Displaying publications 81 - 100 of 380 in total

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  1. Fulltext Leaf Anatomy and Micromorphology Characteristics of Ketum [Mitragyna speciosa (Korth.) Havil.] (Rubiaceae)
    Ghazalli MN, Md Sah MS, Mat M, Awang K, Jaafar MA, Mirad R, et al.
    Trop Life Sci Res, 2021 Mar;32(1):107-117.
    PMID: 33936554 DOI: 10.21315/tlsr2021.32.1.7
    Mitragyna speciosa (Korth.) Havil. or locally known as ketum/daun sebiak/biak-biak belongs to Rubiaceae family and generally occurs in secondary forest or disturbed areas in tropical and subtropical region. This research enumerated the characterisation of Mitragyna speciosa leaf anatomy and micromorphology features which is still not well documented. This medium to large sized tree species characterised with opposite arrangement, ovate-acuminate leaf and with 12-17 pairs of veins. Transverse sections of petioles showed that this species has petiole outlines with slightly convex at the middle of the adaxial part and 'U'-shaped on abaxial side. Results also showed that this species has paracytic and hypostomatic stomata, combination of non-glandular (majority) and glandular trichomes (minority), with observation on the secretory cells present in petiole and midrib parenchyma cells. Cuticle on the abaxial and adaxial epidermal surfaces showed the presence granule and wax films with periclinal and anticlinal walls can be differentiated clearly. The results obtained in this study can be used to providing additional systematics information of Mitragyna speciosa with the documentation of the leaf anatomy and micromorphology characters.
    Matched MeSH terms: Forests
  2. Phylogenetic turnover along local environmental gradients in tropical forest communities
    Baldeck CA, Kembel SW, Harms KE, Yavitt JB, John R, Turner BL, et al.
    Oecologia, 2016 10;182(2):547-57.
    PMID: 27337965 DOI: 10.1007/s00442-016-3686-2
    While the importance of local-scale habitat niches in shaping tree species turnover along environmental gradients in tropical forests is well appreciated, relatively little is known about the influence of phylogenetic signal in species' habitat niches in shaping local community structure. We used detailed maps of the soil resource and topographic variation within eight 24-50 ha tropical forest plots combined with species phylogenies created from the APG III phylogeny to examine how phylogenetic beta diversity (indicating the degree of phylogenetic similarity of two communities) was related to environmental gradients within tropical tree communities. Using distance-based redundancy analysis we found that phylogenetic beta diversity, expressed as either nearest neighbor distance or mean pairwise distance, was significantly related to both soil and topographic variation in all study sites. In general, more phylogenetic beta diversity within a forest plot was explained by environmental variables this was expressed as nearest neighbor distance versus mean pairwise distance (3.0-10.3 % and 0.4-8.8 % of variation explained among plots, respectively), and more variation was explained by soil resource variables than topographic variables using either phylogenetic beta diversity metric. We also found that patterns of phylogenetic beta diversity expressed as nearest neighbor distance were consistent with previously observed patterns of niche similarity among congeneric species pairs in these plots. These results indicate the importance of phylogenetic signal in local habitat niches in shaping the phylogenetic structure of tropical tree communities, especially at the level of close phylogenetic neighbors, where similarity in habitat niches is most strongly preserved.
    Matched MeSH terms: Forests
  3. Fulltext Rainfall seasonality and pest pressure as determinants of tropical tree species' distributions
    Baltzer JL, Davies SJ
    Ecol Evol, 2012 Nov;2(11):2682-94.
