Displaying publications 81 - 100 of 445 in total

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  1. Development of microsatellite markers in Gonystylus bancanus (Ramin) useful for tracing and tracking of wood of this protected species
    Smulders MJ, VAN 't Westende WP, Diway B, Esselink GD, VAN DER Meer PJ, Koopman WJ
    Mol Ecol Resour, 2008 Jan;8(1):168-71.
    PMID: 21585747 DOI: 10.1111/j.1471-8286.2007.01914.x
    Ten polymorphic microsatellite markers have been developed for Gonystylus bancanus (Ramin), a protected tree species of peat swamp forests in Malaysia and Indonesia. Eight markers were also shown to be polymorphic in other Gonystylus species. The markers will enable assessing the amount of genetic variation within and among populations and the degree of population differentiation, such that donor populations can be selected for reforestation projects. They may be used for tracing and tracking of wood in the production chain, so that legal trade in this Convention on International Trade in Endangered Species of Wild Fauna and Flora-protected timber species, derived from specifically described origins, can be distinguished from illegally logged timber.
    Matched MeSH terms: Trees
  2. Fulltext Are patterns of fine-scale spatial genetic structure consistent between sites within tropical tree species?
    Smith JR, Ghazoul J, Burslem DFRP, Itoh A, Khoo E, Lee SL, et al.
    PLoS One, 2018;13(3):e0193501.
    PMID: 29547644 DOI: 10.1371/journal.pone.0193501
    Documenting the scale and intensity of fine-scale spatial genetic structure (FSGS), and the processes that shape it, is relevant to the sustainable management of genetic resources in timber tree species, particularly where logging or fragmentation might disrupt gene flow. In this study we assessed patterns of FSGS in three species of Dipterocarpaceae (Parashorea tomentella, Shorea leprosula and Shorea parvifolia) across four different tropical rain forests in Malaysia using nuclear microsatellite markers. Topographic heterogeneity varied across the sites. We hypothesised that forests with high topographic heterogeneity would display increased FSGS among the adult populations driven by habitat associations. This hypothesis was not supported for S. leprosula and S. parvifolia which displayed little variation in the intensity and scale of FSGS between sites despite substantial variation in topographic heterogeneity. Conversely, the intensity of FSGS for P. tomentella was greater at a more topographically heterogeneous than a homogeneous site, and a significant difference in the overall pattern of FSGS was detected between sites for this species. These results suggest that local patterns of FSGS may in some species be shaped by habitat heterogeneity in addition to limited gene flow by pollen and seed dispersal. Site factors can therefore contribute to the development of FSGS. Confirming consistency in species' FSGS amongst sites is an important step in managing timber tree genetic diversity as it provides confidence that species specific management recommendations based on species reproductive traits can be applied across a species' range. Forest managers should take into account the interaction between reproductive traits and site characteristics, its consequences for maintaining forest genetic resources and how this might influence natural regeneration across species if management is to be sustainable.
    Matched MeSH terms: Trees/genetics*; Trees/physiology
  3. Fulltext Soils on exposed Sunda shelf shaped biogeographic patterns in the equatorial forests of Southeast Asia
    Slik JW, Aiba S, Bastian M, Brearley FQ, Cannon CH, Eichhorn KA, et al.
    Proc Natl Acad Sci U S A, 2011 Jul 26;108(30):12343-7.
    PMID: 21746913 DOI: 10.1073/pnas.1103353108
    The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. An additional explanation might be related to the coarse sandy soils of central Sundaland. To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them. We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. For drought tolerance, no such pattern was detected. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. However, we could not confirm the presence of a savanna corridor. This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated.
    Matched MeSH terms: Trees*
  4. Fulltext PLANT CONSERVATION STATUS AND SPECIES DIVERSITY OF HUTAN LIPUR JERAM LINANG, KELANTAN
    Siti Mariam, M.N, Jivitra, B.
    UMT Journal of Undergraduate Research, 2019;1(4):37-50.
