Mediterranean Island Of Corsica Research Articles

Macroparasite Communities with Special Attention to Invasive Helminths in European Eels Anguilla anguilla from Freshwaters and Brackish Lagoons of a Mediterranean Island

An extensive survey of macroparasites in 320 European eel Anguilla anguilla (Linnaeus, 1758) was conducted in two brackish lagoons and eleven freshwater localities in the Mediterranean island of Corsica (France) between spring 2021 and winter 2021–2022. It resulted in the identification of nineteen parasites: two Monogea, four Digenea, one Copepoda, four Acanthocephala, three Cestoda, and five Nematoda, including the first geographical records, as Corsican freshwater sites were studied for the first time. The silvering stage was determined, and the eels were aged through otolithometry to compare parasite communities. Classic parasitology indices, a multivariate analysis, and an analysis of indicator values (IndVal) showed clear preferences towards the host’s habitat and salinity. Seasonal variations were shown for several parasites. A dataset from the same two coastal lagoons was used to study the changes in the parasite communities over the last decade, and this showed an increase in the prevalence and abundance of three invasive helminth species: the Monogenea Pseudodactylogyrus bini (Kikuchi, 1929), Pseudodactylogyrus anguillae (Yin and Sproston, 1948) Gusev, 1965 and the Nematoda Anguillicola crassus Kuwahara, Niimi, and Itagaki, 1974. These pathogenic parasites were found in all sampled localities, except for the two Monogenea in the polyhaline-to-euhaline Urbino lagoon. It is thus advised that future management measures take into account the environmental preferences of the most concerning parasites.

Xylem formation patterns from Mediterranean to subalpine climate conditions reveal high growth plasticity of pine species on Corsica

Key messageBlack pine and Maritime pine exhibit considerable differences in growth phenology across elevation belts with a 1-month delay for xylogenesis and increasing growth rates from low, mid to high elevations.Investigating seasonal wood formation is crucial to understand tree growth responses to climate impact. The present study quantifies the variability of xylogenesis along an elevation gradient on the Mediterranean island of Corsica, where two native pine species (Pinus nigra Arnold ssp. laricio Maire and Pinus pinaster Aiton) grow from the upper tree line to sea level, partly in sympatry. We extracted microcores from 35 trees at 5 sites along an East–West transect from the coasts (10 m asl) to the island's central mountain ridge (1600 m asl) during bi-weekly sampling campaigns between 2017 and 2019. We applied generalised additive models to detect radial growth differences in elevation and species along with minimum temperatures for growth initiation. We found that trees in low elevations experienced over 2 months longer growth periods with higher maximum growth rates than in high elevations. The results show a 1-month delay for the beginning of tracheid formation between the low, mid and high-elevation belts but comparable timing for its termination. At the sites where both species co-occur, P. nigra accumulates more radial cells in a shorter time than P. pinaster. Trees at the two contrasting coastal sites have similar growth period lengths, but exhibit a time shift of over a month. Minimum temperatures around growth initiation vary between 3.1 °C for P. nigra and 9.9 °C for P. pinaster. These findings emphasise the high plasticity in the growth behaviour of one of the most widespread tree genera in Mediterranean and temperate zones.

Temporal offset between precipitation and water uptake of Mediterranean pine trees varies with elevation and season

