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Mediterranean Species (mediterranean + species)
Selected AbstractsBioclimatic perspectives in the distribution of Quercus ithaburensis Decne. subspecies in Turkey and in the LevantJOURNAL OF BIOGEOGRAPHY, Issue 3 2004Jean-Marc Dufour-Dror Abstract Aim, To define the bioclimatic tolerance ranges of the two Tabor oak subspecies. Prior to this definition, and considering the confusion in the literature regarding the Tabor oak subspecies geography, a reassessment of their present distribution is proposed. Location, Turkey and the Levant. Methods, The bioclimatic tolerance range of each subspecies was characterized by four parameters: (1) the humidity category (Q2), (2) the winter variant (m) , the two basic variables used in Emberger's method for the definition of Mediterranean bioclimates, (3) the length of the dry season (LDS) and (4) its severity, expressed by the dry season water deficit (DSWD). The reference to the last two variables in the definition of bioclimatic tolerance ranges of Mediterranean species has so far never been considered. The concept of bioclimatic niche, based on the reference to these four parameters, is proposed and discussed. Results, The reassessment of the Tabor oak subspecies distribution shows that their extents of occurrence do not overlap and are significantly distant. The comparison between the characteristics of each subspecies bioclimatic niche has highlighted three major differences: (1) The bioclimatic niche of the subspecies macrolepis is characterized by a great heterogeneity as it includes up to 10 distinct bioclimate types, whereas only four types have been found in the bioclimatic niche of the subspecies ithaburensis. (2) A 10 °C gap has been found between the winter variants of both bioclimatic niches. (3) The third major difference relates to the dry season characteristics: the bioclimatic niche of the subspecies ithaburensis is characterized by an LDS 40,75% longer than it is in the bioclimatic niche of the subspecies macrolepis. Moreover, and surprisingly, although the most arid humidity categories are found in the bioclimatic niche of the subspecies macrolepis, the bioclimatic niche of the subspecies ithaburensis is characterized by a significantly more severe dry season as the DSWD is 36,180% greater than in the bioclimatic niche of the subspecies macrolepis. It is suggested that the duration and the severity of the dry season is a major limiting factor in the spatial distribution of the subspecies macrolepis. Main conclusions, The reference to the duration (LDS) and severity (DSWS) of the dry season is essential when defining the bioclimatic niche of Mediterranean species. [source] Spatial patterns of recruitment in Mediterranean plant species: linking the fate of seeds, seedlings and saplings in heterogeneous landscapes at different scalesJOURNAL OF ECOLOGY, Issue 6 2008Lorena Gómez-Aparicio Summary 1Plant recruitment is a multiphase process that takes place in environments that are heterogeneous in space and time. In this work, I analyse how environmental heterogeneity in Mediterranean forests affects dynamics of early recruitment at different scales, using the wind-dispersed tree Acer opalus subsp. granatense as a case study. 2Seed dispersal and viability, post-dispersal predation, seedling emergence and seedling and sapling survival were evaluated in different habitats (regional scale) and microhabitats (local scale). Simultaneously, a review of the literature on spatial dynamics of plant recruitment in Mediterranean systems was conducted to look for general patterns and investigate their fit to the Acer system. Nineteen woody and herbaceous species were included in the review. 3At the regional scale, Acer recruitment dynamics strongly converged among sites of the same habitat. This was mainly due to large seedling emergence and survival differences among habitats. Although most of the studies reviewed analyzed only one site per habitat type, they also support strong regional variation (either site- or habitat-specific) in recruitment patterns. 4At the local scale, Acer recruitment was microhabitat-specific, a result shared by almost all the reviewed species independently of their life form and dispersal syndrome. This was mostly due to spatial differences in seed arrival (higher under conspecifics) and seedling survival (higher under nurse shrubs). 5Spatial discordance among seed rain and recruitment was found in 60% of the reviewed species at the regional scale, and in 67% at the local scale. Acer results supported this predominant lack of concordance. Discordance among seed rain and recruitment suggests that regeneration is largely limited by safe sites than by seed availability. Because seedling survival was the limiting process with a larger impact on the magnitude and spatial pattern of recruitment, safe sites might be defined as those where seedlings have a higher survival probability. 