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Summary Forty -thalassemia genes from unrelated German heterozygotes with no known foreign ancestry were examined using the oligonucleotide technique and DNA restriction analysis, with the aim of determining the contribution of Mediterranean -thalassemia mutations to the prevalence of this trait in the German population. Of the 40 -thalassemia genes, 26 were identified as Mediterranean types (20 39 nonsense, 3 IVS2 nt 110, 2 IVS2 nt1, 1 IVS1 ntl GA). The geographic distribution of the birthplaces of the probands' grandparents revealed no difference in the proportion of Mediterranean and unidentified -thalassemia genes in the west and the north of Germany. 相似文献
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The family Mugilidae (Pisces, Mugiliformes) includes species which are present in all tropical and temperate regions. Six species, Chelon labrosus, Mugil cephalus, Liza aurata, L. ramada, L. saliens, Oedalechilus labeo, are commonly found in the Mediterranean. These species have been widely studied through morphological, biochemical, and molecular markers. However, their phylogenetic relationships, and therefore the assumed monophyly of Liza species, still remain unclear: To further investigate this topic, gene-enzyme systems and sequences of the partial 16S rRNA mitochondrial gene were analyzed in Italian samples of all six Mediterranean species. The phylogenetic reconstructions indicated M. cephalus as being the most divergent species and the existence of a main cluster including all the Mediterranean species of Liza and C. labrosus. The parametric bootstrap approach adopted to test alternative phylogenetic hypotheses indicated that the Mediterranean species of Liza do not form a monophyletic group exclusive of Chelon. 相似文献
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La?la Rhazi Patrick Grillas Er-Riyahi Saber Mouhssine Rhazi Luc Brendonck Aline Waterkeyn 《Hydrobiologia》2012,689(1):23-36
Although Mediterranean temporary pools are of great value for conservation, they are in rapid decline under the impact of
various forms of anthropogenic pressure. Their disappearance from the landscape may result in a weakening of the biological
connections between pools due to increasing isolation and the impoverishment of their communities. In Western Morocco (province
of Benslimane), temporary pools have undergone severe regression over the past decades. The quantification of these losses
and the impact on the richness of plant communities remain, however, unstudied. Since this is of vital importance for the
conservation of the biodiversity of these habitats, a study has been undertaken associating (1) an assessment of the pool
losses (both in density and surface area) between 1955 and 2001 using remote sensing, (2) surveys of vegetation and water
depth (in 2006) in 48 pools, and (3) an assessment of the density and surface area of pools occurring within a 3 km radius
around each of the sampled pools. The results show a loss of 23% in number and 61% in surface area of pools in the province
over a period of 47 years. This decline, promoted by their small size and shallowness, is probably related to socio-economic
changes (intensification of agricultural practices and population growth). The richness in characteristic and rare species
of the pools was related to both local (water depth) and regional features (land use, pool density and total water surface
area in the surrounding landscape). The significant impact of the current density of pools and their total surface area on
the conservation value of the studied pools suggests a weakening of the metacommunity dynamics between pools. Given the rapid
socio-economic changes in the province and the current rate of pool disappearance (0.5% per year) we predict a continuing
reduction in pool density with a high risk of the widespread loss of their unique flora in the long term. 相似文献
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Bella S. Galil 《Biological invasions》2000,2(2):177-186
Exotic macrophytes, invertebrates and fish are found in most coastal habitats in the Mediterranean Sea. The Mediterranean
Sea has been subjected to introductions of non-indigenous species by ship traffic since the opening of interoceanic maritime
routes five centuries ago. The Sea, a hub of shipping, is exceptionally susceptible to invaders that arrive in fouling communities
or ballast. The Suez Canal has been the largest pathway for the entry of these species: more than 300 Erythrean species –
principally molluscs, fish, decapod crustaceans, polychaetes and algae – have become established in the eastern Mediterranean,
primarily along the Levantine coasts. Mariculture of nonindigenous shellfish predominates in the northern Mediterranean lagoonar
environments. Unrestricted transport of commercially important exotic shellfish has resulted in numerous unintentional introductions
of pathogens, parasites and pest species. Some invaders have outcompeted or replaced native species locally, severely reducing
biodiversity; some other invaders are so abundant they are exploited commercially. The rate of these biotic invasions has
increased in recent decades, and they collectively have significant ecological and economic impacts in the Mediterranean Sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Coexistence in Mediterranean warblers: ecological differences or interspecific territoriality? 总被引:1,自引:0,他引:1