For climate models that use paleo-environment data to predict future climate change, tree-ring isotope variations are one important archive for the reconstruction of paleo-hydrological conditions. Due to the rather complicated pathway of water, starting from precipitation until its uptake by trees and the final incorporation of its components into tree-ring cellulose, a closer inspection of seasonal variations of tree water uptake is important. In this study, branch and needle samples of two pine species (Pinus pinaster and Pinus nigra subsp. laricio) and several water compartments (precipitation, creek, soil) were sampled over a two-year period and analyzed for the temporal variations of their oxygen and hydrogen stable isotope ratios (δ18O and δ2H) at five sites over an elevation gradient from sea level to around 1600 m a.s.l. on the Mediterranean island of Corsica (France). A new model was established to disentangle temporal relationships of source water uptake of trees. It uses a calculation method that incorporates the two processes mostly expected to affect source water composition: mixing of waters and evaporation. The model results showed that the temporal offset from precipitation to water uptake is not constant and varies with elevation and season. Overall, seasonal source water origin was shown to be dominated by precipitation from autumn and spring. While autumn precipitation was a more important water source for trees growing at mid- (~800–1000 m a.s.l) and high-elevation (~1600 m a.s.l.) sites, trees at coastal sites mostly took up water from late winter and spring. These findings show that predicted decreases in precipitation amounts during the wet season in the Mediterranean can have strong impacts on water availability for pine trees, especially at higher elevations.

How Do Mediterranean Pine Trees Respond to Drought and Precipitation Events along an Elevation Gradient?

Drought is a major factor limiting tree growth and plant vitality. In the Mediterranean region, the length and intensity of drought stress strongly varies with altitude and site conditions. We used electronic dendrometers to analyze the response of two native pine species to drought and precipitation events. The five study sites were located along an elevation gradient on the Mediterranean island of Corsica (France). Positive stem increment in the raw dendrometer measurements was separated into radial stem growth and stem swelling/shrinkage in order to determine which part of the trees’ response to climate signals can be attributed to growth. Precipitation events of at least 5 mm and dry periods of at least seven consecutive days without precipitation were determined over a period of two years. Seasonal dynamics of stem circumference changes were highly variable among the five study sites. At higher elevations, seasonal tree growth showed patterns characteristic for cold environments, while low-elevation sites showed bimodal growth patterns characteristic of drought prone areas. The response to precipitation events was uniform and occurred within the first six hours after the beginning of a precipitation event. The majority of stem circumference increases were caused by radial growth, not by stem swelling due to water uptake. Growth-induced stem circumference increase occurred at three of the five sites even during dry periods, which could be attributed to stored water reserves within the trees or the soils. Trees at sites with soils of low water-holding capacity were most vulnerable to dry periods.

How language becomes a political issue: Social change, collective movements and political competition in Corsica

AbstractThe Mediterranean island of Corsica became French in 1768–1769, and Corsican is one of the most widely used regional languages in France. In Corsica, the language issue is politically prominent, with a very strong opposition between the nationalist regional government, which claims a co-official status for the Corsican language, and the French national government, which advocates the supremacy of the national language. However, the French linguistic integration process has been an astonishing success since the end of the nineteenth century, and the first mass mobilisations in favour of the Corsican language did not take place until the 1970s. In this article, I try to explain why the politicisation of Corsican language came so late; how this language became a politically salient issue; and how public attitudes and policies towards this language have substantially evolved. Since 1982, the state and the state-wide parties on the island have amended their strategy and challenged the near-monopoly of Corsican nationalists with regard to the defence of the Corsican language. Especially in the field of education, they promoted and implemented a language policy shift, and tried to depoliticise this issue. Nonetheless, political positions remain polarised regarding measures such as compulsory education and co-official status.

Isolation and Characterization of a Novel Pathogenic Strain of Ehrlichia minasensis.

