1,721,068 research outputs found
An “Uncertainty Principle” for the Mediterranean annual dry grasslands
No full textPreliminary results of diachronic researches on the spatial arrangement and species richness in Mediterranean annual dry grasslands (Tuberarietea guttatae) demonstrated that the patchiness resulted minimized and the temporal stability maximized at elevations offering the best compromise between the summer drought stress and the winter cold stress. Moreover, the temporal stability of the Mediterranean annul dry grasslands could not necessarily be related with their demographic inertia, meaning that the turnover and rearrangement of species within the community do not necessarily implicate significant changes in the average species composition over time. On the other hand, the survival chances of Mediterranean annual dry grasslands are enhanced by disturbances, such as higher temperatures, periodical fires, seed rearrangement and predation by ants. The influence of stochastic disturbances, acting together with year-to-year climatic fluctuations that are typical of the Mediterranean climate, drives the Mediterranean annual dry grasslands to acquire a dynamic long-term flow equilibrium, defined as homeorhesis (“preserving the flow”), that in thermodynamic terms can be seen as a system depending on the existence of dissipative structures (perturbations) producing high internal entropy that impede to the system to achieve an homeostatic equilibrium.
We can assume that the Mediterranean annual dry vegetation consists of chaotic assemblages of species constrained within certain limits of predictability by the spatial heterogeneity and stochastic disturbance. In particular, frequent disturbances of low intensity do increase the species richness and unpredictability of a Mediterranean annual dry grassland, but under such conditions its spatial patchiness is minimized and its temporal stability maximized (so that the distribution pattern of species is more predictable and homogeneous). On the other hand, intense disturbances, although less frequent, decrease the species richness of a Mediterranean annual dry grassland and makes it more predictable, but the species assemblage and temporal stability undergo greater fluctuation.
These considerations lead to postulate a “uncertainty principle” for the Mediterranean dry grasslands: if the spatial pattern is predictable, the species composition is largely unpredictable and fortuitous; if the species composition is predictable, the spatial pattern and temporal stability are largely unpredictable and changeable
Re-evaluation and typification of Foeniculum piperitum (Apiaceae), an underknown medicinal plant and crop wild relative
No full textFoeniculum piperitum was described as Anethum piperitum based on plants collected in Sicily, Italy. Currently it is treated either as a synonym of Foeniculum vulgare, or as one of two subspecies within that taxon. Here we show that F. vulgare and F. piperitum are two different, sometimes co-occurring, taxa and that given clear morphological and ecological separation, they should be treated as distinct species. Anethum piperitum is typified. Owing to misapplication of names and wrong synonymizations, the ecology and chorology of F. vulgare and F. piperitum have to be better defined
Aspetti del Rosmarino-Thymetum capitati Furnari, 1965 presso la Torre di Monterosso (Sicilia centro-meridionale)
No full textA phytosociological study on the garrigue characterized by Rosmarinus officinalis and Thymbra capitata, settled on coastal lithosols unsuitable for agriculture, in the municipality of Realmonte (Southern Sicily, Agrigento province), is presented. The field work allowed, as well, to ascertain
the vulnerability of the studied sites, due to the instability and erosion of the substrates, along with anthropogenic threats related to the urban sprawl affecting the area
Aspetti floristico-vegetazionali di un ambiente di torbiera delle alte Madonie e stato attuale di conservazione
No full textLe torbiere del sud Europa sono di notevole importanza biogeografica, in quanto testimonianza diretta delle rigide fluttuazioni climatiche che hanno caratterizzato il Pleistocene. Sono ambienti tutelati ai sensi della direttiva europea 92/43/CEE per la loro estrema fragilità e suscettibilità a trasformazioni irreversibili. Le torbiere sono presenti in Sicilia unicamente all’interno dei territori del Parco delle Madonie, limitatamente alle alture del complesso montuoso di natura quarzarenitica di Pizzo Catarineci - Cozzo Argentiera, nel comune di Geraci Siculo. Si riscontrano all’interno dell’orizzonte fitoclimatico dell’Ilici aquifolii-Quercetum austrotyrrhenicae Brullo & Marcenò in Brullo 1984, sempre su substrati silicei derivanti da depositi sedimentari di correnti torbiditiche riconducibili al Flysh numidico. Con riferimento alle stazioni termopluviometriche poste nei comuni prospicienti, il bioclima dell’area è ascrivibile al termotipo Supramediterraneo inferiore con ombrotipo subumido inferiore. In questo studio vengono presentati i risultati di una indagine parziale sulla componente biologico-vegetale rilevata in una torbiera ricadente in prossimità del màrcato Scaletta d’Alfano, sfuggito ai botanici del passato probabilmente perché occultata da densi nuclei monofitici di Ilex aquifolium che crescono nell’area circostante. L’analisi della florula è stata effettuata durante la primavera e l’estate del 2010. Nel corso dei rilevamenti floristici sono stati censiti in totale 80 taxa specifici e intraspecifici la maggior parte dei quali, in conseguenza della estrema specializzazione ecologica, risultano molto rari e localizzati nel territorio siciliano. Si tratta di briofite come Sphagnum sp. pl., Polytrichum commune Hedw. e piante vascolari quali Hypericum androsaemum L., Lysimachia nemorum L., Osmunda regalis L., Blechnum spicant L. (Roth),Athyrium filix-foemina (L.) Roth, Carex punctata Gaudin, C. echinata Murray., C. remota L., Deschampsia caespitosa (L.) P. Beauv.
