196,543 research outputs found
From the Apennines to the Alps: recent range expansion of the crested porcupine Hystrix cristata L., 1758 (Mammalia: Rodentia: Hystricidae) in Italy
No full textIn the last few decades, the crested porcupine (Hystrix cristata L., 1758) showed a marked range expansion in Italy. Published and unpublished material was collected to reconstruct this phenomenon. Data were gathered by means of: (i) specific papers on crested porcupine distribution and more generic books and articles, (ii) expert collaboration in various Italian regions and (iii) information from the national Vertebrates mailing list. Until the 1970s, H. cristata was only present in Central and Southern Italy, mostly in the western part. Since 1978, the porcupine has been protected by Italian national law. The species first crossed the Apennines from the Tyrrhenian coast to the Marche, where the expansion to the north may have begun, and then reached the northernmost regions. An analysis of the potential distribution of the species was performed in a species distribution modeling framework (Maxent). The model suggested a high suitability of most of the Central and Southern Italian Peninsula for H. cristata, including the two major islands. Northern Italy proved suitable for the species' establishment only in some central and western areas of the Po Valley. The core areas of the Apennines and of the Alps, as well as some areas characterized by low annual rainfall, were predicted as unsuitable. Historical and social factors related to the progressive urbanization and the consequent abandonment of the traditional land use in mountain landscapes probably helped the re-expansion of forests and uncultivated fields. Three introduced populations have been detected in Sardinia, Liguria and the province of Varese. In order to make the data collected easily consultable and to give people the opportunity to contribute to a continuous updating of the distributional map of the species, a web page dedicated to H. cristata was set up, in the framework of an open-source wildlife mapping project. © 2013 Unione Zoologica Italiana
Optimal Handling of Hazardous Freights in Distributed Supply Chains
No full textAbstractThe developments of telecommunication and intelligent transportation technologies have led to an increase in the safety level of freight transportation and have enabled making the routing decisions based on real-time information and an updated condition of the network, the suppliers, and the receivers. This paper proposes a dynamic decentralized optimization case, in which the network of freight distribution, presented as a distributed Supply Chain (DSC), expands or changes temporally. The proposed optimization problem should be solved repeatedly on a rolling horizon basis which enables optimizing a certain time period in advance. At each step, the problem is modeled using discrete event systems (DESs) and a transportation model is proposed for transferring freights between any two nodes of the supply chain. This model supports the decision making process for routing and scheduling of delivery shipments that arrive dynamically at a supplier, which is of major importance and directly affects the performance of a freight distribution system
One-Way Car-Sharing Profit Maximization by Means of User-Based Vehicle Relocation
No full textOne-way car-sharing systems, which allow customers to return vehicles to the stations where they were picked up, offer greater flexibility compared to conventional car-sharing services. Nevertheless, to guarantee this flexibility, such systems have to face difficult problems of vehicle relocation in order to be ready to satisfy as many trip reservations as possible. This paper proposes a user-based relocation methodology in which the users may accept to leave the car in a different location in exchange for fare discounts. To this aim, a two-stage optimization problem is formulated for optimizing the alternative destinations proposed to users and for maximizing the profit of car-sharing operators. The extensive analysis of results shows that, with the proposed user-based relocation strategy and without the operator-based relocation, the number of rejected reservations can be significantly reduced, even with a relatively small number of vehicles and, at the same time, the operator's profit can be increased
Modeling distribution of Mediterranean beech forests and soil carbon stock under climate change scenarios
No full textClimate change is forecasted to alter forest species distributions and the organic carbon cycle, particularly in the Mediterranean region. In this context, one of the most important carbon reservoirs, both in terms of living biomass and soil organic matter, is represented by beech forests, which are highly vulnerable to global warming. Accordingly, we investigated how the effects of climate change predicted for 2070 could affect both beech distribution and soil carbon stocks in Italy. In order to achieve this goal, we predicted beech distribution using state of the art ecological niche modeling, projecting its potential range under climate change scenarios. Moreover, a field survey was carried out to quantify the proportion of organic carbon in the first 5 cm of soil, which are the most sensitive to climate effects. The latter results were used to explore the relationship between organic carbon and ecogeographical variables, projecting this relationship onto the predicted beech distribution. Our outcomes showed a substantial reduction in beech distribution, especially at its southern range limits, along with a remarkable shift towards higher elevations and latitudes. The organic carbon in beech forests was significantly related to temperature seasonality and elevation, showing a decrease between 64.5 and 98.8% under different IPCC scenarios
Topographic analysis for the understanding of the erosion processes in the Febbraro valley (Sondrio, Italy)
No full textAn example of a GIS topographic analysis is here presented, regarding the study of the erosion processes in the Febbraro valley (N of Valchiavenna, Sondrio, Northern Italy).