6Synthesis: This study indicates that the influence of seed dispersal on the spatial patterns and demography of plant species could be limited in heterogeneous and stressful environments (as are found in the Mediterranean), where recruitment is restricted to a small fraction of the landscape. If we are to preserve the distribution and abundance of Mediterranean species in the face of environmental changes, we need to explicitly consider the strong patch-specificity that characterizes their recruitment process at all scales. [source] Gonadal maturation in the blackspot seabream Pagellus bogaraveo: a comparison between a farmed and a wild broodstockJOURNAL OF FISH BIOLOGY, Issue 2004V. Micale The blackspot seabream Pagellus bogaraveo(Brünnich, 1768) has been regarded as a possible alternative to traditionally cultured Mediterranean species such as seabream and seabass, due to its high market value and good adaptation to captivity. Broodstock establishment and management represent the first step towards reliable production of eggs and fry, which is required to develop aquaculture of this new species. Two different broodstocks were tested for gonadal maturation and spawning, one constituting of wild fish caught as juveniles and reared in tanks until sexual maturity (4 years), and one assembled from wild adult fish caught during or just before the reproductive season. All fish were maintained under the same rearing conditions and fed the same diet. Gonadal stripping and biopsies were performed weekly to monitor maturation in both males and females. Ovarian samples were staged for maturity on the basis of follicular diameter and migration of germinal vesicle. Sperm samples were tested for density (number of spermatozoa ml,1) and motility. The fish reared in captivity reached ovarian maturity during the breeding season of the wild stock. Eggs were obtained by stripping from both farmed and wild specimens, but appeared degenerated as a result of being retained too long in the ovarian cavity due to the absence of spontaneous spawning. Spermiation was prolonged in the farmed fish, but appeared to be blocked in the wild breeders after first sampling. However, the sperm was very viscous and the motile spermatozoa did not exceed 10%. [source] Phylogenetic relationships of the European lacertid genera Archaeolacerta and Iberolacerta and their relationships to some other ,Archaeolacertae' (sensu lato) from Near East, derived from mitochondrial DNA sequencesJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2003W. Mayer Abstract Parts of the mitochondrial genes coding for 12SrRNA and 16SrRNA (together about 960 bp) were sequenced for all Mediterranean species of ,Mountain lizards' of the genera Archaeolacerta (sensu lato) and Iberolacerta. All subspecies of the Iberian species Iberolacerta cyreni and I. monticola were included in this study. In addition, samples of Apathya cappadocica and Darevskia rudis were analysed to elucidate the relationships of the European ,Mountain lizards' to their possible relatives in the Near East. Maximum parsimony and neighbour joining analyses lead to the following major conclusions: (i) the monophyly of the genus Iberolacerta is very well supported; (ii) Archaeolacerta bedriagae (the type species of the genus) is most basal with respect to the ingroup taxa. If we accept Iberolacerta as a genus, Archaeolacerta becames paraphyletic. Therefore, we propose to restrict Archaeolacerta to the type species and to treat A. mosorensis and A. oxycephala provisionally as members of the collective genus Lacerta; (iii) within the genus Iberolacerta three groups were found: a Pyrenean group, an Iberian group and I. horvathi. The relationships among these groups remain unresolved; and (iv) the Peña de Francia lizards, described originally as a subspecies of I. cyreni, are in fact more closely related to I. monticola. Zusammenfassung Wir sequenzierten Teilabschnitte der Gene für 12SrRNA und 16SrRNA (zusammen ungefähr 960 Basenpaare) von allen europäischen ,Gebirgseidechsen' der Gattungen Archaeolacerta (sensu lato) und Iberolacerta. Alle Subspezies der iberischen Arten Iberolacerta cyreni und I. monticola wurden in die Studie aufgenommen. Zusätzlich wurden Proben von Apathya cappadocica und Darevskia rudis untersucht, um die phylogenetischen Beziehungen der europäischen ,Gebirgseidechsen' zu ihren möglichen Verwandten im Nahen Osten aufzuklären. Maximum Parsimony und Neighbor Joining Analysen führten zu folgenden wesentlichen Ergebnissen: i) Die Monophylie der Gattung Iberolacerta ist gut abgesichert. ii) Archaeolacerta bedriagae (die species typica der Gattung) hat eine basale Position innerhalb der Gruppe der ,Gebirgseidechsen'. Daher schlagen wir vor, Archaeolacerta auf die species typica zu restringieren und A. mosorensis und A. oxycephala provisorisch in der Sammelgattung Lacerta zu belassen. iii) Die Gattung Iberolacerta zerfällt in drei Gruppen: eine Pyrenäen-Gruppe, eine iberische Gruppe und I. horvathi. Die Beziehungen zwischen diesen Gruppen konnten nicht aufgeklärt werden. iv) Die Eidechsen von Peña de Francia, ursprünglich als Subspezies von I. cyreni beschrieben, sind tatsächlich näher mit I. monticola verwandt. [source] Mediterranean commercial sponges: over 5000 years of natural history and cultural heritageMARINE ECOLOGY, Issue 2 2008Roberto Pronzato Abstract This paper deals with the history of the exploitation of a natural resource made up of various types of Mediterranean horny sponges. It also provides an update on trends in the trade of these sponges. The distribution and taxonomic status of Mediterranean species of commercial interest belonging to the genera Spongia and Hippospongia are reported upon and partly emended by (i) the selection of neotypes