We studied the coexistence of four species of Sylvia warblers living in Mediterranean matorral in order to identify the respective role of ecological segregation and of interspecific territoriality in explaining the local distribution of these four species. Data on habitat use, foraging behaviour and interspecific spacial segregation were collected on Corsica and on Spargi (Sardinia) islands. Despite large overlap in patch selection and in foraging behaviour the four species did segregate ecologically and behaviourally while foraging (differences in the choice of plant species used for foraging, in the height of the plant selected, in the selection of the portion of the plant volume used and in the selection of the plant structure explored). Complementarity in foraging behaviour was observed in the morphologically and ecologically closest species: the Dartford ( Sylvia undata ) and the Marmora's ( Sylvia sarda ) warblers. We did not observe any evidence of direct interspecific interactions in song, alarm, or aggressive behaviour. Nor did we observe patterns of spatial distribution that would support the idea of coexistence by interspecific territorial exclusion. These results contrast with the results of Cody & Walter (1976) suggesting interspecific territoriality in Mediterranean Sylvia warblers. They are consistent with other published results emphasizing ecological differences as explanation for species coexistence. 相似文献
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MIGUEL VERDÚ JUAN A. BARRÓN-SEVILLA ALFONSO VALIENTE-BANUET NOE FLORES-HERNÁNDEZ PATRICIO GARCÍA-FAYOS 《Botanical journal of the Linnean Society. Linnean Society of London》2002,138(3):297-303
The sclerophyllous, evergreen vegetation found in Mexico under tropical climate is named 'Mexical' (MEX) and presents many traits that have been thought to converge under a Mediterranean climate. Flowering phenology is strongly similar across Mediterranean-type ecosystems (MTEs) and this paper investigates MEX plant phenology in this context. The common history of the vegetation and the differences in the climatic conditions experienced by MEX and MTE taxa provide an ideal scenario to infer the relative importance of natural selection and historical constraints in the phenological response of plants to climatic conditions. This study has involved collecting field and bibliographic data on flowering phenology of MEX communities to detect (1) similarities at the community level between MTEs and MEX, (2) similarities between Tertiary and Quaternary taxa in MTEs and MEX, and (3) similarities between congeneric taxa from MEX and MTEs (taxa sharing a common ancestor but having evolved under different climates). Flowering in MEX does not occur mainly in spring, as in MTEs, but in summer, suggesting a response that maximizes water use in the rainy season. Flowering phenology of MEX species differed from their MTE congeneric species, suggesting that even though a common ancestor is shared, environmental pressures have led to different phenological responses in MEX and MTE plants. The flowering season for species that originated in the Tertiary and Quaternary did not differ in MEX, as expected, because of climatic uniformity along the whole time line. In MTEs, flowering differences between Tertiary and Quaternary species were not congruent, suggesting that the balance between the historical constraints and the selective force of the Mediterranean climate is different among the three MTEs, and a particular explanation is needed for each. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 297–303. 相似文献
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Eleni Voultsiadou 《Helgoland Marine Research》2005,59(3):237-251
The purpose of this paper was to investigate patterns of demosponge distribution along gradients of environmental conditions in the biogeographical subzones of the eastern Mediterranean (Aegean and Levantine Sea). The Aegean Sea was divided into six major areas on the basis of its geomorphology and bathymetry. Two areas of the Levantine Sea were additionally considered. All available data on demosponge species numbers and abundance in each area, as well as their vertical and general geographical distribution were taken from the literature. Multivariate analysis revealed a NW–SE faunal gradient, showing an apparent dissimilarity among the North Aegean, the South Aegean and the Levantine Sea, which agrees with the differences in the geographical, physicochemical and biological characteristics of the three areas. The majority of demosponge species has been recorded in the North Aegean, while the South Aegean is closer, in terms of demosponge diversity, to the oligotrophic Levantine Sea. The number of studies in the Aegean and Levantine subareas was positively correlated with the number of species recorded within each Aegean subarea. Demosponge species with an Altanto-Mediterranean distribution prevailed in the Aegean and the Levantine. The reduced contribution of the endemic component, as compared to the western Mediterranean, is consistent with the general NW–SE decrease in the number of endemic species in the Mediterranean. Demosponge distribution at the order level showed also a NW–SE gradient, similar to that observed in the entire Atlantic–Mediterranean region, suggesting a warm water affinity. Sublittoral, circalittoral and bathyal zones were clearly distinguishable in the Aegean Sea on the basis of their sponge fauna. The total number of species was an exponential negative function of depth. 相似文献
