bluuebunny/crossref_metadata_2025_split huggingface dataset:
The extent and intensity of management burning in the English uplands
Authors: YALLOP A. R. , THACKER J. I. , THOMAS G. , STEPHENS M. , CLUTTERBUCK B. , BREWER T. , SANNIER C. A. D. 
Published: August 2006

Summary

World‐wide, the controlled use of fire is an important ecological management tool and is essential for the continuance of many communities. It is used extensively in upland regions of England to maintain dwarf shrub habitats for game‐bird rearing. Inappropriate burning, however, is now cited as the second most important reason for the poor condition of conservation sites in these areas. Despite this there are few data on the extent and frequency of its use to help judge its potential impact on biodiversity.
This study, using aerial photography of a 2% sample (208 km2) of the English uplands, surveyed the national scale of fire management for the first time, and used historical photography to identify medium‐term trends in its use.
Management burning in the English uplands is now widespread on ericaceous‐dominated moorland; in the year 2000 17% of the area of this habitat had been burned within the previous 4 years, equivalent to 114 km2 year−1. The present median burn repeat time of consistently managed sites is approximately 20 years.
Within most of the English national parks there has been a significant increase in the extent of new burns (from 15·1% to 29·7%) over this period, indicating an intensification of burning regimes in some areas.
Synthesis and applications. The extent and frequency of burning, and the habitats in which this management occurs, are contentious issues. Reconciling the differing objectives of conservation, game rearing and agricultural stakeholders to allow the development of both strategic and local management planning to address these issues requires information on the extent and history of burning practices. This study provides a much needed first national estimate of burning practices in England and serves as a baseline against which changes in management regimes and their impacts on habitats can be judged.
Glacial survival or late glacial colonization? Phylogeography of the root vole (Microtus oeconomus) in north‐west Norway
Authors: Brunhoff Cecilia , Yoccoz Nigel G. , Ims Rolf A. , Jaarola Maarit 
Published: August 2006

AbstractAim It has been proposed that the root vole subspecies,Microtus oeconomus finmarchicus, survived the last glacial period on islands on the north‐west coast of Norway. The Norwegian island of Andøya may have constituted the only site with permanent ice‐free conditions. Geological surveys and fossil finds from Andøya demonstrate that survival throughout the last glacial maximum was probably possible for some plants and animals. In this study we aim to infer the recent evolutionary history of Norwegian root vole populations and to evaluate the glacial survival hypothesis.Methods DNA sequence variation in the mitochondrial cytochromebgene was studied in 46 root voles from 19 localities.Location Northern Fennoscandia and north‐west Russia with a focus on islands on the north‐west coast of Norway.Results The phylogeographical analyses revealed two North European phylogroups labelled ‘Andøya’ and ‘Fennoscandia’. The Andøya phylogroup contained root voles from the Norwegian islands of Andøya, Ringvassøya and Reinøya and two localities in north‐west Russia. The Fennoscandian phylogroup encompassed root voles from the three Norwegian islands of Kvaløya, Håkøya and Arnøya and the remaining specimens from Norway, northern Sweden and Finland. Nucleotide diversity within the Andøya and Fennoscandian phylogroups was similar, ranging from 0.5% to 0.7%.Main conclusions Both our genetic data and previously published morphological data are consistent within situglacial survival of root voles on Andøya during the last glacial maximum. However, the level of genetic diversity observed in the extant island populations, the past periods of severe climatic conditions on Andøya and the ecology of the root vole are somewhat difficult to reconcile with this model. A biogeographical scenario involving late glacial recolonization along the northern coasts of Russia and Norway therefore represents a viable alternative. Our results demonstrate that complex recolonization and extinction histories can generate intricate phylogeographical patterns and relatively high levels of genetic variation in northern populations.
ORIGINAL ARTICLE: Comparison of predictor sets for species richness and the number of rare species of butterflies and birds
Authors: Thomson James R. , Fleishman Erica , Nally Ralph Mac , Dobkin David S. 
Published: August 2006