    MyJurnal
    utan Lipur Jeram Linang in Kelantan was carried out within 0.1 ha plot. All vascular plants (except lianas and epiphytes) were enumerated and identified. A total of 255 taxa representing 121 species belonging to 87 genera in 47 families were identified. Among these were 24 species endemic to Peninsular Malaysia and 47 species with medicinal values. Plants were categorized according to growth forms as follows: 67% trees, 17% shrubs, 7% palms, 6% herbs, and 3% ferns. Based on Important value index (IVI), Elateriospermum tapos, Goniothalamus umbrosus, and Monocarpia marginalis were the most dominant species whilst Rubiaceae, Arecaceae and Fabaceae were the three most diverse families. Species diversity was high based on the Shannon-Weiner index with the value of 4.38. In this study, two species from Dipterocarpaceae, which were Dipterocarpus grandiflorus and Shorea collina, were listed as Endangered (E) and Critically Endangered (CE) species respectively according to IUCN Red List. Information gained from this study showed that the forest harbored high plant diversity and endemism, so proper management is needed to protect and conserve this forest for sustainability and development.
    Matched MeSH terms: Trees
  5. Margosa oil poisoning as a cause of Reye's syndrome
    Sinniah D, Baskaran G
    Lancet, 1981 Feb 28;1(8218):487-9.
    PMID: 6110100
    Vomiting, drowsiness, metabolic acidosis, polymorphonuclear leucocytosis, and encephalopathy developed in thirteen infants within hours of ingestion of margosa oil. Liver biopsy of one infant and necropsy examination of ICR strain mice after experimentally induced margosa-oil poisoning demonstrated pronounced fatty infiltration of the liver and proximal renal tubules as well as cerebral oedema. Electron microscopy demonstrated mitochondrial damage. These findings indicate that margosa oil may be involved in the aetiology of Reye's syndrome among Indians in Malaysia.
    Matched MeSH terms: Trees
  6. The Use of Benzodiazepines among Kratom (Mitragyna Speciosa Korth.) Users
    Singh D, Narayanan S, Grundmann O, Boyer EW, Vicknasingam B
    J Psychoactive Drugs, 2019 06 20;52(1):86-92.
    PMID: 31218929 DOI: 10.1080/02791072.2019.1632505
    The leaves from Mitragyna speciosa (Korth.) trees, also known as kratom, are traditionally used in Southeast Asia as a mild psychotropic agent. We investigated the demographic characteristics of persons who used both kratom cocktail and benzodiazepines (BZO) in a sample drawn from a rural area in Penang, Malaysia, and the reasons for BZO use. Seventy-seven participants who currently use a kratom cocktail along with BZO were recruited through snowball sampling for this cross-sectional study. The participants were male, and the majority were Malays (99%, n = 76/77), single (57%, n = 44/77) and employed (91%, n = 70/77). BZO was used with kratom cocktail 1) to increase euphoria; 2) to reduce dependence on methamphetamine; 3) to promote sleep; 4) to ease methamphetamine-associated psychological symptoms and 5) to decrease the craving for kratom. There were no significant differences in the intake of kratom use (p = .751), BZO use duration (p = .259), frequency (p = .188) and quantity (p = .888) of BZO use in the last 7 days, and quantity of BZO use in the last 30 days (p = .337) between kratom users and kratom poly-drug users. An awareness of the health consequences of the co-use of kratom with BZO is needed to prevent untoward health incidents.
    Matched MeSH terms: Trees
  7. Fulltext Changes to Sabah's orangutan population in recent times: 2002-2017
    Simon D, Davies G, Ancrenaz M
    PLoS One, 2019;14(7):e0218819.
    PMID: 31314781 DOI: 10.1371/journal.pone.0218819
    The Bornean orangutan is critically endangered and monitoring its population is needed to inform effective conservation management. In this paper, we present results of 2014-17 aerial nest surveys of the major orangutan populations in Sabah and compare them with baseline data produced during surveys conducted in 2002-03 using similar methods. Our results show three important points: a) by increasing the survey effort (estimated at 15-25% cover), sparsely scattered orangutan sub-populations not recorded in the previous aerial surveys were located and the accuracy of the nest count estimates is expected to improve; b) large populations in the interior forests of Sabah, occupying sustainably managed logged and unlogged forests, have been stable over 15 years and are of vital importance for the species' conservation; c) fragmented populations located in eastern Sabah, that are surrounded by extensive oil palm plantations, have declined at varying rates.
    Matched MeSH terms: Trees
  8. Utilizing decision tree machine model to map dental students' preferred learning styles with suitable instructional strategies
    Shoaib LA, Safii SH, Idris N, Hussin R, Sazali MAH
    BMC Med Educ, 2024 Jan 11;24(1):58.
