Superconducting RFQs

n/

Effects of late summer burning in a Mediterranean pasture

An experiment on the use of three burning schedules (annual, biennial and occasional) in a a pasture dominated by the perennial Mediterranean grasses Dactylis glomerata ssp. hispánica (Roth) Nyman and Phleum pratense ssp. bertolonii (DC) Bomm. is reported. If not repeated annually or biennially, burning increased the occurence of legumes and decreased the dominance of the grasses. When repeated the effect on herbage yield and pasture stability was extremely detrimental.L’effet de trois régimes de feu contrôlé (annuel, bisannuel et occasionnel ) a été étudié dans un pâturage dominé par des graminées méditerranéennes vivaces (Dactylis glomerata ssp. hispanica (Roth) Nyman et Phleum pratense ssp. bertolonii (DC) Bomm. Si les feux sont occasionnels ils augmentent la présence des légumineuses et font diminuer la dominance des graminées. Répétés fréquemment (chaque année ou deux fois par an), les feux diminuent notablement la production herbagère et la stabilité des pâturages.Boscagli A. Effects of late summer burning in a Mediterranean pasture. In: Ecologia mediterranea, tome 15 n°1-2, 1989. pp. 35-43

La vegetazione dei suoli argillosi pliocenici della Toscana meridionale. 3. Evoluzione dei pascoli nelle Crete senesi

Vegetation on pliocene clay soils of the Southern Tuscany. 3. Evolution of the pastures in the Crete senesi area. Pastures established by sown and spontaneous re-vegetation have been examined. Persistence degree of sown species (Hedysarum coronarium L. and Medicago sativa L. ) affects the initial evolution while an old-field colonization occurs in the unsown pastures. However a convergent evolution occurs and there is also a significant similarity among pastures from the fifth year. Number and cover of perennial species increase to the detriment of annual ones ; grasses and legumes dominate in cover, forbs in flora.Sono stati esaminati pascoli costituiti in tre differenti modi : con la semina di Hedysarum coronarium L., con la semina di Medicago sativa L. e con l'inerbimento spontaneo. Nei primi due l'evoluzione iniziale è influenzata dal grado di persistenza detta specie seminata, mentre negli altri consiste in una tipica colonizzazione post-colturale. C’è, comunque, un'evidente convergenza e un buon livello di somiglianza a partire dal quinto anno, ovunque aumentano il numero e la copertura dette specie perenni a danno di quelle annuali, dominano le graminacee e le leguminose netta copertura e le forbe nella flora.Boscagli A. La vegetazione dei suoli argillosi pliocenici della Toscana meridionale. 3. Evoluzione dei pascoli nelle Crete senesi. In: Ecologia mediterranea, tome 14 n°3-4, 1988. pp. 85-94

Bruciatura e presenza di sulla nei pascoli seminati con questa specie

Effects of burning on sulla (Hedysarum coronarium L.) occurence in pastures sown with this species. Effects of burning on sulla (Hedysarum coronarium L.) density, biomass and contribution to total yield were examined over a three-year period on four different aspects of pastures originally sown with this species. Fire increased sulla's occurrence on all aspects examined except in the aspect with wet soil for long time, and showed a greater effectiveness on southern slopes than on norther ones. In the latter differences among the examined aspects did not occur.Gli effetti della bruciatura sulla presenza di sulla (Hedysarum coronarium L.), espressa come densità, biomassa e contributo al prodotto totale, sono stati esaminati durante tre anni e in quattro differenti aspetti di pascoli originariamente seminati con questa specie. Il fuoco ha aumentato la presenza di sulla in tutti gli aspetti esaminati meno che in quello con suolo umide per lunghi periodi e ha mostrato una maggiore efficacia nelle esposizioni meridionali che in quelle settentrionali. In queste i differenti aspetti esaminati hanno mostrato la stessa riposta.Boscagli A. Bruciatura e presenza di sulla nei pascoli seminati con questa specie. In: Ecologia mediterranea, tome 13 n°1-2, 1987. pp. 87-91

Germination of Nine Species of A Pioneer Plant Community of Pliocene Clay Soils of Central Western Italy Under Different Photo- and Thermo-Periods

Germination response under different photo- and thermo-periods was investigated in nine species of the association Parapholido-Artemisietum cretaceae, a typical plant community of clay badland vegetation in central western Italy. The species showed: (i) more rapid germination under the photo- and thermo-period emulating autumn conditions than under the one emulating early spring conditions; (ii) different germination rates under condition emulating periods with high diurnal insolation followed by high or low nocturnal heat dispersion: Aegilops geniculata, Parapholis strigosa and Artemisia cretacea were indifferent, Hordeum maritimum, Trifolium scabrum, Brachypodium distachyum and Parapholis incurva responded positively to higher thermal dispersion, whereas Medicago minima and Scorpiurus muricatus responded negatively; (iii) different responses to a constant low temperature of 2oC: Artemisia cretacea, Parapholis incurva, Parapholis strigosa and Scorpiurus muricatus showed complete or very high dormancy; the other species showed a germination capacity between 55 and 87% in the following decreasing order: Medicago minima > Hordeum maritimum > Trifolium scabrum > Aegilops geniculata > Brachypodium distachyum. All species had delayed and reduced germination responses at 2oC. Grasses showed prompt, quick and high germination as environmental conditions became more favourable; legumes showed a similar response when their coat-imposed dormancy was removed, while the asteracea A. cretacea showed only a moderate germination capacity and one of the lowest germination rates. Nomenclaure: Pignatti (1982)

