bluuebunny/crossref_metadata_2025 huggingface dataset:
Are habitat islands islands? Woodliving beetles (Coleoptera) in deciduous forest fragments in boreal forest
Authors: Ås Stefan
Published: July 2006

Modern forestry has changed the fire dynamics in the boreal forest and as a result the size and number of deciduous forest patches have been reduced as well as the number of deciduous trees within the coniferous forest This has exaggerated the insularity of deciduous forest patches within the boreal coniferous forest zone In this paper I examine whether the diversity of beetles living in dead stems of deciduous trees follows the relationship with patch area to be predicted from island biogeographic theory, and to what extent the species assemblages differ between large and small patches and single deciduous trees within managed coniferous forests Three larger patches of deciduous forest (>120 ha) arisen as successions after forest fires in the late 1880's are compared with 6 small (<20 ha) patches of similar origin No difference in diversity could be detected between large and small patches A statistically significant difference between assembly composition was detected using matrix regression between a matrix of observed assembly similarities and a hypothetical similarity matrix based on the type of area in which the plot was situated (large‐ small or matrix) Finally I examined the distribution of the 56 most common beetle species over the habitat types investigated Thirty four species did not show any Significant habitat preference, 12 were found more often in clear‐cut areas than expected 5 were over‐represented in small patches, and 4 in large areas My explanation to this apparent lack of insularity effects is the relative recent commencement of intensive forestry in these areas and the fact that the matrix is of rather high quality that is inhabitable for numerous beetle species Thus the patches may be viewed as incipient islands still exchanging biota with their surroundings
Naïve birds and noble savages ‐ a review of man‐caused prehistoric extinctions of island birds
Authors: Milberg Per , Tyrberg Tommy
Published: July 2006

Many bird species were extirpated or became extinct when prehistoric man reached oceanic islands We list > 200 species of extinct island birds only recorded as sub‐fossils and which probably vanished due to prehistoric man In addition we list c 160 cases where an extant species has been found as subfossil on islands where it no longer occurs Several species today considered endemic to single islands of island groups had a much wider distribution in the past Biogeographic analyses of insular avifaunas are almost meaningless it the extensive prehistoric extinctions are not taken into account

Most extinct species belong to Anatidae Rallidae and Drcpanididae while local extirpations are numerous among doves and seabirds Smaller birds are rare mainly due to sampling bias and taphonomic factors The bird populations were depleted mainly by overhunting predation by introduced vertebrates and alteration of the original vegetation

Prehistoric humans on islands although dependent on limited animal resources regularly failed to exploit these in a sustainable way Several cases where human populations disappeared from islands in the Pacific may have been due to over‐exploitation of native animals

Prehistoric man reached most tropical and temperate islands and most of the few remaining island faunas have been severely depleted in historic times The prehistoric extinctions emphasize the extreme vulnerability and value of the very few pristine island faunas that still remain
Factors affecting species number and density of dabbling duck guilds in North Europe
Authors: Elmberg Johan , Nummi Petri , Poysa Hannu , Sjoberg Kjell
Published: July 2006

We addressed how species number and pair density in guilds of co‐existing species is related to habitat structure, and to the abundance and diversity of food resources using the assemblage of seven species of dabbling ducks (genus Anas) breeding in 60 lakes distributed over six regions in temperate north Europe

Partial correlation and multiple regression revealed that species richness was best predicted by habitat structural diversity as indexed by a principal component analysis based on 18 vegetation and lake characteristics, and by the abundance of aquatic and emergent prey We found no effect of lake size or prey size diversity on species richness Pair density was correlated with the percentage of shoreline with horsetails (Equisetum), by habitat structural diversity and by the abundance of emergent invertebrate prey Neither prey size diversity nor abundance of aquatic prey correlated with pair density Species richness and pair density in North European duck guilds vary both with habitat structure and prey availability
Interaction between the black yeast Aureobasidium pullulans and the gall midge Lasioptera ephedricola in gall formation on the desert shrub Ephedra trifurca
Authors: Herman R. Peter , Bynum Holly G. , Alexander Anthony B.
Published: July 2006

Galls produced by the cecidomynd Lastoptera ephedncola on Ephedia trifurca always have a black ring associated with them while galls produced by the congener L ephedrae never do Black ring material after microscopic examination and culture proved to be Aureobasidium pullulans In addition to lacking black ring material neither L ephedrae galls nor healthy stems consistently yielded Aureobasidium on culture Gall and larva size measurements indicated that continued larval presence is not necessary for gall development, suggesting fungus initiated gall formation However inoculation of healthy stems with Aureobasidium caused lesions hut not galls The mycelium m galls did not appear grazed and neither larvae nor pupae contained Aureobasidium propagules suggesting that larvae do not feed directly on fungi These data also suggest that there is no trans‐pupal passage of fungus from larvae or pupae to adults Newly emerged females do not carry fungal propagules suggesting that thcy are not inoculated upon exiting the gall Gall position leaf culture and stem culture data suggest that the fungus is picked up from leaves prior to oviposition
Temporal variation in species‐area curves for invertebrates in clumps of an intertidal mussel
Authors: Peake Anthony J. , Quinn G. P.
Published: July 2006

