7 resultados para geographic distribution

em Plymouth Marine Science Electronic Archive (PlyMSEA)


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The Continuous Plankton Recorder survey provides pan-oceanic data on geographic distribution, species composition, seasonal cycles of abundance, and long-term change during the last 70 years. In this paper we compare and contrast some of the historic data-analytic protocols of the survey, focusing primarily on the various means by which spatio-temporal information in CPR data has been exposed. Relative strengths and limitations are assessed, followed by suggestions for future approaches to the visualisation and summarising of CPR data.

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Background The seas around Scotland are rich and diverse – Scotland’s position at the edge of the continental shelf, the long coastline, large area of sea and the mixing of warm and coldwater currents combine to make its waters a special place for marine wildlife and habitats. Scotland has over 18,000 km of coastline and its inshore and offshore areas are among the largest of any EU country, representing 13% of all European seas. Scotland’s seas are of outstanding scenic, historical and cultural value and are part of the national identity at home and abroad. The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers and duties to ensure that our seas are managed sustainably for future generations, integrating the economic growth of marine industries with the need to protect these assets. Measures to conserve Scotland’s marine natural heritage are based on a three pillar approach, with action at the wider seas level (e.g. marine planning or sectoral controls); specific species conservation measures (e.g. improved protection for seals); and through site protection measures - the identification of new Marine Protected Areas (MPAs). To help target action under each of the three pillars, Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have generated a focused list of habitats and species of priority conservation importance - the Priority Marine Features (PMFs). The aim of the current study was to produce a descriptive catalogue of the Scottish PMFs (including component habitats and species where appropriate) to serve as a reference for future nature conservation action. Whilst derived from available existing accounts, the succinct 1-page descriptions are written from a Scottish perspective, refining, but clearly linking to more generic UK, EC or OSPAR (Oslo and Paris Commission) commentary. Available information on the geographic distribution of the features was collated as part of the project and a summary map is provided in each description. Main findings  This project has generated a descriptive catalogue of the 81 PMFs that have been identified in the seas around Scotland (out to the limit of the UK continental shelf). The list comprises 26 broad habitats (e.g. burrowed mud), seven low or limited mobility species (e.g. ocean quahog) and 48 mobile species, including fish (e.g. blue ling) and marine mammals (e.g. minke whale).  Information on the distribution of the PMFs was collated within a Geographic Information System (GIS). This is the first time that data about such a diverse range of Scottish marine nature conservation interests have been compiled within a single repository. These data have and will be used in conjunction with other contextual base-mapping to inform the development of nature conservation advice and commentary (e.g. in the production of the Scotland’s Marine Atlas - Baxter et al., 2011).  The feature distribution mapping used in the production of this report is being made available to view online via the National Marine Plan Interactive web portal (NMPi - http://www.gov.scot/Topics/marine/seamanagement/nmpihome). As new or refined data on Scottish PMFs become available, these will be fed into updates to the project geodatabase and NMPi.

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Background The seas around Scotland are rich and diverse – Scotland’s position at the edge of the continental shelf, the long coastline, large area of sea and the mixing of warm and coldwater currents combine to make its waters a special place for marine wildlife and habitats. Scotland has over 18,000 km of coastline and its inshore and offshore areas are among the largest of any EU country, representing 13% of all European seas. Scotland’s seas are of outstanding scenic, historical and cultural value and are part of the national identity at home and abroad. The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers and duties to ensure that our seas are managed sustainably for future generations, integrating the economic growth of marine industries with the need to protect these assets. Measures to conserve Scotland’s marine natural heritage are based on a three pillar approach, with action at the wider seas level (e.g. marine planning or sectoral controls); specific species conservation measures (e.g. improved protection for seals); and through site protection measures - the identification of new Marine Protected Areas (MPAs). To help target action under each of the three pillars, Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have generated a focused list of habitats and species of priority conservation importance - the Priority Marine Features (PMFs). The aim of the current study was to produce a descriptive catalogue of the Scottish PMFs (including component habitats and species where appropriate) to serve as a reference for future nature conservation action. Whilst derived from available existing accounts, the succinct 1-page descriptions are written from a Scottish perspective, refining, but clearly linking to more generic UK, EC or OSPAR (Oslo and Paris Commission) commentary. Available information on the geographic distribution of the features was collated as part of the project and a summary map is provided in each description. Main findings  This project has generated a descriptive catalogue of the 81 PMFs that have been identified in the seas around Scotland (out to the limit of the UK continental shelf). The list comprises 26 broad habitats (e.g. burrowed mud), seven low or limited mobility species (e.g. ocean quahog) and 48 mobile species, including fish (e.g. blue ling) and marine mammals (e.g. minke whale).  Information on the distribution of the PMFs was collated within a Geographic Information System (GIS). This is the first time that data about such a diverse range of Scottish marine nature conservation interests have been compiled within a single repository. These data have and will be used in conjunction with other contextual base-mapping to inform the development of nature conservation advice and commentary (e.g. in the production of the Scotland’s Marine Atlas - Baxter et al., 2011).  The feature distribution mapping used in the production of this report is being made available to view online via the National Marine Plan Interactive web portal (NMPi - http://www.gov.scot/Topics/marine/seamanagement/nmpihome). As new or refined data on Scottish PMFs become available, these will be fed into updates to the project geodatabase and NMPi.

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Aim Recent studies have suggested that global diatom distributions are not limited by dispersal, in the case of both extant species and fossil species, but rather that environmental filtering explains their spatial patterns. Hubbell's neutral theory of biodiversity provides a framework in which to test these alternatives. Our aim is to test whether the structure of marine phytoplankton (diatoms, dinoflagellates and coccolithophores) assemblages across the Atlantic agrees with neutral theory predictions. We asked: (1) whether intersite variance in phytoplankton diversity is explained predominantly by dispersal limitation or by environmental conditions; and (2) whether species abundance distributions are consistent with those expected by the neutral model. Location Meridional transect of the Atlantic (50 degrees N50 degrees S). Methods We estimated the relative contributions of environmental factors and geographic distance to phytoplankton composition using similarity matrices, Mantel tests and variation partitioning of the species composition based upon canonical ordination methods. We compared the species abundance distribution of phytoplankton with the neutral model using Etienne's maximum-likelihood inference method. Results Phytoplankton communities are slightly more determined by niche segregation (24%), than by dispersal limitation and ecological drift (17%). In 60% of communities, the assumption of neutrality in species' abundance distributions could not be rejected. In tropical zones, where oceanic gyres enclose large stable water masses, most communities showed low species immigration rates; in contrast, we infer that communities in temperate areas, out of oligotrophic gyres, have higher rates of species immigration. Conclusions Phytoplankton community structure is consistent with partial niche assembly and partial dispersal and drift assembly (neutral processes). The role of dispersal limitation is almost as important as habitat filtering, a fact that has been largely overlooked in previous studies. Furthermore, the polewards increase in immigration rates of species that we have discovered is probably caused by water mixing conditions and productivity.