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Several Localities (several + locality)
Selected AbstractsEVIDENCE FOR HISTORICAL INTROGRESSION ALONG A CONTACT ZONE BETWEEN TWO SPECIES OF CHAR (PISCES: SALMONIDAE) IN NORTHWESTERN NORTH AMERICAEVOLUTION, Issue 5 2002Z. Redenbach Abstract Phylogeographic analyses can yield valuable insights into the geographic and historical contexts of contact and hybridization between taxa. Two species of char (Salmonidae), Dolly Varden (Salvelinus malma) and bull trout (S. confluentus) have largely parapatric distributions in watersheds of northwestern North America. They are, however, sympatric in several localities and hybridization and some introgression occurs across a broad area of contact. We conducted a comparative phylogenetic analysis of Dolly Varden and bull trout to gain a historical perspective of hybridization between these species and to test for footprints of historical introgression. We resolved two major Dolly Varden mitochondrial DNA (mtDNA) clades (with 1.4,2.2% sequence divergence between haplotypes) that had different geographical distributions. Clade N is distributed across most of the range of Dolly Varden, from southern British Columbia through to the Kuril Islands in Asia. Clade S had a much more limited distribution, from Washington state, at the southern limit of the Dolly Varden range, to the middle of Vancouver Island. The distribution and inferred ages of the mtDNA clades suggested that Dolly Varden survived the Wisconsinan glaciation in a previously unsuspected refuge south of the ice sheet, and that Dolly Varden and bull trout were probably in continuous contact over most of the last 100,000 years. When bull trout were included in the phylogenetic analysis, however, the mtDNA of neither species was monophyletic: Clade S Dolly Varden clustered within the bull trout mtDNA clade. This pattern was discordant with two nuclear phylogenies produced (growth hormone 2 and rRNA internal transcribed sequence 1), in which Dolly Varden and bull trout were reciprocally monophyletic. This discordance between mtDNA- and nDNA-based phylogenies indicates that historical introgression of bull trout mtDNA into Dolly Varden occurred. Percent sequence divergence within these introgressed Dolly Varden (clade S) was 0.2,0.6%, implying that the introgression occurred prior to the most recent glaciation. Our analysis and other evidence of contact between divergent lineages in northwestern North America strongly suggests that the area may be the site of previously unsuspected suture zones of aquatic biotas. [source] Mycosphaerella species associated with leaf disease of Eucalyptus globulus in EthiopiaFOREST PATHOLOGY, Issue 4 2006Alemu Gezahgne Summary Eucalyptus spp. are among the most widely planted exotic trees in Ethiopia. Several damaging leaf pathogens are known from Eucalyptus spp. worldwide. Of these, Mycosphaerella spp. are among the most important, causing the disease known as Mycosphaerella leaf disease (MLD). Characteristic symptoms of MLD include leaf spot, premature defoliation, shoot and twig dieback. Recent disease surveys conducted in Ethiopian Eucalyptus plantations have revealed disease symptoms similar to those caused by Mycosphaerella spp. These symptoms were restricted to E. globulus trees growing in several localities in south, south western and western Ethiopia. The aim of this study was to identify the fungi associated with this disease. This was achieved by examining ascospore germination patterns, anamorph associations and sequence data from the Internal Transcribed Spacer (ITS) region of the rRNA operon, for representative isolates. Several different ascospore germination patterns were observed, suggesting that more than one species of Mycosphaerella is responsible for MLD on E. globulus in Ethiopia. Analysis of sequence data showed that three Mycosphaerella spp., M. marksii, M. nubilosa and M. parva were present. This is the first report of these three species from Ethiopia and represents a valuable basis on which to build further studies in the region. Résumé Les Eucalyptus comptent parmi les essences d'arbres exotiques les plus plantées en Ethiopie. Plusieurs pathogènes foliaires sont connus dans le monde pour occasionner des dégâts sur Eucalyptus. Parmi ceux-ci, les espèces de Mycosphaerella sont parmi les plus importantes, causant la maladie connue comme Maladie Foliaire àMycosphaerella (MFM, MLD en anglais). Les symptômes caractéristiques de la MFM comprennent des taches foliaires, une défoliation précoce et des dépérissements de pousses et de rameaux. Des campagnes de surveillance menées récemment dans les plantations éthiopiennes d'Eucalyptus ont révélé la présence de tels symptômes. Ces symptômes sont uniquement observés sur E. globulus dans plusieurs localités du sud, sud-ouest et ouest de l'Ethiopie. L'objectif de cette étude était d'identifier les champignons associés à cette maladie. Pour cela, des isolats représentatifs ont étéétudiés pour les modalités de germination des ascospores, les anamorphes associés ainsi que les données de séquence de la région ITS de l'opéron ADNr. Différentes modalités de germination des ascospores ont été observées, suggérant que plusieurs espèces de Mycosphaerella seraient associées à la MFM sur E. globulus en Ethiopie. L'analyse des données de séquence a montré la présence de 3 espèces : M. marksii, M. nubilosa et M. parva. Ceci