Phytosociological and ecological study of springs in Trentino (south-eastern Alps, Italy)

A phytosociological survey of the crenic vegetation was made in Trentino (south-eastern Alps), combining the field method of the Braun-Blanquet approach with a numerical syntaxonomical analysis. A set of 139 phytosociological releves, including vascular plants and bryophytes, were classified using cluster analysis. The vegetation types were assigned to 7 different phytosociological classes: Platyhypnidio-Fontinalietea antipyreticae, Montio-Cardaminetea, Adiantetea, Scheuchzerio-Caricetea nigrae, Molinio- Arrhenatheretea, Galio-Urticetea, Mulgedio-Aconitetea. The classes Platyhypnidio-Fontinalietea antipyreticae and Montio- Cardaminetea represent the core of crenic vegetation, including permanently or intermittently submerged plant communities, mostly made up of bryophytes, or non-submerged communities dominated by bryophytes or vascular plants. The other classes include chasmophytic bryophyte-rich communities and hygrophilous or tall herb communities lying around the periphery of the springs. 23 vegetation types were identified and, whenever possible, classified at the association level, or as phytocoena. The environmental parameters showed different ranges among vegetation types. A number of environmental variables were recorded during the vegetation survey, including altitude, shading, discharge, flow velocity, with exhaustive hydrochemical sampling. Conductivity, alkalinity and pH showed similar distribution patterns, clearly separating the vegetation types into two distinct groups, differing in the nature of the substratum. The altitudinal range was very broad and shading was also very variable. Nitrate and phosphate levels showed that the majority of vegetation types were irrigated by oligotrophic crenic waters. Finally, the bryophyte-dominated vegetation types belonging to the class Platyhypnidio-Fontinalietea antipyreticae occurred in springs with the highest discharge values and variation. Discriminant analysis confirmed that the environmental descriptors that best accounted for the among-group variation were pH and alkalinity (first variate); the second variate reflected a gradient of altitude and discharge

Bryophytes and vascular plants in springs of Italian Alps: biodiversity analysis at large spatial scale and mechanisms of distribution at fine spatial scale

This work at large spatial scale deal with bryophyte and vascular plant biodiversity in the springs of Trentino Province (Italy); at fine spatial scale it deal with several experimental investigations on the mechanisms of bryophytes spatial distribution. 86 springs located uniformly in the Trentino Province have been examined. 167 bryophyte species and 201 vascular plants were identified and this study represent the first accurate check list for these habitats in Trentino and also in Italy. Statistical classification on these environments was able to identify the main groups and even most threatened situation from conservation point of view. Statistical model elaborated to study bryophyte and vascular plant richness showed different patterns for the two groups of plants. Spatial distribution of several bryophyte species at fine spatial scale was experimentally studied investigating the hydrological niche breadth. Theoretical distance from water level was estimated using photosynthetic pigments as indicator of stress. In particular, aquatic species have a wide niche overlapped even though the tails of distribution were different in some species explaining to some extend the species coexistence. With the second experiment, positive and negative interactions among several bryophyte species were studied. In synthesis, this experiment confirmed the correctness of some theoretical models for the balance between competition and facilitation in relation to environmental conditions; moreover, it underlined the importance of natural climatic fluctuations in determining the weight of these interactions.Il lavoro presentato tratta la biodiversità delle briofite e piante vascolari delle sorgenti del Trentino (Italia) a grande scala spaziale e alcuni approfondimenti sperimentali sui meccanismi di distribuzione a piccola scala. Sono state esaminate 86 sorgenti localizzate uniformemente in tutta la provincia di Trento. Sono state identificate 167 specie di briofite e 201 di piante vascolari che vanno a costituire la prima accurata check list per questi ambienti in Trentino e in Italia. La classificazione statistica di questi ambienti ha permesso di identificare i gruppi principali e le situazioni più problematiche dal punto di vista della conservazione. Il modello statistico elaborato per lo studio della ricchezza di specie delle briofite e delle piante vascolari ha evidenziato diversi pattern per i due gruppi. Lo studio della distribuzione spaziale a piccola scala di alcune specie di briofite è stato affrontato sperimentalmente indagando l’ampiezza della nicchia idrologica. Usando i pigmenti fotosintetici come indicatori di stress è stato possibile stabilire l’ordine teorico con cui le specie si dispongono rispetto al livello dell’acqua. In particolare le specie più acquatiche studiate hanno un’ampia sovrapposizione della nicchia idrologica anche se è stato possibile stabilire una diversa ampiezza che ne giustificherebbe la coesistenza. Con il secondo esperimento si è studiato l’interazione positiva e negativa tra alcune specie di briofite. Nel complesso l’esperimento ha potuto confermare la correttezza dei modelli teorici per quanto riguarda il bilancio tra competizione e facilitazione in relazione alle condizioni ambientali e ha inoltre sottolineato l’importanza degli eventi climatici naturali nel determinare il peso delle diverse interazioni

