Biodiversity issues for the forthcoming tropical Mediterranean Sea

Bianchi, Carlo Nike

doi:10.1007/978-1-4020-6156-1_1

Cited by 182 publications

(232 citation statements)

References 55 publications

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“…The geographical spread of species with affinities to warm water, similar to most species that enter from the Atlantic into the Mediterranean, has been observed in the Mediterranean region since the 1980s and correlates with direct and indirect recent global warming effects (BIANCHI, 2007) Because of the "meridionalisation" of the Mediterranean Sea, more intensive efforts should be devoted to the monitoring of the northward expansion of indigenous and allochthonous thermophilic species. Additionally, a parallel study of the evolution in water mass circulation may be undertaken to detect biodiversity changes, particularly in the top mid-water predators.…”

Section: Spatio-temporal Distribution and Biological Characteristics mentioning

confidence: 99%

Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae) in the eastern Mediterranean and the implication on its range expansion

et al. 2011

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The neon flying squid Ommastrephes bartramii is found circumglobally in subtropical, temperate waters and sustains important fisheries in the North Pacific, but it is rarely encountered in the Mediterranean Sea. During the last decade, and particularly since 2004, the frequency of its presence in the Aegean Sea and nearby regions has increased, raising a question about a change in the species distribution and abundance in this area. In this study, we reviewed the literature on O. bartramii findings in the Mediterranean Sea and present new data describing body and beak morphometry, diet and the maturity of specimens recently collected from the easternmost basins. According to data from the entire Mediterranean Sea, collected individuals reached 66 cm in mantle length (ML), wherein only females were larger than 32 cm in ML. An isometric growth in body weight (BW) was shown, whereas the growth of the lower beak rostral length (LRL) was allometrically positive in relation to the ML. Occasional catches by jigs during experimental cruises provided most of the individuals recorded in the period from 1982-1992. In contrast, the most recent records are primarily comprised of mature females collected on or near the shore in the eastern basin and of predominantly smaller individuals from the western basin caught by professional jigging fisheries. The distribution of the specimen recorded from the Aegean Sea indicates an association between the species distribution and the circulation of the warm Levantine Intermediate Water. The more frequent observations of moribund spawning females at the periphery of the Cretan Sea are indicative of a spawning ground at this area. The suspected recent increase of O. bartramii abundance in both the northeastern and northwestern basins might be due to the warming of upper sea layers, which has been observed since the mid-1980s and is considered to be the main factor driving the northward expansion of the warm-water species' range within the Mediterranean Sea.

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Section: Spatio-temporal Distribution and Biological Characteristics mentioning

confidence: 99%

Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae) in the eastern Mediterranean and the implication on its range expansion

et al. 2011

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“…Yet, these and other factors, such as the area of rocky substrate at present and at LGM, summer maxima and winter minima in SST, distance to nearest potential refugia in both shallow and deeper water, cannot be ignored and should be further explored to better our understanding of sponge diversity patterns in this area. Furthermore, understanding the relationships between biological traits of individual species or groups and their ecological requirements, in addition to their responses to past climate, will prove essential in predicting future climate effects on marine biodiversity (see Bianchi, 2007).…”

Section: Diversity Patterns Of the Northeast Atlantic And Mediterranementioning

confidence: 99%

Diversity patterns and zoogeography of the Northeast Atlantic and Mediterranean shallow-water sponge fauna

