169,755 research outputs found
Editorial: Floristic and vegetation studies in the era of big data: challenges, trends and applications
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Thirty years unmanaged green roofs: Ecological research and design implications
No full textThe variations in species composition and assemblage of unmanaged simple-intensive green roofs in
Hannover, Germany, were investigated over a thirty year period, in order to assess the persistence of
the initial seed mixture and to evaluate floristic changes. The roofs were greened in 1985 with soilbased
turf rolls sown with a mixture of five grasses (Festuca rubra, Festuca ovina, Agrostis capillaris, Lolium
perenne and Poa pratensis). Three sets of 120 phytosociological relevés, sampled in 1987, 1999 and 2014,
have been compared to assess: (1) nestedness vs spatial turnover, (2) functional diversity and (3) the
importance of vegetation dynamics on green roof performance and design. Results demonstrated that
from 1987 to 1999 the species diversity increased and the species turnover prevailed over nestedness,
due to the progressive niche occupation by new species. In contrast, from 1999 to 2014 species diversity
remained steady, suggesting that nestedness prevailed over species turnover. The main driver of the
observed functional changes was a shift towards relatively more thermoxeric conditions. In terms of
plant life strategies, the competitive species sown on the roof gradually gave way to stress-tolerant and
ruderal species, along with a progressive increase in species with shortdistance seed dispersal strategies.
It is concluded that: (a) to create resilient green roofs, spontaneous colonisation should be accepted
and considered as a design factor; and (b) regional plant communities could serve as a model for seed
recruitment and installations
Alien plant invasions in Mediterranean habitats. An assessment for Sicily
No full textLevels of plant invasions in different habitat types were assessed in several regional studies, but few of them were from the Mediterranean. Here we compare the levels of vascular plant invasion across habitats and plant communities of Sicily. We used a large dataset of plant species presences/absences in vegetation plots to analyze the invasion patterns across habitats considering biogeography, life form and phenology of alien plants. Vegetation plots were classified based on the EUNIS classification of European habitats. The invasiveness of each species was expressed in terms of its absolute and percentage frequency. Representation of different life forms and phenological patterns was compared between alien and native species. The fidelity of alien species to individual habitats was calculated using the phi coefficient. Our analysis shows that annual and woody species are the most represented life forms in the alien flora of Sicily and that alien species tend to have a longer flowering period than the native species. The investigated habitats differed strongly in their level of invasion by alien species, ranging from 0 to 15.6% of aliens of all species recorded. Most of the habitats were colonized by very few alien species or completely lacked them, except for sandy coasts, naturally-disturbed riverbeds, and synanthropic habitats. It must be noted, however, that the number of alien species occurring in a given habitat does not relate to the severity of the impact of invasion in that habitat. Some habitats are invaded by few (or single) species, which attain a high cover, transforming the whole ecosystem. The habitat-based approach proved to be suitable for evaluating the habitat specificity and frequency of alien species at a regional scale, improving the capacity for risk assessment in different ecological contexts
Reciprocal extrapolation of species distribution models between two islands – Specialists perform better than generalists and geological data reduces prediction accuracy
No full textThis study aims to test the extrapolation effects of species distribution models (SDM) using three groups of predictor variables: climate, relief and geology (bedrock type). We highlight potential ecological differences for selected taxa, regarding both generalists and specialists in terms of edaphic conditions. We used distributional data of 12 woody species shared by two large Mediterranean islands (Crete and Sicily) to calibrate Maxent models of their potential distribution. We trained models with data from Crete and extrapolated to Sicily and vice versa. We tested ten proxies for the three variable groups and compared AUC values as a measure of model performance. Extrapolation of SDMs worked fairly well across species and islands for those models including climatic and relief data, while those including geological information performed worse for the tested species. Edaphic generalists performed less well compared to edaphic specialists. The latter performed best with climate data included in models and more poorly with only geological data. This may be due to differences in bedrock type affinities of species between the two islands
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Unraveling the Influences of Edaphic and Topographic Factors on High-Mountain Plant Communities: first results from the MO.MO.ME. Project
No full textThe Project ‘Monitoring Network for Studying the Effects of Climate Change on Mediterranean High-Mountain Grasslands
in Natura2000 Sites (MO.MO.ME.)’ aims at analyzing the differences in plant communities, microclimate, and
topography across various study areas. The main goal is to improve understanding of the biotic and abiotic factors
regulating the assembly of high-mountain communities, focusing on the functional and structural dynamics of Mediterranean
grasslands.
