La genre Scinaia (Rhodophycées,Nemalionales) de la Méditerranée occidentale

Abstract

The genus Scinaia (Rhodopbyta. Nemalionales) of the western Mediterranean sea. Only 3 species of Scinaia are to be found in Western Mediterranean sea. Scinaia complanala, S. furcellata and S. turgida. Scinaia sanctaluciana Funk is considered as a juvenile thallus of Scinaia complanala. Scinaia turgida is recorded for the first time in the Tyrrhenian sea since MAZZA (1902, 1903). A new anatomical character for the distinction of the Scinaia complanala and Scinaia turgida is also given.     

A new taxonomic treatment of the Festuca ovina L. aggregate (Poaceae) in the British Isles

A new taxonomic treatment of the Festuca ovina L. aggregate (Poaceae) in the British Isles. A wide range of morphological, anatomical and cytological characters was collected and analysed by a variety of methods, some taxometric. As a result nine species are recognized in the British Isles, one (F. glauca Vill.) only as a garden plant and two (F. huonii Auquier and F. armoricana Kerguélen) only in the Channel Isles. Two other species sometimes claimed for the British Isles (F. guestfalica Boenn. ex Reichb. and F. indigesta Boiss.) are excluded for various reasons given. One species (F. ovina L.) is divided into three subspecies: the diploid subsp. ovina (commonest in the north); and the tetraploid subsp. hirtula (Hackel ex Travis) M. Wilkinson (the commonest taxon of the aggregate in the British Isles) and subsp. ophioliticola (Kerguélen) M. Wilkinson (scattered throughout the British Isles, but commonest on chalk and limestone and not restricted to serpentine soils as once thought).     

The metazoan parasites of freshwater fishes in the Corrib catchment area, Ireland

A survey of the parasites of 243 fish belonging to 13 species, from the Corrib catchment area, western Ireland, was undertaken. At least 32 species of metazoan parasites were shown to be present. Diplostomum gasterostei, Tylodelphys clavata, Eubothrium salvelini, Cucullanus truttae, Raphidascaris acus, Ergasilus gibbus and Salmincola gordoni appear to be first records for Ireland and Phyllodistomum conostomum has not previously been reported from the British Isles. New host records involving Lamptera planeri, Salvelinus alpinus, Abramis brama, Noemacheilus barbatulus, Anguilla anguilla and Pungitius pungitius for the British Isles are given.     

Phylogeography of the common goby, Pomatoschistus microps, with particular emphasis on the colonization of the Mediterranean and the North Sea

The phylogeographical patterns of a small marine fish, the common goby, Pomatoschistus microps, were assessed at 12 sites along the northeastern Atlantic coasts and the western Mediterranean Sea. A combination of two genetic markers was employed: cellulose acetate allozyme electrophoresis (CAGE) and sequence analysis of a 289 bp fragment of the mitochondrial locus cytochrome b. Both markers were congruent in revealing significant differences between samples (global FST = 0.247 for the allozymes and PhiST = 0.437 for the mitochondrial DNA data) and a pattern of isolation-by-distance. Phylogeographical analyses yielded a shallow branching structure with four groups. Three of those were confined to the Atlantic basin and showed a star-like pattern. The fourth group contained a central haplotype occurring at the edges of the species' distribution, accompanied by a few more rare variants, which were restricted to the Mediterranean Sea. A genetic break was observed around the British Isles, with distinct haplotypes dominating at either side of the English Channel. A significantly negative correlation between the degree of genetic diversity and latitude was recorded both for mitochondrial DNA (mtDNA) and allozymes in the Atlantic basin. Gene flow analysis suggested that recolonization of the North Sea and the coasts of western Scotland and Ireland may have taken place from a glacial refugium in the Southern Bight of the North Sea. These results are discussed in the perspective of possible postglacial migration routes of marine fish along the northeastern Atlantic coasts.     

Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread

Since its first occurrence at Plymouth, southern England, in 1952 the East Asiatic ascidianStyela clava has spread to many localities along the coasts of the south and west British Isles, Ireland, northern France, Belgium, the Netherlands, Denmark and Germany. While some dispersal may occur by natural means, spreading over long distances is probably due to transfer along with oysters when relaid elsewhere. Transport while attached to the hulls of ships or driftingSargassum is also possible.Styela clava is a large, hardy and fast-growing species with a tough, leathery tunic, and has no recorded enemies or native analogues among the NW European ascidian fauna. At many sites it has established dense populations of 500–1000 specimens/m² and in some cases has nearly outcompeted some of the native ascidian species.     