AbstractAim Accurate inventories of biota are typically restricted to few locations within an extensive region. Accordingly, effective planning must involve some form of surrogate measures coupled with spatial modelling. We conducted a simultaneous comparison of models of both species richness and the number of rare species using three types of surrogates (indicator species, vegetation composition and structure, and topoclimate) as predictors. We evaluated each type of surrogate alone and in combination with others.Location Data for our analyses were collected from 1996–2004 in three adjacent mountain ranges in the central Great Basin (Lander and Nye counties, Nevada, USA), the Shoshone Mountains, Toiyabe Range and Toquima Range.Methods Data on species richness and species composition of butterflies and birds and measures of vegetation composition and structure were obtained in the field. Topoclimatic variables were derived by GIS from digital sources and satellite images. We used Poisson regression with Bayesian model averaging to predict species richness and the number of rare species. We compared the expected prediction success of all models on the basis of internal and external validation trials.Results Same‐taxon indicator species were the most accurate predictors of species richness and of the number of rare species of butterflies and birds. Cross‐taxon indicator species and topoclimate variables were reasonably accurate predictors of species richness of butterflies and birds and of the number of rare butterfly species. Although vegetation variables were more effective for predicting species richness and number of rare species of birds than of butterflies, they were the least accurate predictors overall.Main conclusions Although indicator species may provide the most accurate predictions of species richness, their practical value, like any surrogate measure, depends greatly on ecological considerations and land‐use context. In general, the ability to predict numbers of rare species based on any set of candidate predictors was weaker than the ability to predict species richness, which may result from the high degree of stochasticity that often characterizes distributions of rare species. Our statistical approach for objective examination of different candidate predictors can help ensure that selection of species‐richness surrogates in any system is scientifically reliable and cost‐effective.
ORIGINAL ARTICLE: Phylogeography and refugia of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae)
Authors: Ikeda Hajime , Setoguchi Hiroaki 
Published: August 2006

AbstractAim  This study aims to elucidate the phylogeography of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae) and to infer the location of refugia of alpine plants in Japan during climatic oscillations.Location  Alpine zone in the Japanese archipelago.Methods  We determined the chloroplast (cp) DNA haplotypes of 155 individuals (22 populations) based on sequence data from the trnL‐F and trnT‐L intergenic spacers and the trnL intron, whose phylogenetic relationships were analysed using the program tcs. To examine the genetic structure, analysis of molecular variance (amova) was carried out and the population differentiation was shown by the parameters GST and NST.Results  The haplotype composition and the results of amova showed that populations in the Japanese Central Mountain Region (JCMR) and in the westernmost region were highly divergent (18.8%). The diversity within populations was very high in the JCMR (hS = 0.421); less variation was found within populations located in other regions at lower elevations.Main conclusions  Phyllodoce nipponica survived climatic changes during the Quaternary in the JCMR and the westernmost region. Most of the distribution range was colonized during only one range expansion. The source location from which the range expansion occurred was unclear.
Breathlessness, phlegm and mortality: 26 years of follow‐up in healthy middle‐aged Norwegian men
Authors: STAVEM K. , SANDVIK L. , ERIKSSEN J. 
Published: August 2006

