Fouling Communities of Mussel Aquaculture Installations in the White Sea

We have classified fouling communities developing on artificial substrates of mussel mariculture plants in Kandalakshskii Bay of the White Sea. Several major types of fouling have been distinguished: mussel fouling; fouling similar to the epifauna of the benthos biocenosis of Laminaria saccharinadominated by the ascidian Styela rusticaor sponges Halichondria paniceaand Halisarca dujardini; young fouling developed by algae and the ascidians of the genus Molgula; and ecotone communities in-between these types of fouling. The characteristics of the distinguished communities are provided.     

Pollen-Mesophyll Protoplast Fusion and Hybrid Plant Regeneration in Nicotiana

Isolated pollen protoplasts of Nicotiana tabacum L. N364 Km+ were fused with mesophyll protoplasts of N. rustica L. using PEG-high Ca/pH method. The cells resulted from fusion between immature (early-middle bicellular) pollen protoplasts and mesophyll protoplasts could divide to produce microcalli and regenerated plantlets when cultured in a selection KM8p medium containing 50 g/L kanamycin. Four plantlets were regenerated. The isoenzyme patterns of leaf peroxidases of these plantlets had bands characteristic of both parents. Root-tip squash showed that the gameto-somatic hybrids had the expected triploid chromosome number. Aside from these kanamycin-selected plantlets, six of the twenty-one plantlets that had not undergone selection were also evidenced to be gameto-somatic hybrids.     

SEXUAL SELECTION IN THE BARN SWALLOW HIRUNDO RUSTICA. III. FEMALE TAIL ORNAMENTS

Male secondary sexual characters are often expressed in females, and the maintenance of the character in females can be due to either direct selection on females favoring the maintenance of the trait, or a correlated response to selection in males. Here I report on determinants of and phenotypic selection on tail length of female barn swallows Hirundo rustica. The homologous trait in males is under strong directional sexual selection. Female tail length was positively associated with several reproductive parameters including total seasonal reproductive success, even when controlling for year and age effects. A change in female tail length from one year to another was often associated with a change in the reproductive parameters correlated with absolute tail length. There was little evidence for an association between female tail length and the duration of the incubation period (only females incubate) and absolute and relative female provisioning rates of offspring, and subsequent size of offspring. Tail length of female barn swallows was positively correlated with that of their mates. Female tail length was a heritable trait as determined from regression of the tail trait of offspring on that of their mother and their father, and there was a positive genetic correlation between the tail trait in males and females. In conclusion, female tail length reliably reflects female reproductive potential, and the trait appears to be under directional selection, which may result in an evolutionary response to selection because of the heritability of the tail trait.     

Changes in the metabolism of nucleic acids during the growth and senescence of tobacco callus

Changes in DNA and RNA metabolism, DNA composition and RNA species in callus of tobacco ( Nicotiana rustica L. cv. Gansu Yellow Flower) were investigated during the growth and senescence. DNA and RNA contents remained almost unchanged during the callus growth period, but started to decrease synchronously at the time that callus senescence was initiated. Synthesis of DNA and RNA, as measured by incorporation of [³H]-labelled precursor, increased during the growth period and did not decrease until late in senescence. The activities of DNase and RNase (pH 4.5) increased during the early senescence period in accordance with the decrease in the levels of DNA and RNA, but appeared to decrease during late senescence. These results suggest that the decrease in the levels of DNA and RNA in senescing tobacco callus may stem from the increase in the hydrolytic activities of DNase and RNase (pH 4.5) in the early stage of senescence, and that the slowdown of synthesis in the late senescence period may also be a cause. DNA and RNA electrophoresis showed that a low-molecular-weight satellite DNA band disappeared after the onset of senescence and that the nuclear main band DNA gradually decreased, whereas the high-molecular-weight satellite DNA seemed to undergo no significant changes during the senescence period tested. Of the RNA species, 4–5S RNA was far more susceptible to damage during senescence than 25S and 18S rRNA. This suggests different susceptibilities of different DNA and RNA components to damage during the senescence of tobacco callus or alternatively a highly sequenced degradation of DNA and RNA molecules.     