    PMID: 23170205 DOI: 10.1002/ece3.383
    Drought and pests are primary abiotic and biotic factors proposed as selective filters acting on species distributions along rainfall gradients in tropical forests and may contribute importantly to species distributional limits, performance, and diversity gradients. Recent research demonstrates linkages between species distributions along rainfall gradients and physiological drought tolerance; corresponding experimental examinations of the contribution of pest pressure to distributional limits and potential interactions between drought and herbivory are limited. This study aims to quantitate differential performance and herbivory as a function of species range limits across a climatic and floristic transition in Southeast Asia. Khao Chong Botanical Garden, Thailand and Pasoh Forest Reserve, Malaysia straddle the Kangar-Pattani Line. A reciprocal transplantation across a seasonality gradient was established using two groups of species ("widespread" taxa whose distributions include seasonally dry forests and "aseasonal" taxa whose distributions are limited to aseasonal forests). Growth, biomass allocation, survival, and herbivory were monitored for 19 months. Systematic differences in performance were a function of species distribution in relation to rainfall seasonality. In aseasonal Pasoh, aseasonal species had both greater growth and survivorship than widespread species. These differences were not a function of differential herbivory as widespread and aseasonal species experienced similar damage in the aseasonal forest. In seasonally dry Khao Chong, widespread species showed higher survivorship than aseasonal species, but these differences were only apparent during drought. We link this differential performance to physiological mechanisms as well as differential tolerance of biotic pressure during drought stress. Systematic decreases in seedling survival in aseasonal taxa during drought corresponded with previously documented physiological differences and may be exacerbated by herbivore damage. These results have important implications for tropical diversity and community composition in light of predicted increases in the frequency and severity of drought in hyperdiverse tropical forests.
    Matched MeSH terms: Forests
  4. Fulltext Crown damage and the mortality of tropical trees
    Arellano G, Medina NG, Tan S, Mohamad M, Davies SJ
    New Phytol, 2019 01;221(1):169-179.
    PMID: 30067290 DOI: 10.1111/nph.15381
    What causes individual tree death in tropical forests remains a major gap in our understanding of the biology of tropical trees and leads to significant uncertainty in predicting global carbon cycle dynamics. We measured individual characteristics (diameter at breast height, wood density, growth rate, crown illumination and crown form) and environmental conditions (soil fertility and habitat suitability) for 26 425 trees ≥ 10 cm diameter at breast height belonging to 416 species in a 52-ha plot in Lambir Hills National Park, Malaysia. We used structural equation models to investigate the relationships among the different factors and tree mortality. Crown form (a proxy for mechanical damage and other stresses) and prior growth were the two most important factors related to mortality. The effect of all variables on mortality (except habitat suitability) was substantially greater than expected by chance. Tree death is the result of interactions between factors, including direct and indirect effects. Crown form/damage and prior growth mediated most of the effect of tree size, wood density, fertility and habitat suitability on mortality. Large-scale assessment of crown form or status may result in improved prediction of individual tree death at the landscape scale.
    Matched MeSH terms: Forests*
  5. Damage to living trees contributes to almost half of the biomass losses in tropical forests
    Zuleta D, Arellano G, McMahon SM, Aguilar S, Bunyavejchewin S, Castaño N, et al.
    Glob Chang Biol, 2023 Jun;29(12):3409-3420.
    PMID: 36938951 DOI: 10.1111/gcb.16687
    Accurate estimates of forest biomass stocks and fluxes are needed to quantify global carbon budgets and assess the response of forests to climate change. However, most forest inventories consider tree mortality as the only aboveground biomass (AGB) loss without accounting for losses via damage to living trees: branchfall, trunk breakage, and wood decay. Here, we use ~151,000 annual records of tree survival and structural completeness to compare AGB loss via damage to living trees to total AGB loss (mortality + damage) in seven tropical forests widely distributed across environmental conditions. We find that 42% (3.62 Mg ha-1  year-1 ; 95% confidence interval [CI] 2.36-5.25) of total AGB loss (8.72 Mg ha-1  year-1 ; CI 5.57-12.86) is due to damage to living trees. Total AGB loss was highly variable among forests, but these differences were mainly caused by site variability in damage-related AGB losses rather than by mortality-related AGB losses. We show that conventional forest inventories overestimate stand-level AGB stocks by 4% (1%-17% range across forests) because assume structurally complete trees, underestimate total AGB loss by 29% (6%-57% range across forests) due to overlooked damage-related AGB losses, and overestimate AGB loss via mortality by 22% (7%-80% range across forests) because of the assumption that trees are undamaged before dying. Our results indicate that forest carbon fluxes are higher than previously thought. Damage on living trees is an underappreciated component of the forest carbon cycle that is likely to become even more important as the frequency and severity of forest disturbances increase.