A phylogeographic analysis of Viola rupestris: three post-glacial immigration routes into the Nordic area?

Morphology and isoenzyme patterns support the taxonomic delimitation of two subspecies of Viola rupestris F. W. Schmidt in the Nordic area, i.e. ssp. rupestris and ssp. relicta Jalas. Three different, geographically distinctly defined genotypes, are revealed (based on seven enzyme systems): one in north Scandinavia (= ssp. relicta , distinct in AAT-I, AMP-I and PGM-3), one in north Finland (distinct in AMP-2), and one widespread in the southern and central parts of Norden. Two of the three unique bands in ssp. relicta are also detected in British material. The data are consistent with the scenario of three post-glacial immigration routes into the Nordic area: one from the south-west, today represented by the north Scandinavian populations, one from the east, today represented by the populations in the Kuusamo area of north Finland, and one from the south-east, today represented by widespread populations south of the mentioned areas.     

AN ATLANTIC POPULATION OF PIKEA CALIFORNICA (DUMONTIACEAE,RHODOPHYTA)1

The marine red alga Pikea californica Harvey, previously known only from the east coast of Japan and the west coast of North America, was found in 1983 to be abundant in the surge zone throughout the Isles of Scilly archipelago, off SW England. Examination of herbarium material showed that the population was present in 1967. All plants observed in July 1983 and September 1984 were sterile, but reproductive male and female plants were collected in November 1983. The habitat and phenology of P. californica in the Isles of Scilly closely resemble those of Pacific populations. English plants are vegetatively and reproductively identical to the type and other California specimens. They can easily be distinguished from Sphaerococcus coronopifolius Stackhouse (Sphaerococcaceae, Gigartinales), the most similar species in the flora of the British Isles, by the presence in transverse sections of several lacunae, representing axial and whorl-branchlet filaments, in contrast to the single axial filament of S. coronopifolius. It is possible that the Isles of Scilly population of P. californica is a relict of a species once more widespread, but it seems more likely that it is another example of the well-established pattern of marine introductions into the British Isles from the North Pacific. The range of temperature regimes occupied by P. Californica in the Pacific suggests that the species could become more widespread in Europe, but at present it appears to be confined to the Isles of Scilly.     

Phylogeography and recent historical biogeography of Hydroporus glabriusculus Aubé (Goleoptera: Dytiscidae) in the British Isles and Scandinavia

The genetic relationships of populations of the diving beetle Hydroporus glabriusculus in the British Isles and Sweden were examined using allozyme electrophoresis. H. glabriusculus is widespread in the far north of Eurasia, and occurs further south in western and central Europe as isolated relict colonies in fens whose development dates back to the early Postglacial. Study of genetic distance data reveals that the relict colonies of this insect in the British Isles do not form a distinct phylogeographic lineage, but instead belong to a number of separate groups, one of which also occurs in Sweden. Beetles from Ireland, Scotland and Norfolk appear to have diverged from each other during the Pleistocene, and colonized the British Isles in the early Postglacial in separate waves. Populations in the Norfolk Breck are closely related to the Swedish population studied, these two groups apparently having diverged during the Windermere Interstadial. All Norfolk colonies show remarkably similar depauperate levels of genetic variability, which is considered to have resulted from bottlenecking of an ancestral populaton in the Late Glacial. This study demonstrates that the recent historical biogeography of the biota of north-west Europe may be more complex than would appear from a simple consideraton of Holocene events.     

Grauhörnchen vs. Eichhörnchen

Competition for resources in Europe's forests – grey versus red squirrels As a result of the introduction of the north American grey squirrel in Britain, Ireland and Italy in the 19th and 20th century, the sole native tree squirrel species in Europe – the red squirrel – faced a completely novel competitor. In order to understand the interactions between the two species and to develop a conservation strategy, the two species' biology and ecology was the focus of intense research over the last 25 years. We provide an overview of research findings and the complex competitive interactions for resources and the curcial role of disease in the replacement of native red by introduced grey squirrels. Key factors in the competitive replacement process are habitat composition and patterns of seed food availability, which directly influence individual body condition and reproductive success. In addition, in the British Isles a squirrelpox virus for which grey squirrels act as a reservoir and vector has a drastic impact on the competitive interactions between the two species.     

