1,720,955 research outputs found
C, N and P dynamics during litter decomposition in pure and mixed beech – conifer stands: Effects of litter species, site conditions and native vs non-native conifer species
No full texthttp://dx.doi.org/10.13039/501100001659 German Research Foundatio
Reduced predation and energy flux in soil food webs by introduced tree species: Bottom‐up control of multitrophic biodiversity across size compartments
No full textAbstract The introduction of non‐native tree species has become a global concern and may disrupt native communities and related ecosystem functions. Soil food webs regulate organic matter decomposition and nutrient cycling in forests with their feeding activities, but evaluating consequences of the introduction of tree species on soil invertebrates is challenging due to the complex trophic structure and wide range in body size of soil invertebrates. Here, we employed an energetic food web approach and estimated the energy flux in soil food webs using a four‐node model including soil meso‐ and macrofauna decomposers and predators. We examined pure and mixed stands of native European beech ( Fagus sylvatica ), introduced Douglas fir ( Pseudotsuga menziesii ) and native range‐expanding Norway spruce ( Picea abies ) across site conditions. Compared to native forests, introduced tree species reduced total fresh mass of macrofauna predators by 92% at sandy sites but not that of decomposers, suggesting trophic downgrading in soil food webs by Douglas fir. The energy flux in mixed forests was intermediate between respective monocultures, suggesting that tree mixtures mitigate potential negative impacts of introduced tree species on food web functioning. Across size classes, soil macrofauna responded more sensitively to changes in environmental conditions than soil mesofauna. Additionally, total energy flux positively correlated with species richness, pointing to the significance of soil biodiversity for trophic functionality. The energy flux through mesofauna outweighed that through macrofauna when considering energy loss to predators, highlighting the importance of mesofauna for decomposition processes in forest soil food webs. Overall, the study emphasizes the critical role of tree species composition, site conditions and soil biodiversity in driving energy flux through soil food webs and maintaining forest ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.Zusammenfassung Die Einführung nicht‐einheimischer Baumarten ist ein globales Problem und kann einheimische Gemeinschaften und die damit verbundene Ökosystemfunktionen beeinträchtigen. Bodennahrungsnetze regulieren den Abbau organischer Stoffe und den Nährstoffkreislauf in Wäldern, jedoch sind die Auswirkungen der Einführung von nicht‐einheimischen Baumarten auf Bodeninvertebraten aufgrund der komplexen trophischen Struktur und der großen Bandbreite an Körpergrößen von Bodeninvertebraten wenig untersucht. Wir untersuchten den Energiefluss in Bodennahrungsnetzen mit einem Vier‐Knoten‐Modell, das Bodenmeso‐ und Makrofauna‐Zersetzer sowie Bodenmeso‐ und Makrofauna‐Prädatoren umfasste. Wir analysierten reine und gemischte Bestände der einheimischen europäischen Buche ( Fagus sylvatica ), der eingeführten Douglasie ( Pseudotsuga menziesii ) und der einheimischen Fichte ( Picea abies ) unter verschiedenen Standortbedingungen. Im Vergleich zu einheimischen Wäldern reduzierte die Douglasie die Gesamtmasse der Makrofauna‐Prädatoren auf sandigen Böden um 92%, jedoch nicht die der Zersetzer, was auf ein trophisches “downgrading” der Bodennahrungsnetze hindeutet. Der Energiefluss in Mischwäldern lag zwischen den jeweiligen Monokulturen, was darauf hindeutet, dass Baummischungen potenzielle negative Auswirkungen eingeführter Baumarten auf die Funktionsweise von Nahrungsnetzen abmildern. Über alle Größenklassen hinweg reagierte die Bodenmakrofauna empfindlicher auf Umweltveränderungen als die Bodenmesofauna. Zudem korrelierte der Gesamtenergiefluss positiv mit der Artenvielfalt, was die Bedeutung der Bodenbiodiversität für die trophische Funktionalität unterstreicht. Trotz der geringeren Gesamtmasse überwog der Energiefluss durch die Mesofauna den durch die Makrofauna, wenn der Energieverlust durch Prädation berücksichtigt wurde, was die Bedeutung der Mesofauna für Zersetzungsprozesse in Bodennahrungsnetzen hervorhebt. Insgesamt betont die Studie die entscheidende Rolle der Baumarten‐Zusammensetzung, der