    Matched MeSH terms: Forests
  6. Psychiatry and mental health in Malaysia
    Deva MP
    Int Psychiatry, 2005 Apr;2(8):14-16.
    PMID: 31507809
    Malaysia is a tropical country in the heart of South East Asia, at the crossroads of the ancient east-west sea trade routes. Although independent from British colonial rule only in 1957, it has a recorded history dating back to at least the first century CE, when the region was already the source of valuable mineral and forest produce that found markets in China, India and further west.
    Matched MeSH terms: Forests
  7. Fulltext Local human movement patterns and land use impact exposure to zoonotic malaria in Malaysian Borneo
    Fornace KM, Alexander N, Abidin TR, Brock PM, Chua TH, Vythilingam I, et al.
    Elife, 2019 10 22;8.
    PMID: 31638575 DOI: 10.7554/eLife.47602
    Human movement into insect vector and wildlife reservoir habitats determines zoonotic disease risks; however, few data are available to quantify the impact of land use on pathogen transmission. Here, we utilise GPS tracking devices and novel applications of ecological methods to develop fine-scale models of human space use relative to land cover to assess exposure to the zoonotic malaria Plasmodium knowlesi in Malaysian Borneo. Combining data with spatially explicit models of mosquito biting rates, we demonstrate the role of individual heterogeneities in local space use in disease exposure. At a community level, our data indicate that areas close to both secondary forest and houses have the highest probability of human P. knowlesi exposure, providing quantitative evidence for the importance of ecotones. Despite higher biting rates in forests, incorporating human movement and space use into exposure estimates illustrates the importance of intensified interactions between pathogens, insect vectors and people around habitat edges.
    Matched MeSH terms: Forests
  8. Fulltext Effect of different habitat types on abundance and biting times of Anopheles balabacensis Baisas (Diptera: Culicidae) in Kudat district of Sabah, Malaysia
    Chua TH, Manin BO, Vythilingam I, Fornace K, Drakeley CJ
    Parasit Vectors, 2019 Jul 25;12(1):364.
    PMID: 31345256 DOI: 10.1186/s13071-019-3627-0
    BACKGROUND: We investigated the effect of five common habitat types on the diversity and abundance of Anopheles spp. and on the biting rate and time of Anopheles balabacensis (currently the only known vector for Plasmodium knowlesi in Sabah) at Paradason village, Kudat, Sabah. The habitats were forest edge, playground area, longhouse, oil palm plantation and shrub-bushes area. Sampling of Anopheles was done monthly using the human landing catch method in all habitat types for 14 months (October 2013 to December 2014, excluding June 2014). The Anopheles species were morphologically identified and subjected to PCR assay for the detection of Plasmodium parasites. Generalised linear mixed models (GLMM) were applied to test the variation in abundance and biting rates of An. balabacensis in different habitat types.

    RESULTS: A total of 1599 Anopheles specimens were collected in the village, of which about 90% were An. balabacensis. Anopheles balabacensis was present throughout the year and was the dominant Anopheles species in all habitat types. The shrub bushes habitat had the highest Anopheles species diversity while forest edge had the greatest number of Anopheles individuals caught. GLMM analysis indicated that An. balabacensis abundance was not affected by the type of habitats, and it was more active during the early and late night compared to predawn and dawn. PCR assay showed that 1.61% of the tested An. balabacensis were positive for malaria parasites, most of which were caught in oil palm estates and infected with one to two Plasmodium species.

    CONCLUSIONS: The identification of infected vectors in a range of habitats, including agricultural and farming areas, illustrates the potential for humans to be exposed to P. knowlesi outside forested areas. This finding contributes to a growing body of evidence implicating environmental changes due to deforestation, expansion of agricultural and farming areas, and development of human settlements near to forest fringes in the emergence of P. knowlesi in Sabah.

    Matched MeSH terms: Forests
  9. Fulltext Exposure and infection to Plasmodium knowlesi in case study communities in Northern Sabah, Malaysia and Palawan, The Philippines
    Fornace KM, Herman LS, Abidin TR, Chua TH, Daim S, Lorenzo PJ, et al.
