%0 Journal Article %J ICES Journal of Marine Science %D 2018 %T Marine sublittoral benthos fails to track temperature in response to climate change in a biogeographical transition zone %A François Gaudin %A Nicolas Desroy %A Stanislas Dubois %A Caroline Broudin %A Louis Cabioch %A Jérôme Fournier %A Franck Gentil %A Jacques Grall %A Céline Houbin %A Patrick Le Mao %A Eric Thiébaut %X
Species ranges are shifting globally to track temperature changes in response to climate warming, with substantial variability among taxa. In
the English Channel, a biogeographical transition zone between the cold temperate and warm temperate provinces of the North-East Atlantic, distribution shifts have been relatively well documented for plankton, fish and intertidal benthic organisms, but little information is available on sublittoral benthos. Following a description of the magnitude of the sea bottom temperature (SBT) rise, the changes in the distribution and occupancy of 65 benthic invertebrate species were analysed by comparing data collected throughout the English Channel at more
than 200 stations sampled during a cool period in the 1960s–1970s and at present in 2012–2014. A non-uniform rise in SBT for the last three
decades was observed at the regional scale, varying from 0.07 to 0.54C per decade. This rise differs from that reported for sea surface temperature
(SST) in stratified areas suggesting that SBT should be used rather than SST to analyse responses of subtidal organisms to climate change. Despite shifts in both minimum and maximum sea bottom isotherms (2.5 and 3.2 km.year1, respectively), the distribution centroid shift of most species remained <1.0 km.year1, regardless of the average temperatures they usually experience. Conversely, decreases were observed in the occurrence of most cold-water species and increases were found in the occurrence of most warm-water species. These 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.
This study aims to describe the patterns of soft bottom macrozoobenthic richness along French coasts. It is based on a collaborative database developed by the “Réseau des Stations et Observatoires Marins” (RESOMAR). We investigated patterns of species richness in sublittoral soft bottom habitats (EUNIS level 3) at two different spatial scales: 1) seaboards: English Channel, Bay of Biscay and Mediterranean Sea and 2) 0.5° latitudinal and longitudinal grid. Total observed richness, rarefaction curves and three incidence-based richness estimators (Chao2, ICE and Jacknife1) were used to compare soft bottom habitats species richness in each seaboard. Overall, the Mediterranean Sea has the highest richness and despite higher sampling effort, the English Channel hosts the lowest number of species. The distribution of species occurrence within and between seaboards was assessed for each major phylum using constrained rarefaction curves. The Mediterranean Sea hosts the highest number of exclusive species. In pairwise comparisons, it also shares a lower proportion of taxa with the Bay of Biscay (34.1%) or the English Channel (27.6%) than that shared between these two seaboards (49.7%). Latitudinal species richness patterns along the Atlantic and English Channel coasts were investigated for each major phylum using partial LOESS regression controlling for sampling effort. This showed the existence of a bell-shaped latitudinal pattern, highlighting Brittany as a hotspot for macrobenthic richness at the confluence of two biogeographic provinces.
%B Journal of Sea Research %V 130 %P 96 - 106 %G eng %U http://www.sciencedirect.com/science/article/pii/S1385110116302660 %R https://doi.org/10.1016/j.seares.2017.03.011