Displaying publications 1 - 20 of 999 in total

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  1. Mesjasz-Przybylowicz J, Przybylowicz W, Barnabas A, van der Ent A
    New Phytol, 2016 Mar;209(4):1513-26.
    PMID: 26508435 DOI: 10.1111/nph.13712
    Phyllanthus balgooyi (Phyllanthaceae), one of > 20 nickel (Ni) hyperaccumulator plant species known in Sabah (Malaysia) on the island of Borneo, is remarkable because it contains > 16 wt% Ni in its phloem sap, the second highest concentration of Ni in any living material in the world (after Pycnandra acuminata (Sapotaceae) from New Caledonia with 25 wt% Ni in latex). This study focused on the tissue-level distribution of Ni and other elements in the leaves, petioles and stem of P. balgooyi using nuclear microprobe imaging (micro-PIXE). The results show that in the stems and petioles of P. balgooyi Ni concentrations were very high in the phloem, while in the leaves there was significant enrichment of this element in the major vascular bundles. In the leaves, cobalt (Co) was codistributed with Ni, while the distribution of manganese (Mn) was different. The highest enrichment of calcium (Ca) in the stems was in the periderm, the epidermis and subepidermis of the petiole, and in the palisade mesophyll of the leaf. Preferential accumulation of Ni in the vascular tracts suggests that Ni is present in a metabolically active form. The elemental distribution of P. balgooyi differs from those of many other Ni hyperaccumulator plant species from around the world where Ni is preferentially accumulated in leaf epidermal cells.
    Matched MeSH terms: Ecosystem
  2. Sugau JB, van der Ent A
    Bot Stud, 2015 Dec;57(1):4.
    PMID: 28510789 DOI: 10.1186/s40529-016-0119-9
    BACKGROUND: Kinabalu Park, in Sabah (Malaysia) on Borneo Island, is renowned for the exceptionally high plant diversity it protects, with at least 5000 plant species enumerated to date. Discoveries of plant novelties continue to be made in Sabah, especially on isolated ultramafic outcrops, including in the genus Pittosporum (Pittosporaceae) with P. linearifolium from Bukit Hampuan on the southern border of the Park, and P. silamense from Bukit Silam in Eastern Sabah, both narrow endemics restricted to ultramafic soils.

    RESULTS: A distinctive new species of Pittosporum (P. peridoticola J.B.Sugau and Ent, sp. nov.) was discovered on Mount Tambuyukon in the north of Kinabalu Park during ecological fieldwork. The diagnostic morphological characters of this taxon are discussed and information about the habitat in which it grows is provided. The soil chemistry in the rooting zone of P. peridoticola has high magnesium to calcium quotients, high extractable nickel and manganese concentrations, but low potassium and phosphorus concentrations, as is typical for ultramafic soils. Analysis of foliar samples of various Pittosporum-species originating from ultramafic and non-ultramafic soils showed a comparable foliar elemental stoichiometry that is suggestive of 'Excluder-type' ecophysiology.

    CONCLUSION: Pittosporum peridoticola is an ultramafic obligate species restricted to Kinabalu Park with only two known populations within the boundaries of the protected area. It is vulnerable to any future stochastic landscape disturbance events, such as forest fires or severe droughts, and therefore its conservation status is 'Near Threatened'.

    Matched MeSH terms: Ecosystem
  3. Wang S, Loreau M, Arnoldi JF, Fang J, Rahman KA, Tao S, et al.
    Nat Commun, 2017 May 19;8:15211.
    PMID: 28524860 DOI: 10.1038/ncomms15211
    The spatial scaling of stability is key to understanding ecological sustainability across scales and the sensitivity of ecosystems to habitat destruction. Here we propose the invariability-area relationship (IAR) as a novel approach to investigate the spatial scaling of stability. The shape and slope of IAR are largely determined by patterns of spatial synchrony across scales. When synchrony decays exponentially with distance, IARs exhibit three phases, characterized by steeper increases in invariability at both small and large scales. Such triphasic IARs are observed for primary productivity from plot to continental scales. When synchrony decays as a power law with distance, IARs are quasilinear on a log-log scale. Such quasilinear IARs are observed for North American bird biomass at both species and community levels. The IAR provides a quantitative tool to predict the effects of habitat loss on population and ecosystem stability and to detect regime shifts in spatial ecological systems, which are goals of relevance to conservation and policy.
    Matched MeSH terms: Ecosystem*
  4. 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: Ecosystem*
  5. Graham LE, Knack JJ, Graham ME, Graham JM, Zulkifly S
    J Phycol, 2015 Jun;51(3):408-18.