    PLoS Negl Trop Dis, 2018 Jun;12(6):e0006432.
    PMID: 29902171 DOI: 10.1371/journal.pntd.0006432
    BACKGROUND: Primarily impacting poor, rural populations, the zoonotic malaria Plasmodium knowlesi is now the main cause of human malaria within Malaysian Borneo. While data is increasingly available on symptomatic cases, little is known about community-level patterns of exposure and infection. Understanding the true burden of disease and associated risk factors within endemic communities is critical for informing evidence-based control measures.

    METHODOLOGY/PRINCIPAL FINDINGS: We conducted comprehensive surveys in three areas where P. knowlesi transmission is reported: Limbuak, Pulau Banggi and Matunggung, Kudat, Sabah, Malaysia and Bacungan, Palawan, the Philippines. Infection prevalence was low with parasites detected by PCR in only 0.2% (4/2503) of the population. P. knowlesi PkSERA3 ag1 antibody responses were detected in 7.1% (95% CI: 6.2-8.2%) of the population, compared with 16.1% (14.6-17.7%) and 12.6% (11.2-14.1%) for P. falciparum and P. vivax. Sero-prevalence was low in individuals <10 years old for P. falciparum and P. vivax consistent with decreased transmission of non-zoonotic malaria species. Results indicated marked heterogeneity in transmission intensity between sites and P. knowlesi exposure was associated with agricultural work (OR 1.63; 95% CI 1.07-2.48) and higher levels of forest cover (OR 2.40; 95% CI 1.29-4.46) and clearing (OR 2.14; 95% CI 1.35-3.40) around houses. Spatial patterns of P. knowlesi exposure differed from exposure to non-zoonotic malaria and P. knowlesi exposed individuals were younger on average than individuals exposed to non-zoonotic malaria.

    CONCLUSIONS/SIGNIFICANCE: This is the first study to describe serological exposure to P. knowlesi and associated risk factors within endemic communities. Results indicate community-level patterns of infection and exposure differ markedly from demographics of reported cases, with higher levels of exposure among women and children. Further work is needed to understand these variations in risk across a wider population and spatial scale.

    Matched MeSH terms: Forests
  10. Fulltext Ridleyandra merohmerea (Gesneriaceae), a new species from Kelantan, Peninsular Malaysia
    Yunoh SM, Dzulkafly Z
    PhytoKeys, 2017.
    PMID: 29362547 DOI: 10.3897/phytokeys.89.20344
    Ridleyandra merohmerea, a new species of Gesneriaceae, is described and illustrated. It is endemic in Peninsular Malaysia and known from a few populations along the Tuang River in the lowland dipterocarp forest of the Ulu Galas Forest Reserve in Kelantan, Peninsular Malaysia. Its conservation status is assessed as Critically Endangered.
    Matched MeSH terms: Forests
  11. Fulltext Selective logging in tropical forests decreases the robustness of liana-tree interaction networks to the loss of host tree species
    Magrach A, Senior RA, Rogers A, Nurdin D, Benedick S, Laurance WF, et al.
    Proc Biol Sci, 2016 Mar 16;283(1826):20153008.
    PMID: 26936241 DOI: 10.1098/rspb.2015.3008
    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'.
    Matched MeSH terms: Forestry*; Forests*
  12. Isolation and identification of endophytic fungi from uitm reserve forest, Negeri Sembilan
    Siti Nursyazwani Maadon, Sarini Ahmad Wakid, Iwana Izni Zainudin, Lili Syahani Rusli, Mohd Syahril Mohd Zan, Nor’Aishah Hasan, et al.
    Sains Malaysiana, 2018;47:3025-3030.
    Endophytic fungi are those living inside the host plant without causing any apparent negative effect on the host plant. Two
    isolates endophytic fungi from leaves and two isolates from root at Universiti Teknologi MARA (UiTM) Reserve Forest,
    Negeri Sembilan were successfully isolated and identified by morphology and molecular characteristic. Samples were
    surface sterilized and sub-cultured to obtain a pure culture. Characteristics of the isolates such as colony appearance,
    mycelial texture, conidia/spores and pigmentation were studied to explore their morphology. Isolates were also subjected to
    a PCR-based genotyping test. There were noticeable differences in morphological characteristics among the four isolates.