AN ATLANTIC POPULATION OF PIKEA CALIFORNICA (DUMONTIACEAE,RHODOPHYTA)1

The marine red alga Pikea californica Harvey, previously known only from the east coast of Japan and the west coast of North America, was found in 1983 to be abundant in the surge zone throughout the Isles of Scilly archipelago, off SW England. Examination of herbarium material showed that the population was present in 1967. All plants observed in July 1983 and September 1984 were sterile, but reproductive male and female plants were collected in November 1983. The habitat and phenology of P. californica in the Isles of Scilly closely resemble those of Paczfic populations. English plants are vegetatively and reproductively identical to the type and other California specimens. They can easily be distinguished from Sphaerococcus coronopifolius Stackhouse (Sphaerococcaceae, Gigartinales), the most similar species in the flora of the British Isles, by the presence in transverse section of several lacunae, representing axial and whorlbranchletjilaments, in contrast to the single axial filament of S. coronopifolius. It is possible that the Isles of Scilly population of P. californica is a relict of a species once more widespread, but it seems more likely that it is another example of the well-established pattern of marine introductions into the British Isles from the North Paczfic. The range of temperature regimes occupied by P. californica in the Pacific suggests that the species could become more widespread in Europe, but at present it appears to be confined to the Isles of Scilly.     

Phylogeography,population genetics and conservation of the European red deer Cervus elaphus

• 1 During the Last Glacial Maximum, European red deer Cervus elaphus occurred in refugia in Iberia/southern France, Italy, the Balkans and the Carpathians. Most of Europe, including large parts of the east and north‐east, is now inhabited by red deer from the western lineage. The eastern lineage is largely confined to south‐eastern Europe; a third lineage comprises Sardo‐Corsican and Barbary red deer.
• 2 Sardo‐Corsican, Barbary and Mesola red deer are genetically unique units. They exhibit low levels of genetic diversity and deserve particular protection, since conservation strategies should target genetic information.
• 3 Hybridization between sika Cervus nippon and red deer occurs rarely, but may lead to extensive introgression, particularly in parts of the British Isles. Further expansion of both species may lead to increased hybridization in continental Europe.
• 4 Although hunting has an impact on red deer gene pools, the main threat today is habitat fragmentation in human‐dominated landscapes. The resulting increase in genetic drift and inbreeding reduces variability in isolated populations and may lead to inbreeding depression. To support vital meta‐populations, migration corridors should be established.

     

The Fulmar population of Britain and Ireland, 1959

Despite the severity of the 1978/79 winter, at least 1,714 Blackcaps were reported during a special survey; these were heavily concentrated in western and south-western counties. An increase over recent decades in the numbers of Blackcaps wintering in Britain and Ireland is correlated with expansion of north European breeding populations and with a rise in numbers of autumn migrants passing through British east coast bird observatories. Successful overwintering here is attributed to the way the birds have adapted to taking artificial foods at garden bird tables.     

Recent hybrid origin and invasion of the British Isles by a self-incompatible species, Oxford ragwort (Senecio squalidus L., Asteraceae)

Senecio squalidus is a diploid hybrid species which originated in the British Isles following the introduction of material collected from a hybrid zone on Mount Etna, Sicily, approximately 300 years ago. Introduced hybrid material was cultivated in the Oxford Botanic Garden and gave rise to the stabilized diploid hybrid species, which later spread throughout much of the UK and into some parts of Ireland. Unusually for an invasive species, S. squalidus has a strong system of sporophytic self-incompatibility (SSI) that may have become modified as a result of its recent hybrid origin and spread. First, S. squalidus contains relatively few S alleles (between 2 and 6 S alleles within individual UK populations) compared to other species with SSI (estimates average ~17 S alleles per population). This most probably reflects the population bottleneck experienced by introduced hybrid material. Second, dominance relationships among S. squalidus S alleles are more extensive than those reported in other species with SSI. Third, although pseudo-self-compatibility occurs sporadically in S. squalidus, it is not widespread, indicating that SSI is maintained in the species despite potential mate availability restrictions imposed by low numbers of S alleles. Surveys of other forms of genetic diversity in S. squalidus show that allozyme variation is reduced relative to that within the progenitor species, but Randomly Amplified Polymorphic DNA variation is relatively high. Both types of genetic variation show little or no pattern of isolation-by-distance between populations in keeping with the recent range expansion of the species. During its spread in the British Isles, S. squalidus has hybridized with the native self-compatible (SC) tetraploid species, S. vulgaris, which has led to the origin of three new SC hybrid taxa: a radiate form of S. vulgaris (var. hibernicus), a tetrapoid hybrid species (S. eboracensis) and an allohexaploid (S. cambrensis).     

