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Theses

Effets du changement climatique sur la distribution de la macrofaune benthique en Manche

Abstract : In the North-East Atlantic, the English Channel constitutes a biogeographical transition zone between the Boreal and Lusitanian provinces. Thus, many species reach there their distribution range limits. The aim of this thesis is to assess the effects of recent climate change on the distribution of the subtidal benthic macrofauna, poorly studied to date, basing on the comparison of data collected during a cool period (i.e. 1960s-70s) and during a warm period (i.e. 2012 and 2014) in the circalittoral coarse sediments. Two large communities were highlighted in the study of the structure of the assemblages found in this habitat: the gravelly coarse sand community and the pebbles and gravels community. The analysis of the evolution of seabed temperature for the last 30 years showed the spatial heterogeneity of the warming, varying from 0.1 to 0.5°C per decade from West to East. This warming did not translate into large species distribution shifts but into a sharp decrease in the number of occurrences of cold-water species and a sharp increase in the number of occurrences of warm-water species. Development of species distribution models allowed to identify the relative importance of climatic and edaphic factors in the distribution of benthic invertebrates in the Channel and to assess the species’ ability to adjust their distribution to the rise in temperature. The whole results suggest that ongoing climate change could lead to a decrease in benthic biodiversity at range limits, especially where connection routes are lacking for new migrants.
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Submitted on : Monday, December 11, 2017 - 10:57:08 PM
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  • HAL Id : tel-01661329, version 1

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François Gaudin. Effets du changement climatique sur la distribution de la macrofaune benthique en Manche. Océanographie. Université Pierre et Marie Curie - Paris VI, 2017. Français. ⟨NNT : 2017PA066182⟩. ⟨tel-01661329⟩

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