The genus Ehrlichia is composed of tick-borne obligate intracellular gram-negative alphaproteobacteria of the family Anaplasmataceae. Ehrlichia includes important pathogens affecting canids (E. canis, E. chaffeensis, and E. ewingii), rodents (E. muris), and ruminants (E. ruminantium). Ehrlichia minasensis, an Ehrlichia closely related to E. canis, was initially reported in Canada and Brazil. This bacterium has now been reported in Pakistan, Malaysia, China, Ethiopia, South Africa, and the Mediterranean island of Corsica, suggesting that E. minasensis has a wide geographical distribution. Previously, E. minasensis was found to cause clinical ehrlichiosis in an experimentally infected calf. The type strain E. minasensis UFMG-EV was successfully isolated from Rhipicephalus microplus ticks and propagated in the tick embryonic cell line of Ixodes scapularis (IDE8). However, the isolation and propagation of E. minasensis strains from cattle has remained elusive. In this study, the E. minasensis strain Cuiabá was isolated from an eight-month-old male calf of Holstein breed that was naturally infected with the bacterium. The calf presented clinical signs and hematological parameters of bovine ehrlichiosis. The in vitro culture of the agent was established in the canine cell line DH82. Ehrlichial morulae were observed using light and electron microscopy within DH82 cells. Total DNA was extracted, and the full genome of the E. minasensis strain Cuiabá was sequenced. A core-genome-based phylogenetic tree of Ehrlichia spp. and Anaplasma spp. confirmed that E. minasensis is a sister taxa of E. canis. A comparison of functional categories among Ehrlichia showed that E. minasensis has significantly less genes in the ‘clustering-based subsystems’ category, which includes functionally coupled genes for which the functional attributes are not well understood. Results strongly suggest that E. minasensis is a novel pathogen infecting cattle. The epidemiology of this Ehrlichia deserves further attention because these bacteria could be an overlooked cause of tick-borne bovine ehrlichiosis, with a wide distribution.

Rodents as Reservoirs of the Zoonotic Pathogens Coxiella burnetii and Toxoplasma gondii in Corsica (France).

Coxiella burnetii and Toxoplasma gondii are intracellular pathogens that cause important reproductive disorders in humans and animals worldwide, which translates into high economic losses. The aim of this study was to analyze the possible role of peridomestic small mammals in the maintenance and transmission of C. burnetii and T. gondii in the Mediterranean island of Corsica, by the analysis of the seroprevalence in rodents. Our results showed a wide distribution of C. burnetii and T. gondii in Corsica in Rattus rattus and Mus musculus domesticus. The overall seroprevalence of anti-C. burnetii was 9.32%, being 8.73% from R. rattus and 13.33% from M. m. domesticus. With respect to T. gondii, seropositive rodents were observed in 12.96% of total animals, being 12.76% from rats and 14.29% from mice. Taking into consideration the large range of host these pathogens can infect, including humans and livestock, and their pathologies, the results provided by this study are relevant for public health and veterinary, and could help the governmental entities to prevent possible infectious focuses of Q fever and toxoplasmosis.

Island vulnerability and resilience to wildfires: A case study of Corsica

The number of wildfires occurring globally is exacerbated by urbanisation and changes in weather patterns. In response, researchers have conducted studies of wildfires and human behaviour in regions such as Australia and the USA. Regions in Europe have received less attention, despite facing the same issues. Even more overlooked are one particular type of territory: islands. With their climates, islands across the Mediterranean remain attractive second home and tourist destinations, resulting in urban development. Yet due to certain features (e.g. cultural, socio-political, geographical), the ways in which their people deal with wildfires may differ somewhat from that in some mainland territories. This paper explores human behaviour in wildfire emergencies in the context of island vulnerability and resilience in Europe, with the Mediterranean island of Corsica as a case study. Qualitative analysis of semi-structured interviews (n = 8) with Corsican professionals involved in wildfire management and quantitative analysis of around 100 surveys from civilians was conducted. This analysis revealed that Corsica's population approach to wildfire safety is shaped by available information as well as a strong risk culture, which stands in contrast with new/temporary residents moving into the island each summer season. The results drawn from the analysed sample suggest potential social vulnerability in wildfires when a decision to evacuate the population is taken by emergency managers as the most effective emergency response. Population behaviour were not influenced by property attachment, perceived risk, hazard knowledge, community closeness and locus of control, suggesting that island WUI resident characteristics may not be generalised from human behaviour in wildfires studies carried out in the USA or Australia.