We examined the temporal variation in the relationships between the number of invertebrate species, and of total individuals inhabiting clumps of the intertidal mussel Brachidontes rostratus and the area of the clumps We collected clumps in four seasons ‐ autumn, winter, spring and summer ‐ from a rocky shore in south‐eastern Australia Positive curvilinear relationships between species number and area were recorded for all seasons but fewer species for a given area were found in autumn and summer compared with winter and spring These species‐area relationships were different from those predicted from a passive sampling model (Random Placement Model) Positive relationships between number of individuals and area were also recorded but these did not vary between seasons There was no short‐term difference (i e between phases of tide and day) in species or individual number in clumps Seasonal variation, and small‐scale spatial unpredictability in recruitment patterns are potentially important determinants of species numbers in this system The seasonal differences we have recorded for mussel clumps suggest that future studies on island systems particularly in marine habitats should consider temporal variation in species‐area relationships and that conclusions from previous comparisons of species‐area curves based on one‐off sampling must only be tentative
Habitat associations of ducks during different phases of the breeding season
Authors: Nummi Petri , Pòysá Hannu
Published: July 2006

Habitat use of mallard Anas platvrhynchos, teal A crecca. wigeon A penelope and goldeneye Bucephala clangula was studied m southern Finland during 1988–1991 Emphasis included evaluation of the importance of food and vegetation structure and revealing of the patterns of habitat use throughout the breeding season Average lake scores of pairs, broods, and juveniles of all species were on the luxunant end of a principal component analysis axis describing habitat structure A more detailed examination, however, revealed clear differences in habitat distributions both between and within species Generally, habitat distributions seemed to shift toward the luxuriant from pairs to broods However, goldeneye juveniles used both the most luxuriant and the poorest habitats more than expected When all phases of the breeding cycle are considered, habitat luxuriance seemed to be more important for dabbling ducks and nektonic invertebrates more important for the goldeneye Emerging insects were most important to the teal
The distribution of Salix species in Fennoscandia ‐ a numerical analysis
Authors: Myklestad Åse
Published: July 2006

This paper aims to detect, describe, and interpret the major distributional patterns of species within the genus Salix in Fennoscandia, and to compare these results with a European‐scale analysis of Salix distributional patterns

The occurrences of the 24 native Salix species in the 558.50 km grid squares that comprise Fennoscandia, were recorded on the basis of distnbutional maps in Atlas Florae Europaeae Distnbutional patterns were summarised numencally by means of two‐way indicator species analysis and detrended correspondence analysis, and were related numerically to 42 climatic, geographical, topographical, geological, land‐use and edaphic variables by means of canonical correspondence analysis The possible importance of the relationships between species distributions and the environment was tested statistically

Regional climate, the most important components being related to summer temperatures, largely accounts for the regional distributional patterns within Salix in Fennoscandia This result agrees with the European‐scale results for Salix, and suggests that these two scales may belong to the same domain

The regionalisation based on Salix is similar to earlier phytogeographical regionalisations of Fennoscandia, suggesting that the climatic factors proposed as being important for Salix distributions may also be important for regional vegetation patterns at the scale of Fennoscandia
Thermal advantage of pale coloured morphs of the snail Arianta arbustorum (Helicidae, Pulmonata) in alpine habitats
Authors: Burla Hans , Gosteli Margret
Published: July 2006

In alpine grasslands pale colour morphs of the snail Arianta arbustorum are more frequent than dark ones As pale morphs absorb less solar radiation, they may forage for longer in sunlight and/or have a lower mortality risk from overheating This hypothesis was tested Equal numbers of pale and dark morphs were kept in enclosures in an alpine meadow During the day, more pale morphs were seen than dark ones, the latter obviously remaining hidden The difference was not significant in enclosures set up in a nearby forest, confirming that the inequality in behaviour depends on the amount of sunlight Dark snails are on average warmer than pale ones

Experiments were also conducted in grassland on a mountain slope at altitudes between 1200 and 2000 m Snails were marked with a paint which fades in light, and released When recaptured several days later, the marks were more faded in pale morphs than in dark, suggesting that they had been more exposed to sunlight, supporting our hypothesis The difference in fading was more pronounced at high than at low altitude
Cost of reproduction in the perennial herb Asphodelus albus (Liliaceae)
Authors: Obeso J. R.
Published: July 2006