Abstract.Objectives. It is well known that pulmonary function is associated with all‐cause and cardiovascular (CV) death. Less is known about the association between respiratory symptoms and mortality and whether such an association is independent of physical fitness. In this study, we assessed the association of breathlessness and productive cough with CV and all‐cause mortality over 26 years.Design. Prospective occupational cohort study.Setting and subjects. In 1972–75, 1999 apparently healthy men aged 40–59 years were recruited to the study from five companies in Oslo, Norway. At study entry clinical, physiological and biochemical parameters including respiratory symptoms, spirometry, and an objective assessment of physical fitness were measured in all subjects, of whom 1623 had acceptable spirometry. The data was analysed using Cox proportional hazards analysis, adjusting for age, lung function, physical fitness, and other possible confounders, with mortality until 2000.Results. After 26 years (range 25–27), 615 men (38%) had died, of whom 308 (50%) from CV deaths. In multivariable proportional hazards models, ‘having phlegm winter mornings’ [hazard ratio (HR) 1.30,P = 0.01], ‘breathlessness when hurrying/walking uphill’ (HR 1.43,P = 0.005) and combinations of the two symptoms remained significant predictors of all‐cause mortality. None of six respiratory symptoms were significant predictors of CV mortality in multivariable models.Conclusions. Phlegm, breathlessness and combinations of them were associated with all‐cause mortality, even after adjusting for physical fitness, known CV and other risk factors such as smoking, and lung function. The finding of an association also after adjustment for physical fitness is new. In contrast, none of the six respiratory symptoms individually or in combination were associated with CV mortality in multivariable analysis.
Effects of antihypertensive drug treatments on fracture outcomes: a meta‐analysis of observational studies
Authors: WIENS M. , ETMINAN M. , GILL S. S. , TAKKOUCHE B. 
Published: August 2006

Abstract.Objective.  To quantitatively pool findings from observational studies on the risk of fracture outcomes associated with exposure to five antihypertensive drug classes: angiotensin‐converting enzyme (ACE) inhibitors, diuretics (in particular thiazide diuretics), β‐blockers, calcium‐channel blockers and alpha‐blockers.Design.  Systematic review and meta‐analysis.Data sources.  Publications listed in the MEDLINE, EMBASE and LILACS databases, the ISI proceedings, and bibliographies of retrieved articles. Sources were searched from the earliest possible dates through December 2005.Review methods.  We included case–control and cohort studies presenting relative risks and confidence intervals (CIs) for the association between exposure to antihypertensive agents and fracture outcomes. Data were extracted onto a standardized computer worksheet. Study quality was assessed using a 10‐point questionnaire specific to case–control or cohort study design.Results.  Fifty‐four studies were identified. Pooled estimates were computed using the software HEpiMA. The pooled relative risk (RR) of any fracture with use of thiazide diuretics was 0.86 (95% CI 0.81–0.92) and 1.14 (95% CI 0.84–1.54) with use of nonthiazide diuretics. There was a statistically significant reduction of any fracture with use of β‐blockers, (RR 0.86, 95% CI 0.70–0.98). The one study with ACE inhibitor data showed protection (RR 0.81, 95% CI 0.73–0.89). No significant associations were found between fractures and exposure to α‐blockers or calcium‐channel blockers.Conclusions.  Thiazide diuretics and β‐blockers appear to lower the risk of fractures in older adults. However, these agents cannot be recommended as preventive therapies for fractures until data from randomized controlled trials have established their efficacy. Patients who use these inexpensive drugs as treatments for hypertension may also benefit from a reduction in fracture risk.
Spatial and temporal genetic structure of the planktonicSagitta setosa(Chaetognatha) in European seas as revealed by mitochondrial and nuclear DNA markers
Authors: PEIJNENBURG K. T. C. A. , FAUVELOT C. , BREEUWER J. A. J. , MENKEN S. B. J. 
Published: August 2006

AbstractLittle is known about the spatial and temporal scales at which planktonic organisms are genetically structured. A previous study of mitochondrial DNA (mtDNA) in the holoplanktonic chaetognathSagitta setosarevealed strong phylogeographic structuring suggesting that Northeast (NE) Atlantic, Mediterranean and Black Sea populations are genetically disjunct. The present study used a higher sampling intensity and a combination of mitochondrial and four microsatellite markers to reveal population structuring between and within basins. Between basins, both marker sets indicated significant differentiation confirming earlier results that gene flow is probably absent between the respectiveS. setosapopulations. At the within‐basin scale, we found no evidence of spatial or temporal structuring within the NE Atlantic. In the Mediterranean basin, both marker sets indicated significant structuring, but only the mtDNA data indicated a sharp genetic division between Adriatic and all other Mediterranean populations. Data were inconclusive about population structuring in the Black Sea. The levels of differentiation indicated by the two marker sets differed substantially, with far less pronounced structure detected by microsatellite than mtDNA data. This study also uncovered the presence of highly divergent mitochondrial lineages that were discordant with morphology, geography and nuclear DNA. We thus propose the hypothesis that highly divergent mitochondrial lineages may be present within interbreedingS. setosapopulations.
Temporal recruitment patterns and gene flow in kelp rockfish (Sebastes atrovirens)
Authors: GILBERT‐HORVATH ELIZABETH A. , LARSON RALPH J. , GARZA JOHN CARLOS 
Published: August 2006