constitue la première mention de ces 3 espèces en Ethiopie et une première étape pour envisager d'autres études dans cette région. Zusammenfassung Eucalyptus -Arten sind die am häufigsten angepflanzten exotischen Bäume in Äthiopien. An Eucalyptus kommen verschiedene Blattkrankheiten vor, wobei die Mycosphaerella -Arten als Verursacher der Mycosphaerella -Blattkrankheit (MLD) am bedeutendsten sind. Charakteristische Symtpome der MLD sind Blattnekrosen und vorzeitiger Blattfall sowie Trieb- und Zweigsterben. Bei der Inventur von Krankheiten in äthiopischen Eucalyptusplantagen wurden Symptome entdeckt, die denen von Mycosphaerella spp. ähnlich waren. Diese traten nur an E. globulus lokal in S-, SW- und W-Äthiopien auf. Ziel dieser Untersuchung war es, die damit assoziierten Pilze zu identifizieren. Hierzu wurde an repräsentativen Isolaten das Keimverhalten der Ascosporen, das Vorkommen von Anamorphen und die ITS-Sequenz des rRNA-Operons untersucht. Es wurden verschiedene Keimungstypen der Ascosporen beobachtet, was darauf schliessen liess, dass mehr als eine Mycosphaerella -Art für die Krankheit an E. globulus in Äthiopien verantwortlich ist. Anhand der Sequenzen wurden M. marksii, M. nubilosa und M. parva identifiziert. Dies ist der Erstnachweis für diese drei Arten in Äthiopien und eine Grundlage für weitere Studien. [source] Effects of forest fragmentation on European birds: implications of regional differences in species richnessJOURNAL OF BIOGEOGRAPHY, Issue 4 2003José Luis Tellería Abstract Aim, In this paper, we adopted a large-scale approach to evaluate the effect of regional richness of forest birds on the number of bird species retained by forest fragments in several localities across Europe. Location, We studied bird assemblages in fourteen forest archipelagos embedded in agricultural matrices from southern Norway to central Spain. Tree composition varied from oak and beech forests of the northern localities to oak and pine xerophitic woodlands of the southern ones. The number of fragments in each forest archipelago ranged from eighteen to 211. Methods, We used the Gleason equation (s = a + z log A; where s and A are, respectively, the species richness and size of forest fragments and z the rate of species loss) to estimate the species richness for 1- and 15-ha fragments in each archipelago. The regional richness of forest birds was estimated by modelling the geographical distribution of species richness in the European atlas of breeding birds. Results, The latitudinal distribution of regional richness displayed a convex form, with the highest values being in central Europe. Along this gradient, the number of species retained by fragments and the rate of species loss was positively related to regional richness. In addition, the percentage of the regional pool of species sampled by fragments decreased in the southern localities. Main conclusions, Relationships between regional richness of forest birds and richness in fragments seem to explain why fragments in central Europe shelter more species than their southern counterparts. The decreased ability of southern forest fragments to sample the regional richness of forest birds, could be explained as an effect of the low abundance of many species in the Mediterranean, which could depress their ability to prevent extinction in fragments by a rescue effect. Alternatively, high beta diversity in the Mediterranean could produce undersampling by fragments of the regional pool of species. These regional differences in the response of bird assemblages to forest fragmentation are used to discuss the usefulness of large-scale, biogeographical approaches in the design of conservation guidelines. [source] World phylogeography and male-mediated gene flow in the sandbar shark, Carcharhinus plumbeusMOLECULAR ECOLOGY, Issue 10 2010DAVID S. PORTNOY Abstract The sandbar shark, Carcharhinus plumbeus, is a large, cosmopolitan, coastal species. Females are thought to show philopatry to nursery grounds while males potentially migrate long distances, creating an opportunity for male-mediated gene flow that may lead to discordance in patterns revealed by mitochondrial DNA (mtDNA) and nuclear markers. While this dynamic has been investigated in elasmobranchs over small spatial scales, it has not been examined at a global level. We examined patterns of historical phylogeography and contemporary gene flow by genotyping 329 individuals from nine locations throughout the species' range at eight nuclear microsatellite markers and sequencing the complete mtDNA control region. Pairwise comparisons often resulted in fixation indices and divergence estimates of greater magnitude using mtDNA sequence data than microsatellite data. In addition, multiple methods of estimation suggested fewer populations based on microsatellite loci than on mtDNA sequence data. Coalescent analyses suggest divergence and restricted migration among Hawaii, Taiwan, eastern and western Australia using mtDNA sequence data and no divergence and high migration rates, between Taiwan and both Australian sites using microsatellite data. Evidence of secondary contact was detected between several localities and appears to be discreet in time rather than continuous. Collectively, these data suggest complex spatial/temporal relationships between shark populations that may feature pulses of female dispersal and more continuous male-mediated gene