    Microscopic analysis showed four isolates consist of septa and conidia/spores. The pigmentation result showed that
    colony in A1leaf samples demonstrated an orange color on potato dextrose agar (PDA) media, colony in A1root demonstrate
    a black texture in PDA media while hairy colonies in the others two isolates showed a white color on PDA media. Based on
    molecular analyses the fungal genera showed 99-100% similarity with the related fungi recorded in the GenBank. Both
    morphology and molecular sequencing of internal transcribed spacer (ITS) regions of endophytic fungi showed that three
    isolates (A1root, C2leaf, and C3root) were grouped in Basidiomycota while one isolate (A1leaf) belonged to Ascomycota. The
    endophyte funguses were identified as Daldinia sp. (A1leaf), Polyporales sp. (A1root,) Lentinus sp. (C2leaf,) and Rigidoporus
    sp. (C3root). Overall, the new discoveries of isolated endophyte fungal have dyeing potential of fungal pigments which
    offer a viable alternative to natural vegetable and harmful synthetic dyes.
    Matched MeSH terms: Forests
  13. Carbon emissions from South-East Asian peatlands will increase despite emission-reduction schemes
    Wijedasa LS, Sloan S, Page SE, Clements GR, Lupascu M, Evans TA
    Glob Chang Biol, 2018 10;24(10):4598-4613.
    PMID: 29855120 DOI: 10.1111/gcb.14340
    Carbon emissions from drained peatlands converted to agriculture in South-East Asia (i.e., Peninsular Malaysia, Sumatra and Borneo) are globally significant and increasing. Here, we map the growth of South-East Asian peatland agriculture and estimate CO2 emissions due to peat drainage in relation to official land-use plans with a focus on the reducing emissions from deforestation and degradation (REDD+)-related Indonesian moratorium on granting new concession licences for industrial agriculture and logging. We find that, prior to 2010, 35% of South-East Asian peatlands had been converted to agriculture, principally by smallholder farmers (15% of original peat extent) and industrial oil palm plantations (14%). These conversions resulted in 1.46-6.43 GtCO2 of emissions between 1990 and 2010. This legacy of historical clearances on deep-peat areas will contribute 51% (4.43-11.45 GtCO2 ) of projected future peatland CO2 emissions over the period 2010-2130. In Indonesia, which hosts most of the region's peatland and where concession maps are publicly available, 70% of peatland conversion to agriculture occurred outside of known concessions for industrial plantation development, with smallholders accounting for 60% and industrial oil palm accounting for 34%. Of the remaining Indonesian peat swamp forest (PSF), 45% is not protected, and its conversion would amount to CO2 emissions equivalent to 0.7%-2.3% (5.14-14.93 Gt) of global fossil fuel and cement emissions released between 1990 and 2010. Of the peatland extent included in the moratorium, 48% was no longer forested, and of the PSF included, 40%-48% is likely to be affected by drainage impacts from agricultural areas and will emit CO2 over time. We suggest that recent legislation and policy in Indonesia could provide a means of meaningful emission reductions if focused on revised land-use planning, PSF conservation both inside and outside agricultural concessions, and the development of agricultural practices based on rehabilitating peatland hydrological function.
    Matched MeSH terms: Forests
  14. The status of forest carbon markets in Latin America
    Blanton A, Mohan M, Galgamuwa GAP, Watt MS, Montenegro JF, Mills F, et al.
    J Environ Manage, 2024 Feb 14;352:119921.