AbstractPelagic dispersal of marine organisms provides abundant opportunity for gene flow and presumably inhibits population genetic divergence. However, ephemeral, fine‐scale, temporal and spatial genetic heterogeneity is frequently observed in settled propagules of marine species that otherwise exhibit broad‐scale genetic homogeneity. A large variance in reproductive success is one explanation for this phenomenon. Here, genetic analyses of 16 microsatellite loci are used to examine temporal patterns of variation in young‐of‐year kelp rockfish (Sebastes atrovirens) recruiting to nearshore habitat in Monterey Bay, California, USA. Population structure of adults from central California is also evaluated to determine if spatial structure exists and might potentially contribute to recruitment patterns. Genetic homogeneity was found among 414 young‐of‐year sampled throughout the entire 1998 recruitment season. No substantial adult population structure was found among seven populations spanning 800 km of coastline that includes the Point Conception marine biogeographic boundary. Comparison of young‐of‐year and adult samples revealed no genetic differentiation and no measurable reduction in genetic variation of offspring, indicating little variance in reproductive success and no reduction in effective population size for this year class. Simulation analyses determined that the data set was sufficiently powerful to detect both slight population structure among adults and a small reduction in effective number of breeders contributing to this year class. The findings of high gene flow and low genetic drift have important implications for fisheries management and conservation efforts.
Genetic tagging reveals extreme site fidelity in territorial male Antarctic fur seals Arctocephalus gazella
Authors: HOFFMAN J. I. , TRATHAN P. N. , AMOS W. 
Published: August 2006

AbstractGenetic tagging, the identification of individuals using their genotypes, provides a powerful tool for studying animals that are difficult to observe or identify using conventional techniques. However, despite being widely adopted by conservation biologists, the full potential of this approach has yet to be realized. Here we used genetic recapture data to quantify male site fidelity at a colony of Antarctic fur seals where an aerial walkway provides unprecedented access and individual positions are determined daily to 1 m accuracy. Because males are too large and aggressive to be captured and fitted with conventional tags, we remotely collected 770 tissue samples over eight consecutive seasons and used nine‐locus microsatellite genotypes to reveal 306 genetic recaptures among 464 unique individuals. Within seasons, males are highly site‐faithful, with any movements that occur tending to take place before the period when females come into oestrus. Of those males that return to breed over successive seasons, almost half return to within a body length of where they were before. The discovery of such extreme site faithfulness has implications for the population structure and mating system of fur seals and potentially other colonially breeding species.
Refugia ofPotentilla matsumurae(Rosaceae) located at high mountains in the Japanese archipelago
Authors: IKEDA HAJIME , SENNI KEI , FUJII NORIYUKI , SETOGUCHI HIROAKI 
Published: August 2006

