Displaying publications 81 - 100 of 995 in total

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  1. Alshiyab H, Kalil MS, Hamid AA, Yusoff WM
    Pak J Biol Sci, 2008 Sep 01;11(17):2073-82.
    PMID: 19266920
    The aim of this study was to investigate the influence of some environmental factors on bacterial metabolism. Fermentative hydrogen production by C. acetobutylicum, using glucose as the substrate. The effect of initial pH (4-8), inoculum size (1-20% (v/v)) and glucose concentration (1-30 g L(-1)) on hydrogen production were studied. The optimum cultivation temperature for hydrogen production was at 30 degrees C. The results show that substrate concentration and inoculum size resulted in hydrogen yield (Y(P/S)) of 391 mL g(-1) glucose utilized with maximum hydrogen productivity of 77.5 mL/L/h. Higher substrate concentration or inoculum size adversely affects hydrogen production, which decreases hydrogen yield by 15% to 334 mL g(-1) glucose utilized when 30% (v/v) inoculum size was used. The use of 30 g L(-1) substrate concentration resulted in a 75% decrease to 97 mL g(-1) glucose supplied. Concluded that proper Xo/So enhanced the hydrogen production.
    Matched MeSH terms: Ecosystem*
  2. Sonak S, Pangam P, Giriyan A
    J Environ Manage, 2008 Oct;89(1):14-23.
    PMID: 17544565
    A tsunami, triggered by a massive undersea earthquake off Sumatra in Indonesia, greatly devastated the lives, property and infrastructure of coastal communities in the coastal states of India, Andaman and Nicobar Islands, Indonesia, Sri Lanka, Malaysia and Thailand. This event attracted the attention of environmental managers at all levels, local, national, regional and global. It also shifted the focus from the impact of human activities on the environment to the impacts of natural hazards. Recovery/reconstruction of these areas is highly challenging. A clear understanding of the complex dynamics of the coast and the types of challenges faced by the several stakeholders of the coast is required. Issues such as sustainability, equity and community participation assume importance. The concept of ICZM (integrated coastal zone management) has been effectively used in most parts of the world. This concept emphasizes the holistic assessment of the coast and a multidisciplinary analysis using participatory processes. It integrates anthropocentric and eco-centric approaches. This paper documents several issues involved in the recovery of tsunami-affected areas and recommends the application of the ICZM concept to the reconstruction efforts.
    Matched MeSH terms: Ecosystem*
  3. Abdullah F, Sina I, Fauzee F
    Pak J Biol Sci, 2008 Nov 01;11(21):2478-83.
    PMID: 19205267
    An assemblage of beetle specimens from family Carabidae (ground beetles) was carried out at Kenyir water catchment as an indicator to measure disturbance. The samplings were conducted from 30th July to 1st August 2007 at limestone forest of Teluk Bewah and the dipterocarp forest of Sungai Cicir. 28 individuals from 13 species were collected from Teluk Bewah whereas 54 individuals from ten species was sampled from Sungai Cicir. The carabids were more specious (Simpson Diversity index: 0.97) and more abundant (Margalef index: 5.35) at Teluk Bewah compared to Sungai Cicir (Simpson Diversity index, 0.72: Margalefindex, 2.22). Light trapping was most efficient assembling 97.56% of ground beetles compared to Malaise trap, pitfall and net sweeping. This is the first record of beetle assemblage at Kenyir water catchment, Malaysia. New records for Kenyir, Terengganu, Malaysia are Abacetus sp. 1, Abacetus sp. 2, Acupalpus rectifrotis, Aephnidius adelioides, Dischissus notulatus, Dolichoctis sp., Dolichoctis sp. 2, Dolichoctis straitus, Ophinoea bimaculata, Perigona sp., Pheropsophus piciccollis, Pheropsophus occipitalis, Stenolophus quinquepustulatus, Stenolophus smaragdulus, Stenolophus sp., Tachys coracinus, Casnoidea sp., Orthogonius sp. Seven species coded as Cara C, Cara J, Cara M, Cara N, Cara O, Cara R and Cara S were unidentified and are probably new species to be described in another report. There is moderately high diversity (Simpson Diversity index: 0.846) of Carabidae indicating that ecotourism does not affect diversity of ground beetle at Kenyir Lake.
