Search results for "GRASSLAND"

Turnover and availability of soil organic carbon under different Mediterranean land-uses as estimated by13C natural abundance

2013

Summary Soil organic matter (SOM) is an important factor in ecosystem stability and productivity. This is especially the case for Mediterranean soils suffering from the impact of human degradation as well as harsh climatic conditions. We used the carbon (C) exchange resulting from C3-C4 and C4-C3 vegetation change under field conditions combined with incubations under controlled conditions to evaluate the turnover and availability of soil organic C under different land-uses. The 40-year succession of Hyparrenia hirta L. (C4 photosynthesis) after more than 85 years of olive tree (Olea europaea L.; C3 photosynthesis) growth led to the exchange of 54% of soil organic C from C3 to C4 forms. In …

The Influence of Land Surface Temperature in Evapotranspiration Estimated by the S-SEBI Model

2020

Evapotranspiration (ET) is one of the least understood components of the hydrological cycle. Its applications are varied, from agricultural, ecological and hydrological monitoring, to control of the evolution of climate change. The goal of this work was to analyze the influence that uncertainties in the estimate of land surface temperature (Ts) can cause on ET estimates by S-SEBI model in the Pampa biome area. Also, the specificities of native grassland of Pampa biome related to energy balance were analyzed. The results indicate that the daily evapotranspiration is higher when the pixel Ts is lower, which also shows the influence of land use on the variability of ET. The results demonstrate…

Indagine fitosociologica sulle praterie a Brachypodium retusum (Pers.) Beauv. della Sardegna.

2005

The grasslands characterized by the dominance of Brachypodium retusum occurring in Sardinia are examined. These communities, belonging to the Thero-Brachypodion ramosi alliance (Lygeo-Stipetea class), are quite widespread in the Island, where they usually grow on carbonate substrata from the sea level up to 1300 m of altitude. On the basis of several phytosociological relevés, it has been possible to recognize six associations well-differentiated from the floristic, ecological and syndynamic point of view. The autonomy of these associations is also supported by a numerical multivariate analysis based on quantitative data (dendrogram and P.C.A.). The associations surveyed are the following: …

Proposals for improvement of Annex I of Directive 92/43/ EEC: Central Italy

2021

The main purpose of the 92/43/EEC Habitats Directive is to contribute to the conservation of biodiversity, understood as habitat types and species of the flora and fauna of the European Union. To achieve this goal, natural and semi-natural biodiversity as a whole must be recognized and included in its annexes. As for the conservation of biotopes, named habitat types, Italy is unfortunately lacking as it the Annex I does not include important ecosystems that are typical of its territory, rare for biogeographical reasons or threatened. Therefore, the opportunity to identify a first list of significant habitats for central Italy is discussed here. For each of the new proposed types (new habita…

2016

Rivers carry large amounts of dissolved organic matter (DOM) to the oceans thereby connecting terrestrial and marine element cycles. Photo-degradation in conjunction with microbial turnover is considered a major pathway by which terrigenous DOM is decomposed. To reveal globally relevant patterns behind this process, we performed photo-degradation experiments and year-long bio-assays on DOM from ten of the largest world rivers that collectively account for more than one-third of the fresh water discharge to the global ocean. We furthermore tested the hypothesis that the terrigenous component in deep ocean DOM may be far higher than biomarker studies suggest, because of the selective photoche…

Can grassland plant communities be preserved on road and railway verges?

2000

Semi-natural grasslands are a threatened biotope type in many countries. Typical grassland plant species are adapted to continuous grazing or mowing that keeps the envi- ronment open. With the decline in grassland area, these spe- cies are ever more reliant on alternative habitats such as road verges. To find out whether plant communities comparable to those of semi-natural grasslands can be maintained on modern road and railway sides, the vegetation of 92 grasslands and 90 road and railway verges was studied. These biotope types were compared with each other according to their community structure, total number of species, number of grassland species and restricted-range diversity. Further …

Floristic and phytosociological features of the Brachypodium rupestre communities in Italy

2018

The pale green dense Tor-grass (Brachypodium rupestre) tufts are a quite distinctive aspect of the Italian grassland pattern of the colline and submontane belts. B. rupestre is used to be found in secondary grasslands both in natural environments and in some aspects of the post-coltural environments such as forest clearances, abandoned terraced and extensive pastures. In northern Italy (Alps, Prealps and northern Apennines) B. rupestre has only sporadically been considered in the grasslands syntaxonomic frameworks. On the contrary it occurs in those regarding the central Italy where several semi-natural and post-coltural grassland associations (e.g. Polygalo flavescentis-Brachypodietum, Gal…

Effects of mountain grassland maturity stage and grazing managment on carotenoids in sward and cows’ milk.

2006

The maturity stage of the grass affects milk fatty acids of cows grazing a mountain grassland

2010

International audience; We aimed to quantify the effect of the growth stage of a mountain grassland pasture on the fatty acid (FA) composition of grass and milk. In June (growth) and October (regrowth), a mountain pasture was continuously grazed by six dairy cows in a strip grazing system. During June, the grass C18:3n-3 content decreased while C16:0, c9-C18:1 and C18:2n-6 content increased. During October, the grass FA composition was similar to that observed in the first part of June. During June, milk saturated FA (SFA) content increased while the sum of the trans FA and polyunsaturated FA (PUFA) content decreased, mainly due to the decrease in C18:3n-3 and c9t11-CLA percentages. At the …

Nitrogen and phosphorus budgets in experimental grasslands of variable diversity.

2007

Previous research has shown that plant diversity influences N and P cycles. However, the effect of plant diversity on complete ecosystem N and P budgets has not yet been assessed. For 20 plots of artificially established grassland mixtures differing in plant diversity, we determined N and P inputs by bulk and dry deposition and N and P losses by mowing (and subsequent removal of the biomass) and leaching from April 2003 to March 2004. Total deposition of N and P was 2.3 +/- 0.1 and 0.2 +/- 0.01 g m(-2) yr(-1), respectively. Mowing was the main N and P loss. The net N and P budgets were negative (-6.3 +/- 1.1 g N and -1.9 +/- 0.2 g P m(-2) yr(-1)). For N, this included a conservative estimat…