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Nāgpur, India

Sahu A.,Indian Institute of Science | Singh S.K.,Banaras Hindu University | Sahu N.,GIS Section | Manna M.C.,Indian Institute of Science
Ecology, Environment and Conservation | Year: 2016

Heavy metals are potentially toxic to human life and the environment. Various extraction procedures were employed for measuring extractable concentrations of potential toxic elements in soil. In a greenhouse pot experiment, three taxonomically different soil orders viz. Typic Ustochrepts (alluvial soil), Typic Rhodustalfs (red soil) and Entic Chromusterts (karail soil) with pH ranging from 5.7 to 8.2 were used. These soils were artificially spiked with different Cd levels (0,5,10,25,50 and 100 mg Cd kg-1). After one month of incubation, extractability of Cd in soils was compared by six extractants:DTPA, AB-DTPA, Mehlich 1, Mehlich III, 0.1 N HC1 and CH3COOH to predict Cd bioavailability in soils. African Marigold (Tagetes erecta L.) was used as test species. Suitability of these extractants in relation to plant tissue concentration and uptake of Cd were also investigated. Extractability of Cd in soils varied depending on extractants used. It was found that 0.1 N HC1 extracted the largest portion of Cd irrespective of soil types. Correlation study of Cd content in soil extracted by different extractants with plant tissue concentration and uptake revealed that best extractant was AB DTP A in Typic Ustochrepts, Mehlich 1 in Typic Rhodustalfs and CH3COOH in Entic Chromusterts. Copyright © EM International.

Oo K.S.,University of Tokyo | Van Ngoc A.,University of Tokyo | Takeuchi W.,University of Tokyo | Hlaing N.,GIS Section | Than M.M.,Research and Training
32nd Asian Conference on Remote Sensing 2011, ACRS 2011 | Year: 2011

National land covers for 10 years (2001 - 2010) are generated from MODIS monthly composites (Takeuchi W. and et al. 2010). The auto-generated land covers are needed to validate based on the local knowledge and local legend. On the other hand, SAFE's technical support provided AVNIR2 images for some training sites in Myanmar. The AVNIR2 image has advantage with better spatial resolution than MODIS. This advantage could be applied to validate the MODIS data. Thus, the training forest cover could be generated from the AVNIR2 image. In the satellite remote sensing, vegetation reflectance could be calculated from the multispectral images. While the land cover reflectance indexes are available, the forest types could be detected based on the decision logic classification. The study maps the mangrove forests of Meinmahla Island and Bogalay area in Ayeyarwaddy delta with overall accuracy of 92%.

Stanton P.,PO Box 154 | Stanton D.,719 Logan Road | Stott M.,GIS Section | Parsons M.,Recreation
Australian Forestry | Year: 2014

The vegetation and geology of the Wet Tropics Bioregion of North Queensland, covering 1 998 150 ha, were mapped at a scale of 1:50 000. The resulting geographic information system (GIS) data base provided an unprecedented opportunity to examine vegetation condition across the entire bioregion. Mapping used colour aerial photography at 1:25 000, informed by ground truthing. Vegetation type, nature of the understory and ground cover, degree and type of disturbance, and the presence of secondary vegetation were described by a coding system, with codes marked directly on the aerial photos.Analysis of these data has confirmed a picture, which emerged from ground truthing, of large areas of sclerophyll woodland and forest being invaded by a rainforest understory that prevents regeneration of the sclerophyll canopy. Fifty-three per cent of the native vegetation of the bioregion consists of non-rainforest vegetation types, dominated in both area and number by sclerophyll woodlands and forests. Seventeen per cent of the 735 713 ha of sclerophyll woodland and forest types were assessed as having suffered irreversible change. Between 25% and 79% of individual forest vegetation types were judged to have been affected by irreversible change. No climatic changes, or changes in the environment, apart from those related to changing fire regimes, were identified as causative factors. Changed fire regimes, predominantly fire exclusion, are considered to be the most likely cause. © 2014 Institute of Foresters of Australia (IFA).

Stanton P.,PO Box 154 | Parsons M.,Recreation | Stanton D.,719 Logan Road | Stott M.,GIS Section
Australian Forestry | Year: 2014

Meeting all four natural criteria for United Nations World Heritage listing, the Wet Tropics World Heritage Area that covers 61% of the remaining vegetation of the bioregion conserves, on a biodiversity basis, habitats containing threatened species of outstanding universal value from the point of view of science or conservation. As discussed in an accompanying paper by the same authors, the Wet Tropics Bioregion faces a level of habitat change unprecedented in threat and scale and manifested in the transition of sclerophyll forests and woodlands to closed forest habitats, a change attributable to the absence of fire or reduction in its frequency.The implications of habitat change for certain threatened species and ecosystems present a challenge to conserving the ark of biodiversity the Wet Tropics represents. Evidence indicates that the dominant reason for these changes in vegetation patterns is the reduction in fire or its exclusion across a bioregion with the highest rainfall of the nation. It is clear that the bioregion is suffering and with present trends, will continue to suffer, a major loss of habitat diversity. © 2014 Institute of Foresters of Australia (IFA).

Van Dongen R.,GIS Section | Huntley B.,GIS Section | Gibson L.,Keiran mara Conservation Science Center
PLoS ONE | Year: 2014

The Montebello archipelago consists of 218 islands; 80 km from the north-west coast of Western Australia. Before 1912 the islands had a diverse terrestrial fauna. By 1952 several species were locally extinct. Between 1996 and 2011 rodents and cats were eradicated, and 5 mammal and 2 bird species were translocated to the islands. Monitoring of the broader terrestrial ecosystem over time has been limited. We used 20 dry-season Landsat images from 1988 to 2013 and estimation of green fraction cover in nadir photographs taken at 27 sites within the Montebello islands and six sites on Thevenard Island to assess change in vegetation density over time. Analysis of data averaged across the 26-year period suggests that 719 ha out of 2169 ha have increased in vegetation cover by up to 32%, 955 ha have remained stable and 0.6 ha have declined in vegetation cover. Over 492 ha (22%) had no vegetation cover at any time during the period analysed. Chronological clustering analysis identified two breakpoints in the average vegetation cover data occurring in 1997 and 2003, near the beginning and end of the rodent eradication activities. On many islands vegetation cover was declining prior to 1996 but increased after rodents were eradicated from the islands. Data for North West and Trimouille islands were analysed independently because of the potential confounding effect of native fauna being introduced to these islands. Mala (Lagorchestes hirsutus) and Shark Bay mice (Pseudomys fieldi) both appear to suppress native plant recruitment but not to the same degree as introduced rodents. Future research should assess whether the increase in vegetation cover on the Montebello islands is due to an increase in native or introduced plants. © 2014 Lohr et al.

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