    PMID: 38219661 DOI: 10.1016/j.jenvman.2023.119921
    Tropical rainforests of Latin America (LATAM) are one of the world's largest carbon sinks, with substantial future carbon sequestration potential and contributing a major proportion of the global supply of forest carbon credits. LATAM is poised to contribute predominantly towards high-quality forest carbon offset projects designed to reduce emissions from deforestation and forest degradation, halt biodiversity loss, and provide equitable conservation benefits to people. Thus, carbon markets, including compliance carbon markets and voluntary carbon markets continue to expand in LATAM. However, the extent of the growth and status of forest carbon markets, pricing initiatives, stakeholders, amongst others, are yet to be explored and extensively reviewed for the entire LATAM region. Against this backdrop, we reviewed a total of 299 articles, including peer-reviewed and non-scientific gray literature sources, from January 2010 to March 2023. Herein, based on the extensive literature review, we present the results and provide perspectives classified into five categories: (i) the status and recent trends of forest carbon markets (ii) the interested parties and their role in the forest carbon markets, (iii) the measurement, reporting and verification (MRV) approaches and role of remote sensing, (iv) the challenges, and (v) the benefits, opportunities, future directions and recommendations to enhance forest carbon markets in LATAM. Despite the substantial challenges, better governance structures for forest carbon markets can increase the number, quality and integrity of projects and support the carbon sequestration capacity of the rainforests of LATAM. Due to the complex and extensive nature of forest carbon projects in LATAM, emerging technologies like remote sensing can enable scale and reduce technical barriers to MRV, if properly benchmarked. The future directions and recommendations provided are intended to improve upon the existing infrastructure and governance mechanisms, and encourage further participation from the public and private sectors in forest carbon markets in LATAM.
    Matched MeSH terms: Forests
  15. Fulltext Increasing land-use intensity reverses the relative occupancy of two quadrupedal scavengers
    Twining JP, Bernard H, Ewers RM
    PLoS One, 2017;12(5):e0177143.
    PMID: 28494004 DOI: 10.1371/journal.pone.0177143
    Human land use is continuously altering the natural environment, yet the greater ecological implications of this change for many groups that are key to healthy ecosystem functioning remains uncharacterised in the tropics. Terrestrial scavenging vertebrates are one such group, providing integral ecosystem services through the removal of carrion which is a crucial component of both nutrient cycling and disease dynamics. To explore how anthropogenic processes may affect forest scavengers, we investigated the changes in the relative occupancy of two important terrestrial scavengers along a gradient of land use intensity, ranging from protected forest to oil palm plantation in Borneo. We found the Malay civet (Viverra tangalunga) had highest, albeit variable, occupancy in areas of low land use intensity and the Southeast Asian water monitor (Varanus salvator macromaculatus) had highest occupancy in areas of high land use intensity. Land use had no effect on the combined occupancy of the two species. In high land use intensity sites, individual water monitors were larger and had better body condition, but at population level had a highly biased sex ratio with more males than females and increased signs of intraspecific conflict. We did not assess scavenging rate or efficiency as a process, but the high occupancy rates and apparent health of the scavengers in high land use intensity landscapes suggests this ecological process is robust to land use change.
    Matched MeSH terms: Forests
  16. Fulltext Land-use change alters the mechanisms assembling rainforest mammal communities in Borneo
    Wearn OR, Carbone C, Rowcliffe JM, Pfeifer M, Bernard H, Ewers RM
    J Anim Ecol, 2019 01;88(1):125-137.
    PMID: 30178485 DOI: 10.1111/1365-2656.12903
    The assembly of species communities at local scales is thought to be driven by environmental filtering, species interactions and spatial processes such as dispersal limitation. Little is known about how the relative balance of these drivers of community assembly changes along environmental gradients, especially man-made environmental gradients associated with land-use change. Using concurrent camera- and live-trapping, we investigated the local-scale assembly of mammal communities along a gradient of land-use intensity (old-growth forest, logged forest and oil palm plantations) in Borneo. We hypothesised that increasing land-use intensity would lead to an increasing dominance of environmental control over spatial processes in community assembly. Additionally, we hypothesised that competitive interactions among species might reduce in concert with declines in α-diversity (previously documented) along the land-use gradient. To test our first hypothesis, we partitioned community variance into the fractions explained by environmental and spatial variables. To test our second hypothesis, we used probabilistic models of expected species co-occurrence patterns, in particular focussing on the prevalence of spatial avoidance between species. Spatial avoidance might indicate competition, but might also be due to divergent habitat preferences. We found patterns that are consistent with a shift in the fundamental mechanics governing local community assembly. In support of our first hypothesis, the importance of spatial processes (dispersal limitation and fine-scale patterns of home-ranging) appeared to decrease from low to high intensity land-uses, whilst environmental control increased in importance (in particular due to fine-scale habitat structure). Support for our second hypothesis was weak: whilst we found that the prevalence of spatial avoidance decreased along the land-use gradient, in particular between congeneric species pairs most likely to be in competition, few instances of spatial avoidance were detected in any land-use, and most were likely due to divergent habitat preferences. The widespread changes in land-use occurring in the tropics might be altering not just the biodiversity found in landscapes, but also the fundamental mechanics governing the local assembly of communities. A better understanding of these mechanics, for a range of taxa, could underpin more effective conservation and management of threatened tropical landscapes.