The cost of reproduction has been studied in two populations of the polycarpic herb Asphodelus albus under natural conditions The percentage of plants with flowers was determined in four sites and varied markedly among them The occurrence of reproduction was size‐dependent, increasing flowering probability with plant size The cost of reproduction was assessed in terms of modular growth in reproductive plants relative to modular growth in vegetative ones I compared the modular growth of vegetative and reproductive plants considering two different densities m each of two populations Neither incidence of flowering nor modular growth were affected by density Flowering plants exhibited a withinramet demographic cost (in terms of modular growth) relative to non‐flowering ramets in one population but not in the other This cost was greater in larger plants These results were concordant with the occurrence of flowering at both sites Both populations exhibited size‐dependent patterns of allocation to reproduction, but no significant relationships were found between allocation to reproduction and cost of reproduction The data presented demonstrate differences in the cost of reproduction within a species This cost might determine whether a plant begins the reproduction, but probably have no effect on the reproductive allocation since the weight of the reproductive structures was not related to modular growth
Rarity and species/area relationships of vascular plants in deciduous woods, western Norway ‐ applications to nature reserve selection
Authors: Sætersdal Magne
Published: July 2006

The Rabinowitz s model of rarity was applied to a vascular plant census list from 60 deciduous woods in western Norway By applying information from distribution maps and plant sociological literature from western Norway it was possible to obtain data on geographical distribution, habitat specificity, and maximum local population size at the regional‐scale of western Norway This enabled a comparison between rarity at the local scale and rarity at the regional scale At the local scale rarity was primarily due to narrow geographic distribution At the regional scale, however, the most frequent form of rarity was due to restricted habitat specificity The species/area relationship and the SLOSS effect for the rare species at the regional scale are compared with patterns involving the total species list It is shown that a single large wood supports fewer regional‐scale rare species than do combinations of two small woods of equal area The species/area relationship for species with small population sizes at the regional scale has a different slope from the species/area relationship for all species Area is a better predictor of regional‐scale rarity than is the number of common species
Microsite and regional variation in the potential decay rate of Sphagnum magellanicum in south Swedish raised bogs
Authors: Hogg E. H. , Maimer N. , Wallén B.
Published: July 2006

In southern Sweden there are regional gradients in the rate of atmospheric deposition of nitrogen, and the rate of N deposition has increased in recent decades This may have caused a shift in the growth‐limiting nutrient of Sphagnum growth from nitrogen to phosphorus In this study, the influence of N and P concentrations on the decay of litter peat formed by Sphagnum magellanicum was examined A total of 90 litter peat samples formed by this species was collected from 15 raised bogs (3 sites per bog, 2 microsites per site) Total N and P of samples were determined and the rate of decomposition (C02 release) was measured under aerated, laboratory conditions at 18°C Differences in decomposition rates, N and P concentrations were most pronounced among microsites within sites, whereas no significant differences were observed among bogs The results indicate that decomposition of 5 magellanicum litter peat is influenced more by P than by N Thus, it appears that the recent increase in atmospheric N deposition has not had a large direct effect on peat decomposition rates It is suggested that the efficient uptake of N and P by the Sphagnum plant may lead to a positive feedback mechanism, whereby more slowly growing Sphagnum produces more nutrient‐enriched litter peat with a more rapid decay Such a mechanism could promote the development of microtopography (hummocks and hollows) on bogs
Reproductive patterns of Betula pendula and B. pubescens coll. along a regional altitudinal gradient in northern Sweden
Authors: Holm Stig‐Olov
Published: July 2006

The Scandinavian birches have different distribution patterns Betula pendula reaches its upper tree limit at the bottom of the valleys in the Scandes, while B pubescens ssp pubescens extends above the B pendula limit, and merges into B pubescens ssp tortuosa at higher elevations In a 6 yr study I quantified the spatial and temporal variation in the reproduction of these species along a regional altitudinal gradient Betula pendula showed a steeper altitudinal decrease of seed germinability and seed germination rate than B pubescens coll Seed weight was strongly and positively correlated with altitude for B pubescens, but not for B pendula The proportion of seeds infected by gall midges Semudobia coll, was much higher in B pendula than in B pubescens coll especially in the mountain area All birch taxa showed large annual variations in quantity and quality of seeds The sapling density was higher in B pubescens ssp pubescens stands than in B pendula and B pubescens ssp tortuosa stands in the mountains The vegetative reproduction was about three times higher for B pubescens ssp tortuosa, than for the other two birches These results indicate that the altitudinal variation in reproduction among the birch taxa mirror their present distribution patterns
Reproductive variability and pollen limitation in three Betula taxa in northern Sweden
Authors: Holm Stig‐Olov
Published: July 2006