    Matched MeSH terms: Ecosystem
  4. van der Werf GR, Dempewolf J, Trigg SN, Randerson JT, Kasibhatla PS, Giglio L, et al.
    Proc Natl Acad Sci U S A, 2008 Dec 23;105(51):20350-5.
    PMID: 19075224 DOI: 10.1073/pnas.0803375105
    Drainage of peatlands and deforestation have led to large-scale fires in equatorial Asia, affecting regional air quality and global concentrations of greenhouse gases. Here we used several sources of satellite data with biogeochemical and atmospheric modeling to better understand and constrain fire emissions from Indonesia, Malaysia, and Papua New Guinea during 2000-2006. We found that average fire emissions from this region [128 +/- 51 (1sigma) Tg carbon (C) year(-1), T = 10(12)] were comparable to fossil fuel emissions. In Borneo, carbon emissions from fires were highly variable, fluxes during the moderate 2006 El Niño more than 30 times greater than those during the 2000 La Niña (and with a 2000-2006 mean of 74 +/- 33 Tg C yr(-1)). Higher rates of forest loss and larger areas of peatland becoming vulnerable to fire in drought years caused a strong nonlinear relation between drought and fire emissions in southern Borneo. Fire emissions from Sumatra showed a positive linear trend, increasing at a rate of 8 Tg C year(-2) (approximately doubling during 2000-2006). These results highlight the importance of including deforestation in future climate agreements. They also imply that land manager responses to expected shifts in tropical precipitation may critically determine the strength of climate-carbon cycle feedbacks during the 21st century.
    Matched MeSH terms: Ecosystem
  5. Tan CH, Vythilingam I, Matusop A, Chan ST, Singh B
    Malar J, 2008;7:52.
    PMID: 18377652 DOI: 10.1186/1475-2875-7-52
    A large focus of human infections with Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques was discovered in the Kapit Division of Sarawak, Malaysian Borneo. A study was initiated to identify the vectors of malaria, to elucidate where transmission is taking place and to understand the bionomics of the vectors in Kapit.
    Matched MeSH terms: Ecosystem*
  6. Suzuki RO, Numata S, Okuda T, Nur Supardi MN, Kachi N
    J Plant Res, 2009 Jan;122(1):81-93.
    PMID: 19037582 DOI: 10.1007/s10265-008-0198-0
    We examined relationships between mortality rate, relative growth rate (RGR), and spatial patterns of three growth stages (small, medium, and large trees) for 11 dipterocarp species in the Pasoh 50-ha plot. Mortality rates for these species tended to be positively correlated with RGRs, although the correlation was significant only at the small-tree stage. Seven species with high growth and mortality rates exhibited peaks in spatial aggregation at small distances (<100 m) in small trees, but this aggregation disappeared in medium and large trees. In contrast, the other four species with low growth and mortality rates aggregated at large distances (>200 m) throughout the three growth stages in all but one species. Negative associations between different growth stages were observed only for the high-mortality species, suggesting density-dependent mortality. The high-mortality species showed habitat associations with topography, soil type, and the forest regeneration phase after gap formation, whereas the three low-mortality species only had associations with the forest regeneration phase. A randomization procedure revealed that these habitat associations explained little of their spatial aggregation. Our results suggest that the growth strategy has a large effect on the structuring of the spatial distribution of tree species through mortality processes.
    Matched MeSH terms: Ecosystem
  7. Jackson CR, Liew KC, Yule CM
    Microb Ecol, 2009 Apr;57(3):402-12.
