1,721,035 research outputs found
Community weighted mean trait data of Italian forest understories
Full text linkPlant functional trait data aggregated at the community level (i.e., community weighted mean, CWM) are fundamental to study plant-environment relationships. Here, we provide a large database of CWM values of twelve traits reflecting several plant functions, including leaf, seed, whole-plant, clonal and bud bank traits. The CWMs were calculated in 201 forest stands (a statistically representative sample of all the Italian forests) across three biogeographic regions: Alpine, Continental, and Mediterranean. © 2019 The Author(s
Unimodal relationships of understory alpha and beta diversity along chronosequence in coppiced and unmanaged beech forests
Full text linkPatterns of diversity across spatial scales in forest successions are being overlooked, despite their importance for developing sustainable management practices. Here, we tested the recently proposed U-shaped biodiversity model of forest succession. A chronosequence of 11 stands spanning from 5 to 400 years since the last disturbance was used. Understory species presence was recorded along 200 m long transects of 20 X 20 cm quadrates. Alpha diversity (species richness, Shannon and Simpson diversity indices) and three types of beta diversity indices were assessed at multiple scales. Beta diversity was expressed by a) spatial compositional variability (number and diversity of species combinations), b) pairwise spatial turnover (between plots Sorensen, Jaccard, and Bray-Curtis dissimilarity), and c) spatial variability coefficients (CV% of alpha diversity measures). Our results supported the U-shaped model for both alpha and beta diversity. The strongest differences appeared between active and abandoned coppices. The maximum beta diversity emerged at characteristic scales of 2 m in young coppices and 10 m in later successional stages. We conclude that traditional coppice management maintains high structural diversity and heterogeneity in the understory. The similarly high beta diversities in active coppices and old-growth forests suggest the presence of microhabitats for specialist species of high conservation value
La biodiversità forestale: specie vegetali.
No full textIl monitoraggio dello stato di salute delle foreste nacque nella seconda metà degli anni ’80, nell’ambito della Convenzione sull’Inquinamento Transfrontaliero a Grande Distanza (Convention on Long Range Transboundary Air pollution, CLRTAP), attuata sotto l’egida della Commissione Economica per l’Europa delle Nazioni Unite (United Nations Economic Commission for Europe, UN/ECE). Per dare attuazione alla Convenzione, furono avviati diversi programmi operativi internazionali, tra i quali il Programma Cooperativo Internazionale sul monitoraggio integrato degli effetti dell’inquinamento atmosferico (International Cooperative Programme on Integrated Monitoring of Air Pollution Effects, ICP IM) ed il Programma Cooperativo Internazionale sulla valutazione ed il monitoraggio degli effetti dell’inquinamento atmosferico sulle foreste (International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests, ICP Forests). Il “Programma CON.ECO.FOR.” (CONtrollo ECOsistemi FORestali) rappresenta il ramo istituzionale italiano degli adempimenti derivanti dalle iniziative internazionali citate. La Rete NEC Italia, così come disegnata nel decreto del Ministero della Transizione Ecologica (a seguire MiTE) 26 novembre 2018, n. 319, attuativo del Decreto legislativo di recepimento della Direttiva, si basa sul monitoraggio degli impatti negativi di inquinanti atmosferici quali il biossido di zolfo, gli ossidi di azoto, i composti organici volatili non metanici, l’ammoniaca, il PM 2,5 , il PM 10 e l’ozono: • sugli ecosistemi terrestri, impiegando n°6 aree CON.ECO.FOR. di livello II e il relativo protocollo ICP Forests, dove l’Arma dei Carabinieri partecipa al lavoro dei ricercatori dell’Università di Firenze e di Camerino oltre a quelli del CNR e del CREA; • sugli ecosistemi di acqua dolce, impiegando n°10 siti ICP WATERS gestiti dal Consiglio Nazionale delle Ricerche CNR-IRSA, secondo le modalità di campionamento ed analisi previste dal protocollo ICP Waters; • dei danni da ozono, utilizzando i dati monitorati dal Consiglio Nazionale delle Ricerche CNR-IRET, in n° 11 stazioni forestali, selezionate per coprire sia ambienti diversi con la stessa specie forestale (il faggio, Fagus sylvatica L.), sia specie forestali temperate e mediterranee
Spatial point pattern analysis of piping erosion in loess-derived soils in Golestan Province, Iran
No full textPoint pattern analysis of collapsed pipes as a subsurface erosion in natural and manmade conditions plays an
important role to understand their landforms/features, predisposing factors, and for prevention and forecasting
purposes. Thus, the present study aimed to evaluate the spatial pattern and the associated land factors of piping
erosion in loess-derived soils in a semiarid climate in Golestan Province, Iran by applying numerical summary
statistics. To this end, a 105 ha area with homogeneous environmental conditions (gentle slope and loess-derived
soil) was selected and the maps related to 101 collapsed pipes and their features were obtained by the aerial
photos provided by an unmanned aerial vehicle (UAV) with a 50 cm resolution and field survey. The mean of
spatial distances between pipe locations was 309 m, and the frequency of pipes per hectare was 0.97. Moreover,
soil samples of the pipe locations were collected and physical-chemical soil properties were measured in laboratory.