    PMID: 26986658 DOI: 10.1111/jpy.12296
    Periphyton dominated by the cellulose-rich filamentous green alga Cladophora forms conspicuous growths along rocky marine and freshwater shorelines worldwide, providing habitat for diverse epibionts. Bacterial epibionts have been inferred to display diverse functions of biogeochemical significance: N-fixation and other redox reactions, phosphorus accumulation, and organic degradation. Here, we report taxonomic diversity of eukaryotic and prokaryotic epibionts and diversity of genes associated with materials cycling in a Cladophora metagenome sampled from Lake Mendota, Dane Co., WI, USA, during the growing season of 2012. A total of 1,060 distinct 16S, 173 18S, and 351 28S rRNA operational taxonomic units, from which >220 genera or species of bacteria (~60), protists (~80), fungi (6), and microscopic metazoa (~80), were distinguished with the use of reference databases. We inferred the presence of several algal taxa generally associated with marine systems and detected Jaoa, a freshwater periphytic ulvophyte previously thought endemic to China. We identified six distinct nifH gene sequences marking nitrogen fixation, >25 bacterial and eukaryotic cellulases relevant to sedimentary C-cycling and technological applications, and genes encoding enzymes in aerobic and anaerobic pathways for vitamin B12 biosynthesis. These results emphasize the importance of Cladophora in providing habitat for microscopic metazoa, fungi, protists, and bacteria that are often inconspicuous, yet play important roles in ecosystem biogeochemistry.
    Matched MeSH terms: Ecosystem
  6. Siti Afida I., Razmah G., Zulina A. M.
    Sains Malaysiana, 2016;45:949-954.
    The concern on the widespread use of surfactants is increasing worldwide as they can be potential toxicants by polluting
    the environment, with the damage formed depending on their exposure and persistence in the ecosystem. This paper
    was intended to evaluate the biodegradability of palm-based surfactant, MES, in order to establish their environmental
    friendliness. The respirometric method was used to monitor the biodegradation of various homologues of MES over 28
    days as described in the OECD 301F Manometric respirometry test method. The results showed all the MES homologues
    tested were readily biodegradable with percentage of biodegradation achieved for C12, C14 and C16 MES was 73%
    within 6 days, 66% within 8 days and 63% within 16 days, respectively, while linear alkylbenzene sulphonates (LAS)
    sample 60% biodegraded within 8 days. From the results, it can be concluded that the longer the carbon chain length, the
    lower is the biodegradability of MES as the microorganisms took longer time to degrade a longer chain surfactant. Other
    than that, the presence of aromatic structure in LAS may also extend the biodegradation process. The use of palm-based
    surfactant, i.e. MES, is more environmental friendly and can be used as an alternative to petroleum-based surfactant to
    reduce adverse environmental effects of surfactant on ecosystem.
    Matched MeSH terms: Ecosystem
  7. Shapawi R, Anyie AL, Hussien MA, Zuldin WH
    Trop Life Sci Res, 2015 Dec;26(2):1-13.
    PMID: 26868706 MyJurnal
    Seahorse diversity (genus Hippocampus, Family Syngnathidae), species identification, size composition and sexual dimorphism were studied from November 2012 to March 2013 in selected coastal waters around Kota Kinabalu, Sabah and the local market trade. Six species of seahorses were identified in the study: (1) Hippocampus barbouri, (2) Hippocampus comes, (3) Hippocampus kelloggi, (4) Hippocampus kuda, (5) Hippocampus spinosissimus and (6) Hippocampus trimaculatus. All six species were sold at the local market, and the dried seahorses were obtained mainly by local fishermen using trawl by-catch method and traded as traditional medicine, souvenirs and other uses. Four species were identified by direct samplings in various different habitats of Kota Kinabalu coastal waters: (1) H. barbouri, (2) H. comes, (3) H. kuda, and (4) H. spinosissimus. Based on the results, H. comes was the largest in size among the four fresh/live species found (mean standard length [SL]: 148.25±1.26 mm), whereas H. barbouri was the smallest species (mean SL: 129±7.81 mm). For the dried samples, H. kelloggi was the largest (mean SL: 245.25±14.55 mm) and H. barbouri was the smallest (mean SL: 127.21±10.01 mm). No significant difference (p>0.05) was observed between the lengths of males and females in every seahorse species, and there was no sexual size dimorphism in any of the species. The findings from the study are significant to provide baseline data for the conservation efforts of these unique marine teleost.
