74 research outputs found

    Invasive Pathogen Threatens Bird-Pine Mutualism: Implications for Sustaining a High-Elevation Ecosystem

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    Human-caused disruptions to seed-dispersal mutualisms increase the extinction risk for both plant and animal species. Large-seeded plants can be particularly vulnerable due to highly specialized dispersal systems and no compensatory regeneration mechanisms. Whitebark pine ( Pinus albicaulis), a keystone subalpine species, obligately depends upon the Clark\u27s Nutcracker (Nucifraga columbiana) for dispersal of its large, wingless seeds. Clark\u27s Nutcracker, a facultative mutualist with whitebark pine, is sensitive to rates of energy gain, and emigrates from subalpine forests during periods of cone shortages. The invasive fungal pathogen Cronartium ribicola, which causes white pine blister rust, reduces whitebark pine cone production by killing cone-bearing branches and trees. Mortality from blister rust reaches 90% or higher in some whitebark pine forests in the Northern Rocky Mountains, USA, and the rust now occurs nearly rangewide in whitebark pine. Our objectives were to identify the minimum level of cone production necessary to elicit seed dispersal by nutcrackers and to determine how cone production is influenced by forest structure and health. We quantified forest conditions and ecological interactions between nutcrackers and whitebark pine in three Rocky Mountain ecosystems that differ in levels of rust infection and mortality. Both the frequency of nutcracker occurrence and probability of seed dispersal were strongly related to annual whitebark pine cone production, which had a positive linear association with live whitebark pine basal area, and negative linear association with whitebark pine tree mortality and rust infection. From our data, we estimated that a threshold level of similar to 1000 cones/ha is needed for a high likelihood of seed dispersal by nutcrackers ( probability \u3e= 0.7), and that this level of cone production can be met by forests with live whitebark pine basal area \u3e5.0 m(2)/ha. The risk of mutualism disruption is greatest in northernmost Montana ( USA), where three-year mean cone production and live basal area fell below predicted threshold levels. There, nutcracker occurrence, seed dispersal, and whitebark pine regeneration were the lowest of the three ecosystems. Managers can use these threshold values to differentiate between restoration sites requiring planting of rust-resistant seedlings and sites where nutcracker seed dispersal can be expected

    Overcoming America\u27s Wood Deficit: An Overlooked Option

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    Nitrogen Spatial Heterogeneity Influences Diversity Following Restoration in a Ponderosa Pine Forest, Montana

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    The resource heterogeneity hypothesis (RHH) is frequently cited in the ecological literature as an important mechanism for maintaining species diversity. The RHH has rarely been evaluated in the context of restoration ecology in which a commonly cited goal is to restore diversity. In this study we focused oil the spatial heterogeneity of total inorganic nitrogen (TIN) following restoration treatments in a ponderosa pine (Pinus ponderosa)/Douglas-fir (Pseudotsuga inenziesii) forest in western Montana, USA. Our objective was to evaluate relationships between understory species richness and TIN heterogeneity following mechanical thinning (thin-only), prescribed burning (burn-only), and mechanical thinning with prescribed burning (thin/burn) to discern the ecological and management implications of these restoration approaches. We employed a randomized block design, with three 9-ha replicates of each treatment and an untreated control. Within each treatment, we randomly established a 20 X 50 in (1000 m(2)) Plot in which we measured species richness across the entire plot and in 12 I-m 2 quadrats randomly placed within each larger plot. Additionally, we measured TIN from a grid consisting of 112 soil samples (0-5 cm) in each plot and computed standard deviations as a measure of heterogeneity. We found a correlation between the net increase in species richness and the TIN standard deviations one and two years following restoration treatments, supporting RHH. Using nonmetric multidimensional scaling ordination and chi-squared analysis, we found that high and low TIN quadrats contained different understory communities in 2003 and 2004, further supporting RHH. A comparison of restoration treatments demonstrated that thin/burn and burn-only treatments created higher N heterogeneity relative to the control. We also found that within prescribed burn treatments, TIN heterogeneity was positively correlated with fine-fuel consumption, a variable reflecting burn severity. These findings may lead to more informed restoration decisions that consider treatment effects on understory diversity in ponderosa pine/Douglas-fir ecosystems

