Regularized solution of a nonlinear problem in electromagnetic sounding

We propose a regularization method to solve a nonlinear ill-posed problem connected to inversion of data gathered by a ground conductivity meter

La flora vascolare della Peninsola del Sinis (Sardegna Occidentale)

La flora vascolare della Penisola del Sinis (Sardegna Occidentale). Viene presentato lo studio della flora vascolare della Penisola del Sinis; in totale sono state rinvenute 760 unità tassonomiche e in particolare 615 specie, 134 sottospecie, 10 varietà e 1 ibrido, riferibili a 365 generi e 87 famiglie. Le Eudicots sono risultate il gruppo sistematico dominante. Le famiglie più rappresentate sono: Poaceae (99 unità tassonomiche), Fabaceae e Asteraceae (85), Caryophyllaceae (33), Apiaceae (27) e Orchidaceae (24). I generi con maggior numero di taxa sono: Trifolium (19), Silene (14), Limonium e Medicago (13), Ophrys (12), Euphorbia e Vicia (10), Plantago (9), Allium (8) e infine Lotus, Ranunculus e Vulpia (7). Il contingente delle endemiche (54 unità tassonomiche) è risultato pari al 8,97% della componente mediterranea e mostra una dominanza degli elementi sardo-corsi (33,33%) e secondariamente sardi (24,10%), i quali unitamente raggiungono il 57,43% del totale. La flora endemica è costituita da 31 specie, 17 sottospecie e 6 varietà, inquadrati in 38 generi e 22 famiglie. Le famiglie più rappresentate sono risultate le Plumbaginaceae (10), Asteraceae e Lamiaceae (5), Fabaceae (4), Alliaceae, Euphorbiaceae e Ranunculaceae (3); il genere più ricco è risultato Limonium (10), seguito da Allium, Delphinium, Euphorbia, Scrophularia, Silene e Teucrium (2). E�stato elaborato un elenco dei taxa inseriti nelle liste rosse regionali d�Italia, al quale sono state aggiunte tutte le endemiche esclusive e le specie di importanza conservazionistica a livello regionale, per le quali vengono proposte le nuove categorie di protezione secondo i criteri della IUCN. Da tale analisi è emerso che sono presenti 12 unità tassonomiche gravemente minacciate, gruppo che include gran parte delle endemiche esclusive del territorio. Sulla base dei dati morfologici, geologici e bioclimatici relativi ai territori studiati, unitamente alle analisi di tipo floristico ed in particolare della componente endemica e d�interesse fitogeografico, viene proposto un inquadramento biogeografico a livello di sottosettoreThe vascular flora of Sinis Peninsula (W Sardinia).The vascular flora of Sinis Peninsula (W Sardinia) has been studied; 760 taxa, 615 of which were species, 134 subspecies, 10 varieties and 1 hybrid were found. They were included in 365 genera and 87 families. The Eudicots were dominant over the other systematic groups. The most represented families were: Poaceae (99 taxonomic units), Fabaceae and Asteraceae (85), Caryophyllaceae (33), Apiaceae (27) and Orchidaceae (24). The most represented genera were: Trifolium (19), Silene (14), Limonium and Medicago (13), Ophrys (12), Euphorbia and Vicia (10), Plantago (9), Allium (8) and, finally, Lotus, Ranunculus and Vulpia (7).The contingent of endemics (54 taxonomic units) was 8,97% of the Mediterranean component showing the dominance of Sardinian-Corsican (33,33%) and in the second place Sardinian elements (24,10%), that together to reach 57,43% of the total. This flora consisted of 31 species, 17 subspecies and 6 varieties; 38 genera and 22 families were recognized. The most represented families were: Plumbaginaceae (10), Asteraceae and Lamiaceae (5), Fabaceae (4), Alliaceae, Euphorbiaceae and Ranunculaceae (3). The most represented genera were: Limonium (10) and Allium, Delphinium, Euphorbia, Scrophularia, Silene, Teucrium (2). Based on the taxa present in the regional Italian Red List, the species exclusive of Sardinia and important for the conservation has been included. For these species we proposed the news categories of preservation following the IUCN criteria. Our analysis, confirmed the presence of 12 taxa critically endangered as well as this group included the majority of exclusive endemism of the territory. According to the geomorphological, geological and bioclimatic data of the territories studied within the floristic analysis and in particular the endemic and phytogeographical component, we proposed the creation of new biogeographic subsector named Sinisico

La flora vascolare della penisola del Sinis (Sandregna occidentale)