    Matched MeSH terms: Ecosystem
  8. Syakirah Samsudin, Zubaid A.
    Space use and activity patterns by 3 species of small mammals, namely, Tupaia glis, Callosciurus notatus and e. nigrovitatus were determined. The home range size of T. glis ranged from 9,544 to 73,470m2, C. notatus from 6,512 to 16,150m2 and C. nigrovitatus 10,970m2. There was no overlap in the ranges between individuals of the same species and sex but the ranges of different species overlapped. There was no significant difference in the mean daily distance moved among the studied individuals. All individuals showed a bimodal type of activity pattern.
    Penggunaan habitat dan corak aktiviti 3 spesies mamalia kecil, Tupaia glis, CalJosciurus notatus dan C. nigrovitatus telah ditentukan. Saiz banjaran kediaman T. glis adalah antara 9,544 hingga 73,470m2, C. notatus daripada 6,512 hingga 16,150m2 dan C. nigrovitatus 10,970m2. Pertindihan banjaran tidak wujud antara spesies atau jantina yang sama. Walau bagaimanapun, berlaku pertindihan banjaran antara spesies yang berbeza. Tiada perbezaan bererti pada purata jarak yang dilalui setiap hari antara individu-individu yang dikaji. Semua individu yang dikaji menunjukan corak aktiviti jenis bimodal.
    Matched MeSH terms: Ecosystem
  9. Chang KY, Riley WJ, Knox SH, Jackson RB, McNicol G, Poulter B, et al.
    Nat Commun, 2021 04 15;12(1):2266.
    PMID: 33859182 DOI: 10.1038/s41467-021-22452-1
    Wetland methane (CH4) emissions ([Formula: see text]) are important in global carbon budgets and climate change assessments. Currently, [Formula: see text] projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent [Formula: see text] temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that [Formula: see text] are often controlled by factors beyond temperature. Here, we evaluate the relationship between [Formula: see text] and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between [Formula: see text] and temperature, suggesting larger [Formula: see text] sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.
    Matched MeSH terms: Ecosystem
  10. Ma H, Crowther TW, Mo L, Maynard DS, Renner SS, van den Hoogen J, et al.
    Nat Plants, 2023 Nov;9(11):1795-1809.
    PMID: 37872262 DOI: 10.1038/s41477-023-01543-5
    Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling.
    Matched MeSH terms: Ecosystem*
  11. Pradisty NA, Amir AA, Zimmer M
    Oecologia, 2021 Apr;195(4):843-858.
    PMID: 33559746 DOI: 10.1007/s00442-021-04865-3
    Leaf litter and its breakdown products represent an important input of organic matter and nutrients to mangrove sediments and adjacent coastal ecosystems. It is commonly assumed that old-grown stands with mature trees contribute more to the permanent sediment organic matter pool than younger stands. However, neither are interspecific differences in leaf decay rates taken into account in this assumption nor is our understanding of the underlying mechanisms or drivers of differences in leaf chemistry sufficient. This study examines the influence of different plant species and ontogenetic stage on the microbial decay of mangrove leaf litter. A litterbag experiment was conducted in the Matang Mangrove Forest Reserve, Malaysia, to monitor leaf litter mass loss, and changes in leaf litter chemistry and microbial enzyme activity. Four mangrove species of different morphologies were selected, namely the trees Rhizophora apiculata and Bruguiera parviflora, the fern Acrostichum aureum and the shrub Acanthus ilicifolius. Decay rates of mangrove leaf litter decreased from A. ilicifolius to R. apiculata to B. parviflora to A. aureum. Leaf litter mass, total phenolic content, protein precipitation capacity and phenol oxidase activity were found to decline rapidly during the early stage of decay. Leaf litter from immature plants differed from that of mature plants in total phenolic content, phenolic signature, protein precipitating capacity and protease activity. For R. apiculata, but not of the other species, leaf litter from immature plants decayed faster than the litter of mature plants. The findings of this study advance our understanding of the organic matter dynamics in mangrove stands of different compositions and ages and will, thus, prove useful in mangrove forest management.
    Matched MeSH terms: Ecosystem*
  12. Gallardo B, Bogan AE, Harun S, Jainih L, Lopes-Lima M, Pizarro M, et al.
    Sci Total Environ, 2018 Sep 01;635:750-760.
