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151.
Daniela Ciccarelli 《Environmental management》2014,54(2):194-204
The aim of the present work was to assess the conservation status of coastal dune systems in Tuscany (Italy). Emphasis was given to the presence and abundance of plant communities identified as habitat in accordance with the Directive 92/43/EEC. Twenty transects perpendicular to the shoreline were randomly positioned on the whole coastal area (30 km in length) in order to sample the full spectrum of plant communities. Vegetation zonation and relationships with the most frequent disturbance factors in the study area—beach cleaning, coastline erosion, presence of paths and roads, bathing settlements and trampling—were investigated through principal coordinate analysis and canonical correspondence analysis. Natural factors, such as distance from the sea and total length, were also considered. Differences in the conservation status of the sites were found, ranging from the total disappearance of the foredune habitats to the presence of the complete psammophilous (sand-loving) plant communities. Erosion, trampling, and paths were found to be closely correlated with degradation and habitat loss. Furthermore, the overall plant species diversity of dunes was measured with NHDune, a modified version of the Shannon index; while the incidence of invasive taxa was calculated using N, a naturalness index. However, these diversity indices proved to be a weaker bioindicator of ecosystem integrity than habitat composition along transects. A possible strategy for the conservation and management of these coastal areas could be to protect the foredunes from erosion and limit trampling through the installation of footbridges or the use of appropriate fences. 相似文献
152.
Analyses of platinum group elements in mosses as indicators of road traffic emissions in Austria 总被引:1,自引:0,他引:1
Harald G. Zechmeister Harald Hagendorfer Daniela Hohenwallner Andrea Hanus-Illnar Alarich Riss 《Atmospheric environment (Oxford, England : 1994)》2006,40(40):7720-7732
The concentrations of platinum group elements (PGE; platinum, palladium, rhodium) and 17 other elements in mosses growing at 32 sampling sites along 12 roads in Austria were analysed. The study included passive monitoring of naturally growing mosses with an experimental design using mosses samples exposed in a tunnel experiment. PGEs (Pt, Pd, Rh) were analysed by ICP-MS (ELAN DRC II, Perkin Elmer SCIEX) according to EN ISO 17294-2 Tl.29. Mean concentrations of PGEs in five moss species were: Pt 7.07±9.97, Pd 2.8±5.2 und Rh 0.6±0.8 ng g−1 dry weight. This is comparable to data derived from measurements of gasoline autocatalyst emissions or airborne particles (<10 μm). Compared to soils and road dust along highways, concentrations in mosses were lower by a factor of ten, compared to grasses they were comparable or somewhat higher. The ratios between the various PGEs were calculated as follows (mean values): Pt/Pd 7.9±10.2, Pt/Rh 12.6±8.3 and Pd/Rh 3.7±2.2. The number of light duty vehicles (<3.5 t) and the distance from the road were the main influential factors for PGE concentrations. Especially strong correlations could be found between Pt and Sb, Cu, Zn, and Cd (in decreasing order), which are all elements derived mainly from road traffic emissions. Cluster analysis (Partioning Around Medoids Method) separated elements derived mainly from soil dust (Ca, Al). An analysis of spatial deposition patterns of PGEs showed a reciprocal decrease of concentrations with increasing distance from the road, reaching background values at distances between 10 and 200 m, sometimes even more, but outside the spatial range of our investigation. 相似文献
153.
154.
Tiziano Tirabassi Alessandro Tiesi Daniela Buske Marco T. Vilhena Davidson M. Moreira 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2221-2227
The moments of the concentration distribution obtained using a recent analytical solution of the steady-state two-dimensional advection–diffusion equation are presented. The solving methodology is the Generalized Integral Laplace Transform Technique, which allows obtaining a reliable solution of the advection–diffusion equation without any restrictive assumption about the eddy diffusivity coefficients and wind speed profiles. The first four moments and value and position of maximum ground level concentration are calculated. The concentration standard deviation is compared against the semi-empirical ones used in operative Gaussian models. 相似文献
155.
156.
157.
Francesca Bruno Peter Guttorp Paul D. Sampson Daniela Cocchi 《Environmental and Ecological Statistics》2009,16(4):515-529
The past two decades have witnessed an increasing interest in the use of space-time models for a wide range of environmental
problems. The fundamental tool used to embody both the temporal and spatial components of the phenomenon in question is the
covariance model. The empirical estimation of space-time covariance models can prove highly complex if simplifying assumptions
are not employed. For this reason, many studies assume both spatiotemporal stationarity, and the separability of spatial and
temporal components. This second assumption is often unrealistic from the empirical point of view. This paper proposes the
use of a model in which non-separability arises from temporal non-stationarity. The model is used to analyze tropospheric
ozone data from the Emilia-Romagna Region of Italy. 相似文献
158.
