Observations on Thorea ramosissimaBory (Batrachospermales,Thoreaceae), a freshwater red alga rarely recorded in the British Isles

The conspicuous macroscopic stage of the freshwater red alga Thorea ramosissima has been re-discovered in the River Thames after a lapse of almost 140 years. In the 1840s it was reported only from Walton-on-Thames, but is now known from 13 localities along a 133 km stretch between Oxford and Teddington. It is transient, often remaining undetected at known localities in subsequent years. All British records are assessed, especially 19th century collections from the Thames. The ecology and the morphology of the macroscopic stage are discussed.     

Notes On Strand Plants. II. Cakile Maritima,Scop

Summary

Buxbaumia aphylla is a rare and enigmatic moss in Britain where it is found regularly and in sizeable populations only on colliery debris (‘bings’) in central Scotland. Its habitat preferences and ecology are described from a range of sites. It has persisted in quantity in several localities for over 20 years, but in other apparently suitable sites it is absent. Destruction and landscaping of bings are seen as the major threat to the species in Scotland.     

Status and Breeding Sites of Three Presumed Endangered Scottish Saproxylic Syrphids (Diptera, Syrphidae)

From 1987 to 1999 efforts were made to understand the status and breeding sites of three presumed endangered flies in Britain: Blera fallax (Linnaeus), Hammerschmidtia ferruginea (Fallén) and Callicera rufa Schummel (Diptera, Syrphidae). Historical data on flight periods, localities and breeding sites were collated from the literature and captured specimens in museums and other collections. Using these data, life cycles were investigated, and cited and other localities searched for adults and early stages. Looking for early stages was more productive than looking for adults. B. fallax is the most endangered. It has declined in abundance, is restricted to two localities and, in 1999, breeding sites were destroyed at one of these localities. In contrast C. rufa is widespread and not uncommon throughout northern Scotland. H. ferruginea is not as endangered as B. fallax but adverse factors such as habitat destruction affect most of its sites.     

Grimmia anomala Schimp., new to Britain and Ireland

Abstract

Grimmia anomala is reported from seven sites in Scotland and Ireland. Confusion in the past with Grimmia hartmanii has meant that this species has been overlooked. Its occurrence in Scandinavia and the Faroes means that its sites in Scotland are not unexpected but the Irish localities for this boreal-montane species are noteworthy.     

Aspects of the population genetics of Mytilus (Mytilidae; Mollusca) in the British Isles

Starch gel electrophoresis was used to study variation at 11 loci in mussels sampled mainly from British coastal sites. Two types of mussel were identified, Mytilus edulis, the common mussel and its southern relative Mytilus galloprovincialis. Several partially diagnostic loci were used to map the distribution of the two forms. Mytilus edulis was present at all sites sampled in Britain and Ireland but was at low frequency in SW England; M. galloprovincialis was detected in SW England, the south and west of Ireland. Scotland and NE England, but was absent from south Wales, the Irish sea coasts of Wales and Ireland, and SE England. Apart from the occurrence of M. galloprovincialis in NE England, this distribution conforms with the results of studies using morphological characters and parallels the distribution of many other southern species in Britain. At the microgeographical level, M. edulis was found to prefer more sheltered and estuarine conditions than M. galloprovincialis. Analysis using the best diagnostic loci showed that hybridization is occurring between M. edulis and M. galloprovincialis at all localities where they occur sympatrically but that the extent of hybridization varies considerably between localities. The distribution of localities having high proportions of hybrid individuals is best interpreted by assuming that hybrids have higher fitness than parental types at these localities. A study was made of variation within and between those localities where only M. edulis individuals were observed. Little significant geographic variation in allele frequency was detected, but significant deficits of heterozygotes compared with Hardy-Weinberg expectations were seen for most loci. Analysis suggests that the Wahlund effect is not involved and that the most likely cause of the deficit is low frequencies of null alleles. In M. edulis no differences in phenotypic variance in shell height and width were observed between samples of multiply heterozygous and multiply homozygous individuals and no genetic differences were found between juveniles and adults. Overall little evidence was found that balancing selection is responsible for maintenance of the polymorphisms studied in M. edulis. The pattern of geographic variation in gene frequencies in Mytilus in the British Isles is discussed in relation to variation in the south and north of Europe and North America. It is concluded that steep clines in gene frequencies in M. edulis observed by other workers in the Baltic and in Long Island Sound cannot be attributed to the presence of M. galloprovincialis.     