    PMID: 29680765 DOI: 10.1016/j.scitotenv.2018.04.056
    Deforestation, climate change and invasive species constitute three global threats to biodiversity that act synergistically. However, drivers and rates of loss of freshwater biodiversity now and in the future are poorly understood. Here we focus on the potential impacts of global change on freshwater mussels (Order Unionida) in Sundaland (SE Asia), a vulnerable group facing global declines and recognized indicators of overall freshwater biodiversity. We used an ensemble of distribution models to identify habitats potentially suitable for freshwater mussels and their change under a range of climate, deforestation and invasion scenarios. Our data and models revealed that, at present, Sundaland features 47 and 32 Mha of habitat that can be considered environmentally suitable for native and invasive freshwater mussels, respectively. We anticipate that by 2050, the area suitable for palm oil cultivation may expand between 8 and 44 Mha, representing an annual increase of 2-11%. This is expected to result in a 20% decrease in suitable habitat for native mussels, a drop that reaches 30% by 2050 when considering concomitant climate change. In contrast, the habitat potentially suitable for invasive mussels may increase by 44-56% under 2050 future scenarios. Consequently, native mussels may compete for habitat, food resources and fish hosts with invasive mussels across approximately 60% of their suitable range. Our projections can be used to guide future expeditions to monitor the conservation status of freshwater biodiversity, and potentially reveal populations of endemic species on the brink of extinction. Future conservation measures-most importantly the designation of nature reserves-should take into account trends in freshwater biodiversity generally, and particularly species such as freshwater mussels, vital to safeguard fundamental ecosystem services.
    Matched MeSH terms: Ecosystem*
  13. Cazzolla Gatti R, Liang J, Velichevskaya A, Zhou M
    Sci Total Environ, 2019 Feb 20;652:48-51.
    PMID: 30359800 DOI: 10.1016/j.scitotenv.2018.10.222
    The globalization of the palm oil trade poses a menace to the ecosystem integrity of Southeast Asia. In this short communication, we briefly discuss why palm oil certifications may have failed as an effective means to halt forest degradation and biodiversity loss. From a comparison of multiple new datasets, we analysed recent tree loss in Indonesia, Malaysia, and Papua New Guinea, and discovered that, from 2001 to 2016, about 40% of the area located in certified concessions suffered from habitat degradation, deforestation, fires, or other tree damages. Certified concessions have been subject to more tree removals than non-certified ones. We also detect significant tree loss before and after the start of certification schemes. Beyond non-governmental organisations' concern that Roundtable on Sustainable Palm Oil (RSPO) and Palm Oil Innovation Group (POIG) certifications allow ongoing clearance of any forest not identified as of high conservation values (HCV) or high carbon stock (HCS), we suggest an alarming and previously overlooked situation, such as that current "sustainable palm oil" is often associated with recent habitat degradation and forest loss. In other words, certified palm oil production may not be so sustainable.
    Matched MeSH terms: Ecosystem
  14. Liu B, Lu Y, Deng H, Huang H, Wei N, Jiang Y, et al.
    Sci Total Environ, 2023 Sep 01;889:164173.
    PMID: 37201824 DOI: 10.1016/j.scitotenv.2023.164173
    Microplastic (MP) pollution is a serious global environmental problem, particularly in marine ecosystems. However, the pollution patterns of MPs in the ocean and atmosphere, particularly the sea-air interrelationship, remain unclear. Therefore, the abundance, distribution patterns, and sources of MPs in the seawater and atmosphere of the South China Sea (SCS) were comparatively investigated. The results showed that MPs were prevalent in the SCS with an average abundance of 103.4 ± 98.3 items/m3 in the seawater and 4.62 ± 3.60 items/100 m3 in the atmosphere. The spatial analysis indicated that the pollution patterns of seawater MPs were mainly determined by land-based discharge and sea surface currents, whereas atmospheric MPs were predominantly determined by air parcel trajectory and wind conditions. The highest MP abundance of 490 items/m3 in seawater was found at a station near Vietnam with current vortices. However, the highest MP abundance of 14.6 items/100 m3 in the atmosphere was found in air parcels with low-speed southerly winds from Malaysia. Similar MP compositions (e.g., polyethylene terephthalate, polystyrene, and polyethylene) were observed in the two environmental compartments. Furthermore, similar MP characteristics (e.g., shape, color, and size) in the seawater and atmosphere of the same region suggested a close relationship between the MPs in the two compartments. For this purpose, cluster analysis and calculation of the MP diversity integrated index were performed. The results showed an obvious dispersion between the two compartment clusters and a higher diversity integrated index of MPs in seawater than in the atmosphere, thus implying higher compositional diversity and more complex sources of MPs in seawater relative to the atmosphere. These findings deepen our understanding of MP fate and patterns in the semi-enclosed marginal sea environment and highlight the potential interrelationship of MPs in the air-sea system.
    Matched MeSH terms: Ecosystem
  15. Lei J, Booth DT, Rusli MU, Zhang Z
    Zoolog Sci, 2021 Feb;38(1):1-7.