AbstractMolecular phylogeographic studies have revealed the genetic patterns and glacial–interglacial history of many plant and animal species. To infer the Quaternary history of alpine plants in the Japanese archipelago, which is poorly known, we investigated 203 individuals ofPotentilla matsumuraeand its varieties from 22 populations. We found 11 haplotypes based on approximately 1400 bp of two intergenetic spacers in chloroplast DNA (trnT‐Landrpl20–rps20). The distribution of these haplotypes was geographically structured, which was supported by haplotype composition, principal component analysis, and unweighted pair group method with arithmetic mean (UPGMA), andNST(0.71) was significantly greater thanGST(0.68). In addition to the positive correlation between genetic and geographic distance (Mantel test,r = 0.497,P < 0.001), an abrupt genetic change was detected between mountains in central Honshu and the Tohoku region. This genetic boundary was further supported by analysis of molecular variance (amova), and high variation (54.0%) was explained by differences on either side of this boundary. Moreover, haplotypes in central Honshu were thought to have diverged, based on an outgroup comparison. These results suggest that mountains in central Honshu served as refugia during the Quaternary climatic oscillation, although the results could not reveal the history of most mountains in the Tohoku region and Hokkaido. Nevertheless, following floristic studies, our results indicate that alpine plants in Japan experienced a history different from that in Europe; i.e. they retreated into refugia during warm periods to avoid forest development, rather than glaciers.
Genetic diversity and phylogeography of the Apennine yellow‐bellied toadBombina pachypus, with implications for conservation
Authors: CANESTRELLI DANIELE , CIMMARUTA ROBERTA , COSTANTINI VERA , NASCETTI GIUSEPPE 
Published: August 2006

AbstractGenetic variation was investigated in 17 populations of the Italian endemic Apennine yellow‐bellied toad using both mitochondrial (598 bp of the cytochromebgene) and nuclear (21 allozyme loci) markers. Populations from central Calabria (southern Italy) showed the highest levels of intrapopulation genetic variation, whereas samples located north of this region were nearly lacking in variation. This appears to be a typical pattern of ‘southern richness and northern purity’, usually attributed to the prolonged population stability within southern refugia coupled with the loss of variation during postglacial northward expansion. However, the overall pattern of genetic variation observed has a strong geographical component, suggesting two Calabrian plains, Catanzaro and Crati‐Sibari, as historical barriers to dispersal separating three population groups. These findings cannot be explained by the prolonged stability of southern populations alone, and suggest that the southern richness has been at least in part shaped by allopatric differentiation within the refugial range, followed by intermixing of previously differentiated lineages. From a conservation standpoint, Calabria is the major genetic diversity reservoir for this species, thus deserving particular conservation efforts. Furthermore, although the low intrapopulation genetic variation outside Calabria appears to be of clear historical origin, evidence of a current reduction of gene flow suggests that human disturbance has also played a part, particularly in the anthropogenic impacted Volturno river drainage basin.
Parallel evolution of ecomorphological traits in the European whitefishCoregonus lavaretus(L.) species complex during postglacial times
Authors: ØSTBYE K. , AMUNDSEN P.‐A. , BERNATCHEZ L. , KLEMETSEN A. , KNUDSEN R. , KRISTOFFERSEN R. , NÆSJE T. F. , HINDAR K. 
Published: August 2006

AbstractThe extensive phenotypic polymorphism in the European whitefish has triggered evolutionary research in order to disentangle mechanisms underlying diversification. To illuminate the ecological distinctiveness in polymorphic whitefish, and evaluate taxonomic designations, we studied nine Norwegian lakes in three watercourses, which each harboured pairs of divergent whitefish morphs. We compared the morphology and life history of these morphs, documented the extent of genetic differentiation between them, and contrasted the niche use of sympatric morphs along both the habitat and resource axes. In all cases, sympatric morphs differed in the number of gill rakers, a highly heritable trait related to trophic utilization. Individual growth rate, age and size at maturity, diet and habitat use also differed between morphs within lakes, but were remarkably similar across lakes within the same morph. Microsatellite analyses confirmed for all but one pair that sympatric morphs were significantly genetically different, and that similar morphs from different lakes likely have a polyphyletic origin. These results are most compatible with the process of parallel evolution through recurrent postglacial divergence into pelagic and benthic niches in each of these lakes. We propose that sparsely and densely rakered whitefish sympatric pairs may be a likely case of ecological speciation, mediated in oligotrophic lakes with few trophic competitors.