    Fire Treatment Effects on Vegetation Structure, Fuels, and Potential Fire Severity in Western US Forests

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    Forest structure and species composition in many western U. S. coniferous forests have been altered through. re exclusion, past and ongoing harvesting practices, and livestock grazing over the 20th century. The effects of these activities have been most pronounced in seasonally dry, low and mid-elevation coniferous forests that once experienced frequent, low to moderate intensity,. re regimes. In this paper, we report the effects of Fire and Fire Surrogate (FFS) forest stand treatments on fuel load profiles, potential fire behavior, and fire severity under three weather scenarios from six western U. S. FFS sites. This replicated, multisite experiment provides a framework for drawing broad generalizations about the effectiveness of prescribed. re and mechanical treatments on surface fuel loads, forest structure, and potential. re severity. Mechanical treatments without. re resulted in combined 1-, 10-, and 100-hour surface fuel loads that were significantly greater than controls at three of five FFS sites. Canopy cover was significantly lower than controls at three of five FFS sites with mechanical-only treatments and at all five FFS sites with the mechanical plus burning treatment;. re-only treatments reduced canopy cover at only one site. For the combined treatment of mechanical plus. re, all five FFS sites with this treatment had a substantially lower likelihood of passive crown. re as indicated by the very high torching indices. FFS sites that experienced significant increases in 1-, 10-, and 100-hour combined surface fuel loads utilized harvest systems that left all activity fuels within experimental units. When mechanical treatments were followed by prescribed burning or pile burning, they were the most effective treatment for reducing crown fire potential and predicted tree mortality because of low surface fuel loads and increased vertical and horizontal canopy separation. Results indicate that mechanical plus fire, fire-only, and mechanical-only treatments using whole-tree harvest systems were all effective at reducing potential. re severity under severe. re weather conditions. Retaining the largest trees within stands also increased. re resistance

    Alternative methods for the treatment of post-menopausal troubles

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    [english] Menopause is described as the transition from the reproductive phase of a women to the non reproductive. Changes in hormone levels might lead to complaints and health consequences especially during peri- and postmenopause. Hormone therapy has a potential damaging health risk profile and is recommended for temporal limited therapy for acute vasomotor symptoms only.The present HTA-report aims to assess the effectiveness and the cost-effectiveness of alternative treatment methods for women with postmenopausal symptoms in Germany regarding patient relevant endpoints (reduction of symptoms and frequency of adverse events and improvement of quality of life).A systematic literature search was carried out in 33 relevant databases in September 2010. Citations were selected according to pre-defined criteria and were extracted and evaluated.In the systematic research 22 studies are identified for the effectiveness evaluation, 22 primary studies and one review.High doses of isolated genistein reduce the frequency/intensity of hot flashes while low doses of genistein show no