for Spongia mollissima, Hippospongia communis, and Spongia agaricina from the Indo-Pacific Ocean versus the Mediterranean Spongia lamella, and (ii) the discussion regarding the problematic status of Spongia zimocca. Attention is also focused upon species that have been of recent commercial interest as sources of metabolites with biomedical potential, such as Dysidea avara, which is considered endangered due to a pressing demand for the industrial extraction of chemicals it produces (e.g. Avarol). The wild harvesting of new target sponges is also discussed, together with a proposal for a rational, sustainable, long-term strategy for Mediterranean sponge management. Sponge culture in situ is suggested as a useful approach that may allow eco-compatible management and conservation of this natural resource. [source] Potential Use of Biomarkers in Zooplankton as Early Warning Signals of Ecotoxicological Risk in the Marine Food ChainMARINE ECOLOGY, Issue 2002Roberta Minutoli Abstract. Zooplankton is an essential component of the marine and brackish food chains. The ecotoxicological risk of zooplanktonic communities, estimated by the modern methodological approach of biomarkers, can be used as an early warning signal of ecosystem health. The aim of this project is to estimate the potential use of several biomarkers (esterases, mixed function oxidases, porphyrins) in zooplanktonic organisms. Studies were carried out with different zooplanktonic crustaceans: the copepods Acartia margalefi and Acartia latisetosa collected in Ganzirri Lake (Messina); the mysid Siriella clausi collected in Faro Lake (Messina); the mysids Diamysis bahirensis, Siriella armata and Mysidopsis gibbosa collected in Stagnone di Marsala (Palermo); the Antarctic euphausiids Euphausia crystallorophias and Euphausia superba; the am-phipod Streetsia challengeri and the euphausiid Meganycthiphanes norvegica collected after a shore-stranding along Messina's Ionian coast. Moreover, experiments were carried out with the benthic decapods Eriphia verrucosa and Pachygrapsus marmoratus from a rocky shore of Messina's Ionian coast. Acetylcholinesterase activity (AChE) was determined in homogenates of whole organisms. The key result of this project concerns the different AChE activity basal values of different crustacean species. Particular attention should be paid to the difference in basal activity found between the Antarctic and the Mediterranean species. [source] Effects of climate change on the distribution of Iberian tree speciesAPPLIED VEGETATION SCIENCE, Issue 2 2008Marta Benito Garzón Question: Will the predicted climate changes affect species distribution in the Iberian Peninsula? Location: Iberian Peninsula (Spain and Portugal). Methods: We modelled current and future tree distributions as a function of climate, using a computational framework that made use of one machine learning technique, the random forest (RF) algorithm. This algorithm provided good predictions of the current distribution of each species, as shown by the area under the corresponding receiver operating characteristics (ROC) curves. Species turnover, richness and the change in distributions over time to 2080 under four Intergovernmental panel on climate change (IPCC) scenarios were calculated using the species map outputs. Results and Conclusions: The results show a notable reduction in the potential distribution of the studied species under all the IPCC scenarios, particularly so for mountain conifer species such as Pinus sylvestris, P. uncinata and Abies alba. Temperate species, especially Fagus sylvatica and Quercus petraea, were also predicted to suffer a reduction in their range; also sub-mediterranean species, especially Q. pyrenaica, were predicted to undergo notable decline. In contrast, typically Mediterranean species appeared to be generally more capable of migration, and are therefore likely to be less affected. [source] Effects of leaf emergence on leaf lifespan are independent of life form and successional statusAUSTRAL ECOLOGY, Issue 7 2008ROGER J. DUNGAN Abstract The longevity of a leaf is related to the benefit that the plant is able to derive from it. This benefit varies among seasons and as more leaves emerge, such that leaf lifespan can be limited by canopy position rather than physiological age. Using interval-censored failure time analysis, we investigate leaf lifespan for 34 Mediterranean species in a previously published dataset involving species with different life forms and functional strategies. Failure time regression models were used to determine leaf lifespan, and to investigate how these effects varied among species. Median lifespan estimated for each species with two methods differed by less than 10% on average, but varied from 0.02,19.5% depending on the shape of the underlying failure time distribution. Within shoots, later-emerging leaves had shorter lifespans for species with longer periods of leaf emergence, and the reverse was true for species with short emergence. Having accounted for the within-shoot effect, leaves emerging in spring had shorter lifespans, particularly herbaceous species, whereas the reverse was true woody species. These effects were consistent among life forms and successional stages, and consistent with theories of within-shoot translocation of resources following self-shading. [source] | |||||||||||||