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Anastasia Chatzimentor Aggeliki Doxa Stelios Katsanevakis Antonios D. Mazaris 《Global Change Biology》2023,29(7):1809-1821
Rapid anthropogenic climate change is driving threatened biodiversity one step closer to extinction. Effects on native biodiversity are determined by an interplay between species' exposure to climate change and their specific ecological and life-history characteristics that render them even more susceptible. Impacts on biodiversity have already been reported, however, a systematic risk evaluation of threatened marine populations is lacking. Here, we employ a trait-based approach to assess the risk of 90 threatened marine Mediterranean species to climate change, combining species' exposure to increased sea temperature and intrinsic vulnerability. One-quarter of the threatened marine biodiversity of the Mediterranean Sea is predicted to be under elevated levels of climate risk, with various traits identified as key vulnerability traits. High-risk taxa including sea turtles, marine mammals, Anthozoa and Chondrichthyes are highlighted. Climate risk, vulnerability and exposure hotspots are distributed along the Western Mediterranean, Alboran, Aegean, and Adriatic Seas. At each Mediterranean marine ecoregion, 21%–31% of their threatened species have high climate risk. All Mediterranean marine protected areas host threatened species with high risk to climate change, with 90% having a minimum of 4 up to 19 species of high climate risk, making the objective of a climate-smart conservation strategy a crucial task for immediate planning and action. Our findings aspire to offer new insights for systematic, spatially strategic planning and prioritization of vulnerable marine life in the face of accelerating climate change. 相似文献
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Štajner Nataša Bohanec Borut Jakše Marijana 《Plant Cell, Tissue and Organ Culture》2002,70(3):269-274
Asparagus maritimus L. Miller is a rare species growing of the Mediterranean region and is morphologically similar to A. officinalis. In order to establish an efficient in vitro propagation protocol, explants were excised from spear segments and cultured on Murashige and Skoog (1962) medium containing 3% sucrose and various concentrations of growth regulators. The best shoot initiation (3–4 per explant) was achieved on a medium containing 0.88 M N6-benzyladenine (BA), 0.93 M kinetin, 1.07 M -naphthaleneacetic acid (NAA) and 3.90 M ancymidol. Shoot initiation could also be achieved without ancymidol but the shoots were thinner and longer. A very high shoot multiplication rate was achieved on media supplemented with 3% sucrose, 1.07 M NAA, 0.93 M kinetin, 0.44 M BA and various concentrations of ancymidol. The lowest concentration of ancymidol (0.39 M) significantly promoted the highest shoot multiplication rate (11.9 shoots/crown). For root formation, media were supplemented with 6% sucrose, 1.07 M NAA and various concentrations of ancymidol. Rooting frequency increased with higher ancymidol concentration up to 5.07 M (82.0% rooting). The number of ex vitro shoots formed was strongly correlated (r=0.66) with the length of roots formed in vitro, which was the highest at a 1.95 M ancymidol. 相似文献
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Does riparian habitat condition influence mammalian carnivore abundance in Mediterranean ecosystems? 总被引:1,自引:0,他引:1
Hugo M. Matos Maria J. Santos Francisco Palomares Margarida Santos-Reis 《Biodiversity and Conservation》2009,18(2):373-386
The severe loss or degradation of riparian habitats has led to their impoverishment and impaired function, which may have
severe consequences on both the riparian habitats themselves and their associated biota, including mammalian carnivores. We
selected 70 riparian habitat reaches to evaluate the condition of the riparian habitats in southern Portugal and their use
by carnivores. These sites were assessed for riparian condition using the stream visual assessment protocol (SVAP) and surveyed
for carnivore presence along the riparian zones and across the surrounding matrix landscape, both in the wet (winter) and
the dry (summer) season. Results show that carnivore surveys adjacent to riparian habitats consistently had significantly
higher species richness than the matrix habitats, in both sampling seasons. Carnivore relative abundance and relative abundance
of stone marten, common genet and Egyptian mongoose also showed higher values in riparian habitats, with significant differences
in at least one season. The Eurasian badger, on the other hand, showed higher relative abundance values in the landscape matrix,
though differences were not significant. The SVAP index ranked about 83% riparian reaches as poor or fair condition, and species
richness was significantly higher in fair condition reaches during the wet season. These results reflect the importance of
riparian habitats in Mediterranean ecosystems for mammalian carnivores. However, the generalized poor condition of these habitats
suggests that direct measures for riparian restoration could be appropriate. The preservation or improvement of riparian habitats
would certainly benefit the mammalian carnivore populations and consequently their conservation. 相似文献
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Argyro Zenetos 《Biological invasions》2010,12(9):3379-3381
The number of marine alien species reported in Galil (Biol Invasions, 2009) is incomplete. Recent literature suggests that