Congruencies between photoautotrophic groups in springs of the Italian Alps: implications for conservation strategies

Even though a number of studies have demonstrated the importance of photoautotrophic organisms in spring habitats, investigations that consider several photoautotrophic taxonomic groups are lacking. Within the framework of a multidisciplinary project on springs of the south-eastern Alps, we studied algae, diatoms, lichens, and bryophytes and (1) compared the alpha, beta and gamma diversity, and the composition of the studied groups between carbonate and siliceous springs, (2) estimated the nonrandomness of species combinations within organismal groups, and (3) examined the congruence in species assemblage patterns across taxonomic groups. In 40 springs, 69 species of algae, 110 species of diatoms, 29 species of lichens, and 62 species of bryophytes were found. Diatoms, lichens and bryophytes had higher species-richness in siliceous springs, while other algae had higher richness in carbonate springs. For all taxonomic groups, carbonate and siliceous springs host different assemblages, indicating that both types of substrata contribute to the overall regional diversity of spring photoautotrophs. In individual springs, the photoautotroph groups are characterised by a similar proportion of species of their regional pool, and form relatively speciespoor communities with a high turnover of species among springs. This pattern has important implications for conservation, suggesting that the protection of single sites might not be effective, and that a biodiversity conservation plan for spring habitats should be developed at the regional level, and include a network of sites. Interestingly, the co-occurrence indices suggested that, in individual springs, stochastic processes might the most important mechanisms in the establishment of local assemblages. A weak cross-taxon congruency was found, suggesting that a single taxon surrogate will not adequately represent other photoautotrophic groups. Therefore, spring conservation plans for photoautotrophs should not use one group as a surrogate for overall photoautotrophic diversity, but should adopt the use of different taxonomic groups

Using different epilithic-diatom assemblage metrics for an ecological characterization of the shores of Lake Garda

It has been proved that littoral diatoms provide a useful marker for detecting localised changes resulting from neve anthropogenic disturbances or intermittent releases of sewage along the shorelines of lakes. This study tested the spatial resolution at which this general observation occurs, by selecting areas with different anthropogenic pressures (urbanization) along a latitudinal gradient in Lake Garda, a deep and wide peri-Alpine lake. The sampling design aimed to detect differences in diatom distribution in terms of species diversity, quality indices, proportion of Red List taxa, assemblages, and individual species. Because the extent to which diatom assemblages respond to these gradients was unknown, we used assemblage metrics of different sensitivities. Results showed that the most important environmental factor was the latitudinal gradient, which was revealed by almost all the assemblage metrics. This dominant trend was explained by two co-occurring environmental gradients: concentration of nutrients and thermal gradient. The importance of different levels of urbanization was unevenly partitioned among locations and latitudes because of the different intensities of urbanization pressure. Only the species Brachysira neglectissima, the quality index (Trophic Index), and to a lesser extent, the metric at assemblage level revealed significant effects. Overall, this study comes to two main conclusions: (1) different metrics are needed to detect the multifaceted effects of anthropogenic disturbances, which by their very nature are unevenly distributed and of different intensities, and therefore affect assemblages to different degrees; (2) for any monitoring program in this lake to be effective, the various gradients revealed in this work should be taken into account. Failing to include these sources of variability might lessen the benefits of monitorin

