Search results for " VEGETATION"
showing 10 items of 435 documents
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…
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…
Retrieving and broadcasting near-real-time biophysical parameters from MODIS and SEVIRI receiving stations at the global change unit of the Universit…
2015
We present here the automatic processing chains implemented at the Global Change Unit of the University of Valencia. These allow for a near-real-time retrieval of various biophysical parameters from both Sun-synchronous TERRA/AQUA Moderate Resolution Imaging Spectroradiometer MODIS and geostationary Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager MSG SEVIRI sensors. Retrieved parameters, namely sea and land surface temperatures SST and LST, respectively, normalized difference vegetation index NDVI, and vegetation condition index VCI, are similar for both sensors, and specific approaches have been developed and implemented for near-real-time parameter retrievals: htt…
Fine-grain beta diversity in Palaearctic open vegetation: variability within and between biomes and vegetation types
2021
Aims: To quantify how fine-grain (within-plot) beta diversity differs among biomes and vegetation types. Study area: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database spanning broad geographic and ecological gradients. Next, we calculated the slope parameter (z-value) of the power-law species–area relationship (SAR) to use as a measure of multiplicative beta diversity. We did this separately for vascular plants, bryophytes and lichens and for the three groups combined (complete vegetation). We then tested whether z-values differed between biomes, ecological-physi…
Berberido aetnensis-Crataegion laciniatae, new orophilous pre-forestal alliance of the class Rhamno-Prunetea
2011
In this paper the results of a phytosociological study carried out on some aspects of shrub vegetation of forest margins are presented, investigated in the higher belt of the Madonie Mts. (Northern-Central Sicily), referred to the order Prunetalia spinosae (Rhamno-Prunetea). Through comparison with other known coenoses in the central- southern part of the Italian Peninsula and in Sicily – especially, the associations of Berberidion vulgaris and those of Pruno-Rubion ulmifolii – a coenological and phytogeographical autonomy has been made evident and has resulted in the recognition of a new alliance, described under the name Berberido aetnensis-Crataegion laciniatae Gianguzzi et al., all. nov…
Temporal species turnover and plant community changes across different habitats in the Lake Engure Nature Park, Latvia
2014
Veģetācijas dinamikas izpētē reti ir gadījumi, kad monitoringu vienlaicīgi veic vairākās atšķirīgās ekosistēmās. Tomēr šāda veida pētījumi ļauj padziļināti izprast veģetācijas struktūras un pazīmju izmaiņu mehānismus. Šajā pētījumā aplūkotas lakstaugu stāva izmaiņas, sugu aprite un sugu skaita-laika attiecība dažādu biotopu griezumā 12 gadu periodā ILTER monitoringa stacijā Engures ezera dabas parkā. Sugu aprite laikā definēta kā atšķirība sugu sastāvā starp diviem laika periodiem. Sugu skaita-laika attiecība tika novērtēta, izmantojot slīdošo logu pieeju. Detrendētā korespondentanalīze izmantota, lai noskaidrotu ikgadējās izmaiņas sugu sastāvā. Sugu skaits un kumulatīvais skaits, kā arī da…
A Methodology for Protection of Trees Against Lightning Strikes as a Measure to Prevent Fires and Loss of Human Life
2021
Some regions may be characterized by a very low annual lightning ground flash density, and yet lightning strikes seem to have been in those areas the cause of widespread wildfires in forested areas. Due to global climate change, these occurrences seem to be an increasing threat. In this paper, the authors discuss the withstand capability of trees against lightning and introduce the criteria for the deployment of tree lightning protection systems (TLPS) to protect forested areas, where deemed necessary by the tree risk assessment. This work analytically identifies the critical trunk radius of the tree below which the tree may explode in the case of a lightning strike and ignite the surroundi…