    PMID: 18548182 DOI: 10.1007/s00248-008-9409-4
    Tropical peat swamp forests are important and endangered ecosystems, although little is known of their microbial diversity and ecology. We used molecular and enzymatic techniques to examine patterns in prokaryotic community structure and overall microbial activity at 0-, 10-, 20-, and 50-cm depths in sediments in a peat swamp forest in Malaysia. Denaturing gradient gel electrophoresis profiles of amplified 16S ribosomal ribonucleic acid (rRNA) gene fragments showed that different depths harbored different bacterial assemblages and that Archaea appeared to be limited to the deeper samples. Cloning and sequencing of longer 16S rRNA gene fragments suggested reduced microbial diversity in the deeper samples compared to the surface. Bacterial clone libraries were largely dominated by ribotypes affiliated with the Acidobacteria, which accounted for at least 27-54% of the sequences obtained. All of the sequenced representatives from the archaeal clone libraries were Crenarchaeota. Activities of microbial extracellular enzymes involved in carbon, nitrogen, and phosphorus cycling declined appreciably with depth, the only exception being peroxidase. These results show that tropical peat swamp forests are unusual systems with microbial assemblages dominated by members of the Acidobacteria and Crenarchaeota. Microbial communities show clear changes with depth, and most microbial activity is likely confined to populations in the upper few centimeters, the site of new leaf litter fall, rather than the deeper, older, peat layers.
    Matched MeSH terms: Ecosystem*
  8. Matsui M
    Zoolog Sci, 2009 Jun;26(6):437-42.
    PMID: 19583504 DOI: 10.2108/zsj.26.437
    A new species in the rhacophorid genus Philautus is described on the basis of five male specimens collected from the Matang Range, a herpetologically well-surveyed area of the lowland of Sarawak, western Borneo. The species possesses a cutaneous pectoris muscle but lacks vomerine teeth, and is assigned to the aurifasciatus group of Philautus. It is superficially similar to some other species of the same group, but can be differentiated from them by a combination of several morphological characters, including lack of a nuptial pad and lingual papilla, and more significantly, by a distinct advertisement call. This discovery underscores the immediate necessity for detailed surveys in the already well-explored lowlands of Borneo.
    Matched MeSH terms: Ecosystem*
  9. Shahidullah SM, Hanafi MM, Ashrafuzzaman M, Salam MA, Khair A
    C. R. Biol., 2009 Oct;332(10):909-16.
    PMID: 19819411 DOI: 10.1016/j.crvi.2009.07.003
    Crop duration of a rice plant, essentially dictated by flowering response, is an important selection criterion. It is determined by the interaction of genotype and environment. A field experiment was conducted with 40 rice genotypes to assess the fluctuation and/or stability of crop duration in a series of 16 environmental conditions. The effects of genotype, environment and all the components of G x E interaction were highly significant. Among the genotypes Benaful and Gandho kasturi were most sensitive to environmental changes, and indicating lower adaptability over the environments. Crop durations of 17 genotypes were comparatively stable against environmental changes. Four genotypes viz. Basmati PNR346, BR28, Neimat and Sarwati showed only nonlinear sensitivity and thus unpredictable fluctuation. Seventeen genotypes indicated average stability over the environments. The AMMI analysis identified Badshabhog, Basmati Tapl-90, Bhog ganjia, BR38, Elai, Jata katari and Radhuni pagal as most stable genotypes over the environment series. It also advocated three comparatively stable environments for all the genotypes.
    Matched MeSH terms: Ecosystem
  10. Clarke CM, Bauer U, Lee CC, Tuen AA, Rembold K, Moran JA
    Biol Lett, 2009 Oct 23;5(5):632-5.
