1,720,962 research outputs found
Management and conservation along the inland margins of the lagoon: the European pond turtle (Emys orbicularis) case study in a protected internal wetland area of the Southern Venice lagoon
No full textNel 2018 è iniziato un programma di monitoraggio sulle testuggini palustri in un’area perilagunare della laguna di Venezia in collaborazione con World Wild Fund for Nature (WWF-Italia). Gli sforzi sono stati incentrati sulla testuggine palustre Europea, Emys orbicularis, considerata nel contesto della biologia di conservazione una surrogate species (es. specie bandiera, sentinella e ombrello). Nonostante questa specie sia utilizzata come strategia di sintesi per monitorare o risolvere problemi di conservazione, le sue conoscenze scientifiche sono ancora in fase di sviluppo e attualmente in discussione, in particolare in relazione al ciclo vitale, all'ecologia comportamentale e ai requisiti ecologici. L'analisi di dati quantitativi con un numero rilevante di individui è pertanto necessaria al fine di aumentare l'insieme di informazioni sulla biologia, il comportamento e la preferenza dell'habitat per la sopravvivenza a lungo termine delle popolazioni di E. orbicularis. In questo lavoro: (1) stimando la densità di una popolazione di E. orbicularis in una area umida della laguna di Venezia con il metodo della cattura-ricattura, è stato possibile osservare una delle are più popolate della penisola italiana (~ 250 ind./ha) (2) analizzando i modelli di comportamento e di dispersione tra il periodo di attività e quello letargico in una popolazione selvatica di testuggine palustre Europea, è stato possibile osservare migrazioni verso habitat acquatici con più alti livelli di salinità in estate 1-17‰ (media: 10.64‰), mentre un’ibernazione gregaria e nessun comportamento migratorio di massa è stata rilevato in autunno (3) sviluppando modelli predittivi sulla distribuzione di E. orbicularis in differenti micro-habitat dell’Oasi di Valle Averto, è stato possibile osservare un effetto positivo della salinità, della vegetazione emergente e dell'esposizione solare sulla presenza e abbondanza di questa specie. Queste indicazioni potrebbero avere valore per ottimizzare gli sforzi di conservazione concentrando i finanziamenti sugli aspetti di gestione e migliorando le caratteristiche paesaggistiche più importanti per la specie e per la biodiversità delle zone umide
Predictive Distribution Modeling of the Medicinal Leech Hirudo verbana Carena, 1820 (Hirudinea, Hirudinidae) in Sicily: Implications for Conservation
Full text linkHirudo verbana, a medicinal leech species of conservation concern, has long been considered rare and fragmented across its distribution range due to overexploitation and habitat alteration. In this study, we present the first predictive distribution model for H. verbana in Sicily, combining field occurrence data (time: 1980–2024) with environmental variables using an ensemble species distribution modeling (SDM) framework. Unlike its typical occurrence in temperate lowland wetlands of central-eastern Europe, the species in Sicily shows a marked shift toward upper hill and montane zones. Species presence was strongly associated with high NDVI values, reflecting a preference for areas with dense and structurally complex vegetation. In contrast, presence probability declined sharply with increasing terrestrial human footprint (THF), indicating a notable sensitivity to anthropogenic disturbance. Aquatic habitat type also emerged as a key predictor: the species was most likely to occur in lentic environments such as standing water bodies, and least likely in lotic systems or areas lacking aquatic habitats. Notably, most high-suitability areas overlapped with sites in the Natura 2000 network, emphasizing the importance of existing protected areas as refugia for the species. Moreover, some previously undocumented areas of high habitat suitability were identified, providing a spatially basis for refining monitoring strategies and informing conservation planning for this ecologically sensitive freshwater invertebrate
Temperature effects on parental care behaviour in native and invasive Palaemon shrimp species
Full text linkEnvironmental changes and the spread of non-native species significantly affect wetland ecosystems, such as coastal lagoons. This study investigates the effects of increased temperature on parental care behaviour, specifically pleopod fanning, in ovigerous females of the following three Palaemon species: the global invader Palaemon macrodactylus and the Mediterranean native Palaemon elegans and Palaemon adspersus. Under controlled laboratory conditions, we measured pleopod beats per minute across a temperature gradient to assess species-specific responses. Our results showed significant inter-species differences in fanning behaviour, with P. elegans exhibiting the lowest pleopod beat rate overall. Temperature showed a strong positive correlation with pleopod beats across all species, whereas dissolved oxygen negatively correlated with pleopod beats in P. adspersus and P. macrodactylus. Interestingly, P. elegans exhibited a unique response compared with its congeneric species, because it was the only species among those studied that did not show a negative correlation between pleopod beat rate and dissolved oxygen concentration. These findings have enhanced our understanding of the behavioural responses of native and invasive Palaemon species to environmental alterations, providing valuable insights into how species interact with their changing environments
Population abundance, structure and movements of the European pond turtle, Emys orbicularis (Linnaeus 1758) based on capture-recapture data in a Venice Lagoon wetland area, Italy
No full textA freshwater turtle monitoring programme along the inland margins of the Venice lagoon was initiated in 2019 in collaboration with the World Wild Fund for Nature (WWF-Italy). From a total of 336 European pond turtles (Emys orbicularis) captured and marked, 97 freshwater turtles were recaptured at least once (28.9% return rate) providing important information on population size, structure and movements of mature individuals within the study area. The population size was estimated with capture-recapture method (Capture-Mark-Recapture-CMR) at 1009.4 ± 365.2 pond turtles, with a mean density of 252.3 ± 91.3 ind./ha. The analysis of the movements showed that the average distance covered intra-water bodies was: 146.79 ± 117.08 m for females and 125.43 ± 112.34 m for males. A total of 17 E. orbicularis (eight females and nine males) out of 97 turtles changed the water body during the study period from April to early September. Only a female freshwater turtle migrated in all three study sites, being recaptured 1502.32 m from the tagging site. The percentage of captures was significantly higher in two canals than in the brackish lake habitat. Further research should address spatial distribution at a finer scale to evaluate the preferential habitat for threatened E. orbicularis populations in a transitional water system as the lagoon
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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