263 research outputs found
Recover of understory vegetation in clearcut stone pine (Pinus pinea L.) plantations
The recovery of understory vegetation after clear-cutting of stone pine (Pinus pinea L.) plantations is crucial for biodiversity conservation. The development of plant cover, and the richness, diversity and composition of understory plant communities were investigated within five years from clear-cutting. After three years, plant cover ranged from 48 to 74%, and was formed by over 90% of shrubs and graminoids. Diversity decreased in cut plots and the index of similarity showed marked shifts in species composition. Richness increased and around 50 new species per plot were inventoried over three years. New species showed a high proportion of annuals with broad ecological amplitude and aliens, which changed life form and chorology spectra. Most new species had low frequency, but some were still present after five years. Extinction of resident species was low, and their frequency increased with time from clear-cutting. Most of them were perennials with sprouting ability. Common features of plant communities developing in clear-cut stone pine plantations were: (1) the linear increase of plant cover during the first three growing seasons, (2) increased species richness, (3) decreased diversity, (4) invasion by annuals, and (5) invasion by Alien and Cosmopolitan species
CHARACTERIZATION OF SERPOTTAS’ STUCCOS BY MEANS OF SIMULTANEOUS THERMAL ANALYSIS: PRELIMINARY RESULTS
In this paper the Simultaneous Thermal Analysis (STA), i.e. thermogravimetric and differential thermal analysis, was used as a diagnostic tool to better understand the matter composition of some very valuable artworks the Serpottas’ stuccoes in Palermo. Particularly the STA was used in order to exclude the presence of an unusual calcium-bearing magnesium carbonate, and the thermal data were also used to quantify the magnesite to calcite ratio. The latter was investigated in order to evaluate the amount of magnesium in the lime used as binder as during 17th and 18th century in Sicily magnesium rich lime was indicated as the most valuable binder probably because this kind of lime has a higher plasticity. The data obtained in this work are not conclusive but indicate a way to contribute to the comprehension of this unique work of art composition
Effect of temperature and phosphorus fertilization on phosphorus and nitrogen uptake by sorghum
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