    PMID: 19515656 DOI: 10.1098/rsbl.2009.0311
    Nepenthes pitcher plants are typically carnivorous, producing pitchers with varying combinations of epicuticular wax crystals, viscoelastic fluids and slippery peristomes to trap arthropod prey, especially ants. However, ant densities are low in tropical montane habitats, thereby limiting the potential benefits of the carnivorous syndrome. Nepenthes lowii, a montane species from Borneo, produces two types of pitchers that differ greatly in form and function. Pitchers produced by immature plants conform to the 'typical' Nepenthes pattern, catching arthropod prey. However, pitchers produced by mature N. lowii plants lack the features associated with carnivory and are instead visited by tree shrews, which defaecate into them after feeding on exudates that accumulate on the pitcher lid. We tested the hypothesis that tree shrew faeces represent a significant nitrogen (N) source for N. lowii, finding that it accounts for between 57 and 100 per cent of foliar N in mature N. lowii plants. Thus, N. lowii employs a diversified N sequestration strategy, gaining access to a N source that is not available to sympatric congeners. The interaction between N. lowii and tree shrews appears to be a mutualism based on the exchange of food sources that are scarce in their montane habitat.
    Matched MeSH terms: Ecosystem
  11. Okie JG, Brown JH
    Proc Natl Acad Sci U S A, 2009 Nov 17;106 Suppl 2:19679-84.
    PMID: 19805179 DOI: 10.1073/pnas.0901654106
    The rising sea level at the end of the Pleistocene that created the islands of the Sunda Shelf in Indonesia and Malaysia provides a natural experiment in community disassembly and offers insights into the effects of body size and niches on abundance, distribution, and diversity. Since isolation, terrestrial mammal communities of these islands have been reduced by extinction, with virtually no offsetting colonization. We document three empirical patterns of disassembly, all of which are significantly different from null models of random assembly: (i) a diversity-area relationship: the number of taxa is strongly and positively correlated with island area; (ii) nested subset composition: species that occur on small islands tend to be subsets of more diverse communities inhabiting larger islands; and (iii) body size distributions: species of intermediate body sizes occur on the greatest number of islands, and smaller islands have smaller ranges of body sizes, caused by the absence of species of both very large and extremely small size. These patterns reveal the role of body size and other niche characteristics, such as habitat requirements and trophic status, in the differential susceptibility of taxa to extinction.
    Matched MeSH terms: Ecosystem*
  12. Neoh KB, Lee CY
    Environ Entomol, 2009 Dec;38(6):1697-706.
    PMID: 20021766
    Flight activities of two sympatric termite species, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), were studied in Penang Island, Malaysia. Herein, we present the first documentation of chronological reproductive isolation of M. gilvus and M. carbonarius. Flights of M. gilvus were recorded over a remarkably long 7-mo period from March to September, whereas swarming of M. carbonarius took place from November to January. Swarming events of M. gilvus and M. carbonarius occurred under atmospheric pressures of 1,005-1,011 and 1,006-1,010 hPa, respectively. Most flights of M. gilvus occurred on days with rain, whereas M. carbonarius avoided rain. Flight activity of M. gilvus was correlated significantly with atmospheric pressure and rainfall. The threshold temperature and relative humidity of M. gilvus flights were between 23 and 26 degrees C and 83 and 98% RH, respectively; M. carbonarius swarmed between 25 and 30 degrees C and 72 and 83% RH, respectively. The flight activity of M. gilvus concentrated in the warmer and humid months with a monthly total rainfall of 228 mm. Both species swarmed at distinct times of day during the limited field observations: Flights of M. gilvus began between 0300 and 0430 hours (light intensity <1 Lx), and flights of M. carbonarius lasted for only 4-10 min between 1900 and 1910 hours (at dusk; light intensity: 20-200 Lx). Windless conditions were preferred for the flights of both species.
    Matched MeSH terms: Ecosystem*
  13. Beaucournu JC, Wells K
    Parasite, 2009 Dec;16(4):283-7.
    PMID: 20092059
    We report on fleas collected from small mammals in a lower mountane rainforest in the Crocker Range National Park, Sabah, Borneo. Macrostylophora durdeni n. sp., collected from Dremomys everetti and, of minor importance, Tupaia montana, is described. Further records include Gryphopsylla jacobsoni segragata and Lentistivalius vomerus from T. montana.
    Matched MeSH terms: Ecosystem
  14. Tani N, Tsumura Y, Kado T, Taguchi Y, Lee SL, Muhammad N, et al.
    Ann Bot, 2009 Dec;104(7):1421-34.