Cetaceans in British waters

Most information on the distribution, movements and ecology of cetaceans in the N.E. Atlantic have come from whale catches mainly in the early part of this century, and from strandings records collected by the British Museum (Nat. Hist.). With the formation of the Cetacean Group in 1973, a scheme for recording live cetaceans at sea was started. This paper summarizes the results of about two thousand sightings involving nearly 25,000 individual animals between the years 1958– 1978 (but mainly from the last 10 years), and relates them to existing information collected from other sources. Difficulties of identification and potential sources of bias are discussed. Most large cetaceans are present in British waters as part of a latitudinal feeding migration whereas smaller species may be present in the N.E. Atlantic throughout the year with movements being mainly of an offshore-inshore nature. Some species are clearly very rare probably as a result of over-exploitation in the last century and early part of this century. These include the Right whale, Blue whale and probably Humpback whale. Other species are rarely recorded because their usual range is some distance from British waters. These include narwhal and White whale (from Arctic waters), Pygmy sperm whale, smaller beaked whales and Euphrosyne dolphin (from warm temperate to tropical waters). The Harbour porpoise is by far the most common and widespread species in British waters, occurring mainly in inshore waters, although it has apparently declined in certain regions (e.g. Southern North Sea, English Channel, Irish Sea) in recent years probably as a result of pollution, disturbance and/or over-exploitation of food resources. Bottle-nosed and Risso's dolphins are also widely distributed close to the coast, although the latter is restricted to the west and south coasts and the former is associated particularly with some large estuaries. Common dolphins are relatively abundant and widespread, and are more pelagic than the previous three species. White-sided dolphins have a mainly pelagic distribution centred on the Northern North Sea whilst the White-sided dolphin has a wider distribution which includes all the western seaboard. Of larger cetaceans, the Killer whale is relatively common particularly on the west coasts and the Pilot whale is locally and seasonally abundant at the north and south ends of Britain and Ireland where they probably represent distinct populations. The Bottlenose whale, Minke, Fin and Sei whales are confined to the west and north coasts, all but the Minke whale having a primarily pelagic distribution. Sperm whales although increasingly commonly stranded on British coasts, are rarely sighted in inshore waters. The west coast of Britain and Ireland are the most important regions for cetaceans whereas the Southern North Sea has the smallest number although in previous decades numbers were probably higher. Most cetacean species occur mainly in the summer months, particularly August and September, although some species, e.g. White-sided Dolphin, Pilot whale and Minke whale show peaks later in the year. A number of species show secondary spring peaks, e.g. Bottle-nosed and Common dolphins, Risso's dolphins, and Pilot whales. Present evidence suggests that only the large whales exhibit definite latitudinal migrations, all other species being resident at high latitudes although they may show offshore-inshore or possibly small latitudinal movements. Many of the movements indicated from the present analysis can be linked to the seasonal changes in food availability and to the timing and geographical location of breeding, and these are described in detail. Many concentrations of a particular cetacean species occur regularly in the same area year after year and these may often be related to spawning concentrations of a particular fish species. Variations in herd size are noted between species and within species at different times of the year. These are related to aggregations associated with feeding, breeding, and long-distance movements winch will vary according to the biology and ecology of different cetacean species.     

Occurrence of tripletail Lobotes surinamensis (Bloch, 1790) in the inner Bristol Channel,UK

A specimen of tripletail Lobotes surinamensis (total length: 402 mm, total mass: 1262 g) was caught in the shallow waters of the inner Bristol Channel on September 2, 2019, with this only the second known capture of this species from the British Isles. Given the cosmopolitan distribution of this species, the potential origin of this specimen is uncertain.     

Rhodymenia delicatula P.J.L. Dangeard (Rhodophyta,Rhodymeniales) en Méditerranée

Abstract

Presence of Rhodymenia delicatula P.J.L. Dangeard in the Mediterranean. - The presence of Rhodymenia delicatula P.J.L. Dangeard (Rhodophyta, Rhodymeniales) in the southern Thyrrhenian sea is reported. Both cystocarpic and tetrasporic individuals have been collected. Anatomical features of the reproductive structures, as well as the position of these on the thallus allowed the identification of this species formerly known for the Atlantic coasts of Morocco and British Isles.     