La végétation des sols argileux pliocènes de la Toscane méridionale. II -- Influence de l exposition et de l intensité du pâturage sur la végétation des prairies des "Cretes Senesi» (Sienne, Italie)

Grasslands on the northern part of the "Crete senesi" (Siennese clay) have been examined. From the phytosociological point of view these communities are a mosaic of vegetational types ecologically very different from one another. The prevailing species belong to the Molinio-arrhenatheretea and Thero-brachypodietea, whilst species belonging to the Festuco-brometea, Chenopodietea, Secalinetea and Plantaginetea majoris are less important. Only in particular conditions the Puccinellio-salicornietea halophytes may become abundant. The percentage of both presence and cover of the above mentioned groups of species have been examined in relation to exposure and grazing intensity. The species of Molinio-arrhenatheretea, prevailing in North-facing slopes but well represented also in the South-facing ones, indicate by their presence the good state of conservation of the grassland. On the contrary the abundance of Puccinellio-salicornietea species must be related to excessive grazing and indicates a degraded condition.Sono stati esaminati i prati-pascoli della parte settentrionale delle "Crete senesi". Dal punto di vista fitosociologico tali cenosi risultano un mosaico di aspetti vegetazionali ecologicamente assai lontani fra loro. Prevalgono le specie dei Molinio-arrhenatheretea e dei Thero-brachipodietea, mentre minore importanza rivestono le specie dei Festuco-brometea, dei Chenopodietea, dei Secalinetea e dei Plantaginetea majoris. Solo in condizioni particolari le alofite dei Puccinellio-salicornietea gioca no un ruolo non secondario. Dei gruppi di specie individuati, sono state messe in evidenza le variazioni percentuali della presenza e della copertura in funzione dell'esposizione e della intensità di pascolamento. Le specie dei Molinio-arrhenatheretea, predominanti nei versanti settentrionali, ma ben rappresentate anche a mezzogiorno, sono indice di un buono stato di conservazione del prato-pascolo. L'abbondanza delle specie dei Puccinellio-salicornietea va messa in relazione a un eccessivo sfruttamento ed è indice della degradazione del prato-pascolo.Nous avons analysé les prairies de la partie septentrionale des "Crete senesi" (Argiles de Sienne). Du point de vue phytosociologique ces cénoses sont une mosaïque d'aspects végétationels très différents entre eux écologiquement. Les espèces des Molinio-Arrhenatheretea et des Thero-brachypodietea prévalent , tandis que les espèces des Festuco-brometea et des Chenopodietea, des Secalinetea et des Plantaginetea majoris revêtent une importance mineure. Les espèces des Puccinellio-salicornietea ne deviennent importantes que dans des conditions particulières. Pour chaque groupe d’espèces, les variations en pourcentage de la présence et de la couverture ont été mises en évidence par rapport à l’exposition et à l’intensité du pâturage. Les espèces des Molinio-arrhenatheretea, qui sont assez développées sur les versants méridionaux et qui prédominent dans les versants septentrionaux, sont indicatrices d'une bonne conservation de la prairie. L'abondance des espèces des Puccinellio-salicornietea indique la dégradation de la prairie due à une exploitation excessive.Boscagli A., De Dominicis Vincenzo, Casini S. La végétation des sols argileux pliocènes de la Toscane méridionale. II -- Influence de l exposition et de l intensité du pâturage sur la végétation des prairies des "Cretes Senesi» (Sienne, Italie). In: Ecologia mediterranea, tome 9 n°2, 1983. pp. 77-89

Chapter 11 Antimony contents in plant species growing in an Sb-mining district (Tuscany, Italy)

We analyzed the antimony contents in 59 plant species (a total of 67 samples) from six sites in an Sb-mining area, each with a different Sb content in the soil. The plants were both cultivated and wild species, mostly herbaceous and tap-rooted, Dicotyledones, composites, grasses and legumes. The Sb concentration in plants is highly correlated with the concentration of total, soluble and extractable Sb in the soil, while the ability of the species to concentrate antimony is correlated only with the concentration of extractable Sb. Accumulation in roots is most responsive to the increase of available antimony in soils passing from the cultivated sampling sites to the mineral processing tailing pond. The most common site of Sb accumulation in the plant shifts from the roots to the leaves as the Sb content in the soil increases. Nevertheless, it appears to be largely species-specific. Antimony levels are high in plants from the tailing pond, above 1000 mg/kg in some wild species (Achillea ageratum, Silene vulgaris and Plantago lanceolata), while they are very low in crops and vegetables. Plant species traits, such as root morphology, life span, habitus and systematic rank, are important, although their influence is not statistically significant. All the plant species with the highest concentrations of antimony are herbaceous, almost all Dicotyledones, tap-rooted and mostly perennials, composites and legumes. The potential risk of the entry of antimony into food chains is discussed. The possible effects of plants on the environmental distribution of the element and the possible exploitation of some plant species as phytoremediators are also considered