    PMID: 19808773 DOI: 10.1093/aob/mcp252
    BACKGROUND AND AIMS: Knowledge of pollen dispersal patterns and variation of fecundity is essential to understanding plant evolutionary processes and to formulating strategies to conserve forest genetic resources. Nevertheless, the pollen dispersal pattern of dipterocarp, main canopy tree species in palaeo-tropical forest remains unclear, and flowering intensity variation in the field suggests heterogeneity of fecundity.

    METHODS: Pollen dispersal patterns and male fecundity variation of Shorea leprosula and Shorea parvifolia ssp. parvifolia on Peninsular Malaysian were investigated during two general flowering seasons (2001 and 2002), using a neighbourhood model modified by including terms accounting for variation in male fecundity among individual trees to express heterogeneity in flowering.

    KEY RESULTS: The pollen dispersal patterns of the two dipterocarp species were affected by differences in conspecific tree flowering density, and reductions in conspecific tree flowering density led to an increased selfing rate. Active pollen dispersal and a larger number of effective paternal parents were observed for both species in the season of greater magnitude of general flowering (2002).

    CONCLUSIONS: The magnitude of general flowering, male fecundity variation, and distance between pollen donors and mother trees should be taken into account when attempting to predict the effects of management practices on the self-fertilization and genetic structure of key tree species in tropical forest, and also the sustainability of possible management strategies, especially selective logging regimes.

    Matched MeSH terms: Ecosystem*
  15. Edwards DP, Ansell FA, Ahmad AH, Nilus R, Hamer KC
    Conserv Biol, 2009 Dec;23(6):1628-33.
    PMID: 19775274 DOI: 10.1111/j.1523-1739.2009.01330.x
    The recent advent of carbon crediting has led to a rapid rise in biosequestration projects that seek to remove carbon from the atmosphere through afforestation and forest rehabilitation. Such projects also present an important potential opportunity to reverse biodiversity losses resulting from deforestation and forest degradation, but the biodiversity benefits of different forms of biosequestration have not been considered adequately. We captured birds in mist nets to examine the effects of rehabilitation of logged forest on birds in Sabah, Borneo, and to test the hypothesis that rehabilitation restores avian assemblages within regenerating forest to a condition closer to that seen in unlogged forest. Species richness and diversity were similar in unlogged and rehabilitated forest, but significantly lower in naturally regenerating forest. Rehabilitation resulted in a relatively rapid recovery of populations of insectivores within logged forest, especially those species that forage by sallying, but had a marked adverse effect on frugivores and possibly reduced the overall abundance of birds within regenerating forest. In view of these results, we advocate increased management for heterogeneity within rehabilitated forests, but we strongly urge an increased role for forest rehabilitation in the design and implementation of a biodiversity-friendly carbon-offsetting market.
    Matched MeSH terms: Ecosystem*
  16. Hashim R, Jackson DC
    Trop Life Sci Res, 2009 Dec;20(2):29-47.
    PMID: 24575177 MyJurnal
    A three-year study (July 2000 - June 2003) of fish assemblages was conducted in four tributaries of the Big Black River: Big Bywy, Little Bywy, Middle Bywy and McCurtain creeks that cross the Natchez Trace Parkway, Choctaw County, Mississippi, USA. Little Bywy and Middle Bywy creeks were within watersheds influenced by the lignite mining. Big Bywy and Middle Bywy creeks were historically impacted by channelisation. McCurtain Creek was chosen as a reference (control) stream. Fish were collected using a portable backpack electrofishing unit (Smith-Root Inc., Washington, USA). Insectivorous fish dominated all of the streams. There were no pronounced differences in relative abundances of fishes among the streams (P > 0.05) but fish assemblages fluctuated seasonally. Although there were some differences among streams with regard to individual species, channelisation and lignite mining had no discernable adverse effects on functional components of fish assemblages suggesting that fishes in these systems are euryceous fluvial generalist species adapted to the variable environments of small stream ecosystems.