Male labial gland secretions and mitochondrial DNA markers support species status of Bombus cryptarum and B. magnus (Hymenoptera, Apidae)

Summary. Spring queens of Bombus cryptarum and B. magnus from 2 localities in Brandenburg/Germany and Scotland/United Kingdom respectively were determined by morphological characteristics. The lateral border of the collare at the border of the pronotallobus or at the episternum proved to be an especially useful character. Artificial colonies were reared from safely determined spring queens and the cephalic part of the labial glands of males from these colonies were investigated by GC/MS. The investigation identified approximately 50 compounds, as a mixture of straight chain fatty acid derivatives (alcohols, esters and hydrocarbons). The labial secretions of B. cryptarum and B. magnus are significantly different. Mitochondrial cytochrome oxidase 1 (CO1) of two queens from each locality and species were sequenced. Each species from the different localities formed a cluster. Sequence divergence between B. cryptarum and B. magnus was about 30 base substitutions and approximately 0.04 in Tamura-Nei genetic distance. Bombus cryptarum and B. magnus were closer to each other than to B. lucorum and made the sister group in the topology of the tree. Both the CO1 sequences and the labial gland secretions of males of B. cryptarum from Brandenburg and of males from artificial colonies reared from safely determined spring queens from Scotland are identical. B. cryptarum has thus, for the first time, been identified as part of the British bumble bee fauna. The differences of both the labial gland secretions, used as species recognition signals, and the genetic differences established by sequencing CO1 confirm the morphological findings that B. cryptarum and B. magnus are distinct taxa which should be treated as distinct species.Received 25 March 2004; revised 13 June 2004; accepted 15 June 2004.     

Taxonomic notes on Cheilothela (Lindb.) Broth. and Dicranella (C. Muell.) Schimp.

Abstract

The widespread occurrence of a number of bryophytes on British saltmarshes is reported. The communities in which bryophytes are most frequently found are discussed. These communities are more common on marshes on the west coast of Britain. Differences between moss assemblages on salt marshes in England and Wales and in Scotland are emphasised and the greater range of habitat preference demonstrated by Grimmia maritima in Scotland is commented upon.     

Arctoa anderssonii Wich. (Dicranaceae), new to the British Isles

Abstract

Arctoa anderssonii Wich. is described as a species new to the British Isles with an account of its habitat on Ben Hope, a mountain in Sutherland, north-west Scotland. The differences between this species and Arctoa fulvella and A. hyperborea are specified.     

Four closely related but forgotten species of Rhipidocotyle Diesing, 1858 (Digenea: Bucephalidae) in fishes from European seas

The following species of Rhipidocotyle are described: R. minima (Wagener, 1852) from Chelidonichthys gurnardus, C. lastoviza and Aspitrigla cuculus at various localities off the British Isles; R. nicolli n. sp. from A. cuculus off Plymouth, SW England; R. triglae (van Beneden, 1870) from C. lucernus in the Gulf of Marseilles, western Mediterranean; and R. viperae (van Beneden, 1870) from Echiichthys vipera at various localities off the British Isles. The distinguishing features of the species are discussed in detail. A list of the bucephalid species reported from the Mediterranean Sea is appended.     