The relationship between climate and the intra-annual oxygen isotope patterns from pine trees: a case study along an elevation gradient on Corsica, France

Intra-annual oxygen isotope patterns of tree-ring cellulose from Pinus nigra subsp. laricio and Pinus pinaster along an elevation gradient can be divided into four distinct patterns ((1) high values in the beginning of the tree ring, declining trend afterwards; (2) low values in the beginning, increasing trend afterwards; (3) high values in the middle of the tree ring; (4) declining trend over the whole tree ring). These patterns reflect the dependency on local site conditions and different water sources. Intra-annual oxygen isotope chronologies from tree-ring cellulose can serve as a proxy for past climate conditions at inter- or even intra-seasonal resolution. We explore the potential of these chronologies from pine trees (Pinus nigra J.F. Arn subsp. laricio (Poiret) Maire var Corsicana Hyl. and Pinus pinaster Aiton) growing on the Mediterranean island of Corsica, France, along an elevation gradient ranging from sea level to 1600 m asl. We developed high-resolution intra-annual oxygen isotope chronologies from tree-ring cellulose of eight trees from five sites along the elevation gradient. The analysis period covers the decade 2007–2016 for seven trees and the period 1987–2016 for one tree, respectively. The chronologies show a high variability between trees, sites, and years. We identified four different intra-annual oxygen isotope patterns which reflect the dependency of tree growth on different water sources (precipitation during the growing season vs. deeper soil water reservoirs) and climate conditions during the growth season. Trees at coastal sites have access to groundwater, while trees growing in high elevations mostly depend on precipitation during the growth season as water source. The different patterns can be attributed to the use of different water sources. The intra-annual chronology covering 30 years indicates an increasing frequency of dry-warm summers after 2007.

Aujeszky's Disease and Hepatitis E Viruses Transmission between Domestic Pigs and Wild Boars in Corsica: Evaluating the Importance of Wild/Domestic Interactions and the Efficacy of Management Measures.

Wildlife species as reservoirs of infectious pathogens represent a serious constraint in the implementation of disease management strategies. In the Mediterranean island of Corsica, the dynamics of hepatitis E virus (HEV) and Aujeszky’s disease virus (ADV) are suspected to be influenced by interactions between wild and domestic pigs. To improve our understanding of these influences, we first compared the seroprevalences of both viruses in domestic pig populations from different locations with contrasted levels of wild–domestic interactions, ADV vaccination, biosafety, and farm husbandry. Second, we performed an analysis at a more restricted geographical scale, to assess the matching of ADV or HEV prevalence between sympatric wild boar and outdoor pig farms most exposed to interactions with wildlife. Logistic models were adjusted to the observed data. A high seroprevalence of HEV (>80%) and ADV (40%) in pigs, with no significant difference according to the region, confirms that both pathogens are enzootic in Corsica. Vaccination against ADV had a strong protective effect, even when performed voluntarily by farmers. Farm biosafety had an additional effect on pigs’ exposure, suggesting that contact between wild boars and pigs were involved in disease transmission. A strong correlation in HEV seroprevalence was observed between pigs and wild boars that were in close contact, and significantly lower seroprevalence was observed in pigs when they had little contact with wild boars due to spatial segregation. These results suggest a regular HEV circulation between sympatric wild boar and domestic pigs. The high HEV seroprevalence observed in domestic pigs (>80%) suggests a spillover of the virus from domestic to wild populations through environmental contamination, but this hypothesis has to be confirmed. Conversely, even though avoiding sows’ release on pasture during estrus showed some protecting effect in the free ranging pig farms regarding ADV, ADV seroprevalence was not dependent on the swine populations (wild or domestic) or on the wild–domestic spatial overlap, suggesting two quasi-separate enzootic cycles. This information will prove useful for designing more efficient disease management strategies in Corsica and similar contexts.

Faecal Escherichia coli as biological indicator of spatial interaction between domestic pigs and wild boar (Sus scrofa) in Corsica.

