1,720,960 research outputs found
The use of maps as a monitoring tool of protected area management
No full textLeaf area index (LAI) of vegetation types developing inside the protected Estate of Castelporziano was analyzed in the year 2013 and compared with the previous studies carried out in the years 1995-1997. Our recent data do not show significant differences in the structure and LAI of the vegetation types not subjected to thinning respect to the previous studies. The results on the whole highlight that the conservative management carried out in the Castelporziano Estate has had positive effects leading to a high number of large tree size in the forest stands. The multiple linear regression analysis shows that the photon flux density monitored at soil level (PFD%) is related to plant height (H), total plant basal area (TBA) and LAI in the considered forest types. In addition, plants renewal was analyzed in some thinned and un-thinned areas of Quercus ilex forests and broadleaf mixed forests inside the Estate. The spatial patterns of light availability within these forest types influence the regeneration patterns of woody species: a higher seedling regeneration both in un-thinning and thinning areas was observed in Q. ilex evergreen forests (5.0±2.0 and 1.0±0.5 seedlings m-2, respectively) than in broadleaf mixed forests (0.40±0.10 and 0.10±0.03 seedlings m-2, respectively) due to the large germination capability of Q. ilex. LAI is a key parameter in evaluating ecosystem structure. The used maps may be considered a rapid and cost-effective method to have an overview on the functional state of the forest ecosystems as well as the possibility to highlight rapidly the occurrence of a local disturbance state. Old-growth forests like those under study, are important reference sites for conservation strategies involving a broad range of ecosystem services. These types of data may be useful to achieve a database for management projects in the Presidential Estate of Castelporziano
Researches in Castelporziano test site: ecophysiological studies on Mediterranean vegetation in a changing environment
No full textUrbanization processes increased dramatically in the past century leading to the emission of large quantities of air pollutants over relatively small areas. The consequent high concentration of pollutants and particulate matter (PM) have clear detrimental effects not only on human health, but also on urban and peri-urban vegetation. In this context, the Castelporziano Presidential Estate, a protected natural area located at the southeastern edge of the large conurbation of Rome (Italy), represents an ideal site to study the interaction between vegetation and atmospheric pollutants. Here we present an overview of the international field campaigns carried out in Castelporziano during the past 20 years, and of the ongoing research activities aimed to understanding the role of the estate in the provision of ecosystem services to the Metropolitan area of Rome. The exposure and potential detrimental effects of air pollutants such as tropospheric ozone and PM on natural vegetation have been assessed, investigating also the potential capacity of vegetation to ameliorate air quality under Mediterranean climatic condition. The results show that a correct assessment of the Ecosystem Services (ESs) provided by Mediterranean vegetation must consider the functional strategies that different species adopt to cope with drought stress, including the species-specific response of stomatal conductance to atmospheric water pressure difference, as well as the length of the drought period and its inter annual variability. Our results highlight the need to adopt managements strategies to mainten and implement the ESs provided by the important peri-urban natural area of Castelporziano
Pinus pinea L. plant trait variations in response to tree age and silvicultural management and carbon storage capability
No full textPinus pinea plant trait variations in response to tree age and silvicultural practices were analyzed. Samplings were carried out in stands with trees of different ages inside the Presidential Estate of Castelporziano (Italy). The results highlight the largest structural changes occurring between 15- and 45-year-old trees when the ratio between tree height (H) and crown height (C H ) largely increased (from 1.45 to 3.48). The C H decrease (tree stands older than 45 years) was due to the transformation of the crown from a spherical shape in young trees to an umbrella-shaped in adult trees when most of the basal branches were lost. Leaf area index (LAI) changed with stand density and in response to the stone pine developmental stage showing the largest value in 34-year-old tree stands. The biomass was the largest in 104-year-old tree stands (241.1 ± 9.8 t ha−1) and carbon stored (C st) varied from 0.01 ± 0.005 to 1.63 ± 0.07 t (15- and 104-year-old trees, respectively). Morphology varied significantly between 1- and 2-year-old needles, with the specific needle weight (SNW) having the highest values in 2-year-old needles. LAI was correlated (p < 0.05) to H/C H ratio and crown volume (V c) which changed in response to stone pine growth and silvicultural treatments. The long-term monitoring of P. pinea stands could be easily achieved by LAI measurements
The nutritional carrying capacity of four Mediterranean habitats for Fallow Deer (Dama dama)
No full textThe assessment of the trophic value of the most consumed feed by fallow deer in a coastal mediterranean landscape (Rubus ulmifolius, Cistus salvifolius, Phyllirea latifolia, Quercus ilex and graminoids) was based on in vitro digestibility trials, performed throughout the year (1 set of samples per season) using rumen inocula from wild fallow deer from the Preserve of Castelporziano, collected simultaneously with the vegetal samples. Moreover, in vivo digestibility coefficients have been estimated by using standard feed (for fallow deer) of known in vivo digestibility.
Using the digestibility coefficients, the metabolizable energy yield of studied forage items was computed. Information about plant biomass, structure of fallow deer population, metabolizable energy yields, estimates of forage intake and energy requirements were combined using the model presented by Hobbs & Swift (1985) to evaluate the nutritional carrying capacity of four typical mediterranean habitats (natural evergreen oak wood, scrub, mixed plantations of Quercus ilex and Pinus pinea, open pastures).
Spring represents the most favourable situation, while summer, autumn and winter exhibit similar values of carrying capacity of about 15-20 deer/100 ha. Mixed plantations of Pinus pinea and Q. ilex seem to be the most productive condition for fallow deer.Une évaluation de la valeur trophique des aliments les plus consommés par le daim dans un paysage côtier méditerranéen (Rubus ulmifolius, Cistus salvifolius, Phyllirea latifolia, Quercus ilex et graminoïdes) a été menée, basée sur des essais de digestibilité in vitro effectués tout au long de l’année (un jeu d’échantillons par saison) à l’aide d’inocula de rumen de daims sauvages de la Réserve de Castelporziano, prélevés en même temps que les échantillons végétaux. En outre, des coefficients de digestibilité in vivo ont été estimés à l’aide d’aliments standards pour daim de digestibilité in vivo connue.
Ces coefficients de digestibilité ont permis de calculer le rendement en énergie métabolisable des items alimentaires. Les informations sur les biomasses végétales, la structure des populations de daim, les rendements en énergie métabolisable, les estimations de prises alimentaires et les besoins énergétiques, ont été combinées pour utiliser le modèle de Hobbs & Swift (1985) et estimer la capacité limite alimentaire de quatre habitats méditerranéens typiques (boisements sempervirents naturels de chênes, maquis, plantations mixtes de Quercus ilex et Pinus pinea, pâturages).Focardi Stefano, Poli Bianca Maria, Tinelli Aleandro. The nutritional carrying capacity of four Mediterranean habitats for Fallow Deer (Dama dama). In: Revue d'Écologie (La Terre et La Vie), tome 50, n°2, 1995. pp. 97-107
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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