1,720,956 research outputs found
Associations between forest specialist birds and composition of woodland habitats in a highly modified landscape
No full textIn Europe land use change has produced loss and fragmentation of the original forest habitat. On the other hand, the area covered by tree plantations and altered stands dominated by exotic tree species is increasing. Forest specialist birds are considered to be among the best candidates to assess the consequences of this transformation on wildlife. Here we investigate the link between the abundances of three forest specialist bird species (the Eurasian Nuthatch Sitta europaea, the Marsh Tit Poecile palustris and the Lesser Spotted Woodpecker Dryobates minor) and the woodland habitats of a highly modified landscape located in north-western Italy. In the area, the cover of anthropogenic woodland habitats, such as poplar plantations and Black Locust (Robinia pseudoacia) stands, exceeds that of native oak and riparian forests. During breeding season, birds were counted for three times along 105 transects of 300 m each, scattered in all the wooded contexts of the study area. Using n-mixture models, we investigated the effect of the amount and configuration of woodland habitats on the abundances of each species. First we selected for each variable the strongest scale of effect, ranging from 0.1 to 4 km. Then we built a full model including all variables at selected scales, accounting for correlation among variables and possible interactions. Forest specialists’ abundances were affected by the composition of the entire woodland mosaic, not of native forests only. A high cover of nonnative woodlands in the landscape showed a null or positive effect on the species, if combined with a high cover of native forests. However, at a local scale and when dominating in the landscape, nonnative woodlands had mostly a detrimental effect. Alongside with the protection of remnant native forests, it should be contemplated the retention of nonnative woodland habitats when these contribute to enhance the heterogeneity of the landscape
Habitat loss, extinction debt and climate change threaten terricolous lichens in lowland open dry habitats
Full text linkHabitat loss is the main driver of biodiversity decline worldwide. An immediate consequence can be extinction debt, i.e. time-delayed extinction of species following habitat loss. We tested extinction debt in terricolous lichen communities in 45 patches of lowland open dry habitats in the western Po Plain (northern Italy) considering richness of four species groups: total, red-listed, rare, and common species. The distance from the currently nearest patch and the annual precipitation correlated – negatively and positively, respectively – with all the groups. Total, red-listed, and rare species were positively related to the oldest available patch extent (1954). Common species were positively related to the current (2020) patch extent. Total and red-listed species were negatively related to the extent difference (1954–2020). Results reveal an extinction debt which has not yet been completely paid and that could be exacerbated by climate change. To counteract this trend, management should conserve habitat patches with the highest species richness, improve connectivity between habitat patches, and provide suitable microrefugia for species with different ecological requirements
Intensive forestry and biodiversity: Use of poplar plantations by woodpeckers in a lowland area of Northern Italy
No full textA growing portion of woodlands worldwide is allocated to tree plantations. These are intensively managed and support significantly lower biodiversity than natural forests. However, given their rising extension and importance, understanding how to enhance the role of plantations in aiding biodiversity is crucial. In the present study, we assessed the suitability of traditional poplar plantations for two woodpecker species (Great Spotted Woodpecker Dendrocopos major and Lesser Spotted Woodpecker Dryobates minor), in the western Po Plain (Northern Italy). During Spring 2019, we counted woodpeckers in 29 plots located in plantations. As a comparison, 30 plots placed in semi-natural woodlands nearby were also surveyed. Moreover, within plantations, we monitored the breeding activity of woodpeckers by camera inspection, and we recorded micro-habitat, stand, and landscape variables for every plot. Densities of both species were significantly lower in plantations than in woodlands. In plantations, the occurrence of Lesser Spotted Woodpecker and abundances of Great Spotted Woodpecker were positively related to the amount and size of standing dead trees, respectively. No relationship with the landscape composition were detected. Only 11 woodpecker nests were found in a surveyed area of 274 ha, indicating scarce breeding activity. In stands with breeding woodpeckers, the loss of revenue due to the presence of dead trees ranged from 0.15% to 1.81%. We conclude that poplar plantations are marginal habitats for woodpeckers. To improve the suitability of plantations for these species, a management strategy should pursue the retention of standing dead wood, the increment of natural elements within and close by the plantation and the establishment of multi-age stands. Simultaneous implementation of these measures would buffer the detrimental effects of intensive management, thus acting as a step forward towards the achievement of a multipurpose forest
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
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