During various surveys on the area, 88 earth flows, with a maximum dimension of ten meters, were spotted. The aim of the analysis is to describe the sites morphology in terms of: altitude, slope, exposure and curvature. The derived properties were subsequently determined: flow accumulation, Topographic Wetness Index, Erosion Index and Stream Power Index. The index determination required a preliminary hydrologic analysis through the application of both the D8 algorithm, the multidirectional and through a different algorithm (the MDD8) combining the preceding two.
The flow accumulation map was used to classify the earth flow, as a function of the flow type: overland flow (83) and channel flow (5). The erosion processes are located in areas with a medium-high saturation and with high values of the erosion and stream power indexes; this defines a kind of processes with strong flow and erosive capacity and high solid transport. Slope and flow accumulation have a greater impact on the calculated indexes than altitude and exposure
Modelling habitat suitability of Pinguicula crystallina sibth. & sm. subsp. hirtiflora (Ten.) Strid (Lentibulariaceae) in Campania (Southern Italy) through an expert based approach.
No full textIn the last few decades, modelling species’ distribution and habitat suitability has greatly improved as a result of new powerful statistics and GIS tools which can use a wide number of ecological variables. Species distribution models represent an important technique for the conservation of biodiversity and for town-and-country planning (Guisan & Zimmermann, 2000). Rare and threatened plant species, particularly the ones with known scattered distribution, can be of highest interest in modelling to assess conservation priorities and evaluate habitat suitability.
Pinguicula crystallina Sibth. & Sm. subsp. hirtiflora (Ten.) Strid (Lentibulariaceae) is a carnivorous plant which has sticky leaves used as flypaper-type traps and grows on dripping carbonate or serpentine rocks primarily in mountain ecosystems such as wet cliffs inside ravines which can be mainly ascribed to Natura 2000 priority habitat 7220, which is petrifying springs with tufa formation (Cratoneurion W. Koch). Current distribution of this taxon is in South-Eastern Europe (mainly Albania and Greece), with only few populations living in Southern Italy (Campania and Calabria) (Innangi et al. 2011). Many studies about karyology (Casper & Stimper, 2009) and molecular data (Degtjareva et al., 2006), suggest that P. crystallina subsp. hirtiflora along with P. crystallina could be the sister group of all the other species in the genus Pinguicula, which comprises 74 species distributed in the Northern hemisphere, South America and South-Eastern Asia.
In Campania, where the vast majority of Italian populations are found, according to IUCN the plant has been assessed as Vulnerable (VU). Within this region, the plant is known to grow only in ravines and river gorges of two mountain systems, namely Monti Lattari and Monti Picentini (Innangi et al., 2011). For this region, an expert-based habitat suitability model has been developed in order to look for unknown locations and/or plan possible repopulation strategies. Expert-based models, although introducing a subjective component in their development, can take into account a wide range of ecological needs for a taxon and their results are extremely synthetic (Boitani et al., 2002).
According to the ecological features of known presence points of in Campania (Innangi et al., 2011), a set of five variables has been chosen, namely altitude, slope, rock type, CORINE land cover, and distance from rivers. For each variable, four scores have been assigned, that is zero for no suitability to three for best suitability. The results highlight the strict connection of this plant to water streams and courses, thus, in order to correlate chemical and biological features of the water to the habitat suitability for P. crystallina subsp. hirtiflora, water has been sampled in both presence and not-presence locations for chemical analysis, namely chromatography and toxicity tests, using bioassay organisms such as Daphnia magna Straus, Sorghum saccharatum Pers., and Lepidium sativum L. (APAT, 2002).