    PMID: 38212703 DOI: 10.1186/s12909-023-05022-5
    BACKGROUND: Growing demand for student-centered learning (SCL) has been observed in higher education settings including dentistry. However, application of SCL in dental education is limited. Hence, this study aimed to facilitate SCL application in dentistry utilising a decision tree machine learning (ML) technique to map dental students' preferred learning styles (LS) with suitable instructional strategies (IS) as a promising approach to develop an IS recommender tool for dental students.

    METHODS: A total of 255 dental students in Universiti Malaya completed the modified Index of Learning Styles (m-ILS) questionnaire containing 44 items which classified them into their respective LS. The collected data, referred to as dataset, was used in a decision tree supervised learning to automate the mapping of students' learning styles with the most suitable IS. The accuracy of the ML-empowered IS recommender tool was then evaluated.

    RESULTS: The application of a decision tree model in the automation process of the mapping between LS (input) and IS (target output) was able to instantly generate the list of suitable instructional strategies for each dental student. The IS recommender tool demonstrated perfect precision and recall for overall model accuracy, suggesting a good sensitivity and specificity in mapping LS with IS.

    CONCLUSION: The decision tree ML empowered IS recommender tool was proven to be accurate at matching dental students' learning styles with the relevant instructional strategies. This tool provides a workable path to planning student-centered lessons or modules that potentially will enhance the learning experience of the students.

    Matched MeSH terms: Decision Trees
  9. Antigenic classification of Rickettsia tsutsugamushi isolates from small mammals trapped in developing oil palm complex in Peninsular Malaysia
    Shirai A, Dohany AL, Gan E, Chan TC, Huxsoll DL
    Jpn. J. Med. Sci. Biol., 1980 Aug;33(4):231-4.
    PMID: 6783774
    Fifty-one Rickettsia tsutsugamushi isolates from small mammals collected in central Peninsular Malaysia serologically characterized by direct immunofluorescence using eight prototype strains. Karp-related (TA763, TA686, TA716) antigens were found in 90.2% of the isolates.
    Matched MeSH terms: Trees
  10. Fulltext Dynamics of Tree Species Diversity in Unlogged and Selectively Logged Malaysian Forests
    Shima K, Yamada T, Okuda T, Fletcher C, Kassim AR
    Sci Rep, 2018 01 18;8(1):1024.
    PMID: 29348596 DOI: 10.1038/s41598-018-19250-z
    Selective logging that is commonly conducted in tropical forests may change tree species diversity. In rarely disturbed tropical forests, locally rare species exhibit higher survival rates. If this non-random process occurs in a logged forest, the forest will rapidly recover its tree species diversity. Here we determined whether a forest in the Pasoh Forest Reserve, Malaysia, which was selectively logged 40 years ago, recovered its original species diversity (species richness and composition). To explore this, we compared the dynamics of secies diversity between unlogged forest plot (18.6 ha) and logged forest plot (5.4 ha). We found that 40 years are not sufficient to recover species diversity after logging. Unlike unlogged forests, tree deaths and recruitments did not contribute to increased diversity in the selectively logged forests. Our results predict that selectively logged forests require a longer time at least than our observing period (40 years) to regain their diversity.
    Matched MeSH terms: Trees*
  11. Fulltext Mango (Mangifera indica L.) germplasm diversity based on single nucleotide polymorphisms derived from the transcriptome
    Sherman A, Rubinstein M, Eshed R, Benita M, Ish-Shalom M, Sharabi-Schwager M, et al.
    BMC Plant Biol, 2015;15:277.
    PMID: 26573148 DOI: 10.1186/s12870-015-0663-6
    Germplasm collections are an important source for plant breeding, especially in fruit trees which have a long duration of juvenile period. Thus, efforts have been made to study the diversity of fruit tree collections. Even though mango is an economically important crop, most of the studies on diversity in mango collections have been conducted with a small number of genetic markers.
    Matched MeSH terms: Trees
  12. Fulltext Forecasting shear stress parameters in rectangular channels using new soft computing methods
    Sheikh Khozani Z, Sheikhi S, Mohtar WHMW, Mosavi A
    PLoS One, 2020;15(4):e0229731.