    PMID: 33639712 DOI: 10.2108/zs200071
    Nest predation is the main cause of hatching failure for many turtle populations. For green turtles (Chelonia mydas) nesting at Chagar Hutang in Redang Island, Malaysia, Asian water monitors (Varanus salvator) are a potential nest predator. However, no studies have documented the space use of this species in coastal habitat adjacent to a sea turtle nesting beach to assess its potential impact on turtle nests. Here, we used Global Positioning System (GPS) data loggers to quantify space use of Asian water monitors in order to establish the extent to which they use sea turtle nesting areas. Asian water monitors had a diurnal activity pattern and spent most of their time in rain forest habitat behind the sea turtle nesting beach. The home range occupied by Asian water monitors varied between 0.015 and 0.198 km2 calculated by the Kernel Brownian Bridge method. The space use patterns of individual Asian water monitors varied between individuals. Two males had relatively small home ranges, whereas one male and the female had a relatively large home range. Because tracked Asian water monitors in this study rarely visited the sea turtle nesting areas, it is probable that only a few individuals are responsible for opening nests.
    Matched MeSH terms: Ecosystem*
  16. Henriksson PJG, Rico A, Troell M, Klinger DH, Buschmann AH, Saksida S, et al.
    Sustain Sci, 2018;13(4):1105-1120.
    PMID: 30147798 DOI: 10.1007/s11625-017-0511-8
    Global seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture's greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR.
    Matched MeSH terms: Ecosystem
  17. Chen A, Jiang J, Luo Y, Zhang G, Hu B, Wang X, et al.
    PeerJ, 2023;11:e16337.
    PMID: 38130929 DOI: 10.7717/peerj.16337
    Drought monitoring is crucial for assessing and mitigating the impacts of water scarcity on various sectors and ecosystems. Although traditional drought monitoring relies on soil moisture data, remote sensing technology has have significantly augmented the capabilities for drought monitoring. This study aims to evaluate the accuracy and applicability of two temperature vegetation drought indices (TVDI), TVDINDVI and TVDIEVI, constructed using the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) vegetation indices for drought monitoring. Using Guangdong Province as a case, enhanced versions of these indices, developed through Savitzky-Golay filtering and terrain correction were employed. Additionally, Pearson correlation analysis and F-tests were utilized to determine the suitability of the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) in correlation with TVDINDVI and TVDIEVI. The results show that TVDINDVI had more meteorological stations passing both significance test levels (P 
    Matched MeSH terms: Ecosystem*
  18. Dickinson L, Noble H, Gardner E, Puad ASA, Zakaria WNFW, Zerega NJC
    PeerJ, 2020;8:e9897.
    PMID: 33005490 DOI: 10.7717/peerj.9897
    Limestone karsts of Southeast Asia can harbor high levels of endemism, but are highly fragmented, increasingly threatened, and their biodiversity is often poorly studied. This is true of the Padawan Limestone Area of Sarawak, Malaysia, home to the endemic Artocarpus annulatus, the closest known wild relative of two important and underutilized fruit tree crops, jackfruit (A. heterophyllus) and cempedak (A. integer). Identifying and conserving crop wild relatives is critical for the conservation of crop genetic diversity and breeding. In 2016 and 2017, five A. annulatus populations were located, and leaf material, locality information, and demographic data were collected. Microsatellite markers were used to assess genetic diversity and structure among populations, and to compare levels of genetic diversity to closely related congeneric species. Results indicate no evidence of inbreeding in A. annulatus, and there is no genetic structure among the five populations. However, diversity measures trended lower in seedlings compared to mature trees, suggesting allelic diversity may be under threat in the youngest generation of plants. Also, genetic diversity is lower in A. annulatus compared to closely related congeners. The present study provides a baseline estimate of A. annulatus genetic diversity that can be used for comparison in future studies and to other species in the unique limestone karst ecosystems. Considerations for in situ and ex situ conservation approaches are discussed.
    Matched MeSH terms: Ecosystem
  19. Sullivan MJ, Talbot J, Lewis SL, Phillips OL, Qie L, Begne SK, et al.
    Sci Rep, 2017 01 17;7:39102.
    PMID: 28094794 DOI: 10.1038/srep39102
    Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.
    Matched MeSH terms: Ecosystem
  20. Grill G, Lehner B, Thieme M, Geenen B, Tickner D, Antonelli F, et al.
    Nature, 2019 05;569(7755):215-221.
    PMID: 31068722 DOI: 10.1038/s41586-019-1111-9
    Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them.
    Matched MeSH terms: Ecosystem
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