The vascular flora of Sinis Peninsula (W Sardinia).The vascular flora of Sinis Peninsula (W Sardinia) has been studied; 760 taxa, 615 of which were species, 134 subspecies, 10 varieties and 1 hybrid were found. They were included in 365 genera and 87 families. The Eudicots were dominant over the other systematic groups. The most represented families were: Poaceae (99 taxonomic units), Fabaceae and Asteraceae (85), Caryophyllaceae (33), Apiaceae (27) and Orchidaceae (24). The most represented genera were: Trifolium (19), Silene (14), Limonium and Medicago (13), Ophrys (12), Euphorbia and Vicia (10), Plantago (9), Allium (8) and, finally, Lotus, Ranunculus and Vulpia (7). The contingent of endemics (54 taxonomic units) was 8,97% of the Mediterranean component showing the dominance of Sardinian-Corsican (33,33%) and in the second place Sardinian elements (24,10%), that together to reach 57,43% of the total. This flora consisted of 31 species, 17 subspecies and 6 varieties; 38 genera and 22 families were recognized. The most represented families were: Plumbaginaceae (10), Asteraceae and Lamiaceae (5), Fabaceae (4), Alliaceae, Euphorbiaceae and Ranunculaceae (3). The most represented genera were: Limonium (10) and Allium, Delphinium, Euphorbia, Scrophularia, Silene, Teucrium (2). Based on the taxa present in the regional Italian Red List, the species exclusive of Sardinia and important for the conservation has been included. For these species we proposed the news categories of preservation following the IUCN criteria. Our analysis, confirmed the presence of 12 taxa critically endangered as well as this group included the majority of exclusive endemism of the territory. According to the geomorphological, geological and bioclimatic data of the territories studied within the floristic analysis and in particular the endemic and phytogeographical component, we proposed the creation of new biogeographic subsector named Sinisico

Studi di biologia della conservazione di specie vegetali endemiche della Sardegna nell'ambito del progetto "GENMEDOC"

Conservation biology studies on the endemic species from Sardinia within the "GENMEDOC" Project - The achieved results of the Interreg IIIB "Genmedoc" project (2004-2006) are here reported. Data focused on the conservation biology studies of Sardinian endemic species are showed in this work. During the project 26 populations of 16 species were investigated and the ex situ conservation for these species was guaranteed by storage of 65 seed lots in the seedbank. Furthermore 8 species were analysed by in situ characterization of 17 populations: for each population ecological studies were carried out. Real and possible threats that affect these populations were detected. For 6 species effective germination protocols were identified and also valied by other two project partners. These protocols allow evaluating seed quality for the stored lots and their longevity during next years; moreover the knowledge of the best germination conditions will be able to schedule a possible cultivation or an in situ re-introduction for these species. These results were obtained by sistematic conservation biology studies of threatened endemic species of Sardinia by a tested and internationally acknowledged methodology

Block Gauss and anti-Gauss quadrature with application to networks

Approximations of matrix-valued functions of the form WT f(A)W, where A ∈Rm×m is symmetric, W ∈ Rm×k, with m large and k ≪ m, has orthonormal columns, and f is a function, can be computed by applying a few steps of the symmetric block Lanczos method to A with initial block-vector W ∈ Rm×k. Golub and Meurant have shown that the approximants obtained in this manner may be considered block Gauss quadrature rules associated with a matrix-valued measure. This paper generalizes anti-Gauss quadrature rules, introduced by Laurie for real-valued measures, to matrix-valued measures, and shows that under suitable conditions pairs of block Gauss and block anti-Gauss rules provide upper and lower bounds for the entries of the desired matrix-valued function. Extensions to matrix-valued functions of the form WT f(A)V , where A ∈ Rm×m may be nonsymmetric, and the matrices V, W ∈ Rm×k satisfy VT W = Ik also are discussed. Approximations of the latter functions are computed by applying a few steps of the nonsymmetric block Lanczos method to A with initial block-vectors V and W. We describe applications to the evaluation of functions of a symmetric or nonsymmetric adjacency matrix for a network. Numerical examples illustrate that a combination of block Gauss and anti-Gauss quadrature rules typically provides upper and lower bounds for such problems. We introduce some new quantities that describe properties of nodes in directed or undirected networks, and demonstrate how these and other quantities can be computed inexpensively with the quadrature rules of the present paper

From global to local scale: where is the best for conservation purpose?

AbstractDemographic analysis of plant populations represents an essential conservation tool allowing to identify the population trends both at global and at the local level. In this study, the population dynamics of Helianthemum caput-felis (Cistaceae) was investigated at the local level by monitoring six populations distributed in Sardinia, Balearic Islands and Ibero-Levantine coast (Alicante). Demographic data for each population were analysed by performing Integral Projection Models (IPMs). Our results showed that, although the local trend of the main basic demographic functions was similar, vital rates and demographic dynamics varied among populations indicating high variability. In fact, asymptotic growth rate in Spanish populations widely varied both between years and populations (some populations growth, decline or strongly decline), while Sardinian populations showed greater equilibrium or a slight increase. Also, the typical pattern of a long-lived species was not supported by the results at the local scale. These results indicated that different populations of the same species can present extremely different population dynamics and support the belief that, for conservation needs, local studies are more informative than global ones: the conservation status of H. caput-felis could notably vary at a small spatial scale and, accordingly, the conservation efforts must be planned at the population level and supported by local analysis

Using species distribution models at local scale to guide the search of poorly known species: Review, methodological issues and future directions