We present the first results of our analysis focused on the role of edaphic and topographic gradients on vegetation
patterns above 1900 m a.s.l. on Pizzo Carbonara (Madonie Mountains, Northern Sicily), a carbonate massif shaped by
karst erosion, resulting in a system of sinkholes and windy ridges across the summit plateau. We sampled 42 vegetation
plots, georeferenced using sub-metric GPS. Various topographic variables were derived from Sicily’s regional
technical map (2 m resolution) using QGIS. Additionally, chemical and biochemical soil parameters were analyzed for
each plot.
Plant species were classified into three life-form groups: chamaephytes, hemicryptophytes, and therophytes. Data
were analyzed using three response variables: species richness, vegetation cover, and species composition. For the
first two, we applied a Generalized Linear Model (GLM), while compositional data were processed using distance-based
redundancy analysis (db-RDA) with variation partitioning.
The results indicate that life forms are differentially filtered by edaphic and topographic variables. The topographic
factors influence the relative performance of co-occurring vascular plant species, shaping the structure and composition
of local plant communitie
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Conservation status of Italian coastal dune habitats in the light of the 4th Monitoring Report (92/43/EEC Habitats Directive)
No full textCoastal dunes are among habitats with the worst conservation status on a global, European and national scale. Monitoring and reporting are of strategic importance to determine the effectiveness of the implementation of Habitats Directive and to preserve the unique biodiversity heritage of the Italian dunes. In this study we show main results of the 4th National Report with specific reference to the macro-habitat "Coastal Sand Dunes and Inland Dunes", highlighting its updated current conservation status at the national and Biogeographical level. A comprehensive Working Group of territorial experts collected, updated, validated and integrated the data available for 11 Annex I Habitats, distributed in the Alpine, Continental and Mediterranean Biogeographical Regions. The conservation status was evaluated through the following criteria: Geographic range, surface area, structure, functions, pressures, threats, conservation measures and prospects. Results highlighted the dramatically bad conservation status of Italian dune Habitats: The overall assessment reported 88% of habitats in bad conservation status and the remaining 12% is in inadequate conditions. Results showed a generalised threat and a worrying conservation status both on herbaceous and wooded communities, in particular in some relevant habitats, such as the shifting dunes. Main pressures and threats were linked to residential, commercial and industrial activities, as well as alien species. Although some of the changes in distribution and trends are probably deriving from more accurate and updated data, the alarming conservation status of Italian sand dunes requires a better knowledge of pressures and threats for further management actions and monitoring plans, inside and outside protected areas
Ecosystem state assessment after more than 100 years since planting for dune consolidation
No full textThe assessment of the ecosystem state is fundamental to understand the success of ecological rehabilitation, especially in the long term. We aim to evaluate the rehabilitation success of a unique Mediterranean dune system site along the Tyrrhenian coast of Italy which underwent a dune consolidation intervention and species planting at the beginning of the twentieth century after the destruction of the natural ecosystem. We used three nearby non-rehabilitated protected coastal sites with different degrees of disturbance as reference sites encompassing different potential rehabilitation outcomes of the target site. To assess the overall result of the intervention, we used several plant characteristics and measured taxonomic and functional beta-diversity between all sites. We compared the proportions of typical and ruderal species of dune habitat types across sites. We further used the species–area relationship to examine if the number of observed species in our sites differed from the expected. Our analyses revealed that the rehabilitated site was taxonomically and functionally more similar to the least disturbed site. We suggest that plant characteristics arising from botanical inventories can be fruitfully used in rehabilitation assessment as they value the taxonomic and functional species diversity at the community scale. We conclude that plant characteristics compared across sites are useful tools in ecosystem state assessment if they reflect the ecological functions and conservation values of the natural ecosystems
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