This 3‐yr study documents large variation in pollination and seed quality in birches (Betula) in northern Sweden between taxa, high and low altitude populations, and among years Seed quality was positively correlated with pollination degree and improved by pollen supplementation in B pubescens ssp pubescens in the mountain area, indicating pollen limitation Betula pendula showed the same tendency, but less pronounced Reduced sexual reproduction of B pendula in the mountain area might more often be due to limited resources for seed maturation and defense of the seeds against predispersal seed predation In contrast, coastal populations of both species display relatively high pollination rates and supplemental pollination had no effect on seed quality, suggesting that pollen limitation is rare or absent here The mountain birch Betula pubescens ssp tortuosa showed generally lower pollination and seed quality compared with B pubescens ssp pubescens, but not compared with mountain populations of B pendula It is concluded that pollen limitation may occur in Betula, but to what extent varies with taxon, altitude and year The seed quality is also strongly affected by other factors such as infections of gall midges (Semudobia spp, Diptera Cecidomyndae) and incomplete seed maturation
Colonization of new host plant individuals by locally adapted thrips
Authors: Karban Richard , Strauss Sharon Y.
Published: July 2006

This study considered the dispersal and subsequent reproduction of Apterothrips aptens a wingless, folivorous thrips species that is divided into local populations, each adapted to its individual host plant We placed host plants with no thrips into the field and observed the rate at which thrips colonized these plants Colonization events were rare, on average each pot received 1 47 immigrants during the year Immature thrips were found associated with 64 59c of these events, indicating that reproduction had occurred Colonization was most likely to occur during the summer Most colonists walked onto the new host and airborne movements were very rare Plants that were located far from near neighbors were less likely to be colonized although the size of nearby source populations did not influence the rate of colonization

These results suggest that limited movement is associated with division of this population into isolated demes Limited movement appeared to be more important as a barner to successful colonization than was demographic success following arrival at a new host plant
Litter sex ratio variation in laboratory colonies of two geographically distinct strains of the root vole Microtus oeconomus
Authors: Anker Ims Rolf
Published: July 2006

Litter sex ratio at birth was studied in two laboratory colonies of root voles Microtus oeconomus originating from northern and southern Norway, respectively Sex ratio was female biased in the northern (57% females), but not in the southern colony Sex seemed to be binomially distributed within litters of both colonies, and did not show consistent relationships with mother weight, litter size, parity or number of generations bred in the laboratory Both colonies originated from populations exhibiting cyclic population dynamics in the wild Thus different demography as such is unable to explain the difference in sex ratio between the two laboratory colonies Social organization has been shown to differ between the two strains of root voles both in the field and in the laboratory, but it is yet unclear whether this factor is related to the sex ratio difference documented in this laboratory study
Food plant selection by reindeer during winter in relation to plant quality
Authors: Danell Kjell , Mikael Utsi Per , Thomas Palo R. , Eriksson Olof
Published: July 2006

The relative palatabilities of nine plant taxa used as winter food by reindeer were estimated by presenting them in cafeteria and pairwise tests Feeding p reference indices were then related to the chemical composition of the plants High preference indices were obtained for the lichensBryoriaspp,Cladina arbuscula, C rangiferinaandC stellaris,while low values were obtained for the mossPleurozium schrebeland the dwarf shrubsEmpetrum hermaphroditumandVaccinium myrttllusThe grassDeschampsia flexuosaand the lichenStereocaulon paschalereceived intermediate scores Feeding preferences showed a strong negative correlation with acid detergent fiber (ADF)‐values No statistically significant correlations were found between feeding preferences and contents of nitrogen, in vitro organic matter digestibility (IVOMD) or neutral detergent fiber (NDF)
Intraseasonal variation in pollination intensity and seed set in an alpine population of Ranunculus acris in southwestern Norway
Authors: Totland Örjan
Published: July 2006

I studied aspects of the pollination and reproduction ecology of an alpine population of the circurnpolar Ranunculus acris (Ranunculaceae) at Hardangervidda, southwest Norway Dipteran families, mainly Muscidae and Anthomyudae, were the most frequent flower visitors and pollinators A single visit by these insects resulted in a seed set of c 18% of the total potential Visitation rates were highest early m the flowering season The longevity of individual flowers of early flowering plants was c 3 d shorter than that of mid‐season flowering individuals Insect pollinators moved short distances between flowers and they mostly visited near neighbour plants Expenments showed that Ranunculus acris was self‐incompatible and thus dependent on insect visitation for seed production Early flowering individuals had a very high seed set relative to individuals flowering in mid‐ and late season, suggesting a strong selection pressure for early flowering in the population Seed production in this Ranunculus acris population seems to be limited by severe climatic conditions and a low pollination intensity
Distribution of forest dwelling carabids (Coleoptera): spatial scale and the concept of communities
Authors: Niemelä Jari K. , Spence John R.
Published: July 2006

