MeSH terms: Rainforest
  12. Fulltext Termites can decompose more than half of deadwood in tropical rainforest
    Griffiths HM, Ashton LA, Evans TA, Parr CL, Eggleton P
    Curr Biol, 2019 02 18;29(4):R118-R119.
    PMID: 30779897 DOI: 10.1016/j.cub.2019.01.012
    Termite-mediated decomposition is an important, but often overlooked, component of the carbon cycle. Using a large-scale suppression experiment in Borneo, Griffiths et al. found that termites contribute between 58 and 64% of mass loss from dead wood.
    Matched MeSH terms: Rainforest*
  13. Fulltext Tree traits and canopy closure data from an experiment with 34 planted species native to Sabah, Borneo
    Gustafsson M, Gustafsson L, Alloysius D, Falck J, Yap S, Karlsson A, et al.
    Data Brief, 2016 Mar;6:466-70.
    PMID: 26900591 DOI: 10.1016/j.dib.2015.12.048
    The data presented in this paper is supporting the research article "Life history traits predict the response to increased light among 33 tropical rainforest tree species" [3]. We show basic growth and survival data collected over the 6 years duration of the experiment, as well as data from traits inventories covering 12 tree traits collected prior to and after a canopy reduction treatment in 2013. Further, we also include canopy closure and forest light environment data from measurements with hemispherical photographs before and after the treatment.
    Matched MeSH terms: Rainforest
  14. Fulltext Avian data from Kenyir rainforest trail
    Nelson BR, David G, Mokhtar AF, Mamat MA, Rahman AJA
    Data Brief, 2018 Dec;21:2633-2637.
    PMID: 30761345 DOI: 10.1016/j.dib.2018.11.119
    This data article is constructed using avian (bird) counts from a recently identified trail in Kenyir rainforest, East Peninsular Malaysia. Avian chirps and naked eye visual were simultaneously used to locate the birds. After visual binocular and digital image inspection, identification of avian species were carried out using reference books. Data tabulation are divided by monsoon seasons and months before interpret using Shannon and Evenness indices. The highlights like feeding guilds, nativity, iconic species and statuses in the wild are presented with the data to increase its value. Within these, a total of 457 avian individuals from 36 avian family groups were recorded from which, 25 of these avian species occur as near threatened, vulnerable, endangered and critically endangered in the wild. Having these, the tabulated data becomes a calendar for seasonal availability of avian species which considers the 1.0 km trail suitable for bird watching, scientific study and ecotourism purposes.
    Matched MeSH terms: Rainforest
  15. Fulltext The effects of catchment and riparian forest quality on stream environmental conditions across a tropical rainforest and oil palm landscape in Malaysian Borneo
    Luke SH, Barclay H, Bidin K, Chey VK, Ewers RM, Foster WA, et al.
    Ecohydrology, 2017 06;10(4):e1827.
    PMID: 28706573 DOI: 10.1002/eco.1827
    Freshwaters provide valuable habitat and important ecosystem services but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importance of catchment versus riparian-scale disturbance. We studied 16 streams in Sabah, Borneo, including old-growth forest, logged forest, and oil palm sites. We assessed forest quality in riparian zones and across the whole catchment and compared it with stream environmental conditions including water quality, structural complexity, and organic inputs. We found that streams with the highest riparian forest quality were nearly 4 °C cooler, over 20 cm deeper, had over 40% less sand, greater canopy cover, more stored leaf litter, and wider channels than oil palm streams with the lowest riparian forest quality. Other variables were significantly related to catchment-scale forest quality, with streams in the highest quality forest catchments having 40% more bedrock and 20 times more dead wood, along with higher phosphorus, and lower nitrate-N levels compared to streams with the lowest catchment-scale forest quality. Although riparian buffer strips went some way to protecting waterways, they did not maintain fully forest-like stream conditions. In addition, logged forest streams still showed signs of disturbance 10-15 years after selective logging. Our results suggest that maintenance and restoration of buffer strips can help to protect healthy freshwater ecosystems but logging practices and catchment-scale forest management also need to be considered.
    Matched MeSH terms: Rainforest
  16. Fulltext Selective‐logging and oil palm: multitaxon impacts, biodiversity indicators, and trade‐offs for conservation planning
    Edwards DP, Magrach A, Woodcock P, Ji Y, Lim NT-, Edwards FA, et al.
    Ecol Appl, 2014;24(8):2029-49.
    PMID: 29185670 DOI: 10.1890/14-0010.1
    Strong global demand for tropical timber and agricultural products has driven large-scale logging and subsequent conversion of tropical forests. Given that the majority of tropical landscapes have been or will likely be logged, the protection of biodiversity within tropical forests thus depends on whether species can persist in these economically exploited lands, and if species cannot persist, whether we can protect enough primary forest from logging and conversion. However, our knowledge of the impact of logging and conversion on biodiversity is limited to a few taxa, often sampled in different locations with complex land-use histories, hampering attempts to plan cost-effective conservation strategies and to draw conclusions across taxa. Spanning a land-use gradient of primary forest, once- and twice-logged forests, and oil palm plantations, we used traditional sampling and DNA metabarcoding to compile an extensive data set in Sabah, Malaysian Borneo for nine vertebrate and invertebrate taxa to quantify the biological impacts of logging and oil palm, develop cost-effective methods of protecting biodiversity, and examine whether there is congruence in response among taxa. Logged forests retained high species richness, including, on average, 70% of species found in primary forest. In contrast, conversion to oil palm dramatically reduces species richness, with significantly fewer primary-forest species than found on logged forest transects for seven taxa. Using a systematic conservation planning analysis, we show that efficient protection of primary-forest species is achieved with land portfolios that include a large proportion of logged-forest plots. Protecting logged forests is thus a cost-effective method of protecting an ecologically and taxonomically diverse range of species, particularly when conservation budgets are limited. Six indicator groups (birds, leaf-litter ants, beetles, aerial hymenopterans, flies, and true bugs) proved to be consistently good predictors of the response of the other taxa to logging and oil palm. Our results confidently establish the high conservation value of logged forests and the low value of oil palm. Cross-taxon congruence in responses to disturbance also suggests that the practice of focusing on key indicator taxa yields important information of general biodiversity in studies of logging and oil palm.