On the Mediterranean island of Corsica, cohabitation between sympatric domestic pigs and Eurasian wild boar (Sus scrofa) is common and widespread and can facilitate the maintenance and dissemination of several pathogens detrimental for the pig industry or human health. In this study, we monitored a population of free-ranging domestic pigs reared in extensive conditions within a 800-ha property located in Central Corsica which was frequently visited by a sympatric population of wild boar between 2013 and 2015. We used GPS collars to assess evidence of a spatially shared environment. Subsequently, we analysed by PFGE of XbaI-restricted DNA if those populations shared faecal Escherichia coli clones that would indicate contact and compared these results with those collected in a distant (separated by at least 50km) population of wild boar used as control. Results showed that one of eight wild boars sampled in the study area shed E.coli XbaI clones identical to clones isolated from domestic pig sounders from the farm, while wild boar populations sampled in distant parts of the study area shared no identical clone with the domestic pigs monitored. Interestingly, within the sampled pigs, two identical clones were found in 2013 and in 2015, indicating a long-time persisting colonization type. Although the method of isolation of E.coli and PFGE typing of the isolates requires intensive laboratory work, it is applicable under field conditions to monitor potential infectious contacts. It also provides evidence of exchange of microorganisms between sympatric domestic pigs and wild boar populations.

Genomic signatures of adaptive introgression from European mouflon into domestic sheep

Mouflon (Ovis aries musimon) became extinct from mainland Europe after the Neolithic, but remnant populations from the Mediterranean islands of Corsica and Sardinia have been used for reintroductions across Europe since the 19th-century. Mouflon x sheep hybrids are larger-bodied than mouflon, potentially showing increased male reproductive success, but little is known about genomic levels of admixture, or about the adaptive significance of introgression between resident mouflon and local sheep breeds. Here we analysed Ovine medium-density SNP array genotypes of 92 mouflon from six geographic regions, along with data from 330 individuals of 16 domestic sheep breeds. We found lower levels of genetic diversity in mouflon than in domestic sheep, consistent with past bottlenecks in mouflon. Introgression signals were bidirectional and affected most mouflon and sheep populations, being strongest in one Sardinian mouflon population. Developing and using a novel approach to identify chromosomal regions with consistent introgression signals, we infer adaptive introgression from mouflon to domestic sheep related to immunity mechanisms, but not in the opposite direction. Further, we infer that Soay and Sarda sheep carry introgressed mouflon alleles involved in bitter taste perception and/or innate immunity. Our results illustrate the potential for adaptive introgression even among recently diverged populations.

Updated checklist of Balearic leaf beetles (Coleoptera: Chrysomelidae).

The first updated checklist of Balearic leaf beetles (Chrysomelidae) since 1960 is presented here, evincing the presence of 118 species. This estimation is clearly lower than the 141 species reported in the only list available to date (Jolivet, 1953), and the dissimilarity is even more pronounced if we take into account that 22 new species have been added during this period. The possible explanations for these differences are discussed. The main island in the archipelago holds most of the species (Mallorca, 113 spp.), followed by Menorca (71 spp.), Eivissa (39 spp.) and Formentera (19 spp.). Thus, the Gymnesian islands (Mallorca and Menorca) are more species-rich than the Pityusic ones (Eivissa and Formentera). The number of species per island is significantly correlated with their respective areas not only for the Balearic but also for the much larger western Mediterranean islands of Corsica and Sardinia, and these abundances are not related with their nearness to the closest mainland. Among the different subfamilies and tribes, the Balearic flea-beetles (Alticinae) are clearly more prevalent whereas on the contrary, the Clytrini are less represented in comparison with the nearest mainland (Iberian Peninsula). The presented checklist includes four endemic species, Cryptocephalus majoricensis (Mallorca, Menorca and Formentera), C. tramuntanae (Mallorca), Cyrtonus majoricensis (Mallorca) and Timarcha balearica (Mallorca and Menorca). Furthermore, two adventitious species, Monoxia obesula and Epitrix hirtipennis of North American origin, have been reported for the first time in the Balearic Islands, in agreement with previous findings in other Mediterranean countries.