Associations between spatial distribution of ground‐beetles (Carabidae) and environmental variables were studied over three hierarchical scales in deciduous forest in central Alberta, Canada We also examined the relationship between species abundance and distribution on several scales ranging from the local scale of our study to that of the North American temperate deciduous forest Understorey plant cover, tree cover, and occurrence of other carabids were associated with distribution of particular species at the smallest ecological scales within populations However, great differences in population sues of carabid species among five distinct sites several kilometres apart were not correlated with variation in the same environmental variables In central Alberta, abundance and extent of distribution were correlated positively among the 30 carabid species collected, and distributions of the ten species classified as ‘core’ species were generally aggregated at all spatial scales On the continental scale, there was a significant positive correlation between abundance and distribution for the 114 species of the entire data set, and the six species meeting the criteria of ‘core’ taxa on this scale, were also ‘core’ elements in central Alberta Further analysis of covariance of core elements of species assemblages across different taxa provides a sound empirical approach for understanding community organization
Longitudinal distribution and ecophysiological characteristics of Hydropsyche exocellata (Trichoptera: Hydropsychidae) in large rivers
Authors: Guinand Bruno , Tachet Henri , Roux Chantal
Published: July 2006

The position as a potamic or rhithronic species of Hydropsyche exocellata (Trichoptera Hydropsychmae) was analysed with regard to 1) its metabolism temperature curve and the total amplitude of its respiratory metabolism between 5° and 25°C, n) its distribution in some reaches of the Rhône River basin (France), and Hydropsychmae coexisting species in those reaches to assess its place in the stream continuum Metabolism data indicated clearly that H exocellata was a species adapted to the potamon, but distribution data did not confirm metabolism results The absence of H exocellata, for instance, from the lower and potamic reaches from the Rhône River itself, as well as its frequent coexistence with H pellucidula, a well‐established near‐rhithronic species regarding metabolism, suggests a more complex definition of its position as a potamic species
The adaptive role of facultative embryonic diapause in the grasshopper Caledia captiva (Orthoptera: Acrididae) in southeastern Australia
Authors: Groeters Francis R.
Published: July 2006

In a temperate zone population of the grasshopperCaledia captiva(Fabnerus) (Orthoptera Acrididae), facultative embryonic diapause provided the basis for a number of aspects of life cycle flexibility Most offspring produced during the summer entered diapause, destined to overwinter as embryos and hatch in the spring, but a small percentage developed directly to hatching, overwintered as nymphs and reproduced in the spring The two different developmental pathways often occurred among the offspring of the same mother, and could represent a bet‐hedging adaptation Offspring of the small overwintering generation were influenced by a maternal effect which greatly diminished their likelihood of entering diapause This is an adaptation to prevent an inappropriate developmental delay that would negate the fitness advantage of an extra generation Offspring produced in the autumn failed to develop to the stage at which diapause intervenes before winter and overwintered at a pre‐diapause stage They did not enter diapause when development resumed in the spring Facultative diapause in this case also prevented an inappropriate developmental delay in the spring, and provided females with the option of reproducing toward the end of the growing season Life cycle flexibility appears to have evolved to exploit a climate with a short growing season but mild winter
Non flying mammals and landscape changes in the tropical rain forest region of Los Tuxtlas, Mexico
Authors: Estrada Alejandro , Coates‐Estrada Rosamond , Meritt Dennis
Published: July 2006

The rapid and extensive conversion of Neotropical rain forests to a landscape consisting of pasture lands and other agricultural habitats has meant the local disappearance fragmentation and isolation of vertebrate populations To avoid further losses in biodiversity in Neotropical rain forests, it is imperative to determine how the different species that constitute the different vertebrate communities have responded to the anthropogenic alterations of their natural habitats To provide data in this direction we sampled non flying mammals in 35 forest fragments, in six disturbed forest sites in 12 regenerating forests, in 20 arboreal agricultural habitats (cacao coffee, mixed, citrus and allspice), in four live fence sites and in four pasture sites at Los Tuxtlas, Veracruz Mexico Sampling indicated that area of forest fragments and isolating distance were important variables influencing species richness Disturbed forest had fewer species and individuals present and supported a lower non flying mammal biomass than undisturbed and regenerating forests Shaded plantations (cacao coffee and mixed) were richer in species and in individuals than unshaded ones (citrus, allspice) Species richness in forests and agricultural habitats were associated to horizontal plant diversity and vertical foliage diversity Pasture habitats were the poorest man‐made habitats in non flying mammal species Live fences supported a higher biomass and species of non flying mammals than pastures and were similar to forest and shaded man‐made habitats in species assemblages
Patterns in species richness, size, and latitudinal range of East Atlantic fishes
Authors: Macpherson Enrique , Duarte Carlos M.
Published: July 2006

