31 research outputs found

    Molecular systematics and cryptic diversity of the genus <i>Dictyota</i> (Dictyotales: Phaeophyta) with special reference to species occurring in the Philippines

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    In order to study the molecular systematics and cryptic diversity of the brown macroalgal genus, Dictyota (Dictyotales: Phaeophyta), 3 objectives were set: 1. to make an inventory of the Dictyota species occurring in the Philippines; 2. to determine congruence between morphological and phylogenetic species concepts; 3. to study cryptic diversity in the Dictyota dichotoma complex. This thesis puts special emphasis on Philippine Dictyota species.Inventory and morphological examination of specimens collected in the islands of Visayas in the Philippines revealed that at least 7 species of Dictyota can be found in the region. The species identified were the following: Dictyota bartayresiana Lamouroux, D. canaliculata De Clerck & Coppejans, D. cervicornis Kütz., D. ceylanica Kütz, D. ciliolate Sond. ex Kütz, D. crispate J.V. Lamour and D. friabilis Setchell. Dictyota dichotoma which had been frequently reported from several localities throughout the Philippines was not encountered during the present study. De Clerck (2003) seriously doubted the presence of the generitype, D. dichotoma (originally described from England) in tropical latitudes.The phylogenetic analyses (focusing on Maximum likelihood tree outputs) used the LSU nrRNA gene, the plastid encoded rbcL gene, and interleaved nrRNA- LSU gene sequences of Dictyota species and other Dictyotaceae taxa as outgroups. The total numbers of taxa used for each dataset were 44, 35, and 29 taxa, respectively. Apart from Philippine samples, sequences were obtained from Dictyota and Dictyotales specimens from several different geographic regions. Some sequences deposited in GENBANK were also included in the analyses.The family Dictyotaceae, the largest in the order Dictyotales, is subdivided into two tribes: Dictyoteae and Zonariae. The Dictyoteae are recognized by the single lens shaped apical cell as opposed to a row or group of apical cells found in the Zonariae. Scoresbyella, the only genus of Scoresbyellaceae and characterized by a wedge shaped vertically oriented apical cell, appears closely related to the Dictyoteae in the analyses

    Environment and Rural Affairs Monitoring & Modelling Programme - ERAMMP Report-57: Image Resolution Testing for Soil Erosion and Damage Features

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    Maintaining healthy soils in Wales is important in order to ensure the sustainable management of natural resources under the environment act. Monitoring of soils in Wales is conducted in order to assess the state and change of soils and forms part of the state of natural resources reporting cycle (SoNaRR), quantify the impact of Glastir on soil health and contribute to a range of other reporting requirements. Soil monitoring by ERAMMP is primarily based on structured sampling of topsoil but has also used aerial photography for peat condition and modelling. This report details work that examines the potential use of remote sensing for assessing the extent of soil erosion and damage (SED), and landsliding from space. The objective was to test different remote sensing imagery data sources, e.g. sentinel (~10m) and planet data (~3m) against high resolution APGB aerial imagery (~0.25m, by Bluesky International Limited), to determine if the resolution of the imagery is acceptable to replace aerial photographs for identifying features. The report summarises two tests of the data, one on the extent of soil erosion and damage and the other on coastal erosion and landslides
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