Normal and Aberrant Mesocestoides Tetrathyridia from Crocidura spp. (Soricimorpha) in Corsica and Spain

Tetrathyridia of Mesocestoides sp. were collected from the body cavities of the shrews (Insectivora), Crocidura russula, in Valencia, Spain and Crocidura suaveolens on the Mediterranean island of Corsica, France. Specimens were processed by routine microscopic and histological techniques, including examination with brightfield, phase-contrast, and differential-interference-contrast optics. Most tetrathyridia were clustered together inside host-derived fibrotic capsules, but some occurred free in the body cavity. All specimens examined from both locations had solid hindbodies, i.e., lacking a primary lacuna, thus conforming to the plerocercoid metacestode type; all possessed a single normal tetra-acetabulate scolex. All metacestodes from C. russula in Valencia were normal tetrathyridia. Those from C. suaveolens in Corsica were either normal tetrathyridia or had aberrant deep convolutions of an unusually elongated hindbody. No tetrathyridium from either location or host showed tegumental or excretory duct anomalies such as those reported by several authors from aberrant tetrathyridia and spargana in some other locations. No definitive evidence of asexual proliferation was visible in any of the tetrathyridia, but those with abnormally convoluted hindbodies from a single C. suaveolens in Corsica suggest the potential for asexuality by fission of the hindbody. These results add to our understanding of morphological and developmental variation among metacestodes in this widespread and variable genus.

Genetic isolation of insular populations of the Maghrebian bat, Myotis punicus, in the Mediterranean Basin

AbstractAim We investigate the population genetic structure of the Maghrebian bat, Myotis punicus, between the mainland and islands to assess the island colonization pattern and current gene flow between nearby islands and within the mainland.Location North Africa and the Mediterranean islands of Corsica and Sardinia.Methods We sequenced part of the control region (HVII) of 79 bats across 11 colonies. The phylogeographical pattern was assessed by analysing molecular diversity indices, examining differentiation among populations and estimating divergence time. In addition, we genotyped 182 bats across 10 colonies at seven microsatellite loci. We used analysis of molecular variance and a Bayesian approach to infer nuclear population structure. Finally, we estimated sex‐specific dispersal between Corsica and Sardinia.Results Mitochondrial analyses indicated that colonies between Corsica, Sardinia and North Africa are highly differentiated. Within islands there was no difference between colonies, while at the continental level Moroccan and Tunisian populations were highly differentiated. Analyses with seven microsatellite loci showed a similar pattern. The sole difference was the lack of nuclear differentiation between populations in North Africa, suggesting a male‐biased dispersal over the continental area. The divergence time of Sardinian and Corsican populations was estimated to date back to the early and mid‐Pleistocene.Main conclusions Island colonization by the Maghrebian bats seems to have occurred in a stepping‐stone manner and certainly pre‐dated human colonization. Currently, open water seems to prevent exchange of bats between the two islands, despite their ability to fly and the narrowness of the strait of Bonifacio. Corsican and Sardinian populations are thus currently isolated from any continental gene pool and must therefore be considered as different evolutionarily significant units (ESU).

Epidemiological survey of trichinellosis in wild boar ( Sus scrofa) and fox ( Vulpes vulpes) in a French insular region, Corsica

The Mediterranean island of Corsica was considered Trichinella-free until 2004, when T. britovi larvae were discovered in domestic pigs at meat inspection. One red fox was also found infected the same year and in the same area than the infected pigs. This last finding highlighted the presence of trichinellosis in Corsican wildlife. A Trichinella survey was thus performed in wild boar ( Sus scrofa) and fox ( Vulpes vulpes), the two large wild species present on the island, to determine prevalence of muscle larvae and antibodies. Diaphragm muscles of 1881 wild boars and 74 forelegs of foxes were tested by artificial digestion. No Trichinella larva was identified. The highly sensitive ELISA was used to test muscle fluid samples of 1492 wild boars. The apparent serological prevalence of Trichinella infections in wild boar was 2.01% (95% CI: 1.36–2.86). The present results suggest that wildlife is currently exposed to Trichinella in Corsica. In this context, adequate cooking and veterinary controls of meat offer the only complete sanitary warranties to consumers.