Examination of latitudinal patterns in species richness, size, and distributional range of East Atlantic fish, based on a compilation of data encompassing the full latitudinal and depth distribution of 1746 East Atlantic fish species, showed that species richness declined towards higher latitudes at a rate of c 1 % of the number of species present, in five‐degree bands, for each degree of latitude for both teleosts and elasmobranchs, regardless of habitat However, the latitudinal patterns in maximum fish size and latitudinal range differed between teleosts and elasmobranchs, and changed with habitat No clear evidence was obtained that the latitudinal range occupied increased with latitude, indicating that Rapoport's rule does not apply to E Atlantic fishes Rather, the latitudinal patterns in species richness, size, and distributional range of benthic Atlantic fish were depth‐dependent, because species richness, average maximum size, and the average latitudinal range increased with depth and declined with latitude The importance of accounting for this depth‐latitude covariation in the distribution of marine fish demonstrated here, together with recent evidence obtained for deep‐sea benthic macrofauna, points to depth and latitude as the main factors in the distribution of marine animals
Habitat characteristics of Eurasian pine martens Martes martes in an insular Mediterranean environment
Authors: Clevenger Anthony P.
Published: July 2006

Eurasian pine martens are considered habitat specialists, associated primarily with mature stands of mesic mixed wood forest habitats, and avoid areas without overhead cover The species is found throughout the temperate and boreal regions of the continent but on the Mediterranean island of Minorca, introduced pine martens thrive in a competitor‐ and predator‐free environment I test the prediction that because of evolved prey‐capture and predator avoidance strategies Minorcan martens should select habitats most similar to temperate and northern parts of their range Scat index routes were used to quantify pine marten habitat selection Marten did not demonstrate any habitat type preferences although observed use of pine forests and coastal shrublands was slighly greater than expected Marten were indifferent to overhead cover whereas mesic sites and areas of tall high shrub density were favored Small mammal trap indices and preferred prey suggested that martens commonly used non‐forested areas My results demonstrated that on Minorca pine martens were habitat generalists In the absence of predators open non‐forested habitats were equally important to pine marten as were forested ones
Large plant size counteracts early seed predation during the extended flowering season of a Silene uniflora (Caryophyllaceae) population
Authors: Pettersson Mats W.
Published: July 2006

A population of the alvar race of the perennial herb, Silene uniflora (Caryophyllaceae), which grows on thin soils in open alvar habitats on the Baltic island of Oland SE Sweden, was found to have an extended and more or less bimodal flowering phenology Large individuals produced flowers during both periods, while small, and presumably young, individuals only produced flowers in either of the two periods, or in part of both In the early flowering period plants were heavily infested by the seed‐predatory larvae of a noctuid moth, Hadena confusa, but in the late flowering period only a small proportion of the fruits was attacked by the seed predators The proportion of flowers developing into fruits was consistently high throughout the season Both the number of seeds per capsule and the mass of seeds decreased over the flowering season However, the germination success of early and late seeds did not differ Thus, although differing in number of seeds, both early and late flowers contributed to individual reproductive success Large individuals started to flower early in the season and despite their high loss of seeds in the early part of the summer they contributed a larger number of seeds to the seed pool than smaller and later‐flowering individuals Although selection was acting to favour later flowering during a year with high early seed predation, consistency of date of flower initiation and of relative predation impact on individuals across years was low suggesting that recurrent selection by seed predators is weak Seed predation, although heavy, is therefore judged to be unlikely to cause a significant evolutionary response on flowering phenology in this plant
A latitudinal cline in vernalization requirement in Cirsium vulgare
Authors: Wesselingh Renate A. , Klinkhamer Peter G. L. , de Jong Tom J. , Schlatmann Els G. M.
Published: July 2006

We studied geographical variation in the vernalization requirement among European populations of the facultative biennial thistle Cirsium vulgare In two common garden experiments and a growth room experiment we found genotypes that flowered without cold, in their first year These annual types originated mainly from the south of Europe Most of the plants from the northern populations flowered in their second year, after experiencing winter cold We discuss the effects of the absence of a vernalization requirement on the phenotype
Local variation in rodent communities of Sitka spruce plantations: the interplay of successional stage and site‐specific habitat parameters
Authors: Fernandez Fernando A. S. , Evans Peter R. , Dunstone Nigel
Published: July 2006

Habitat associations of wood mouse Apodemus svlvaticus, bank vole Clethrionomvs glareolus and field vole Microtus agrestis were analysed during a chronosequence study of succession in Sitka spruce Picea stichensis plantations in Hamsterley Forest, northeast England In mature plantations (ca 40 yr after planting), A svlvaticus and C glareolus were both abundant, in clear‐felled areas the former was usually dominant, in young plantations (5‐8 yr after planting) either of the three species was dominant at different sites Pooling all sites, in young plantations rodent communities were most diverse, because of an inter‐site component (β‐diversity), although within sites, young plantations and mature plantations had similar diversities Clear‐felled areas showed least rodent diversity Detrended Correspondence Analysis was used to describe the taxonomic and structural changes in vegetation during succession Canonical Correspondence Analysis showed that in young plantations C glareolus was associated with dense ground cover, provided mostly by heather Microtus agrestis was most commonly associated with Deschampsia flexuosa, whereas A svlvaticus was not strongly associated with any plant species Spatial heterogeneity in soils explained much of the inter‐site variation in vegetation winch in turn explained much of the β‐diversity of rodent communities in young plantations
Frugivory and seed dispersal by redwings Turdus iliacus in southwest Iceland
Authors: Guitian José , Munilla Ignacio , Guitian Pablo , Lopez Belén
Published: July 2006