Standortbedingungen und der Bodenbiodiversität für den Energiefluss in Bodennahrungsnetzen und die Erhaltung der Waldökosystemfunktionen.Abstract The introduction of non‐native tree species has become a global concern and may disrupt native communities and related ecosystem functions. Soil food webs regulate organic matter decomposition and nutrient cycling in forests with their feeding activities, but evaluating consequences of the introduction of tree species on soil invertebrates is challenging due to the complex trophic structure and wide range in body size of soil invertebrates. Here, we employed an energetic food web approach and estimated the energy flux in soil food webs using a four‐node model including soil meso‐ and macrofauna decomposers and predators. We examined pure and mixed stands of native European beech ( Fagus sylvatica ), introduced Douglas fir ( Pseudotsuga menziesii ) and native range‐expanding Norway spruce ( Picea abies ) across site conditions. Compared to native forests, introduced tree species reduced total fresh mass of macrofauna predators by 92% at sandy sites but not that of decomposers, suggesting trophic downgrading in soil food webs by Douglas fir. The energy flux in mixed forests was intermediate between respective monocultures, suggesting that tree mixtures mitigate potential negative impacts of introduced tree species on food web functioning. Across size classes, soil macrofauna responded more sensitively to changes in environmental conditions than soil mesofauna. Additionally, total energy flux positively correlated with species richness, pointing to the significance of soil biodiversity for trophic functionality. The energy flux through mesofauna outweighed that through macrofauna when considering energy loss to predators, highlighting the importance of mesofauna for decomposition processes in forest soil food webs. Overall, the study emphasizes the critical role of tree species composition, site conditions and soil biodiversity in driving energy flux through soil food webs and maintaining forest ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.Zusammenfassung Die Einführung nicht‐einheimischer Baumarten ist ein globales Problem und kann einheimische Gemeinschaften und die damit verbundene Ökosystemfunktionen beeinträchtigen. Bodennahrungsnetze regulieren den Abbau organischer Stoffe und den Nährstoffkreislauf in Wäldern, jedoch sind die Auswirkungen der Einführung von nicht‐einheimischen Baumarten auf Bodeninvertebraten aufgrund der komplexen trophischen Struktur und der großen Bandbreite an Körpergrößen von Bodeninvertebraten wenig untersucht. Wir untersuchten den Energiefluss in Bodennahrungsnetzen mit einem Vier‐Knoten‐Modell, das Bodenmeso‐ und Makrofauna‐Zersetzer sowie Bodenmeso‐ und Makrofauna‐Prädatoren umfasste. Wir analysierten reine und gemischte Bestände der einheimischen europäischen Buche ( Fagus sylvatica ), der eingeführten Douglasie ( Pseudotsuga menziesii ) und der einheimischen Fichte ( Picea abies ) unter verschiedenen Standortbedingungen. Im Vergleich zu einheimischen Wäldern reduzierte die Douglasie die Gesamtmasse der Makrofauna‐Prädatoren auf sandigen Böden um 92%, jedoch nicht die der Zersetzer, was auf ein trophisches “downgrading” der Bodennahrungsnetze hindeutet. Der Energiefluss in Mischwäldern lag zwischen den jeweiligen Monokulturen, was darauf hindeutet, dass Baummischungen potenzielle negative Auswirkungen eingeführter Baumarten auf die Funktionsweise von Nahrungsnetzen abmildern. Über alle Größenklassen hinweg reagierte die Bodenmakrofauna empfindlicher auf Umweltveränderungen als die Bodenmesofauna. Zudem korrelierte der Gesamtenergiefluss positiv mit der Artenvielfalt, was die Bedeutung der Bodenbiodiversität für die trophische Funktionalität unterstreicht. Trotz der geringeren Gesamtmasse überwog der Energiefluss durch die Mesofauna den durch die Makrofauna, wenn der Energieverlust durch Prädation berücksichtigt wurde, was die Bedeutung der Mesofauna für Zersetzungsprozesse in Bodennahrungsnetzen hervorhebt. Insgesamt betont die Studie die entscheidende Rolle der Baumarten‐Zusammensetzung, der Standortbedingungen und der Bodenbiodiversität für den Energiefluss in Bodennahrungsnetzen und die Erhaltung der Waldökosystemfunktionen.Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Open-Access-Publikationsfonds 202
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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