British Ornithologists’ Union Records Committee: 31st Report (October 2004)

British Ornithologists’ Union Records Committee: 31st Report (October 2004)

Calibrating the jason-1 measurement system: Initial initial results from the corsica and harvest verification experiments

We present calibration results from Jason-1 (2002-) and TOPEX/Poseidon (1992-) overflights of dedicated verification sites on the Mediterranean island of Corsica and on a California offshore oil platform (Harvest). Harvest served for a decade (1992–2002) as a calibration site for the TOPEX/Poseidon (T/P) mission, and is serving in a similar capacity for Jason-1. Initiated in 1996, the Corsica experiment features a fiducial reference station near Aspretto, and a primary sub-satellite tide-gauge deployment site 40 km south at Cape Senetosa. Both Corsica and Harvest feature carefully designed collocations of space-geodetic and tide-gauge systems to support the absolute calibration of the altimetric sea-surface height (SSH). Early estimates of the SSH bias from Harvest and Corsica are in excellent agreement, indicating that interim SSH measurements from Jason-1 were too high by +5 ± 1 cm (one standard error). By incorporating improved estimates of the Jason-1 sea-state bias and columnar atmospheric wet path delay, we observe a significant increase—to about 12 cm—in the SSH. Excepting the bias, the high accuracy of the Jason-1 measurements is in evidence from early overflights. In addition to providing important insight on the accuracy of the science data products during the validation phase of the mission, the estimates of the SSH bias and stability from Corsica, Harvest and other calibration programs will be used to link the T/P and Jason-1 sea-level records.

Peopling of three Mediterranean islands (Corsica, Sardinia, and Sicily) inferred by Y-chromosome biallelic variability.

An informative set of biallelic polymorphisms was used to study the structure of Y-chromosome variability in a sample from the Mediterranean islands of Corsica and Sicily, and compared with data on Sardinia to gain insights into the ethnogenesis of these island populations. The results were interpreted in a broader Mediterranean context by including in the analysis neighboring populations previously studied with the same methodology. All samples studied were enclosed in the comparable spectrum of European Y-chromosome variability. Pronounced differences were observed between the islands as well as in the percentages of haplotypes previously shown to have distinctive patterns of continental phylogeography. Approximately 60% of the Sicilian haplotypes are also prevalent in Southern Italy and Greece. Conversely, the Corsican sample had elevated levels of alternative haplotypes common in Northern Italy. Sardinia showed a haplotype ratio similar to that observed in Corsica, but with a remarkable difference in the presence of a lineage defined by marker M26, which approaches 35% in Sardinia but seems absent in Corsica. Although geographically adjacent, the data suggest different colonization histories and a minimal amount of recent gene flow between them. Our results identify possible ancestral continental sources of the various island populations and underscore the influence of founder effect and genetic drift. The Y-chromosome data are consistent with comparable mtDNA data at the RFLP haplogroup level of resolution, as well as linguistic and historic knowledge.

Biologie et estimation des menaces pesant sur les populations de l'endémique corso-sarde Anchusa crispa Viv. (Boraginaceae) en Corse

Anchusa crispa, a short-lived perennial herb, endemic to sandy seashores on the Mediterranean islands of Corsica (France) and Sardinia (Italy), is rare and protected by law in France. In Corsica, it occurs on seven localities where the number of individuals is limited and varying. This species is threatened and actions have been carried out to protect the habitats, with no results for the present. In this study, the detailed description of each site in Corsica and the populations analysis during a few years clarify knowledge on the species and its habitat. The recent biological data suggest i) that Anchusa crispa can maintain small populations and ii) new ideas for conservation.