    Matched MeSH terms: Rainforest*
  17. How individual links affect network stability in a large-scale, heterogeneous metacommunity
    Brodie JF, Mohd-Azlan J, Schnell JK
    Ecology, 2016 Jul;97(7):1658-1667.
    PMID: 27859156 DOI: 10.1890/15-1613.1
    Elucidating how dispersal and landscape connectivity influence metacommunity stability will shed light on natural processes structuring ecosystems and help prioritize conservation actions in an increasingly fragmented world. Much of the theoretical and mathematical development of the metacommunity concept has been based on simplified experimental systems or simulated data. We still have limited understanding of how variation in the habitat matrix and species-specific differences in dispersal ability contribute to metacommunity dynamics in heterogeneous landscapes. We model a metacommunity of rainforest mammals in Borneo, a tropical biodiversity hotspot, where protected areas are increasingly isolated by ongoing habitat disturbance and loss. We employ a combination of hierarchical models of local abundance, circuit-theory-based dispersal analysis, and metapopulation models. Our goal was to understand which landscape links were the most important to metapopulation persistence and metacommunity stability. Links were particularly important if they were short and connected two large patches. This was partly because only the very shortest links could be traversed by poorly dispersing species, including small herbivores such as chevrotains (Tragulus spp.) and porcupines. Links that join large patches into a "super-patch" may also promote island-mainland rather than Levins-type metapopulation dynamics for good dispersers, particularly large carnivores such as clouded leopards (Neofelis diardi) and sun bears (Helarctos malayanus), reducing metapopulation extinction risk and thereby enhancing metacommunity stability. Link importance to metacommunity stability was highly correlated between heterogeneous and homogeneous landscapes. But link importance to metapopulation capacity varied strongly across species, and the correlation between heterogeneous and homogeneous landscape matrix scenarios was low for poorly dispersing taxa. This suggests that the environmental conditions in the area between habitat patches, the landscape matrix, is important for assessing certain individual species but less so for understanding the stability of the entire metacommunity.
    Matched MeSH terms: Rainforest
  18. Fulltext Population structure and demographic history of a tropical lowland rainforest tree species Shorea parvifolia (Dipterocarpaceae) from Southeastern Asia
    Iwanaga H, Teshima KM, Khatab IA, Inomata N, Finkeldey R, Siregar IZ, et al.
    Ecol Evol, 2012 Jul;2(7):1663-75.
    PMID: 22957170 DOI: 10.1002/ece3.284
    Distribution of tropical rainforests in Southeastern Asia has changed over geo-logical time scale, due to movement of tectonic plates and/or global climatic changes. Shorea parvifolia is one of the most common tropical lowland rainforest tree species in Southeastern Asia. To infer population structure and demographic history of S. parvifolia, as indicators of temporal changes in the distribution and extent of tropical rainforest in this region, we studied levels and patterns of nucleotide polymorphism in the following five nuclear gene regions: GapC, GBSSI, PgiC, SBE2, and SODH. Seven populations from peninsular Malaysia, Sumatra, and eastern Borneo were included in the analyses. STRUCTURE analysis revealed that the investigated populations are divided into two groups: Sumatra-Malay and Borneo. Furthermore, each group contained one admixed population. Under isolation with migration model, divergence of the two groups was estimated to occur between late Pliocene (2.6 MYA) and middle Pleistocene (0.7 MYA). The log-likelihood ratio tests of several demographic models strongly supported model with population expansion and low level of migration after divergence of the Sumatra-Malay and Borneo groups. The inferred demographic history of S. parvifolia suggested the presence of a scarcely forested land bridge on the Sunda Shelf during glacial periods in the Pleistocene and predominance of tropical lowland rainforest at least in Sumatra and eastern Borneo.
    Matched MeSH terms: Rainforest
  19. Fulltext Reconciling the contribution of environmental and stochastic structuring of tropical forest diversity through the lens of imaging spectroscopy
    Bongalov B, Burslem DFRP, Jucker T, Thompson SED, Rosindell J, Swinfield T, et al.
    Ecol Lett, 2019 Oct;22(10):1608-1619.
    PMID: 31347263 DOI: 10.1111/ele.13357
    Both niche and stochastic dispersal processes structure the extraordinary diversity of tropical plants, but determining their relative contributions has proven challenging. We address this question using airborne imaging spectroscopy to estimate canopy β-diversity for an extensive region of a Bornean rainforest and challenge these data with models incorporating niches and dispersal. We show that remotely sensed and field-derived estimates of pairwise dissimilarity in community composition are closely matched, proving the applicability of imaging spectroscopy to provide β-diversity data for entire landscapes of over 1000 ha containing contrasting forest types. Our model reproduces the empirical data well and shows that the ecological processes maintaining tropical forest diversity are scale dependent. Patterns of β-diversity are shaped by stochastic dispersal processes acting locally whilst environmental processes act over a wider range of scales.
    Matched MeSH terms: Rainforest*
  20. Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule
    Soh EY, Chhabra SR, Halliday N, Heeb S, Müller C, Birmes FS, et al.
    Environ Microbiol, 2015 Nov;17(11):4352-65.
    PMID: 25809238 DOI: 10.1111/1462-2920.12857
    In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.
    Matched MeSH terms: Rainforest
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