Search results for "VEGETATION"

Quantification of land-atmosphere exchanges of water, energy and carbon dioxide in space and time over the heterogeneous Barrax site

2008

International audience; To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. Th…

Multitemporal Unmixing of Medium-Spatial-Resolution Satellite Images: A Case Study Using MERIS Images for Land-Cover Mapping

2011

Data from current medium-spatial-resolution imaging spectroradiometers are used for land-cover mapping and land-cover change detection at regional to global scales. However, few landscapes are homogeneous at these scales, and this creates the so-called mixed-pixel problem. In this context, this study explores the use of the linear spectral mixture model to extract subpixel land-cover composition from medium-spatial-resolution data. In particular, a time series of MEdium Resolution Imaging Spectrometer (MERIS) full-resolution (FR; pixel size of 300 m) images acquired over The Netherlands is used to illustrate this study. The Netherlands was selected because of the following: 1) the fragmenta…

Soil, pasture and animal products quality

2013

The management of pasture, through the use of appropriate stocking rates and grazing systems, influences the feeding behaviour of the animals. The impact of animal behaviour on vegetation can be of great importance for the sustainability of pastures and mantaining their biodiversity. Indeed, a different response in terms of quality of animal products is mediated by the ability of animals to concentrate or transform grass components, according to the characteristics of the soil. The herbage ingested by animals provides them with compounds with aromatic characteristics, such as terpenes, and with functional properties beneficial for human health, such as carotenoids, vitamins, polyphenols and…

Coupling two radar backscattering models to assess soil roughness and surface water content at farm scale

2013

Remote sensing techniques are useful for agro-hydrological monitoring at the farm scale because the availability of spatially and temporally distributed data improves agricultural models for irrigation and crop yield optimization under water scarcity conditions. This research focuses on the surface water content retrieval using active microwave data. Two semi-empirical models were chosen as these showed the best performances in simulating cross and co-polarized backscatter. Thus, these models were coupled to obtain reliable assessments of both soil water content and soil roughness. The use of the coupled model enables one to avoid using roughness measured in situ. Remote sensing images and …

Phytosociological characterization of the Celtis tournefortii subsp. aetnensis microwoods in Sicily

2014

A work on the Celtis tournefortii subsp. aetnensis vegetation, endemic species located in disjointed sites in the Sicilian inland, is here presented. It forms microwoods with a relict character established on screes and detrital coverages, on a variety of lithological substrates (volcanics, limestones, quartzarenites). Based on the phytosociological analysis carried out in the territory, these vegetation aspects are framed in the alliance Oleo-Ceratonion, within which a new association (Pistacio terebinthi-Celtidetum aetnensis) is described, in turn diversified in the following subassociations: a) typicum subass. nova, on detrital calcareous cones of the north-western part of Sicily, in the…

The ancient urban agroforestry systems of the Conca D'Oro (Palermo, Italy) need protection to defend the city

2019

The favorable environmental conditions together with the ancient agronomic practices, e.g. the irrigation systems introduced by the Arabs, have made the plain surrounding Palermo, known as Conca d’Oro, the unique agriculture landscape famous worldwide. Several tree and vegetable species have spread throughout in time but the new crops, instead of replacing the others, were often integrated exploiting the different heights of the tree canopies. The result was the creation of complex agroecosystems characterized by orchards with several layers of trees (as walnut, loquat, citrus) and empty spaces where the farmers cultivated vegetables. The grass fed the animals in the stables while manure wa…

1993

Seven superimposed lithostratigraphic units have been distinguished in the Upper Trias of Los Pastores (Algeciras). The four lower units (1 to 4) show clayey-sandy-evaporitic Keuper facies. Pollen associations obtained from dark pelitic levels, and bivalves sampled from carbonate intercalations within these four lower units allow to date them as Carnian. These lower units can be correlated with the K1 to K3 units of the Keuper of the Subbetic and of other regions of the Iberian Peninsula. Concerning the three higher units, the unit 6 is pelitic-carbonatic and evaporitic and it also bears Carnian pollen associations. The units 5 and 7, however, are carbonatic and show clearly marine facies a…

Holocene vegetation and fire dynamics in the supra-mediterranean belt of the Nebrodi Mountains (Sicily, Italy)

2012

High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous (Quercus cerris, Fagus sylvatica and Fraxinus spp.) and evergreen (Quercus ilex) species. Species-rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifoli…

Fern-dominated Rock Plant Communities of Tajikistan (Middle Asia)

2015

The results of phytosociological research conducted on the fern vegetation of rock crevices and clefts of the Pamir-Alai Mountains in Tajikistan are presented. During field surveys done in 2010–2013, 78 phytosociological relevés were sampled. Plant species were recorded according to the Braun-Blanquet cover-abundance scale. A synopsis of the fern communities of the montane and high altitude zones in Tajikistan is proposed. In the examined vegetation plots, species of 9 ferns, 58 angiosperms and 13 mosses were recorded. The most frequent ferns were: Cystopteris fragilis, Cheilanthes persica, Asplenium ruta-muraria, Asplenium ceterach, Adiantum capillus-veneris and Cryptogramma stelleri. Six …

Different trends of neighboring populations of Lesser Kestrel: Effects of climate and other environmental conditions

2019

The sensitivity of population trends to the climate and environment is generally considered a species-specific trait. However, evidence that populations may show different responses to the climate and environmental conditions is growing. Whether this differential sensitivity may arise even among neighboring populations remains elusive. We compared the trends of two neighboring populations of the Lesser Kestrel Falco naumanni, using data from a 12-year survey of 158 colonies in Sicily, Italy; the two populations inhabiting a lowland and an highland area, respectively. Population trends were modeled through the TRIM algorithms implemented in R (package rtrim). A reversed U-shaped population t…