the number of aliens is nearly 1,000 and that the introduction rate is way off the 10 species per year suggested by Galil
(Biol Invasions, 2009). 相似文献
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Penélope Serrano-Ortiz Cecilio Oyonarte Oscar Pérez-Priego Borja R. Reverter Enrique. P. Sánchez-Cañete Ana Were Olga Uclés Laura Morillas Francisco Domingo 《Oecologia》2014,175(3):1005-1017
Climate change may alter ecosystem functioning, as assessed via the net carbon (C) exchange (NEE) with the atmosphere, composed of the biological processes photosynthesis (GPP) and respiration (R eco). In addition, in semi-arid Mediterranean ecosystems, a significant fraction of respired CO2 is stored in the vadose zone and emitted afterwards by subsoil ventilation (VE), contributing also to NEE. Such conditions complicate the prediction of NEE for future change scenarios. To evaluate the possible effects of climate change on annual NEE and its underlying processes (GPP, R eco and VE) we present, over a climate/altitude range, the annual and interannual variability of NEE, GPP, R eco and VE in three Mediterranean sites. We found that annual NEE varied from a net source of around 130 gC m?2 in hot and arid lowlands to a net sink of similar magnitude for alpine meadows (above 2,000 m a.s.l) that are less water stressed. Annual net C fixation increased because of increased GPP during intermittent and several growth periods occurring even during winter, as well as due to decreased VE. In terms of interannual variability, the studied subalpine site behaved as a neutral C sink (from emission of 49 to fixation of 30 gC m?2 year?1), with precipitation as the main factor controlling annual GPP and R eco. Finally, the importance of VE as 0–23 % of annual NEE is highlighted, indicating that this process could shift some Mediterranean ecosystems from annual C sinks to sources. 相似文献
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Emma Cebrian Enric Ballesteros Cristina Linares Fiona Tomas 《Biological invasions》2011,13(6):1397-1408
Generalist herbivores in marine ecosystems are poorly examined for their potential to serve as a source of biotic resistance
against algal invasion. We assessed how one of the main generalist herbivores in Mediterranean rocky reefs (the sea urchin
Paracentrotus lividus) affects Lophocladia lallemandii and Caulerpa racemosa, two algal invaders with strong detrimental effects on native benthic communities. In a comparison of sea urchin gut contents
to algal community composition, strong preferences were exhibited, leading to no relationship between consumption and availability.
Both C. racemosa and L. lallemandi were abundant in algal assemblages (>60% occurrence), but C. racemosa (20% of diet) was consumed more than L. lallemandi (3.5%). Experimental enclosures of sea urchins (12 sea urchins * m−2) were carried out in locations where L. lallemandii was already established and C. racemosa was rare (new invasion) or abundant (established invasion). C. racemosa was negatively affected by sea urchins only when it was rare, and no effect was detected when the alga was already abundant.
Results for L. lallemandi were exactly opposite: urchins limited seasonal increases in L. lallemandi in highly-invaded areas. Because of the small amount of direct consumption of L. lallemandi, its decrease in abundance may be related to the grazing of native algae where L. lallemandii is attached. Overall, our results show that high densities of native herbivores may reduce invasive algae at low densities,
due to a combination of direct and indirect effects, but it has no significant effect in highly-invaded areas. 相似文献
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Pollination Syndromes in Mediterranean Orchids—Implications for Speciation,Taxonomy and Conservation
The Mediterranean flora is spectacularly rich in orchid species that have evolved remarkable adaptations to their environment.
Orchids have complex and delicate interactions with their pollinators, which makes them particularly prone to local extinction.
Conservation actions should be encouraged for a range of endangered Mediterranean orchid species, but the current taxonomic
confusion in several genera and the apparent disagreement among orchid taxonomists make the situation particularly confusing
from a conservation perspective. In this review, we document how the different pollination syndromes of Mediterranean orchids
(nectar reward, shelter offering, food deception and sexual deception) can have a profound impact on the type of reproductive
barriers among species, on floral phenotypic variation as we perceive it, on potentially related processes of species sorting
and extinction and, consequently, should have a strong influence on the related conservation management programs. We also
highlight that the majority of Mediterranean orchids are pollinated by specialised bees often occupying otherwise narrow ecological
niches (e.g. pollen specialisation, brood cell parasites, specific nesting site). This condition makes the orchid-pollinator
interactions very fragile and several orchid species prone to local extinction. We illustrate this phenomenon by a selection
of case studies that show how the adequate integration of the ecological requirements/traits of the orchids and their associated
pollinators into conservation actions could help protect endangered species and ensure the sustainability of the often complex
local pollination web. 相似文献