Spatial pattern in species richness of demersal fish assemblages on the continental shelf of the northern Mediterranean Sea: a multiscale analysis
|Author(s)||Gaertner J1, Bertrand Jacques2, Relini G3, Papaconstantinou C4, Mazouni N5, De Sola L6, Durbec J1, Jukic Peladic S7, Souplet Arnauld8|
|Affiliation(s)||1 : CNRS, UMR 6117, LMGEM, Ctr Oceanol Marseille, F-13007 Marseille, France.
2 : IFREMER, Lab Ecol Halieutique, F-44311 Nantes, France.
3 : Univ Genoa, I-16126 Genoa, Italy.
4 : NCMR, Aghios Kosmas Hellinikion, GR-16644 Athens, Greece.
5 : Cepralmar, F-34000 Montpellier, France.
6 : Ctr Oceanograph Malaga, Malaga, Spain.
7 : Inst Oceanografiju Ribarstvo, Split 21000, Croatia.
8 : IFREMER, Lab Ressources Halieutiques, F-34203 Sete, France.
|Source||Marine Ecology Progress Series (0171-8630) (Inter-Research), 2007-07 , Vol. 341 , P. 191-203|
|WOS© Times Cited||25|
|Keyword(s)||Lessepsian, Large scale, Mediterranean Sea, Groundfishes, Beta diversity, Species richness|
|Abstract||The species richness pattern of groundfish species in the entire northern Mediterranean Sea was examined at 3 spatial scales: region, large biogeographical zone and basin. We analysed 1914 trawl hauls collected using a single sampling design in the trawlable areas of the continental shelves between the Strait of Gibraltar and the Strait of Dardanelles (from 36.3 to 45.7 degrees N and 5.3 degrees W to 28 E). Spatial pattern in species diversity was assessed using complementary methods (Chao2 estimates of total species richness, mean species richness and beta diversity). No matter which scale was used, the expected longitudinally decreasing trend in species richness, which has been widely described in previous studies, did not appear when comparing estimates of total species richness per unit of area. Only the mean species richness pattern showed a moderate eastwards decrease at the largest spatial scale, but the trend progressively disappeared as the scale of analysis was reduced. In contrast to what is usually expected, our results suggest that Atlantic inflow does not play a key role in the present spatial pattern of fish species richness within the northern Mediterranean Sea. Furthermore, we show that the Aegean Sea can no longer be considered the least species-diverse zone in the northern Mediterranean Sea. Our results provide the first description of a quantitative 'reference state', with which the temporal changes in species richness patterns throughout the entire northern Mediterranean Sea can be compared in the future.|