1,720,962 research outputs found
Effect of spatial and temporal patterns of stress and disturbance intensities in a sub-Mediterranean grassland
No full textThe present study examined a sub-Mediterranean pastoral system in the central Apennines (Italy) with a long history of
grazing, where winter cold stress is alternated with summer drought stress. The research goals were to ascertain whether
different floristic structures correspond to different stress conditions (xeric and semimesic), and whether peculiar functional
plant traits (such as avoidance and tolerance mechanisms) respond to stress/disturbance intensities, and understand how
vegetation reacts to changeable livestock pressure (through floristic and plant trait variations). Cluster analysis indicated that
separate communities develop under different stress intensities. Other analyses highlighted how avoidance strategies predominate within the pastoral system. Observations of grazed and ungrazed patches conducted in 10-m transects revealed spiny cushion formation in semimesic grassland, where a brief period of overgrazing occurs in late summer, causing variations in plant community structure. All these results confirm the importance of historical grazing and current land use, showing how small disturbances and stress variations cause ecosystem responses. Best practices for management were identified. In xeric conditions, it is advisable that the intensity of disturbance be lessened, while in semimesic grassland overgrazing should be forbidden during the dry period, because it could facilitate the development of spiny patches, and subsequent spread of Brachypodium rupestre
Effect of management modification on the coenological composition of the North Adriatic pastoral landscape (Ćićarija, Croatia)
Full text linkThe research aim was to assess the dynamics of the North Adriatic pastoral landscape (Ćićarija, Croatia) with regard to the coenological composition of grassland communities, and, more specifically, to: i) assess the current grassland mosaic from a coenological viewpoint; ii) assess the effects of management abandonment on grassland species composition, also taking into account, as a basis for comparison, data on pastoral communities
collected in the past decades. To achieve the research aims, 73 phytosociological relevés were carried out; for each of them field data (altitude, aspect, slope, landform) and information on grassland management were collected. Multivariate analysis of phytosociological relevés led to the identification of four vegetation types (Danthonio-Scorzoneretum villosae, Carici humilis-Centaureetum rupestris, Brachypodium rupestre-dominated stands, and Anthoxantho-Brometum erecti), which were linked to landform and to grassland management. Comparison in terms of social behaviour type composition of the grassland communities surveyed in the present study with the ones surveyed in the past decades, highlighted that the current management (grassland abandonment, as well as low intensity grazing and not periodic mowing) is leading to a percentage loss of pasture and meadow characteristic species, in favour of successional and ruderal ones
Assessment of floristic diversity, functional composition and management strategy of North Adriatic pastoral landscape (Croatia)
Full text linkEuropean semi-natural calcareous grasslands are species-rich ecosystems, considered as priority habitats by the European Union (92/43/EEC Directive) and judged worthy of conservation. They are in strong decline in extension and are threatened by abandonment throughout Europe. It is known that grasslands management (grazing, mowing) acts as driving force in plant community diversity, which in turn is an important conservation aim of European environmental
policies. The area of current pastoral landscape (about
1000 ha) of the North Adriatic (Æiæarija, Croatia) was studied in order: 1/ to understand which factors drive floristic differentiation – environmental features and/or grassland management conditions, 2/ to identify indicator species sets
linked to those factors and 3/ to appraise the effects
of management type on the coenological and functional composition of indicator species. 73 phytosociological relevés were carried out; for each of them field data (altitude, aspect, slope and land form), productivity measurements and
information on grassland management were collected. Redundancy analysis (RDA) identified a productivity-related soil moisture gradient as the environmental driving force of grassland floristic differentiation. Indicator species analysis (ISA) detected the indicator species sets related to environmental features and management type. The
results indicate that undergrazing and the lack of
periodic mowing are responsible for the higher total variance of floristic data set explained by environmental parameters rather than by management (use/not use). For the same reasons, the variations that emerged from comparison of the
functional characteristics of the indicator species of grazing and of mowing (avoidance strategy, life form, and storage organs) proved more important than those observed in comparing used and abandoned grasslands. The management system adopted (grazing or mowing) appears in turn to be conditioned by the soil moisture/productivity gradient
Effects of abandonment on the functional composition and forage nutritive value of a North Adriatic dry grassland community (Cicarija, Croatia)
Full text linkCarici humilis-Centaureetum rupestris association is one of the most widespread types of pasture in Istria and of great environmental and economic interest. The research aims were to test if forage quantity, nutritive value and functional composition (grasses and grass-like, legumes, and forbs percentage) of these pastures change significantly in relation to: time of the growing season, management type (low use intensity grazing/grazing abandonment) and topographic variables. During 2008, phytomass samples were collected in grazed and ungrazed pastures of Cicarija (Croatia), in May, June, and September. Their composition in dry matter, ash, crude protein (CP), neutral and acid detergent fiber (NDF, ADF), acid detergent lignin (ADL) and in-vitro dry matter digestibility (IVDMD) were determined and net energy for lactation (NEL) and yield NEL were calculated. These variables followed a double trend, linked to the phenological phases of grasslands and to a land use/topographic gradient. Yield, yield NEL, dry matter, NDF, ADF and ADL increased during the growing season, while CP, NEL and IVDMD decreased. Yield, yield NEL, grasses and forbs, ash, and IVDMD were tied to the ungrazed pastures spread on the slopes, while ADF, ADL and dry matter had stronger correlation with grazed grasslands spread on the flat lands
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
A century of changes in wild food plant use in coastal Croatia: the example of Krk and Poljica
No full textThe aim of this study was to document the use of wild foods in two locations in the coastal part of Croatia – on the island of Krk and in the Poljica area, near Split. We chose these places as they have historical data on plant use (1900 and 1903 respectively). We carried out 67 interviews in Poljica and 55 interviews in Krk to estimate the current use and knowledge of wild foods. Altogether, 80 species of wild food and herbal tea species of plants were recorded in Poljica and 76 in Krk. On average, 13.2 species were listed by per interview in Poljica, including 7.1 species of wild vegetables, and in Krk 14.6 species, including 7.9 species of wild vegetables. Out of the list of plant names recorded in the past, in Krk, we identified 82% of the taxa and in Poljica 86%
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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