    PMID: 32271780 DOI: 10.1371/journal.pone.0229731
    Shear stress comprises basic information for predicting the average depth velocity and discharge in channels. With knowledge of the percentage of shear force carried by walls (%SFw) it is possible to more accurately estimate shear stress values. The %SFw, non-dimension wall shear stress ([Formula: see text]) and non-dimension bed shear stress ([Formula: see text]) in smooth rectangular channels were predicted by a three methods, the Bayesian Regularized Neural Network (BRNN), the Radial Basis Function (RBF), and the Modified Structure-Radial Basis Function (MS-RBF). For this aim, eight data series of research experimental results in smooth rectangular channels were used. The results of the new method of MS-RBF were compared with those of a simple RBF and BRNN methods and the best model was selected for modeling each predicted parameters. The MS-RBF model with RMSE of 3.073, 0.0366 and 0.0354 for %SFw, [Formula: see text] and [Formula: see text] respectively, demonstrated better performance than those of the RBF and BRNN models. The results of MS-RBF model were compared with three other proposed equations by researchers for trapezoidal channels and rectangular ducts. The results showed that the MS-RBF model performance in estimating %SFw, [Formula: see text] and [Formula: see text] is superior than those of presented equations by researchers.
    Matched MeSH terms: Decision Trees
  13. Distribution of Lichen Flora at Different Altitudes of Gunung Machincang, Langkawi Islands, Malaysia
    Shahrizim Zulkifly, Young SK, Mohamed Abudl Majid, Amir Feisal Merican
    Sains Malaysiana, 2011;40:1201-1208.
    Lichen samples were collected from Gunung Machincang, Langkawi Islands based on an alternation of altitudes, which are 0, 300 and above 600 m. Morphological identification resulted in 15 genera of microlichens (crustose) and five genera of macrolichens (foliose) and they fall under 14 families. As the altitude increases, the number of foliose type of lichen also increased. The common microlichens obtained were from the Family of Graphidaceae and can be found from the sea level right up to the peak of Gunung Machincang. The most common crustose lichens found were Heterodermia sp., while Eugenia sp. is the most common tree habitat for lichens in Gunung Machincang, Langkawi Islands. This study represents the first record of lichens in Gunung Machincang, Langkawi Islands, Malaysia.
    Matched MeSH terms: Trees
  14. Species richness of riparian vegetation after three decades of Kenyir dam establishment
    Shahimi S, Salam R, Salim JM, Ahmad A
    Data Brief, 2019 Aug;25:104045.
    PMID: 31194175 DOI: 10.1016/j.dib.2019.104045
    This data article is on riparian vegetation species richness in four different streams located in the Sultan Mahmud Hydroelectric dam, also known as Kenyir dam and commonly referred to as Tasik Kenyir, Terengganu. The dataset consists of three reservoir-island streams and the other is a small stream located on the mainland. A total of 41 families and 90 species of riparian plants were reported for the first time after 34 years of the establishment of the Sultan Mahmud Hydroelectric dam. Trees contributing 60% of the species recorded in this study and the others were non-tree species, including climbers, ferns, epiphyte, herbs, shrub, strangling trees and palms. Among the recorded riparian plant species, two are introduced which are Clidemia hirta and Mimosa pigra. The highest diversity of riparian plant found in the stream of Sungai Kiang, followed by Sungai Ikan and Sungai Saok with 46, 29 and 17 species respectively for the reservoir-island streams. The mainland stream, Sungai Siput recorded 37 species. These riparian plants provide important ecosystem services, among others soil stabilization, habitat and food for aquatic fauna and water filtration. In terms of plant utilization potential and values, 47 species are identified having medicinal value, 10 species with ornamental value and another 36 species are timber trees. Our study demonstrates that the riparian plants are closely linked to stream size with variability associated with types of stream systems. The data collected also demonstrates that the riparian plant community is at the seral stages of riparian forest. This is indicated by the increase in plant species richness as the vegetation gradually changes from riparian towards mature forest composition. To secure ecological functions of Tasik Kenyir riparian plant assemblages, particularly in stabilizing the lake's margin and riverbank, it is recommended that monitoring and legal protection may need to be imposed by local authority.
    Matched MeSH terms: Trees
  15. Fulltext Tropical forests are thermally buffered despite intensive selective logging
    Senior RA, Hill JK, Benedick S, Edwards DP
    Glob Chang Biol, 2018 03;24(3):1267-1278.