significant effect. Intake of isoflavone extract such as genistein, daidzein, glycitein in various combinations does not have an effect on improvement of cognitive function or vaginal dryness. The effect of black cohosh and hop extract for menopausal complaints cannot be determined since results are heterogenous. The combination of isoflavone, black cohosh, monk’s pepper, valerian and vitamin E has a positive effect on menopause symptoms. Ginkgo biloba shows no significant effect on menopause symptoms and cognitive improvement beside mental flexibility. Acupuncture has a significant influence on hot flashes especially in severe cases.No final statement can be drawn regarding the effectiveness of alter­ne treatment methods due to qualitative shortcomings of included studies and a general limited availability of studies in this field. Furthermore, the generalization of the present HTA is limited due to the inclusion of only postmenopausal women.<br><br>[german] Als Wechseljahre wird der Übergang von der reproduktiven Phase der Frau zur nicht-reproduktiven beschrieben. Insbesondere in der Peri- und Postmenopause können Beschwerden aufgrund des sich veränderten Hormonspiegels auftreten. Aktuell wird die Hormontherapie wegen der mit dieser verbundenen Risiken nur noch zur kurzfristigen Behandlung akuter vasomotorischer Symptome empfohlen. Von den betroffenen Frauen werden alternative und komplementäre Heilmethoden eingesetzt.Im vorliegenden Health Technology Assessment (HTA) sollen die Effektivität und Kosteneffektivität alternativer Behandlungsmethoden von postmenopausalen Wechseljahresbeschwerden in Deutschland hinsichtlich der patientenrelevanten Endpunkte Verringerung der Symptomatik, Häufigkeit unerwünschter Ereignisse sowie Verbesserung der Lebensqualität bewertet werden. In 33 relevanten Datenbanken wird im September 2010 eine systematische Literatursuche durchgeführt. Gefundene und relevante Literaturstellen werden gemäß vorab definierter Kriterien selektiert. Die Daten der Literaturstellen werden gezielt herausgesucht, bewertet und zusammenfassend beurteilt.Aus der systematischen Recherche werden 22 Studien, davon 15 Primärstudien und ein Review zur Bewertung der Effektivität identifiziert.Hochdosiertes isoliertes Genistein reduziert die Anzahl/Schwere von Hitzewallungen, während niedrig dosiertes Genistein keinen signifikanten Effekt zeigt. Die Gabe von Isoflavonextrakten, die Genistein, Daidzein, Glycitein in unterschiedlicher Zusammensetzung enthalten, hat keinen signifikanten Einfluss auf die Verbesserung kognitiver Fähigkeiten oder vaginale Trockenheit. Traubensilberkerzen- und Hopfenextrakt führen zu unterschiedlichen Ergebnissen bezüglich der Wirksamkeit bei postmenopausalen Beschwerden, sodass keine abschließende Aussage zur Effektivität getroffen werden kann. Die Kombination von Isoflavonen, Traubensilberkerze, Mönchspfeffer, Baldrian und Vitamin E hat eine positive Wirkung auf postmenopausale Symptome. Ginkgo biloba zeigt keinen signifikanten Effekt auf postmenopausale Symptome und eine kognitive Verbesserung mit Ausnahme der mentalen Flexibilität. Akupunktur hat einen signifikanten Einfluss auf Hitzewallungen, insbesondere auf deren Schweregrad.Aufgrund der qualitativen Mängel (Concealment, Randomisierung, Fallzahlplanung) der eingeschlossenen Studien und der begrenzten Anzahl an Studien kann keine abschließende zusammenfassende Bewertung zur Wirksamkeit alternativer Heilmethoden gegeben werden. Die Verallgemeinerbarkeit des vorliegenden HTA wird durch die Beschränkung auf postmenopausale Frauen reduziert