Xavier

Soest

2011

Hydrobiologia

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Recognizing and understanding presentday biodiversity and biogeographical patterns and how these relate to contemporary and past climate is pivotal to predict the effect of future climate on marine biodiversity and promote adequate conservation policies. Sponges constitute an important and dominant component of the marine benthos and are therefore an excellent model group for such investigations. In this study, we assessed the diversity patterns and the zoogeographical affinities of the Northeast Atlantic and Mediterranean shallow-water demosponge assemblages. Data on the distribution of 745 species throughout 28 areas was compiled from the literature and used to build a presence/absence matrix. Diversity patterns were assessed from estimates of species richness (S) and taxonomic distinctness (AvTD). The Mediterranean Sea proved to be more diverse both in terms of species richness and taxonomic distinctness (S = 539, AvTD = 94.74) than the Northeast Atlantic (S = 480, AvTD = 92.42) and the two regions together were found to constitute a diversity hotspot harbouring approximately 11% of the global demosponge diversity. We found an Atlantic N-S and a Mediterranean NW-SE gradient of increasing taxonomic distinctness that is strongly correlated to both contemporary (R 2 = 0.5667; P \ 0.01) and historical values (R 2 = 0.7287; P \ 0.01) of sea surface temperature (SST) at the Last Glacial Maximum (LGM). The zoogeographical affinities examined through classification (cluster analysis) and ordination (nonmetric multidimensional scaling, nMDS) based on the Bray-Curtis similarity index, revealed the presence of three groups approximately corresponding to the Northern European Seas, Lusitanian and Mediterranean provinces outlined in the 'Marine Ecoregions of the World' (MEOW) classification system. Geographical distance and oceanographic circulation were shown to constitute important factors in shaping the zoogeographical affinities among areas. The vast majority of the species occurring in the Northeast Atlantic and the Mediterranean (67 and 57%, respectively) was shown to have extremely restricted geographical ranges, as single-area or narrow-range (2-3 areas) endemics, which raises some concerns regarding their conservation.

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“…Most of the immigrants come from the Red Sea, biogeographically part of the Indo-West Pacific (IWP) realm; a few fish species are coming in from the south and west through the Strait of Gibraltar; and other species are being carried by human-aided transport (Por, 2010). Superficially, this so-called tropicalization (Bianchi, 2007) will restore a biogeographical link between the Mediterranean and IWP that last existed during the Middle Miocene, about 16 million years ago (Ma). This new tropical signature will, however, differ substantially from that prevailing during the warm Early Pliocene (5 to 3 Ma), when most tropical elements in southern Europe had eastern Atlantic (that is, West African) affinities.…”

Section: Introductionmentioning

confidence: 99%

The tropical history and future of the Mediterranean biota and the West African enigma

Vermeij

2011

Journal of Biogeography

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Aim Since the opening of the Suez Canal in 1869, many tropical taxa from the Indo‐West Pacific (IWP) realm have entered the Mediterranean Sea, which is experiencing rising temperatures. My aims are: (1) to compare biogeographically this tropical transformation of the Mediterranean biota with the tropical faunas of the Mediterranean and adjacent southern European and West African seas during the Late Oligocene to Pliocene interval; (2) to infer the relative contributions of the tropical eastern Atlantic and IWP to the tropical component of the marine biota in southern Europe; and (3) to understand why West Africa is not now a major source of warm‐water species. Location Southern Europe, including the Mediterranean Sea, and the coast of tropical West Africa. Methods I surveyed the literature on fossil and living shell‐bearing molluscs to infer the sources and fates of tropical subgenus‐level taxa living in southern Europe and West Africa during the Late Oligocene to Pliocene interval. Results Ninety‐four taxa disappeared from the tropical eastern Atlantic (including the Mediterranean) but persisted elsewhere in the tropics, mainly in the IWP (81 taxa, 86%) and to a lesser extent in tropical America (36 taxa, 38%). Nine taxa inferred to have arrived in the tropical eastern Atlantic from the west after the Pliocene did not enter the Mediterranean. The modern West African fauna is today isolated from that of other parts of the marine tropics. Main conclusions Taxa now entering the Mediterranean through the Suez Canal are re‐establishing a link with the IWP that last existed 16 million years ago. This IWP element, which evolved under oligotrophic conditions and under a regime of intense anti‐predatory selection, will continue to expand in the increasingly warm and increasingly oligotrophic Mediterranean. The IWP source fauna contrasts with the tropical West African biota, which evolved under productive conditions and in a regime of less anti‐predatory specialization. Until now, the post‐Pliocene West African source area has been isolated from the Mediterranean by cold upwelling. If further warming should reduce this barrier, as occurred during the productive and warm Early Pliocene, the Mediterranean could become a meeting place for two tropical faunas of contrasting source conditions.

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Biodiversity issues for the forthcoming tropical Mediterranean Sea

Cited by 182 publications

References 55 publications

Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae) in the eastern Mediterranean and the implication on its range expansion

Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae) in the eastern Mediterranean and the implication on its range expansion

Diversity patterns and zoogeography of the Northeast Atlantic and Mediterranean shallow-water sponge fauna

The tropical history and future of the Mediterranean biota and the West African enigma

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