Approximately 95% simulation envelopes were selected using the 5th-lowest and 5th-highest values of
199 Monte Carlo simulations of the null model of homogeneous complete spatial randomness. Based on the
results of univariate pair correlation function, the significant aggregation of 101 collapsed pipes was observed at
a scale of 0–50m in both rangeland and agricultural land use types. The bivariate pair correlation function,
which is considered to be the most informative second-order summary characteristic, was used for analyzing the
statistical correlations between collapsed pipes and linear phenomena including distance from drainage networks,
ridges, and roads. Based on bivariate summary statistics, collapsed pipes had positively been affected by
both the distribution of drainage networks and ridges. However, the negative statistical correlations occurred
between pipes and roads at the scales of 1–50 m. Also, the correlations of soil characteristics (silt content,
exchangeable sodium percentage (ESP), the weight of soil in a given volume (bulk density), soil electrical conductivity
(EC), and organic matter (O.M.)) of neighboring collapsed pipes were evaluated by mark correlation
function. Based on mark correlation function kmm(r), a significantly positive correlation was found between the
pipes density and silt content, ESP, and bulk density, when they are more than overall average. In addition, less
values of EC and O.M. were positively related to the aggregation of collapsed pipes. Similar to the results of
summary statistics, the maps confirmed all statistical correlations. Consequently, the outcome of this study
highlights the spatial pattern of collapsed pipes and their associations in the study area
Spatial and temporal patterns of plant diversity in the Italian forest monitoring network (CONECOFOR)
Full text linkSince 1996, the Italian network CONECOFOR included Ground Vegetation (GV) within the
forest monitoring actions, in the frame of ICP Forests. Plant diversity variables have been
assessed yearly on 11 of the 31 sites of the intensive network (LII), while a unique survey
was realized for the extensive network (LI) in 2007, within the Biosoil-Biodiversity project.
CONECOFOR is presently undergoing a revision process aimed to assure the financial
sustainability of reliable information on forest status and trends (SMART4Action, LIFE+ ENV
project).
We contribute to the project by analysing spatial and temporal patterns options for GV
assessment.
(i) Aims: suggest an affordable number of sites and the best sampling strategy to provide an
overview of forest plant diversity within both LII and LI network.
(ii) Objectives: estimate the effect of reduced sampling frequency and size, as well as
different sampling designs on GV assessment.
(iii) Methods: previous datasets are examined to test the conformity of LII vs. LI sites, to
compare time-trend descriptors, and to estimate the critical number of sites and sampling
units (SU). Field cross-surveys in next summer will compare different methods on selected
sites.
(iv) Considering LII sites (1999-2102), the reduction from annual to multiple-year surveys
provides incomparable regression functions. The effect of reducing SUs numbers within LII
sites is variable, due to different understory heterogeneity, and arousing misleading plant
diversity description. LII hardly represents the spatial distribution achieved by LI reference (in
2007), due to the “preferential” selection used in the former network. A relevant reduction of
LI sites can be achieved (almost 50%) maintaining the representativeness of plant species
richness; relevant thresholds have been provided considering the stratification by
Biogeographic Regions and the most relevant Forest types (Alpine conifers, Mountinous
Beech, and Thermophilous deciduous forests).
The experimental design of the comparative field test will be presented
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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