The colonial ascidian Didemnum sp. A: Current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America

Didemnum sp. A is a colonial ascidian with rapidly expanding populations on the east and west coasts of North America. The origin of Didemum sp. A is unknown. Populations were first observed on the northeast coast of the U.S. in the late 1980s and on the west coast during the 1990s. It is currently undergoing a massive population explosion and is now a dominant member of many subtidal communities on both coasts. To determine Didemnum sp. A's current distribution, we conducted surveys from Maine to Virginia on the east coast and from British Columbia to southern California on the west coast of the U.S. between 1998 and 2005. In nearshore locations Didemnum sp. A currently ranges from Eastport, Maine to Shinnecock Bay, New York on the east coast. On the west coast it has been recorded from Humboldt Bay to Port San Luis in California, several sites in Puget Sound, Washington, including a heavily fouled mussel culture facility, and several sites in southwestern British Columbia on and adjacent to oyster and mussel farms. The species also occurs at deeper subtidal sites (up to 81 m) off New England, including Georges, Stellwagen and Tillies Banks. On Georges Bank numerous sites within a 230 km² area are 50-90% covered by Didemnum sp. A; large colonies cement the pebble gravel into nearly solid mats that may smother infaunal organisms. These observations suggest that Didemnum sp. A has the potential to alter marine communities and affect economically important activities such as fishing and aquaculture.     

Route,speed and mode of oak postglacial colonisation across the British Isles: Integrating molecular ecology,palaeoecology and modelling approaches

Summary

This paper describes the route, speed and mode of colonisation of oaks by integrating a number of independent analyses using molecular ecology, palaeoecology and simulation modelling approaches. Using a synthetic map of the contemporary distribution of chloroplast DNA (integrating several published and unpublished data sets and describing variation in 1468 trees from 313 autochthonous stands of Q. robur and Q. petraea from Britain and Ireland), and considering the postglacial topographic landscape, the most likely routes of postglacial colonisation across the British Isles are suggested. The overall pattern of these directions agrees with previous interpretations, but several routes, particularly those into Ireland, differ from previous interpretations and benefit here from using a single synthesised data set. Interestingly, the Atlantic oakwoods appear to have been colonised by individuals bearing a single haplotype (type 12). Two palaeoecology data sets, published separately for Britain and Ireland, are synthesised here and used to infer the timing of first arrival of oaks across the British Isles (between 9500 and 6000 years before present). The maximum observed colonisation speed within the British Isles is approximately 500 m year^-1 in central and southern England. Outputs from a simulation model, which mimics postglacial colonisation processes, and which has been parameterised for the colonisation rate observed from the pollen core record and contemporary cpDNA structure, predict that the rapid colonisation rate observed, for at least the southern portion of the British Isles, can only be achieved via very rare (an approximate frequency 0.01%), very long distance seed dispersal events (up to 100 km). Potential agents of such dispersal events are birdsor major meteorological disturbances, e.g. hurricanes. Additional simulation modelling and genetic analysis of latitudinally stratified populations indicate that non-synchronous colonisation fronts, topographic barriers and temperature related survival may also have had an effect on the speed of migration and resulting genetic structure. Finally, in an attempt to record predicted long distance seed dispersal events, a novel curve fitting technique is applied to molecular parentage assignment data for field established seedlings from a contemporary population. A notable discrepancy is recorded between contemporary field estimates (just over 1 km) and those predicted by simulation modelling, and is discussed in detail. A concluding section describes future research priorities.     

MINCHINIA CHITONIS (LANKESTER, 1885) LABBE, 1896, A HAPLOSPORIDIAN PARASITE OF THE CHITON, LEPIDOCHITONA CINEREUS

249 Lepidochitona cinereus were examined from different locationsalong the S.W., S., and S.E. coasts of the British Isles overthe last 12 years and the number infected with Minchinia chitonisrecorded. The spores, each with an operculum and two extensionsof the cytoplasmic envelope are described. The infection didnot appear to be limited to specific tissues, the digestivegland, muscles and gills all being invaded. It is suggestedthat the distribution of this parasite may have increased overthe past 50 years. (Received 3 January 1979;