1,720,961 research outputs found
Manual on methods and criteria for harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on forests. Part VIII, Assessment of Ground Vegetation. Expert Panel on Ground Vegetation Assessment, UN-ECE, ICP-Forests.
No full textManuale pan-Europeo di riferimento per la stima della vegetazione nelle aree della rete Europea dell'International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP-Forests), United Nations Economic Commission For Europe (UN-ECE), Convention On Long-Range Transboundary Air Pollution, Hamburg
DNA-Barcoding – Pflanzen im wald
No full textTo the non-expert, forests may seem monotonous aggregations of ever the same botanical
species; while in fact, they harbor much diversity in the ground flora composition.
Plant communities of forests can be grouped by their tree species composition, but a
refined phytosociological classification, reflecting soils, site type and lastly also productivity,
is based on characteristic and differential species mostly of the herb and shrub
layer (e.g., Willner & Grabherr 2007, Staudinger & Willner 2014). Nevertheless,
the identification of the ground vegetation species in forests often is difficult, because
under a shady canopy only vegetative parts are found and flowers or fruits are missing.
The current estimate of spermatophyta naturally present in Austria’s forest is ca. 1150
(41 % of all spermatophyta), and similarly for ferns and bryophytes (42 %). Five of 51
tree species are considered “endangered”, six more are “vulnerable”. For the rest of the
spermatophyta (in forests), three are “extinct in the wild”, 22 “critically endangered”,
86 are “endangered”, and 159 “vulnerable” (Niklfeld 1986, 1999).
The Austrian Federal Research Centre for Forests (BFW) is currently trying to initiate
a DNA barcoding project for “forest plants”. If funded, the available “research
infrastructure” of BFW can be utilized; the Austrian forest inventory is permanently
sending small groups to a network of forest sampling points, for measurements and observations;
sampling plants for barcoding would be rather easy for them. A herbarium
and DNA laboratories are also available. We are offering DNA-based identification of
plant species as a paid-for service to the public. Chloroplast DNA sequencing is one of
the methods for this service.
A pilot trial for barcoding of forest plants was initiated in Northern Sardinia (Italy),
in pubescent oak (Quercus pubescencs s.l.) forests, which cover sites from the mountain
slopes (approx. 1500 m a.s.l) down to coastal valleys, corresponding to different
vegetation types (Bacchetta et al. 2004). The idea is to characterize these forests according
to any variation found in chloroplast DNA of the ground vegetation. Up to
20 recurring species (multiple samples per species if possible) were collected from each
of 20 sites. Frequencies of the species are being analyzed for use as a classification tool.
The assessment is clearly hampered by human-induced changes (agriculture, pasture,
wood extraction, settlements). In a first next generation sequencing experiment, 384
specimens of eight species were included. Up to eight successfully amplified DNA fragments
were mixed, tagged and sequenced in bulk on an Illumina MiSeq v3 machine.
The resulting approx. 17 million single sequences are currently being analyzed. Average
read length is 81 basepairs (after quality filtering), and 25,000 to 50,000 reads were
obtained for each DNA sample. A first check seems to confirm the presence of the desired
sequences, though the known issues of this technique, e.g. with mononucleotide
repeat tracts, are there as well. Based on these circumstances and experiences, the perspectives for success will be discussed
in this presentation
Assessment of Ground Vegetation. Manual Part VII.
No full textThe Manual describes field sampling methods, measurement methods and data reporting rules for ground vegetation assessment in the European permanent areas network of forest systems. The monitoring scheme has been developed under the United Nation Convention on Long-Range Transboundary Air Pollution, within the “International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests” (ICP Forests), the so-called ‘Level II monitoring’. The programme includes ca. 6000 plots for large scale forest condition monitoring (so-called Level I) and ca. 800 plots for intensive forest ecosystem monitoring (Level II) distributed across 41 participating countries. On level II sites, data on ground vegetation (including terricolous bryophytes and lichens) shall be sampled on a common standard area (CSA) of 400 m2. Species census (referring to a standard reference for taxa attribution) and abundance are recorded by defined vertical layers
Part VII.1: Assessment of Ground Vegetation.
Full text linkThis part of the Manual aims at providing a consistent methodology to collect high quality, harmonized and comparable forest ground vegetation data at selected UN/ECE ICP Forestsmonitoring plots. Harmonization of procedures is essential to enhance comparability of forest ground vegetation data. To have their data used in the international database and evaluations, National Focal Centres and their scientific partners participating to the UN/ECE ICP Forests programme should follow the methods described here
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
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