    PMID: 29052295 DOI: 10.1111/gcb.13914
    Tropical rainforests are subject to extensive degradation by commercial selective logging. Despite pervasive changes to forest structure, selectively logged forests represent vital refugia for global biodiversity. The ability of these forests to buffer temperature-sensitive species from climate warming will be an important determinant of their future conservation value, although this topic remains largely unexplored. Thermal buffering potential is broadly determined by: (i) the difference between the "macroclimate" (climate at a local scale, m to ha) and the "microclimate" (climate at a fine-scale, mm to m, that is distinct from the macroclimate); (ii) thermal stability of microclimates (e.g. variation in daily temperatures); and (iii) the availability of microclimates to organisms. We compared these metrics in undisturbed primary forest and intensively logged forest on Borneo, using thermal images to capture cool microclimates on the surface of the forest floor, and information from dataloggers placed inside deadwood, tree holes and leaf litter. Although major differences in forest structure remained 9-12 years after repeated selective logging, we found that logging activity had very little effect on thermal buffering, in terms of macroclimate and microclimate temperatures, and the overall availability of microclimates. For 1°C warming in the macroclimate, temperature inside deadwood, tree holes and leaf litter warmed slightly more in primary forest than in logged forest, but the effect amounted to <0.1°C difference between forest types. We therefore conclude that selectively logged forests are similar to primary forests in their potential for thermal buffering, and subsequent ability to retain temperature-sensitive species under climate change. Selectively logged forests can play a crucial role in the long-term maintenance of global biodiversity.
    Matched MeSH terms: Trees
  16. Characterising absorption and health-related properties of phytochemicals extracted from Malaysian palm fruit biomass after oil extraction
    Selby-Pham SNB, Siow LF, Bennett LE
    Food Funct, 2020 Jan 29;11(1):907-920.
    PMID: 31942898 DOI: 10.1039/c9fo01149h
    After oil extraction, palm fruit biomass contains abundant water-soluble phytochemicals (PCs) with proven bioactivity in regulating oxidative stress and inflammation (OSI). For optimal bioefficacy following oral consumption, the pharmacokinetic plasma peak (Tmax) should be bio-matched with the onset of OSI, which can be predicted from the Phytochemical Absorption Prediction (PCAP) model and methodology. Predicted absorption and potential for regulation of OSI by measures of total phenolic content, antioxidant capacity and hydrogen peroxide production capacity, were applied to characterise eight extracts from mesocarp fibre and kernel shells of oil-depleted palm fruits. Results indicated post-consumption absorption Tmax ranges of 0.5-12 h and 2-6 h for intake in liquid and solid forms, respectively, and generally high antioxidant activity of the extracts. The research supports that PC extracts of palm fruit biomass have broad potential uses for human health as dietary antioxidants in foods, supplements or functional beverages.
    Matched MeSH terms: Trees*
  17. Fulltext Malaysian Carica papaya L. var. Eksotika: Current Research Strategies Fronting Challenges
    Sekeli R, Hamid MH, Razak RA, Wee CY, Ong-Abdullah J
    Front Plant Sci, 2018;9:1380.
    PMID: 30279695 DOI: 10.3389/fpls.2018.01380
    Carica papaya L. or commonly known as papaya, is a major tropical crop consumed worldwide either as a vegetable or fresh fruit or processed products. In Malaysia, papaya was initially planted as a smallholder crop throughout the country. Eventually after 15 years of breeding and selection, a new variety, named C. papaya L. var. Eksotika, was released by the Malaysian Agricultural Research and Development Institute (MARDI) in 1987. This event changed the outlook of papaya planting from a smallholder crop to a plantation crop. Despite the blooming papaya business, the industry faced various disease issues that jeopardize its future. The most devastating was the papaya dieback disease, which affected approximately 800 hectares of plantation, destroyed approximately 1 million trees nationwide with total losses estimated at US$ 58 million. Even though Eksotika is a favored commercial variety with good eating and aesthetic quality fruit, its potential for more lucrative distant markets is tarnished with its short-shelf life fruits. Several strategies had been reported to address the challenges faced by Eksotika specifically against the dieback disease and the fruit's short shelf-life. This review focuses on C. papaya L. var. Eksotika particularly on the strategies to address the challenges faced in order to sustain the economic value of this crop plant, which had contributed significantly to the Malaysian economy.
    Matched MeSH terms: Trees
  18. Seed dispersal and spatial pattern in tropical trees
    Seidler TG, Plotkin JB
    PLoS Biol, 2006 Oct;4(11):e344.