A spatio-temporal analysis of a New Zealand flatworn (Arthurdendyus triangulatus) population in western Scotland

The New Zealand flatworm (Arthurdendyus triangulatus), which is an obligate predator of native earthworms, is an alien species to the British Isles and is widely distributed in Scotland. What little is known about its biology under field conditions is mainly from Northern Ireland. Samples taken from single sampling dates have shown A. triangulatus to have an aggregated distribution. To determine the spatio‐temporal distribution of A. triangulatus, a grass field in western Scotland was intensively sampled over a 16‐month period. Data indicate an increase in flatworm numbers and seasonal trends in body weight, the appearance of egg capsules and hatchlings. Results also showed that spatially, the flatworms were aggregated, but this was a transient phenomenon over the period of the experiment. The distribution of egg capsules in the study area was strongly aggregated and related to the appearance of hatchlings. Flatworms may aggregate in areas where soil moisture is optimal for the survival of the New Zealand flatworm.     

Athalamia hyalina (Sommerf.) S.Hatt. in Scotland,new to the British Isles

Abstract

The liverwort Athalamia hyalina (Sommerf.) S.Hatt. and the family Cleveaceae are reported as new to the British Isles from the eastern Scottish Highlands. The Scottish plants are described and illustrated and the significance of the discovery is assessed. In Scotland, Athalamia hyalina occurs on thin soil on eroding limestone ledges in a montane habitat with a continental climate. It is in active growth in the winter months, producing spores in spring. Its range is restricted but it occurs within a protected area and is not threatened at present. The species is widespread in the northern hemisphere.     

The geographical distribution of Xiphinema and Longidorus nematodes in the British Isles and Ireland

The distribution of Xiphinema and Longidorus species in the British Isles and Ireland were mapped by means of a computer programme from 5527 records. Longidorus caespiticola, L. elongatus, L. goodeyi and L. leptocephalus were found to be widespread among a wide range of vegetation types, particularly in grassland and arable crops; L. macrosoma and L. profundorum were recorded frequently in southern and central England, and L. attenuatus in East Anglia; L. vineacola was recorded once only in Eire. Paralongidorus maximus was recorded from two localities in eastern Scotland and one in southern England, on each occasion from intensively cultivated ground. Four species of Xiphinema were recorded but only X. diversicaudatum is widespread although apparently with a northerly limit in central Scotland; X. diversicaudatum was equally prevalent in arable crops, grassland and deciduous woodland; X. coxi and X. vuittenezi were recorded from a few scattered localities in England, and the few records for X. mediterraneum were all from Kent, south east England. All species were found in a wide range of soil types but mostly in light soils with a large sand fraction. Many of the species occurred together in mixed populations; L. caespiticola was most frequently associated with X. diversicaudatum and with L. leptocephalus and L. elongatus. X. diversicaudatum also was commonly found with L. goodeyi. Viruses were transmitted in laboratory bait tests in only eighteen of 325 soil samples containing X. diversicaudatum and four of 265 containing L. elongatus.     

Leptodon Smith (Hedw.) Mohr in Ireland

Abstract

A new Irish locality is recorded for L. smithii, and the general features of the station are described. An account of the bryophyte succession on tree trunks in the area is given and the part played by L. smithii indicated. It is shown that gatherings from both Irish localities consisted entirely of male plants and the distribution and age of the antheridia on both specimens are recorded. It is suggested that rarity of sporophyte production in the British Isles is probably due to too great a spatial separation of male and female plants and not to the absence, or low production, of sex organs. It is also suggested that rarity of spores and impermanence of the habitat are the chief factors contributing to its rareness in climatically suitable areas of the British Isles. The known distribution of the plant in the British Isles is related to its European and world distribution, and it is shown that L. smithii may be expected in further Irish vice counties.

I have pleasure in acknowledging my thanks to Mr Wallace for the gift of a specimen of L. smithii from Knocklofty and for details of its habitat; to Mrs C. E. M. Shelswell-White for permission to enter and collect in the grounds of Bantry House, and to my colleague Dr J. G. Hawkes for confirming the identification of the two shrubs.     