Recent changes in the distribution of a marine gastropod,Patella rustica,across the Iberian Atlantic coast did not result in diminished genetic diversity or increased connectivity

Aim The Lusitanian limpet, Patella rustica Linnaeus, 1758, is a rocky shore intertidal mollusc found throughout the Mediterranean and the north‐east Atlantic from Mauritania to southern France. A 280‐km gap in its distribution in the Iberian north‐west was first reported in the early 20th century. Between 2002 and 2005 this gap was bridged, and unusual climatic and hydrographic events that occurred in the late 1990s are hypothesized to have facilitated transport and settlement of colonizers from the southern edge of the gap. In the present work we used genetic data to investigate differentiation between the edges of the former gap, to determine the origin of colonizers and to assess patterns of connectivity across the historical and newly colonized region. Location Atlantic coast of Iberia (Portugal and north‐west Spain) and Biarritz. Methods The genetic variation of 12 sites, sampled between 2004 and 2006, was assessed through the analysis of five microsatellites (n = 412) and of a 650‐bp fragment of the mitochondrial cytochrome c oxidase subunit I gene (COI; n = 163). F‐statistics were used to investigate differentiation and patterns of gene flow across the distribution of P. rustica, from southern Portugal to Biarritz. The mitochondrial DNA (mtDNA) mismatch distribution was analysed and the mutation–drift equilibrium tested to investigate putative demographic changes. Results Levels of differentiation were low and generally non‐significant. Comparisons between regions of the historical distribution were all non‐significant. For microsatellites, low yet significant genetic differentiation was observed when all three regions were included. Levels of genetic diversity of newly founded populations were similar to those observed within the historical range. Evidence of demographic changes was detected with mtDNA and microsatellites. Main conclusions The studied region is inhabited by a single population, suggesting that the gap in the distribution of P. rustica was not an effective barrier to gene flow. If it has ever prevented gene flow, it did not last enough time for genetic differentiation to occur. On the other hand, the main currents flowing along the Atlantic coast of Iberia could have been responsible for maintaining connectivity through occasional larval transport across a considerable stretch of inhospitable habitat.     

Integrating stable isotopes,parasite, and ring‐reencounter data to quantify migratory connectivity—A case study with Barn Swallows breeding in Switzerland,Germany, Sweden,and Finland

Ecosystems around the world are connected by seasonal migration. The migrant animals themselves are influenced by migratory connectivity through effects on the individual and the population level. Measuring migratory connectivity is notoriously difficult due to the simple requirement of data conveying information about the nonbreeding distribution of many individuals from several breeding populations. Explicit integration of data derived from different methods increases the precision and the reliability of parameter estimates. We combine ring‐reencounter, stable isotope, and blood parasite data of Barn Swallows Hirundo rustica in a single integrated model to estimate migratory connectivity for three large scale breeding populations across a latitudinal gradient from Central Europe to Scandinavia. To this end, we integrated a non‐Markovian multistate mark‐recovery model for the ring‐reencounter data with normal and binomial mixture models for the stable isotope and parasite data. The integration of different data sources within a mark‐recapture modeling framework enables the most precise quantification of migratory connectivity on the given broad spatial scale. The results show that northern‐breeding populations and Southern Africa as well as southern‐breeding populations and Western–Central Africa are more strongly connected through Barn Swallow migration than central European breeding populations with any of the African wintering areas. The nonbreeding distribution of Barn Swallows from central European breeding populations seems to be a mixture of those populations breeding further north and south, indicating a migratory divide.     

Observer variation in estimates of Meadow Pipit Anthus pratensis and Skylark Alauda arvensis abundance on moorland

Capsule Counts least susceptible to observer effects were those within 25 m of a transect and the total number along a transect, with observer effects greater for distance sampling.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.