    Matched MeSH terms: Forests
  17. Logging disturbance shifts net primary productivity and its allocation in Bornean tropical forests
    Riutta T, Malhi Y, Kho LK, Marthews TR, Huaraca Huasco W, Khoo M, et al.
    Glob Chang Biol, 2018 07;24(7):2913-2928.
    PMID: 29364562 DOI: 10.1111/gcb.14068
    Tropical forests play a major role in the carbon cycle of the terrestrial biosphere. Recent field studies have provided detailed descriptions of the carbon cycle of mature tropical forests, but logged or secondary forests have received much less attention. Here, we report the first measures of total net primary productivity (NPP) and its allocation along a disturbance gradient from old-growth forests to moderately and heavily logged forests in Malaysian Borneo. We measured the main NPP components (woody, fine root and canopy NPP) in old-growth (n = 6) and logged (n = 5) 1 ha forest plots. Overall, the total NPP did not differ between old-growth and logged forest (13.5 ± 0.5 and 15.7 ± 1.5 Mg C ha-1  year-1 respectively). However, logged forests allocated significantly higher fraction into woody NPP at the expense of the canopy NPP (42% and 48% into woody and canopy NPP, respectively, in old-growth forest vs 66% and 23% in logged forest). When controlling for local stand structure, NPP in logged forest stands was 41% higher, and woody NPP was 150% higher than in old-growth stands with similar basal area, but this was offset by structure effects (higher gap frequency and absence of large trees in logged forest). This pattern was not driven by species turnover: the average woody NPP of all species groups within logged forest (pioneers, nonpioneers, species unique to logged plots and species shared with old-growth plots) was similar. Hence, below a threshold of very heavy disturbance, logged forests can exhibit higher NPP and higher allocation to wood; such shifts in carbon cycling persist for decades after the logging event. Given that the majority of tropical forest biome has experienced some degree of logging, our results demonstrate that logging can cause substantial shifts in carbon production and allocation in tropical forests.
    Matched MeSH terms: Forestry; Forests*
  18. Sympatric primate seed dispersers and predators jointly contribute to plant diversity in a subtropical forest
    Chen Y, McConkey KR, Fan P
    Oecologia, 2023 Aug;202(4):715-727.
    PMID: 37553533 DOI: 10.1007/s00442-023-05430-w
    Mutualistic and antagonistic plant-animal interactions differentially contribute to the maintenance of species diversity in ecological communities. Although both seed dispersal and predation by fruit-eating animals are recognized as important drivers of plant population dynamics, the mechanisms underlying how seed dispersers and predators jointly affect plant diversity remain largely unexplored. Based on mediating roles of seed size and species abundance, we investigated the effects of seed dispersal and predation by two sympatric primates (Nomascus concolor and Trachypithecus crepusculus) on local plant recruitment in a subtropical forest of China. Over a 26 month period, we confirmed that these primates were functionally distinct: gibbons were legitimate seed dispersers who dispersed seeds of 44 plant species, while langurs were primarily seed predators who destroyed seeds of 48 plant species. Gibbons dispersed medium-seeded species more effectively than small- and large-seeded species, and dispersed more seeds of rare species than common and dominant species. Langurs showed a similar predation rate across different sizes of seeds, but destroyed a large number of seeds from common species. Due to gut passage effects, gibbons significantly shortened the duration of seed germination for 58% of the dispersed species; however, for 54% of species, seed germination rates were reduced significantly. Our study underlined the contrasting contributions of two primate species to local plant recruitment processes. By dispersing rare species and destroying the seeds of common species, both primates might jointly maintain plant species diversity. To maintain healthy ecosystems, the conservation of mammals that play critical functional roles needs to receive further attention.