Breeding bird communities on Scottish farms

The Common Birds Census, begun by the British Trust for Ornithology has now been monitoring bird population levels on a nationwide basis since 1962. Separate indices were constructed for Scotland and the rest of Great Britain for 12 of the commonest species. Of the species examined blue tit (Parus caeruleus), wren (Troglodytes troglodytes), song thrush (Turdus philomelos), lapwing (Vanellus vanellus), chaffinch (Fringilla coelebs) and skylark (Alauda arvensis) have increased since 1963 and show very similar population trends to the rest of Great Britain. Whitethroat (Sylvia communis), willow warbler (Phylloscopus trochilus) and swallow (Hirundo rustica) have all declined nationally, the decline in the swallow appears to have begun earlier in Scotland. The blackbird (Turdus merula) and dunnock (Prunella modularis) showed similar upward trends until 1972 when the Scottish population started to decline; a much more noticeable decline in the Scottish robin (Erithacus rubecula) population began in 1966. The total density of territory-holding males has not increased but the biomass has and this is due to more, bigger birds but fewer passerines. The species diversity measured by the Shannon Wiener index (H.) has improved a little since 1971 and it is concluded that during the study period the farmland plots censused in Scotland have on average not shown evidence of deterioration as habitats for territory-holding birds.     

Geographic variation in the colour/ pattern polymorphism of British Philaenus spumarius (L) (Homoptera: Aphrophoridae) populations *

Geographic variation in the frequency of colour/pattern morphs of Philaenus spumarius is described at 48 localities in England and Wales. The sites have been divided into four broad environmental categories, two urban and two rural. There is a distinction between the urban and rural groupings in the relative proportions of the colour morphs; in urban localities there is a higher combined frequency of the eight ‘melanic’ morphs. Differences also exist between locality groupings, and between the sexes, in the relative frequencies of the eight morphs within the ‘melanic’ phenotypic category. Morphs limited to the female sex in some other parts of the species range occur among males in British populations. It is suggested that the different dominance hierarchy between the sexes which exists in Fennoscandian populations may not be characteristic of British populations.     

Pteridophytes as field indicators of natural biodiversity restoration in the Scottish flora

Summary

The pteridophyte flora of Scotland, as with that of the British Isles as a whole, is still recovering from the great reduction of its original diversity caused by the Pleistocene glaciations. However, the isolation of the British Isles, their range of suitable habitats and their climatic and edaphic opportunity has provided conditions in which processes of natural biodiversity restoration in pteridophytes can be demonstrated and monitored. The modern pteridophyte vegetation of Scotland is analyzed in this evolutionary perspective. Using the examples of both ferns and fern allies, it is suggested that it is at least as important to conserve suitable sites for the continued origin of novel taxa as it is to allow for the perpetuation of existing taxa and communities.     

Rumex aquaticus L. at Loch Lomondside

Summary

A new alliance of spring vegetation dominated by the leafy liverwort Anthelia julacea is described from the montane regions of Britain. It is distinguished floristically and ecologically from similar alpine late snow bed communities in Scotland and Scandinavia. The classificatory position of the stands of this vegetation type is discussed with reference to continental and British systems and it is concluded that the erection of a new alliance is justified on floristic grounds.     

Plagiochila britannica,a new species in the British Isles

Abstract

Plagiochila britannica is described as a new species. It differs from P. porelloides and P. asplenioides in many characters, especially its often more narrowly oval leaves with a more variable, often truncate to bilobed apex and larger cells, its wider antical stem cells and its diploid chromosome number. Differences from P. arctica var intermedia include its more variable leaf apex, generally more dentate leaves often with longer teeth, the greater maximum size of its leaf cells and its wider antical stem cells. Male and female inflorescences and sporophytes are known in P. britannica, which favours base-rich substrata and has been found in Wales, N. England, Scotland and N. Ireland. A key to the nine species of Plagiochila in the British Isles is included.