Among specific applications of species distribution models (SDMs), the use of SDMs probabilistic maps for guiding field surveys is increasingly applied. This approach is particularly used for poorly known and/or cryptic species in order to better assess their distribution. One of the most interesting aspects of these applications is that predictions could be clearly validated by real data, subsequently obtained in the field. Despite this important difference from other applications, to our knowledge, the efficiency of different algorithms, metrics for model evaluation and algorithm-specific settings have not yet been sufficiently investigated. This research performs a literature survey to investigate which species, study area characteristics, variables, techniques and settings were used or suggested by previous authors. We then applied the most common approaches to guide field surveys for a set of 70 vascular plants in an endemic-rich area of Sardinia (Italy) of approx. 9000 ha, the flora of which was deeply investigated during the last two years. Our main aims were: (1) to use pre-model records for predicting the potential occurrence of plant species with different sample size, detectability and habitat preference, (2) to apply results for guiding searches for new populations of poorly known species, (3) to calculate the model performance according to independent real presence/absence data (testAUC) and (4) to compare different modelling data input and settings on the testAUC basis. By emphasizing the importance of field verification, both the review and the worked example supported the reliability of SDMs for a wide range of species to understand where a species could potentially be present and therefore to optimise resources for the search of new species localities. This study may help understand and summarise the most applied methodological approaches and to highlight future directions for this practical application. Without underrating the importance of most common recommendations, practitioners are encouraged to test the ability of this SDMs’ application with their own data. Indeed, large gaps in biological groups (e.g. insects) and in regions covered by these kind of studies (e.g. many African and Asian territories) were found. Furthermore, eventual biases due to lack of data, experience or staff, have in this experimental case less irreparable consequences than others, such as conservation assessments based on future projections, which cannot be otherwise adjusted by explicit data from ground validation

Disentangling the influence of environmental and anthropogenic factors on the distribution of endemic vascular plants in Sardinia

Due to the impelling urgency of plant conservation and the increasing availability of high resolution spatially interpolated (e.g. climate variables) and categorical data (e.g. land cover and vegetation type), many recent studies have examined relationships among plant species distributions and a diversified set of explanatory factors; nevertheless, global and regional patterns of endemic plant richness remain in many cases unexplained. One such pattern is the 294 endemic vascular plant taxa recorded on a 1 km resolution grid on the environmentally heterogeneous island of Sardinia. Sixteen predictors, including topographic, geological, climatic and anthropogenic factors, were used to model local (number of taxa inside each 1 km grid cell) Endemic Vascular Plant Richness (EVPR). Generalized Linear Models were used to evaluate how each factor affected the distribution of local EVPR. Significant relationships with local EVPR and topographic, geological, climatic and anthropogenic factors were found. In particular, elevation explained the larger fraction of variation in endemic richness but other environmental factors (e.g. precipitation seasonality and slope) and human-related factors (e.g. the Human Influence Index (HII) and the proportion of anthropogenic land uses) were, respectively, positively and negatively correlated with local EVPR. Regional EVPR (number of endemic taxa inside each 100 m elevation interval) was also measured to compare local and regional EVPR patterns along the elevation gradient. In contrast to local, regional EVPR tended to decrease with altitude partly due to the decreasing area covered along altitude. The contrasting results between local and regional patterns suggest that local richness increases as a result of increased interspecific aggregation along altitude, whereas regional richness may depend on the interaction between area and altitude. This suggests that the shape and magnitude of the species-area relationship might vary with elevation. This work providesâ\u80\u94for the first time in Sardiniaâ\u80\u94a comprehensive analysis of the influence of environmental factors on the pattern of EVPR in the entire territory, from sea level to the highest peaks. Elevation, as well as other environmental and human-related variables, were confirmed to be influencing factors. In addition, variations of EVPR patterns at regional-to-local spatial scales inspire next investigations on the possible interaction between elevation and area in explaining patterns of plant species richness

Conservazione ex situ e in situ della biodiversità vegetale dell'Area Marina Protetta di Capo Carbonara (Sardegna sud-orientale)

The first results of the project "Plant Biodiversity Conservation in the Protected Marine Area of Capo Carbonara (PMA)" are illustrated. This initiative, promoted by the CCB and the Municipality of Villasimius (CA), was funded for three-year period (2005/07) by the Ministry of the Environment and Territory protection. The project provides the study, monitoring and conservation of the coastal habitat, principally on all the Sites of Communitary Importance (pSIC) of the Villasimius Municipality territory, in order to plan a harmonic development between coastal and sea areas unifying the environmental protection secured by the PMA with that relatives to the Natura 2000 network. During the first year there were started ecological, floristic-sociological and chorological studies, in order to value the actual state of conservation and have a possibility to propose adequate measures for a sustainable management. In order to guarantee the effective plant biodiversity conservation, the following ex situ actions have been made: collection, study and conservation for a long time of the seed of selected species in the structures of the Sardinian Seed Bank (BG-SAR), according to international procedures and protocols. At the end of the first year the seed harvest was completed relatively to all the species with a greater risk of extinction. The project provides also actions directed to sensitize the population, local and non, on the thematics of the conservation and the sustainable development of the territory