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Plant diversity and functions in semi-natural grasslands under different management intensities
No full textPlant diversity and functions in semi-natural grasslands under different management intensities
Napoleone Francesca1, Giarrizzo Eleonora1, Argenti Giovanni2, Blasi Carlo1, Burrascano Sabina1
1Department of Environmental Biology - Sapienza University of Rome
Presenting author: [email protected]
Session 3
Question: Main aims of this study are: i) assess the relationships between plant diversity and ecosystem services such as forage for livestock and support to insect pollinators; ii) define compositional, structural and functional traits that indicate a high pastoral value and support to pollinators; iii) identify the management practices that better combine biodiversity conservation and ecosystem functionality.
Methods: The study focuses on the 6210(*) habitat: semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia) (*important orchid sites). The study area includes the Central Apennines and the North-Western Alps. The sampling design is based on management data, sampling units are randomly located in patches subjected to different grazing regimes (number and type of animals) and in abandoned areas. Vascular plant species composition will be recorded together with several information on topography and soil. For each sampling unit, based on vascular plant species abundance we will calculate the pastoral value and the degree of support to insect pollinators as well as the habitat conservation status. These ecosystem properties will be related and associated to different management regimes.
Results: We expect that a higher plant diversity relates to a higher pastoral value and support for insect pollinators and that these positive ecosystem properties are associated with low stocking rates.
Conclusions: Identifying the management practices causing a high degree of conservation for the habitat and maintaining its functions is essential to achieve good governance models
How to measure flower UV-reflectance using digital photography
No full textFlower ultraviolet (UV) reflectance strongly influences insect ability to detect flowers and locate pollen-nectar sources. Although included in the TRY database, the lack of a cost-effective standardized method of measurement hampers the availability of information on this key floral trait. Digital photography and image processing allow for a novel approach to flower UV-reflectance measurement that is both accessible and accurate.
We used a UV-LED light and a mirrorless camera with a filter, which represents a low-cost equipment for narrow emission/reflection photography (350-380nm). Flowers were photographed with two standards of known reflection, and UV-reflectance values were obtained through an open-source image processing software.
We measured UV-reflectance for 57 plant species typical of European semi-natural grasslands. Our values substantially matched the categorical classes obtained through analog photography available in TRY and showed a highly significant relationship with spectrophotometric measures.
The method here proposed overcomes the one based on analog photography and subjective visual estimates, and represents an easy and low-cost alternative to spectrophotometry. It may promote the standardized measurement of flower UV-reflectance and broaden the information of this trait globally, meeting the needs of functional ecology and trait-based community assembly studies
Habitat conservation state and plant diversity respond to different drivers in semi-natural grasslands
No full textQuestions: Semi-natural habitats are threatened by shifts in management with worrying effects on multiple facets of biodiversity. We revisited sites once representing a reference for a calcareous semi-natural grassland habitat aiming to: (a) identify the drivers of taxonomic, functional and phylogenetic diversity, and habitat conservation state; (b) assess the role of characteristic and derived diversity in determining these patterns; and (c) discuss the possibility of reconciling the goals of habitat conservation and enhancement of different facets of plant diversity. Location: Seven sites along the Apennines (Italy), from Mt. Catria (43.46206° N, 12.70397° E) to Mt. Alpi (40.11768° N, 15.98341° E). Methods: For 132 revisited plots, we calculated vascular plant taxonomic, functional and phylogenetic diversity using Hill numbers, and used boosted regression trees to investigate their response to the compositional dissimilarity from historical plots, to grazing intensity and to environmental variables. We identified characteristic and derived diversity and summarized them in an index of habitat conservation state whose drivers were investigated using the same approach. Results: Plant diversity was influenced by the site, whereas the habitat conservation state responded more markedly to vegetation type. Grazing intensity, slope and soil variables drove taxonomic and functional diversity, and the habitat conservation state, with some differences in their relative importance. Phylogenetic diversity responded only partly to grazing intensity, while it showed a major response to increasing temperatures. Conclusions: Patterns and drivers of different facets of plant diversity partially differ from those of the habitat conservation state, suggesting that the management of semi-natural habitats should be carefully tailored on specific conservation objectives. Generalized actions on grazing regimes and litter removal can promote habitat conservation, whereas the outcomes of these actions for plant diversity may differ across sites. Identifying areas particularly subjected to land-use changes and/or climate warming may drive conservation actions
Agri-environmental payments drive the conservation and forage value of semi-natural grasslands by modifying fine-scale grazing intensity
No full textIn Europe, the conservation of extensively grazed semi-natural grasslands is addressed by agricultural policies whose effectiveness is questioned. We studied sub-xerophilous Bromus erectus semi-natural grasslands to analyse the interactions among: i) agri-environmental payments, ii) grazing regimes, iii) environmental conditions, iv) habitat conservation state, and v) forage yield and quality.
We sampled 98 plots across 19 farms and unmanaged control areas in five regions encompassing Italy and Switzerland. We fitted two piecewise structural equation models (SEM) to infer direct and indirect effects of agri- environmental payments, grazing regimes and environmental conditions on proxies of habitat conservation state, (i.e., the number and cover of diagnostic species), and forage yield and quality (i.e., specific leaf area - SLA, leaf dry-matter content - LDMC, sward height and pastoral value).
Agri-environmental payments contributed to maintain grazing management and in turn to preserve the habitat biodiversity and functions. Payments did not affect stocking rates, but determined a more even distribution of grazing intensity, with positive effects on habitat conservation state and negative outcomes for LDMC. Conversely, LDMC increased with stocking rates. Among environmental condition, elevation and soil carbonates content had a positive effect on the habitat conservation state, while slope exerted only indirect effects on forage quality and diagnostic species by reducing fine-scale grazing intensity. Overall, the effectiveness of payments largely depended on the scale of measures' implementation. Farm-level grazing contracts and periodic field monitoring would allow to influence the fine-scale grazing intensity and to implement a result-oriented approach towards the objectives of the post-2020 CAP
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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