We studied consumption of wild fruits by redwings Turdus thacus coburnt at two sites on the southwest coast of Iceland, just prior to the autumn migration During this period the principal study site offers c 800000 fruits ha−1 most of these are of Empetrum nigrum (c 90% of fresh weight), but fruits of Vaccimum uliginosum. Arctostaphylos uva‐ursi, Vaccimum myrtillus and Rubus saxatilis are also present Redwings regularly consumed the fruits of all these species except R saxatilis At both study sites E nigrum fruits were the most important component of the redwing diet (70 ‐ 80% of fruits ingested), followed by V uliginosum (c 20%) Neither species was consumed as predicted on the basis either of overall relative abundance of fruits or of relative frequency of occurrence of fruiting plants in two hundred 0 3 m2 plots In another forty 0 3 m2 plots, the number of E nigrum fruits consumed over a seven‐day penod was not significantly correlated with the number of fruits initially present Empetrum nigrum seed width is positively correlated with fruit size, and the mean width of seeds in droppings suggests that redwings prefer large E nigrum fruits (which have a higher pulp‐to‐seed weight ratio) to small E nigrum fruits Despite the predominance of E nigrum, redwing droppings tend to contain a mix of seeds of different species, the most frequent combination being E nigrum and V uliginosum
Impact of climate change factors on the clonal sedge Carex bigelown: implications for population growth and vegetative spread
Authors: Carlsson Bengt Å. , Callaghan Terry V.
Published: July 2006

Hypothesized life‐cycle responses to climate change for the arctic, clonal perennial Carex bigelown are constructed using a range of earlier observations and experiments together with new information from monitoring and an environmental perturbation study These data suggest, that under current climate change scenarios, increases in CO2, temperature and nutrient availability would promote growth in a qualitatively similar way The evidence suggests that both tiller size and daughter tiller production will increase, and be shifted towards production of phalanx tillers which have a greater propensity for flowering Furthermore, age at tillering as well as tiller life span may decrease, whereas survival of younger age classes might be higher Mathematical models using experimental data incorporating these hypotheses were used to a) integrate the various responses and to calculate the order of magnitude of changes in population growth rate (γ). and b) to explore the implications of responses in individual demographic parameters for population growth rate The models suggest that population growth rate following climate change might increase significantly, but not un‐realistically so. with the younger, larger, guerilla ullers being the most important tiller categones in contributing to X The rate of vegetative spread is calculated to more than double, while cyclical trends in flowering and populauon growth are predicted to decrease substantially
Prey selection in coastal Eurasian otters Lutra Iutra
Authors: Heggberget Thrine Moen , Moseid Kjell‐Erik
Published: July 2006

Prey preferences and dietary differences between sex and age categories of Eurasian otters were studied in coastal Norwegian habitats Relative to their trapping frequency potential prey species with hard, spiny exoskeletons (crabs and sea urchins) or otherwise tough, spiny integuments (Labridae) were much less frequently found in spraints than fish species with soft integuments Spines did not protect fish with otherwise soft integuments from otter predation The number of non‐fish taxa per otter stomach did not vary significantly between otter age categories despite presumed differences in hunting abilities (small cubs large cubs and subadults, adults) Relative frequency of occurrence of crabs and sea urchins was < 5% in the stomachs in each of these otter categories Anadromous, katadromous and freshwater fish species were infrequently eaten The coastal otter population during the study period probably had access to an adequate, and preferred, supply of marine fish prey

At the otter population level no prey size selection was conclusively demonstrated within the range of fish sizes sampled However, fish sizes eaten differed significantly between otter sex and age categories The fish sizes per stomach were on average larger in males than in females, regardless of age Adult males tended to eat the largest fishes Among the self provisioning age categories (subadult and adult otters) fish lengths differed significantly between otter males and females, but not between the otter age categories, and did not covary significantly with otter body length Fish eaten by females with old placental scars (potential mothers of fisheating cubs) were significantly smaller than those eaten by small cubs, provisioned by their mothers
Patterns of abundance and demography: Collembola in a habitat patch gradient
Authors: Hertzberg Karine , Leinaas Hans Petter , Ims Rolf Anker
Published: July 2006