    Matched MeSH terms: Ecosystem
  17. Hamzah KA, Ismail P, Kassim AR, Hassan CH, Akeng G, Said NM
    Trop Life Sci Res, 2009 Dec;20(2):15-27.
    PMID: 24575176 MyJurnal
    Tropical peat swamp forest (PSF) is a unique wetland ecosystem with distinct vegetation types. Due to the waterlogged environment, the stand characteristics in this ecosystem are different from those of other inland forests. This paper highlights stand characteristics of a PSF based on our investigation of a 1 ha ecological plot established in a Virgin Jungle Reserve (VJR) at Compartment 100, Pekan Forest Reserve, Pahang, Malaysia. This site is considered a Gonystylus bancanus-rich area. From the inventory, we recorded a total of 49 tree species from 38 genera and 25 families among all trees of ≥ 10 cm in diameter at breast height. Calophyllum ferrugineum var. ferrugineum was the most abundant species, followed by G. bancanus. The forest appeared healthy, as all tree characteristics (crown shape, log grade and climber infestation) generally fell within Classes 1 and 2 (good and moderate categories), with the exception of crown illumination which majority of the trees were rated as class 3 (received less sunlight). The latter finding indicates that most of the trees living under the canopy received minimal illumination. In terms of total tree biomass, we estimated that about 414.6 tonnes exist in this 1 ha area; this tree biomass is higher than in some PSF areas of Sumatra, Indonesia.
    Matched MeSH terms: Ecosystem
  18. Paramasvaran S, Sani RA, Hassan L, Krishnasamy M, Jeffery J, Oothuman P, et al.
    Trop Biomed, 2009 Dec;26(3):303-11.
    PMID: 20237444 MyJurnal
    A total of 204 rodents comprising 14 host species from four different habitats were examined. Nine rodent species were trapped from the forest and another five species were trapped from the coastal, rice field and urban habitats. Rattus rattus diardii (67%) was the predominant rodent species examined. Fifty six (47.3%) rodents and shrews were found to be infested with at least one of the 20 species of ectoparasite recovered. Mites belonging to the family Trombiculidae were the predominant ectoparasite species recovered. Ticks belonging to the family Ixodidae were recovered mainly from the forest dwelling rodents. Polyplax spinulosa and Hoplopleura pacifica were the common lice species found infesting the urban rodents. Xenopsylla cheopis was the only flea species recovered. The following ecto-parasites have been incriminated as important vectors or as mechanical carriers for the transmission of zoonotic diseases: Ixodes granulatus, Dermacentor sp. Haemaphysalis sp., Amblyomma sp. Ascoschoengastia indica, Leptotrombidium deliense, Ornithonyssus bacoti, Laelaps nuttalli, H. pacifica, P. spinulosa and Xenopsylla cheopis. Urban and forest rodents were significantly higher in ecto-parasitic infestation, compared to rats from the other two habitats. However, there was no significant statistical association between male and female rodents infested with ectoparasites.
    Matched MeSH terms: Ecosystem
  19. Zakri, A.H.
    ASM Science Journal, 2009;3(2):200-202.
    MyJurnal
    Recent studies by the United Nations University - Institute of Advanced Studies (UNU-IAS) demonstrate that bioprospecting is taking place in Antarctica and the Southern Ocean and that related commercial applications were being marketed. The bioprospectors’ interest in Antarctica stems from two reasons. First, the lack of knowledge surrounding Antarctic biota provides opportunities to discover novel organisms of potential use to biotechnology. Second, Antarctica’s environmental extremes, such as cold temperatures, extreme aridity and salinity present conditions in which biota have evolved unique characteristics for survival (UNU-IAS 2003). Thus bioprospecting opportunities include, inter alia, the discovery of novel bioactives in species found in cold and dry lithic habitat, novel pigments found in hyper-saline lakes and antifreezes in sea-lakes (Cheng & Cheng 1999).
    Matched MeSH terms: Ecosystem
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