L’analisi della vegetazione delle torbiere di Scaletta d’Alfano, ha consentito di definire 3 differenti fitocenosi: aggruppamento a Osmunda regalis, aggr. del Dactylorhizo – Juncion effusi, aggr. a Carex oederi e C. punctata. I primi due aggr. sono ascrivibili all’alleanza del Dactylorhizo – Juncion effusi Brullo & Grillo 1978, l’ultimo all’alleanza del Caricion fuscae W. Koch 1926.
Nel corso degli anni successivi alla data dei primi campionamenti, sono stati effettuati diversi sopralluoghi nei pressi della suddetta località, che hanno messo in luce un evidente trend di regressione delle superfici occupate dalla torbiera, culminato nel 2017 con la completa scomparsa delle comunità vegetali di questo particolare ambiente idromorfo.
La causa di ciò è da imputare in prima analisi alla pressione esercitata dalla mammalofauna recentemente introdotta nell’area del parco. In particolare, l’azione fossoria dei cinghiali (Sus scrofa L.) ha determinato una notevole erosione della biodiversità floristica che caratterizza queste cenosi e ne ha compromesso irreparabilmente il substrato di crescita. Inoltre, è altamente probabile che opere di captazione idrica abbiano influito negativamente sul livello della falda freatica, similmente a quanto è avvenuto in passato per le limitrofe torbiere di Pietra Giordano.
Si ritiene necessario mettere a punto delle strategie specifiche finalizzate alla valutazione dello stato di conservazione di specie, comunità ed habitat, particolarmente nel caso di quelli meno rappresentati, per evitarne la definitiva scomparsa
Dispatches with related documents of Milanese ambassadors in France and Burgundy, 1450-1483, Volume I, Edited with translation by Kendall (P. M.) and Ilardi (V.)
No full textVaughan Richard. Dispatches with related documents of Milanese ambassadors in France and Burgundy, 1450-1483, Volume I, Edited with translation by Kendall (P. M.) and Ilardi (V.). In: Revue belge de philologie et d'histoire, tome 51, fasc. 2, 1973. Histoire (depuis l'Antiquité) — Geschiedenis (sedert de Oudheid) pp. 438-439
Identification, intra- and inter-laboratory validation of a diagnostic protocol for ‘Candidatus Liberibacter solanacearum’ in carrot seeds
No full text‘Candidatus Liberibacter solanacearum’ (CaLsol) is a phloem-limited, unculturable, Gram-negative bacterium associated with emerging diseases in crops of the Solanaceae and Apiaceae families. As it has been shown to be seed-transmitted in carrot, emergency measures for exportation require carrot seed to be heat-treated or tested by PCR and found CaLsol free. Therefore, the identification and harmonization of a protocol for CaLsol diagnosis in carrot seed are becoming of socio-economic priority. We initially set up an improved DNA extraction method for Apiaceae seeds and identified, among the widely used PCR tests to detect and identify CaLsol, the real-time PCR developed by Li et al. (Journal of Microbiological Methods, 78(1), 59–65, 2009) and the end-point PCR by Ravindran et al. (Plant Disease, 95(12), 1542–1546, 2011) to be the most sensitive ones. The two PCR methods were initially intra-laboratory validated followed by a “Test Performance Study” involving 11 Italian laboratories that received both the samples and the material necessary to carry out the experiments. The results indicated that the improved DNA extraction method was robust and that the real-time PCR showed the highest analytical sensitivity in the intra-laboratory validation tests. Similarly, the real-time PCR outperformed the end-point PCR in the inter-laboratory comparison assay showing a higher percentage of accuracy, accordance, and concordance. The overall obtained data could be used for the appropriate application of phytosanitary measures against CaLsol
The chemical composition of the aerial parts essential oil of Ammi crinitum Guss. (Apiaceae) endemic of Sicily (Italy)
No full textAmmi L. is a small genus of economically important plants belonging to Apiaceae family that includes only six taxa. In the present study the chemical composition of the essential oil from aerial parts of Ammi crinitum Guss., a very rare plant, endemic of Sicily, was analyzed by GC–MS. No previously paper has been published on this species. The results showed the presence of large quantity of monoterpene hydrocarbons with sabinene (63.9%), as the most abundant component. Other metabolites present in good quantity were γ-terpinene (8.0%), and 4-terpineol (3.7%). Based on the composition of the essential oil of all the other Ammi taxa, several considerations have been carried out
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