    Matched MeSH terms: Forests
  19. Termite associated to oil palm stands in three types of soils in ladang Endau Rompin, Pahang, Malaysia
    Nur-Atiqah Jalaludin, Salmah Yaakop, Faszly Rahim
    Sains Malaysiana, 2018;47:1961-1967.
    Termites are found in various habitats, particularly diverse communities occurring in tropical forest and peatlands.
    Termites are beneficial insects, which function as soil engineers, improving the soil quality. However, in peatlands
    converted to commercial oil palm plantations, they are considered as pests. There is lack of studies on termite communities
    in converted peatlands in Peninsular Malaysia. Thus, this study investigated termite species associated with oil palm
    stands in three soil types (clay, shallow peat and deep peat) in Endau Rompin Plantation. The stand scouting method
    was used to record the numbers and types of termites associated with palm trees in the individual stands on different
    soil types. A total of 29 termite species associated with the palm stands were identified morphologically. All the species
    belonged to the families Rhinotermitidae and Termitidae. Twenty-three of the 29 species were found in the shallow peat,
    16 in clay soil and 15 in deep peat. The community structure was synthesized by two-way cluster analysis with Sorensen
    (Bray Curtis) distance measure. Five termite groups associated with two soil types (clay soil and shallow/deep peat)
    were generated. Moisture levels and organic content were likely to determine the presence of soil feeders identified in
    the presence study. This study provides information on the status of termite species in oil palm plantation areas. Such
    information may be useful in future planning strategies by the plantation management.
    Matched MeSH terms: Forests
  20. Riparian reserves within oil palm plantations conserve logged forest leaf litter ant communities and maintain associated scavenging rates
    Gray CL, Lewis OT, Chung AY, Fayle TM
    The Journal of applied ecology, 2015 Feb;52(1):31-40.
    PMID: 25678717
    The expansion of oil palm plantations at the expense of tropical forests is causing declines in many species and altering ecosystem functions. Maintaining forest-dependent species and processes in these landscapes may therefore limit the negative impacts of this economically important industry. Protecting riparian vegetation may be one such opportunity; forest buffer strips are commonly protected for hydrological reasons, but can also conserve functionally important taxa and the processes they support.We surveyed leaf litter ant communities within oil palm-dominated landscapes in Sabah, Malaysia, using protein baits. As the scavenging activity of ants influences important ecological characteristics such as nutrient cycling and soil structure, we quantified species-specific rates of bait removal to examine how this process may change across land uses and establish which changes in community structure underlie observed shifts in activity.Riparian reserves had similar ant species richness, community composition and scavenging rates to nearby continuous logged forest. Reserve width and vegetation structure did not affect ant species richness significantly. However, the number of foraging individuals decreased with increasing reserve width, and scavenging rate increased with vegetation complexity.Oil palm ant communities were characterized by significantly lower species richness than logged forest and riparian reserves and also by altered community composition and reduced scavenging rates.Reduced scavenging activity in oil palm was not explained by a reduction in ant species richness, nor by replacement of forest ant species by those with lower per species scavenging rates. There was also no significant effect of land use on the scavenging activity of the forest species that persisted in oil palm. Rather, changes in scavenging activity were best explained by a reduction in the mean rate of bait removal per individual ant across all species in the community.Synthesis and applications. Our results suggest that riparian reserves are comparable to areas of logged forest in terms of ant community composition and ant-mediated scavenging. Hence, in addition to protecting large continuous areas of primary and logged forest, maintaining riparian reserves is a successful strategy for conserving leaf litter ants and their scavenging activities in tropical agricultural landscapes.
    Matched MeSH terms: Forests
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