Diatom species richness in Swiss springs increases with habitat complexity and elevation

Understanding the drivers of species richness gradients is a central challenge of ecological and biodiversity research in freshwater science. Species richness along elevational gradients reveals a great variety of patterns. Here, we investigate elevational changes in species richness and turnover between microhabitats in near-natural spring habitats across Switzerland. Species richness was determined for 175 subsamples from 71 near-natural springs, and Poisson regression was applied between species richness and environmental predictors. Compositional turnover was calculated between the different microhabitats within single springs using the Jaccard index based on observed species and the Chao index based on estimated species numbers. In total, 539 diatom species were identified. Species richness increased monotonically with elevation. Habitat diversity and elevation explaining some of the species richness per site. The Jaccard index for the measured compositional turnover showed a mean similarity of 70% between microhabitats within springs, whereas the Chao index which accounts for sampling artefacts estimated a turnover of only 37%. Thus, the commonly applied method of counting 500 valves led to an undersampling of the rare species and might need to be reconsidered when assessing diatom biodiversity

A new Navicula (Bacillariophyta) species from low-elevation carbonate springs affected by anthropogenic disturbance

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Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 7

In this contribution, new data concerning algae, bryophytes, fungi, and lichens of the Italian flora are presented. It includes new records and confirmations for the algae genus Chara, the bryophyte genera Cephalozia, Conardia, Conocephalum, Didymodon, Sphagnum, Tetraplodon, and Tortula, the fungal genera Endophyllum, Gymnosporangium, Microbotryum, Phragmidium, and Pluteus, and the lichen genera Candelariella, Cladonia, Flavoplaca, Lichenothelia, Peltigera, Placolecis, Rinodina, Scytinium, and Solenopsora

Association of GATA3, P53, Ki67 status and vascular peritumoral invasion are strongly prognostic in luminal breast cancer

International audienceIntroduction: Breast cancers are traditionally divided into hormone-receptor positive and negative cases. This classification helps to guide patient management. However, a subgroup of hormone-receptor positive patients relapse irrespective of hormonal therapy. Gene expression profiling has classified breast tumours into five major subtypes with significant different outcome. The two luminal subtypes, A and B, show high expression of ESR1, GATA3 and FOXA1 genes. Prognostic biomarkers for oestrogen receptor (ER)-positive cases include progesterone receptor (PR) and androgen receptor (AR), and proteins related to proliferation or apoptotic resistance. The aim of this study was to identify the best predictors of success of hormonal therapy.Methods: By immunohistochemistry we studied 10 markers in a consecutive series of 832 cases of breast carcinoma treated at the Paoli-Calmettes Institute from 1990 to 2002 and deposited onto tissue microarrays (TMA). These markers were luminal-related markers ER, PR, AR, FOXA1 and GATA3 transcription factors, proliferation-related Ki67 and CCND1, ERBB2, anti-apoptotic BCL2 and P53. We also measured vascular peritumoural invasion (VPI), size, grade and lymph node involvement. For 143 cases, gene expression profiles were available. Adjuvant chemotherapy and hormonal therapy were given to high- and low-risk patients, respectively. The 162 events observed and taken into account were metastases.Results: Molecular expression of the 10 parameters and subtype with ER status were strongly correlated. Of the 67 luminal A cases of this series, 63 were ER-positive. Multivariate analyses showed the highly significant prognostic value of VPI (hazard ratio (HR) = 2.47), Ki67 (HR = 2.9), P53 (HR = 2.9) and GATA3 (HR = 0.5) for the 240 patients who received hormonal therapy.Conclusions: A panel of three antibodies (Ki67, P53 and GATA3) associated with VPI can significantly improve the traditional prognosticators in predicting outcome for ER-positive breast cancer patients receiving hormonal therapy