flow. [source] A New Species of Glypheoid Lobster, Pseudoglyphea Foersteri (Decapoda: Astacidea: Mecochiridae) from the Lower Jurassic (Pliensbachian) of Raasay, Inner Hebrides, UKPALAEONTOLOGY, Issue 1 2002Rodney M. Feldmann Mecochirid lobsters assigned to the genus Pseudoglyphea Oppel, 1861 have previously been recorded from several localities in Europe. In this paper Pseudoglyphea foersteri sp. nov. is described from the Lower Jurassic of Raasay, Inner Hebrides, Scotland, providing the first evidence of a vagile benthic predator/scavenger in the Scalpa Sandstone Formation. Re-examination of the systematic placement of the genus supports allying the Mecochiridae with the Glypheidae within the Astacidea, not the Palinura as traditionally done. [source] Survey-gap analysis in expeditionary research: where do we go from here?BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2005V. A. FUNK Research expeditions into remote areas to collect biological specimens provide vital information for understanding biodiversity. However, major expeditions to little-known areas are expensive and time consuming, time is short, and well-trained people are difficult to find. In addition, processing the collections and obtaining accurate identifications takes time and money. In order to get the maximum return for the investment, we need to determine the location of the collecting expeditions carefully. In this study we used environmental variables and information on existing collecting localities to help determine the sites of future expeditions. Results from other studies were used to aid in the selection of the environmental variables, including variables relating to temperature, rainfall, lithology and distance between sites. A survey gap analysis tool based on ,ED complementarity' was employed to select the sites that would most likely contribute the most new taxa. The tool does not evaluate how well collected a previously visited site survey site might be; however, collecting effort was estimated based on species accumulation curves. We used the number of collections and/or number of species at each collecting site to eliminate those we deemed poorly collected. Plants, birds, and insects from Guyana were examined using the survey gap analysis tool, and sites for future collecting expeditions were determined. The south-east section of Guyana had virtually no collecting information available. It has been inaccessible for many years for political reasons and as a result, eight of the first ten sites selected were in that area. In order to evaluate the remainder of the country, and because there are no immediate plans by the Government of Guyana to open that area to exploration, that section of the country was not included in the remainder of the study. The range of the ED complementarity values dropped sharply after the first ten sites were selected. For plants, the group for which we had the most records, areas selected included several localities in the Pakaraima Mountains, the border with the south-east, and one site in the north-west. For birds, a moderately collected group, the strongest need was in the north-west followed by the east. Insects had the smallest data set and the largest range of ED complementarity values; the results gave strong emphasis to the southern parts of the country, but most of the locations appeared to be equidistant from one another, most likely because of insufficient data. Results demonstrate that the use of a survey gap analysis tool designed to solve a locational problem using continuous environmental data can help maximize our resources for gathering new information on biodiversity. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 549,567. [source] Metamorphism of the Basement of the Qilian Fold Belt in the Minhe-Ledu Area, Qinghai Province, NW ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2002TSAI Chinglang Abstract, The basement of the central Qilian fold belt exposed along the Minhe-Ledu highway consists of psammitic schists, metabasitic rocks, and crystalline limestone. Migmatitic rocks occur sporadically among psammitic schist and metabasitic rocks. The mineral assemblage of psammitic schist is muscovite + biotite + feldspar + quartz ± tourmaline ± titanite ± sillimanite and that of metabasitic rocks is amphibole + plagioclase + biotite ± apatite ± magnetite ± pyroxene ± garnet ± quartz. The migmatitic rock consists of leucosome and restite of various volume proportions; the former consists of muscovite + alkaline feldspar + quartz ± garnet ± plagioclase while the latter is either fragments of psammitic schist or those of metabasitic rock. The crystalline limestone consists of calcite that has been partly replaced by olivine. The olivine was subsequently altered to serpentine. Weak deformations as indicated by cleavages and fractures were imposed prominently on the psammitic schists, occasionally on metabasitic rocks, but not on migmatitic rocks. The basement experienced metamorphism up to temperature 606,778°C and pressure 4.8,6.1 kbar (0.48,0.61 GPa), equivalent to amphibolite-granulite facies. The peak of the metamorphism is marked by a migmatization which occurred at several localities along the studied route 587-535 Ma ago. The basement also recorded a retrograde metamorphism of greenschist facies, during which biotite, garnet, amphibole, and pyroxene were partly altered to chlorite. [source] | |||||||||||||