Sortino O Dipasquale M Montoneri E Tomasso L Perrone DG Vindrola D Negre M Piccone G 《Waste management (New York, N.Y.)》2012,32(10):1792-1801
Municipal bio-refuse (CVD), containing kitchen wastes, home gardening residues and public park trimmings, was treated with alkali to yield a soluble bio-organic fraction (SBO) and an insoluble residue. These materials were characterized using elemental analysis, potentiometric titration, and 13C NMR spectroscopy, and then applied as organic fertilizers to soil for tomato greenhouse cultivation. Their performance was compared with a commercial product obtained from animal residues. Plant growth, fruit yield and quality, and soil and leaf chemical composition were the selected performance indicators. The SBO exhibited the best performance by enhancing leaf chlorophyll content, improving plant growth and fruit ripening rate and yield. No product performance-chemical composition relationship could be assessed. Solubility could be one reason for the superior performance of SBO as a tomato growth promoter. The enhancement of leaf chlorophyll content is discussed to identify a possible link with the SBO photosensitizing properties that have been demonstrated in other work, and thus with photosynthetic performance. 相似文献
159.
Daniela Djikanovi? Jasna Simonovi? Aleksandar Savi? Ivan Risti? Danica Bajuk-Bogdanovi? Aleksandar Kalauzi Suzana Caki? Jaroslava Budinski-Simendi? Milorad Jeremi? Ksenija Radoti? 《Journal of Polymers and the Environment》2012,20(2):607-617
In a plant cell wall, lignin is synthesized from several monomeric precursors, combined in various ratios. The variation in monomer type and quantity enables multifunctional role of lignin in plants. Thus, it is important to know how different combinations of lignin monomers impact variability of bond types and local structural changes in the polymer. Lignin model polymers are a good model system for studies of relation between variations of the starting monomers and structural variations within the polymer. We synthesized lignin model polymers from three monomers, CF??based on coniferyl alcohol and ferulic acid in monomer proportions 5:1 and 10:1 (w/w), CP??based on coniferyl alcohol and p-coumaric acid in proportion 10:1 (w/w) and CA??based on pure coniferyl alcohol. We studied structural modifications in the obtained polymers, by combining fluorescence microscopy and spectroscopy, FT-IR and Raman spectroscopy, in parallel with determination of polymers?? molecular mass distribution. The differences in the low M w region of the distribution curves of the 10:1 polymers in comparison with the CA polymer may be connected with the increased content of C=C bonds and decreased content of condensed structures, as observed in FT-IR spectra and indicated by the analysis of fluorescence spectra. The 5:1 CF polymer contains a different type of structure in comparison with the 10:1 CF polymers, reflected in its simpler M w distribution, higher homogeneity of the fluorescence emitting structures and in the appearance of a new high-wavelength emission component. We propose that this component may originate from ??-conjugated chains, which are longer in this polymer. The results are a contribution to the understanding of the involvement of structural variations of lignin polymers in the cell wall structural plasticity. 相似文献
160.
Elisa Chiarati Daniela Canestrari Marta Vila Ruben Vera Vittorio Baglione 《Behavioral ecology and sociobiology》2011,65(9):1791-1800
Offspring delayed dispersal is the principal mechanism leading to formation of kin-based societies. It has been suggested
that parents promote offspring philopatry by providing them with preferential access to the food resources of the territory
and that parental tolerance may be affected by territory quality. However, few studies have addressed this hypothesis in kin-living
vertebrate species. Here, we show that in cooperative breeding groups of carrion crows (Corvus corone corone) containing retained offspring and immigrants, dominant breeding males behaved nepotistically on an experimental source of
food by (1) attacking immigrants with more frequency and intensity than offspring and (2) associating preferentially with
their offspring on the feeding spot and sharing food with them. This parental facilitation allowed the offspring to spend
more time feeding than higher-rank immigrants. We also found that a year-round experimental food supplementation neither increased
breeding males’ tolerance nor relented the overall aggressiveness in the groups. This indicates that higher natal philopatry
observed on fed territories compared to unfed ones is not a consequence of a more benign social environment. Rather, it suggests
that offspring value territory resource wealth and adjust the timing of dispersal accordingly. 相似文献