The demography and abundance of Collembola in relation to a gradient of increasingly isolated tussocks ofCarex ursinawere investigated near Ny‐Alesund, Svalbard The study area was divided into three zones according to tussock density Ten tussocks were sampled in each zone In addition, samples were taken between tussocks, which consisted of ground covered with a layer of cyanobacteria A total of ten Collembola species were found, five of which were chosen for further studies TheCarextussocks were the preferred habitat for the majority of these species Only one species,Hypogastrura viatica,was found regularly between tussocks, although at low density The gradient in tussock distribution was probably an important factor in determining the distribution, abundance and the underlying demographic processes of most species This was indicated by an increase in demographic heterogeneity with patch isolation The different species were affected differently, however Whereas one species appeared to be unaffected by the gradient(H viatica),two species(H longispina)and(Folsomia sexoculata)were somewhat surprisingly found to have their highest density where tussocks were furthest apart Factors other than the spatial configuration of the habitat are probably important in determining the distribution of these two species, indicated by a positive correlation at tussock level between them In accordance with general hypotheses on the effect of patchiness on population dynamics the remaining two species,F quadrioculataandOnvchiurus groenlandicus,occurred in very low numbers or not at all, respectively, in the zone where tussocks were furthest apart Their response is probably dependent on their ability to successfully colonise isolated tussocks We predict that different species specific demographic strategies, and in particular dispersal rates may account for the observed patterns
Immunoglobulins in human dental plaque
Authors: Newman H. N. , Seymour G. J. , Challacombe S. J.
Published: July 2006

Immunoglobulins have been found previously in human gingiva, gingival fluid, serum and smeas of dental plaque. In the present study their presence and distribution in situ have been studied by immunofluorescence on the approximal surfaces of childen's teeth extracted due to caries or for orthodontic reasons. There wee also preliminary investigations of S. mutans distribution and of plaque immunoglobulins in grossly carious adult teeth. Positive fluorescence was in the order total Ig > IgG > IgA > IgM. S mutans (serotype c) was found in two of seven samples. Fluorescence was most marked at the apical plaque border, especially in relation to the contact area. This may relate to the prevalence of lysed organisms in this region. The topography and distribution of the different immunoglobulins correlate with previous studies suggesting gingival fluid (via plasma and gingival plasma cells) as the main source of the plaque immunoglobulin at the site of onset of approximal caries and chronic inflammatory periodontal disease.
Chemotactic activity in periodontal disease
Authors: Okada H. , Silverman M. S.
Published: July 2006

Extracts of gingival tissue obtained from periodontal patients, but not from patients with clinically jealthu tissue, were found to be chemotactic for human mononuclear cells. The chemotactic activity of the extracts could be suppressed by anti‐C5 serum. The data obtained suggest that C5‐related compound are major factors in the chemotaxis of mono nuclear cells in periodontal disease.
The phenotypic characterization of lymphocyte subpopulations in established human periodontal disease
Authors: Seymour Gregory J. , Greenspan John S.
Published: July 2006

Phenotypic characterization of lymphoid cell subpopulations in the lesionof established chronic inflammatory periodontal disease in man was carried out using indirect immunofluorescence to dectct the presence of human thymocyte antigen, human myeloid antigen, IgG‐and IgM‐bearing cells in situ in the lesion. The majority of lymphiod cells were IgM‐positive T‐cells were found. These results suggest that established chronic infalmmatory periodontal disease in man should be considered as a B‐cell lesion. The role of the T‐cells in the lesion May be primarily one of helper activity, although cell‐mediated immune mechanisms cannot be precluded.
Modulation of gingival cAMP levels by tissue infalmmation
Authors: Grower Marvin F. , Chandler Dorothy
Published: July 2006

The basal levels of the nucletide cAMPin gingiva and the relationship of these levels to gingival tissue health was determined in Rhesus monkeys. It was shown that tissue cAMP levels were negatively correlated ot gingival infalmmation. Infalmed gingiva showed lower tissue cAMP levels that healthy gigiva. In adition, the effect of thetrauma of in the tissues progressively decreased as flaps were reflected for 30,60, or 120 minutes. It is concluded that inflammatory stimuli due to bacterial plaque or tissue trauma both result in lowered tissue cAMP levels which may be one of teh mediators of the physiologic changes seen in gingival tissuess during infalmmation.
Spiramycin as a selective dental plaque control agent
Authors: Rozanis Jacob , Johnson Rohert H. , Haq M. Safiul , Schofield Ian D. F.
Published: July 2006

Spiramycin was tested as a chemotherapeutic plaque control agent. Sixty‐ three volunteers (29 experimental and 34 control) abstained from mechanical oral hygiene procedures for 11 weeks. The participants were divided randomly into exeperimental and control groupa and received, on a double blind basis, either 20–500 mg capsules of spiramycin or 20 capsules of placebo with directions to take 1 capsule 4 times a day for 5 days. At each examination visit intra‐oral photographs were taken, gingival and plaque indices recored, and plaque samples collected for laboratory study. In the experimental group there was a statistically significant decrease in plaque as measured by wet weight, turbidity, nitrogen, and carbogydrat parameters for at least 3 weeks. There was a significant decrease in the number of Streptococcus mutasn and S. sanguis in the plaque samples at weeks 1 and 3, but there was no detectable influence on the number of Gram‐negative organisms.