1,720,969 research outputs found
Forest and Isolation Determine Bat Species Richness on Mediterranean Islands: Conservation Implications
No full textBackground: The study of island species richness has gone far beyond traditional theories, as more and more studies attempt to include new predictor variables besides island area. Despite the rich bat diversity of Mediterranean islands, no studies have examined the factors influencing chiropteran species richness in such a geographic context. Aims: We used Greek islands as a model to detect drivers of bat species richness based on a broad species occurrence dataset from islands of the Aegean and Ionian Seas, which was explored using 10 potential predictor variables. Materials and Methods: Initially, we comprehensively evaluated all available data and sources for 53 Greek islands, deemed essential. This resulted in a reduced set of 28 islands. Predictors were grouped into three categories: island area, landscape diversity and island isolation. Generalised linear models were employed to identify the most significant factors explaining bat species richness in the 28 islands. Results: Tree cover and the distance between the islands and their nearest coast (mainland or island) best performed to predict bat species richness on Greek islands. Discussion: We show the important role of landscape composition and degree of isolation in influencing the distribution of bat species on islands. Conclusion: We highlight the importance of forest habitats and the vital role of their management and protection, especially in the insular systems of the Mediterranean basin, where the risk of forest degradation or loss due to wildfires and land use change is especially high
The importance of forest conservation for the survival of the range-restricted Pipistrellus hanaki, an endemic bat from Crete and Cyrenaica
No full textMediterranean forests have been exploited by humans for centuries, but their present area and condition have been shaped mostly during the recent decades. Overgrazing resulting from national and EU policies, increasing fires and touristic development have led to the shrinkage of forest, threatening forest species. In this study, we examine the relation of Pipistrellus hanaki, a bat species limited to Cyrenaica, Libya and Crete, with the relict forests of Crete. Radiotracking of males (in autumn) and lactating females (in early summer) showed that P. hanaki uses a range of roost types, but Quercus forest stands and old tree cultivations are largely preferred for foraging, while open areas, young Cupressus stands and Mediterranean maquis are avoided. To unveil larger-scale patterns of habitat suitability by the species, we used Maxent to model its potential distribution on Crete using Chelsa Climatology. The resulted model showed high distribution probability around the mountains of central and western Crete, where native Cupressus, Pinus and Quercus stands are still present, and the climatic conditions are favourable. The strong dependence of this strictly southeast Mediterranean bat on forests and old tree cultivations stresses the need for conservation of these habitat types. In situ forest protection and environmental friendly livestock and farming practices are necessary to ensure the long–term survival of the species in Crete
Bat species richness and activity over an elevation gradient in Mediterranean shrublands of Crete [Ricchezza specifica e attività dei chirotteri lungo un gradiente altitudinale nella macchia mediterranea di Creta]
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
The diet of the Eleonora's falcon (Falco eleonorae) in the Aegean archipelago (Greece)
No full textXirouchakis, S. M., Alivizatos, H., Georgopoulou, E., Dimalexis, A., Latsoudis, P., Portolou, D., Karris, G., Georgiakakis, P., Fric, J., Saravia, V., Barboutis, C., Bourdakis, S., Kakalis, E., Kominos, T., Simaiakis, S. (2019): The diet of the Eleonora's falcon (Falco eleonorae) in the Aegean archipelago (Greece). Journal of Natural History 53 (29): 1767-1785, DOI: 10.1080/00222933.2019.166897
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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