Acknowledgements. The authors are grateful to Prof. M. Guida and M. Trifuoggi for the toxicity tests and chemical analyses
Potential distribution of Xylella fastidiosa in Italy: a maximum entropy model
No full textSpecies distribution models may provide realistic scenarios to explain the influence of bioclimatic variables in the context of emerging plant pathogens. Xylella fastidiosa is a xylem-limited Gram-negative bacterium causing severe diseases in many plant species. We developed a maximum entropy model for X. fastidiosa in Italy. Our objectives were to carry out a preliminary analysis of the species' potential geographical distribution and determine which eco-geographical variables may favour its presence in other Italian regions besides Apulia. The analysis of single variable contribution showed that precipitation of the driest (40.3%) and wettest (30.4%) months were the main factors influencing model performance. Altitude, precipitation of warmest quarter, mean temperature of coldest quarter, and land cover provided a total contribution of 19.5%. Based on the model predictions, X. fastidiosa has a high probability (> 0.8) of colonizing areas characterized by: i) low altitude (0-150 m a.s.l.); ii) precipitations in the driest month < 10 mm, in the wettest month ranging between 80-110 mm and during the warmest quarter < 60 mm; iii) mean temperature of coldest quarter ≥ 8°C; iv) agricultural areas comprising intensive agriculture, complex cultivation patterns, olive groves, annual crops associated with permanent crops, orchards and vineyards; forest (essentially oak woodland); and Mediterranean shrubland. Species distribution models showed a high probability of X. fastidiosa occurrence in the regions of Apulia, Calabria, Basilicata, Sicily, Sardinia and coastal areas of Campania, Lazio and south Tuscany. Maxent models achieved excellent levels of predictive performance according to area under curve (AUC), true skill statistic (TSS) and minimum difference between training and testing AUC data (AUCdiff). Our study indicated that X. fastidiosa has the potential to overcome the current boundaries of distribution and affect areas of Italy outside Apulia
ONE-WAY CAR-SHARING: SOLVING THE RELOCATIONPROBLEM
No full textCar-Sharing (CS) services allow users to benefit from the advantages of private cars, without the
costs of owning one. In this framework, “one-way” car-sharing systems are able to provide users
with a higher level of service through offering them flexibility in time and location of leaving the service, since they do not require the “return trip” to the origin station. Moreover, the possibility of
leaving the vehicle at any free parking area which is not necessarily a “station” would increase the
flexibility offered by the system.
Introducing this improvement to car-sharing systems leads to the vehicle relocation problem, which
should be addressed carefully to avoid concentration of vehicles in certain areas. This issue is
studied in this paper using Discrete Event Systems (DESs), which allow an easy representation of
the complex dynamics of the system. A user-based methodology is proposed based on an optimal
relocation policy in a rolling horizon framework. This methodology, in addition to offering greater
flexibility to the users, maximizes the operator benefits by reducing the number of required staff for relocating vehicles among the stations, and determines the minimum number of vehicles to satisfy
the system demand. The DES model is then applied to a case study to evaluate the proposed
approach. The results show a significant decrease in the rejection rate from the worst scenario (no relocation) to the best scenario (relocation of all vehicles by the users). In the end, some suggestions
for additional research and developments of this study are identified
A systematic conservation planning approach to fire risk management in Natura 2000 sites
No full textA primary challenge in conservation biology is to preserve the most representative biodiversity while simultaneously optimizing the efforts associated with conservation. In Europe, the implementation of the Natura 2000 network requires protocols to recognize and map threats to biodiversity and to identify specific mitigation actions.
We propose a systematic conservation planning approach to optimize management actions against specific threats based on two fundamental parameters: biodiversity values and threat pressure. We used the conservation planning software Marxan to optimize a fire management plan in a Natura 2000 coastal network in southern Italy. We address three primary questions: i) Which areas are at high fire risk? ii) Which areas are the most valuable for threatened biodiversity? iii) Which areas should receive priority risk-mitigation actions for the optimal effect?, iv) which fire-prevention actions are feasible in the management areas?.
The biodiversity values for the Natura 2000 spatial units were derived from the distribution maps of 18 habitats and 89 vertebrate species of concern in Europe (Habitat Directive 92/43/EEC). The threat
pressure map, defined as fire probability, was obtained from digital layers of fire risk and of fire frequency. Marxan settings were defined as follows: a) planning units of 40 40 m, b) conservation features defined as all habitats and vertebrate species of European concern occurring in the study area, c) conservation targets defined according with fire sensitivity and extinction risk of conservation features, and d) costs determined as the complement of fire probabilities.
We identified 23 management areas in which to concentrate efforts for the optimal reduction of fireinduced effects. Because traditional fire prevention is not feasible for most of policy habitats included in the management areas, alternative prevention practices were identified that allows the conservation of the vegetation structure.
The proposed approach has potential applications for multiple landscapes, threats and spatial scales and could be extended to other valuable natural areas, including protected areas
The Monetary‐Equivalent Effect of Voluntary Work on Mental Wellbeing in Europe
No full textThe hypothesis that active community involvement and, more specifically,
voluntary work is beneficial for mental wellbeing has an established tradition.
Community involvement is one of the main suggestions in policy guidelines
for active ageing1 formulated in most high-income countries (see, among others,
those of Australia, New Zealand, the US and UK in Hutchison et al., 2006). The
rationale behind this policy is well explained by Watson and Hall (2001), who
argues that “continued participation in the workforce, volunteering, community
activities or family responsibilities contributes to the maintenance of mental
capacity and a sense of well-being in older adults. This is a type of psychological
capital or the extent to which the person can deal with threats to mental health –
whether, for example, they can resist depression and anxiety when under stress.
Individuals who have built up their psychological capital are resilient and able
to cope with change and other stresse
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