    PMID: 17048988
    Theories of tropical tree diversity emphasize dispersal limitation as a potential mechanism for separating species in space and reducing competitive exclusion. We compared the dispersal morphologies, fruit sizes, and spatial distributions of 561 tree species within a fully mapped, 50-hectare plot of primary tropical forest in peninsular Malaysia. We demonstrate here that the extent and scale of conspecific spatial aggregation is correlated with the mode of seed dispersal. This relationship holds for saplings as well as for mature trees. Phylogenetically independent contrasts confirm that the relationship between dispersal and spatial pattern is significant even after controlling for common ancestry among species. We found the same qualitative results for a 50-hectare tropical forest plot in Panama. Our results provide broad empirical evidence for the importance of dispersal mode in establishing the long-term community structure of tropical forests.
    Matched MeSH terms: Trees/physiology*
  19. The contribution of insects to global forest deadwood decomposition
    Seibold S, Rammer W, Hothorn T, Seidl R, Ulyshen MD, Lorz J, et al.
    Nature, 2021 Sep;597(7874):77-81.
    PMID: 34471275 DOI: 10.1038/s41586-021-03740-8
    The amount of carbon stored in deadwood is equivalent to about 8 per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2-5 with decomposer groups-such as microorganisms and insects-contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the decomposition of deadwood and carbon release remains poorly understood7. Here we present a field experiment of wood decomposition across 55 forest sites and 6 continents. We find that the deadwood decomposition rates increase with temperature, and the strongest temperature effect is found at high precipitation levels. Precipitation affects the decomposition rates negatively at low temperatures and positively at high temperatures. As a net effect-including the direct consumption by insects and indirect effects through interactions with microorganisms-insects accelerate the decomposition in tropical forests (3.9% median mass loss per year). In temperate and boreal forests, we find weak positive and negative effects with a median mass loss of 0.9 per cent and -0.1 per cent per year, respectively. Furthermore, we apply the experimentally derived decomposition function to a global map of deadwood carbon synthesized from empirical and remote-sensing data, obtaining an estimate of 10.9 ± 3.2 petagram of carbon per year released from deadwood globally, with 93 per cent originating from tropical forests. Globally, the net effect of insects may account for 29 per cent of the carbon flux from deadwood, which suggests a functional importance of insects in the decomposition of deadwood and the carbon cycle.
    Matched MeSH terms: Trees/metabolism*
  20. Fulltext Projecting range-wide sun bear population trends using tree cover and camera-trap bycatch data
    Scotson L, Fredriksson G, Ngoprasert D, Wong WM, Fieberg J
    PLoS One, 2017;12(9):e0185336.
    PMID: 28961243 DOI: 10.1371/journal.pone.0185336
    Monitoring population trends of threatened species requires standardized techniques that can be applied over broad areas and repeated through time. Sun bears Helarctos malayanus are a forest dependent tropical bear found throughout most of Southeast Asia. Previous estimates of global population trends have relied on expert opinion and cannot be systematically replicated. We combined data from 1,463 camera traps within 31 field sites across sun bear range to model the relationship between photo catch rates of sun bears and tree cover. Sun bears were detected in all levels of tree cover above 20%, and the probability of presence was positively associated with the amount of tree cover within a 6-km2 buffer of the camera traps. We used the relationship between catch rates and tree cover across space to infer temporal trends in sun bear abundance in response to tree cover loss at country and global-scales. Our model-based projections based on this "space for time" substitution suggested that sun bear population declines associated with tree cover loss between 2000-2014 in mainland southeast Asia were ~9%, with declines highest in Cambodia and lowest in Myanmar. During the same period, sun bear populations in insular southeast Asia (Malaysia, Indonesia and Brunei) were projected to have declined at a much higher rate (22%). Cast forward over 30-years, from the year 2000, by assuming a constant rate of change in tree cover, we projected population declines in the insular region that surpassed 50%, meeting the IUCN criteria for endangered if sun bears were listed on the population level. Although this approach requires several assumptions, most notably that trends in abundance across space can be used to infer temporal trends, population projections using remotely sensed tree cover data may serve as a useful alternative (or supplement) to expert opinion. The advantages of this approach is that it is objective, data-driven, repeatable, and it requires that all assumptions be clearly stated.
    Matched MeSH terms: Trees*
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