    The National Fire and Fire Surrogate Study: Effects of Fuel Reduction Methods on Forest Vegetation Structure and Fuels

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    Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed. re, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface. re regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an information-theoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wild. re damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass). In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed. re treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment

    On Scottish sawflies, with results of the 14th International Sawfly Workshop, in the southern Highlands, 2010 (Hymenoptera, Symphyta).

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    Die Ergebnisse der Feldarbeit aus dem 14. Internationalen Sawfly Workshop werden vorgestellt. Dies fand im südlichen schottischen Hochland, überwiegend in Perthshire, statt. Einige Nachweise von Pflanzenwespen aus anderen Teilen von Schottland sind enthalten. Erstnachweise für die Britischen Inseln werden für acht tenthredinide Arten erbracht: Amauronematus mimus, Phyllocolpa alienata, P. erythropyga, P. plicalapponum, P. plicaphylicifolia, P. prussica, Pristiphora thalictri und Tenthredo ignobilis. A. mimus ist auch aus Irland nachgewiesen. Amauronematus stenogaster ist aus der Liste der Symphyta der Britischen Inseln zu entfernen. Erstmalig sind in Schottland eine Cephiden-Art (Hartigia xanthostoma) und zehn Tenthrediniden gefunden worden (Claremontia uncta, Dolerus brevicornis, Empria basalis, Empria parvula, Parna apicalis, Pristiphora decipiens, Pristiphora leucopus, Pristiphora testacea, Tenthredo mandibularis und Tenthredopsis ornata). Merkmale für die Unterscheidung einzelner Arten werden dargestellt. Der Locus typicus von Nematus herbaceae Cameron, 1876 ist geklärt. Geranium pratense ist als Wirtspflanze von Macrophya albipuncta bestätigt. Salix reticulata ist eine Wirtspflanze von Amauronematus mcluckieae. Sedum rosea kann eine Wirtspflanze von Tenthredo ignobilis sein. Allgemeine Schlussfolgerungen: hoher Artenreichtum der Pflanzenwespenfauna von Perthshire im Vergleich zu anderen Regionen in Schottland, darunter mehrere Arten, die auf den Britischen Inseln nur von dort bekannt sind; die Wichtigkeit der Erhaltung der Lebensräume von Felssimsen; große Defizite in unseren Kenntnissen bei vielen Arten, insbesondere zu Wirtspflanzen, Phänologie und Verbreitung; hoher Wert der Malaise-Falle in faunistischen Untersuchungen von Symphyta, weil das Spektrum von erfassten Taxa sich unterscheidet von dem was mit Streifnetz erfasst wird; Zusammensetzung des 'fall-out’ auf Schneeresten deutet darauf hin, dass Pflanzenwespen in einem größeren Ausmaß als bisher angenommen, aktiver Dispersion innerhalb von Landmassen unterliegen.StichwörterBritish Isles, Cephidae, Pamphiliidae, Tenthredinoidea, hosts, phenology, distribution.Results of fieldwork are presented from the 14th International Sawfly Workshop, held in the southern Highlands of Scotland, mostly in Perthshire. Some records of Symphyta from other parts of Scotland are included. First records in the British Isles are given for eight tenthredinid species: Amauronematus mimus, Phyllocolpa alienata, P. erythropyga, P. plicalapponum, P. plicaphylicifolia, P. prussica, Pristiphora thalictri and Tenthredo ignobilis. A. mimus is also recorded from Ireland. Amauronematus stenogaster is removed from the list of British Isles Symphyta. Recorded for the first time in Scotland are one cephid (Hartigia xanthostoma) and ten tenthredinids (Claremontia uncta, Dolerus brevicornis, Empria basalis, Empria parvula, Parna apicalis, Pristiphora decipiens, Pristiphora leucopus, Pristiphora testacea, Tenthredo mandibularis and Tenthredopsis ornata). Characters useful for the distinction of some species are illustrated. The type locality of Nematus herbaceae Cameron, 1876 is clarified. Geranium pratense is confirmed as a host of Macrophya albipuncta. Salix reticulata is a host of Amauronematus mcluckieae [mandatory correction of spelling of species name]. Sedum rosea may be a host of Tenthredo ignobilis. General conclusions: high species richness of Perthshire sawfly fauna compared to other regions of Scotland, including several species only known in British Isles from there; importance to conservation of rock-ledge habitats; large data deficits for many species, particularly on hosts, phenology and distribution; high value of Malaise traps in faunal survey of Symphyta, because spectrum of taxa captured differs from that recorded by hand-netting; as indicated by species and sex composition of ‘fall-out’ on snow patches, adult sawflies undertake active dispersal, within landmasses, to a greater extent than is often assumed.KeywordsBritish Isles, Cephidae, Pamphiliidae, Tenthredinoidea, hosts, phenology, distribution

    NOX1 loss-of-function genetic variants in patients with inflammatory bowel disease.

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    Genetic defects that affect intestinal epithelial barrier function can present with very early-onset inflammatory bowel disease (VEOIBD). Using whole-genome sequencing, a novel hemizygous defect in NOX1 encoding NAPDH oxidase 1 was identified in a patient with ulcerative colitis-like VEOIBD. Exome screening of 1,878 pediatric patients identified further seven male inflammatory bowel disease (IBD) patients with rare NOX1 mutations. Loss-of-function was validated in p.N122H and p.T497A, and to a lesser degree in p.Y470H, p.R287Q, p.I67M, p.Q293R as well as the previously described p.P330S, and the common NOX1 SNP p.D360N (rs34688635) variant. The missense mutation p.N122H abrogated reactive oxygen species (ROS) production in cell lines, ex vivo colonic explants, and patient-derived colonic organoid cultures. Within colonic crypts, NOX1 constitutively generates a high level of ROS in the crypt lumen. Analysis of 9,513 controls and 11,140 IBD patients of non-Jewish European ancestry did not reveal an association between p.D360N and IBD. Our data suggest that loss-of-function variants in NOX1 do not cause a Mendelian disorder of high penetrance but are a context-specific modifier. Our results implicate that variants in NOX1 change brush border ROS within colonic crypts at the interface between the epithelium and luminal microbes
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