Search results for "Geta"
showing 10 items of 3789 documents
Changes in vegetation spring dates in the second half of the twentieth century
2011
This study aims at estimating trends in spring phenology from vegetation index and air temperature at 2 m height. To this end, we have developed a methodology to infer spring phenological dates from Global Inventory Modeling and Mapping Studies GIMMS Normalized Difference Vegetation Index NDVI time-series, which are then extrapolated to the period 1948–2006 with the help of Reanalysis data, using its 2 m height air temperature parameter. First, yearly NDVI is fitted to a double-logistic function for the whole extent of the GIMMS database 1981–2003. This fitting procedure allows us to describe, on a yearly basis, the NDVI evolution for each pixel through the estimation of six parameters whic…
Syntaxonomic survey of the class Pegano harmalae‐Salsoletea vermiculatae Br.‐Bl. & O. Bolos 1958 in Italy
2013
After a general outline on the syntaxonomical framework of the class Pegano harmalae-Salsoletea vermiculatae Br.-Bl. & O. Bolos 1958, the occurrence of this vegetation in the Italian territory is examined. In Italy, this vegetation is mostly found on clayish or marly substrata, particularly if slightly enriched with nitrates and chlorides. With reference to the Rivas-Martinez bioclimatic classification, the Italian stands have an infra- to thermo-Mediterranean thermotype (marginally up to the meso-Mediterranean one) with dry or arid ombrotype. In particular, this vegetation is well represented in Sicily, while in Sardinia and along the Italian Peninsula, it progressively becomes more rare a…
Spatial patterns of, and environmental controls on, soil properties at a riparianepaddock interface
2012
Abstract Riparian zones are prominent features of agricultural landscapes because they are the last point to intercept nutrients and sediments before they enter water bodies. We investigated the soil properties, nutrient dynamics and vegetation composition at the riparian–agriculture interface. Soil physicochemical and vegetation properties were spatially heterogeneous along the transition from the grazed paddock into the un-grazed and revegetated riparian zone. Soil C stocks varied considerably across the site, with values ranging from 2% in the paddock to 5% in the riparian zone. Using Bayesian model selection, a predictive model for total soil carbon was developed. By including soil mois…
Soil geography and diversity of the European biogeographical regions
2013
For decades, soil geography has beenmainly a qualitative and descriptive discipline. There are nowtechnologies and mathematical tools available that allow formalizing soil geography in more quantitative terms. In this paper, the distribution and diversity of the soils of Europe are analyzed using GIS tools and pedodiversity algorithms. Soil data were taken from the European Soil Database (V2.0) and computed within the spatial framework of the Biogeographical Regions of Europe (BGRE) as defined by the European Environmental Agency (EEA) on the basis of climate and vegetation. The results obtained show the soil assemblages, including dominant soils and endemic and non-endemic soil minorities,…
Flow-induced vegetation uprooting in a meandering bend : experimental investigation
2022
Abstract Vegetation uprooting is a complex process which depends on many interrelated factors. In this paper, attention is focused on the flow-induced uprooting in river bends, where the flow characteristics vary as effected by the channel's curvature and its continuous changing in the downstream direction. Results are presented by an experimental work done in a high-amplitude meandering flume with mature herbaceous vegetation on the bed. In the first part of the paper, the variation along the bend of the geometrical (length, thickness, and radical architecture) and the mechanical (resistance force) characteristics of the roots are analyzed. In the second part of the paper, the transition f…
Urban landscape selection by Eurasian collared dove (<i>Streptopelia decaocto</i>) in eastern Spain
2020
The Eurasian collared dove (Streptopelia decaocto) is an invader species, and its distribution is continuously on the increase. Today its expansion has spread to the American continent. In this study we describe the effects of the urban environment on the Eurasian collared dove in eastern Spain. The abundance and presence of this dove were analyzed in 46 localities using counting points. Overall, 220-point counts were surveyed between autumn 2015 and late-winter 2016. A hierarchical partitioning analysis was used to identify explanatory variables of different types such as resources, climate and urban structure, and human presence, which may influence the presence and abundance of this spec…
Sweet chestnut (Castanea sativa) leaves as a bio-indicator of volcanic gas, aerosol and ash deposition onto the flanks of Mt Etna in 2005–2007
2009
Sweet chestnut leaves (Castanea sativa) collected from the flanks of Mt Etna volcano in 2005-2007 were analysed by inductively-coupled plasma mass spectrometry to investigate the spatial and temporal variability of element concentrations. The aim of this work was to determine whether these leaves are a bio-indicator for volcanic gas, aerosol and ash deposition and to gain new insights into the environmental effects of quiescent and eruptive volcanic plumes. Results show a positive correlation between sample variability in the concentration of elements in Castanea sativa and enrichment factors of elements in the plume. The spatial and temporal variability of chalcophilic elements (As, Cd, Cu…
A full‐scale study of Darcy‐Weisbach friction factor for channels vegetated by riparian species
2021
In this article, an open channel flow resistance equation, deduced applying dimensional analysis and incomplete self-similarity condition for the flow velocity distribution, was tested using measurements carried out in a full-scale channel equipped with three types of riparian plants (Salix alba L., Salix caprea L. and Alnus glutinosa L.). In the experimental channel, having banks lined with boulders, the vegetation branches were anchored in a concrete bottom. For each species, the measurements were carried out with plants having different amounts of leaves, different plant density and plant area index. The relationship between the scale factor Γ of the velocity profile and the Froude numbe…
Mid-Holocene forests from Eastern Hungary: New anthracological data
2013
Charcoal remains found in five archaeological sites provided an important source of information about the woody vegetation that developed during the Atlantic period in eastern Hungary. The results are presented jointly since all sites are located in very similar habitats, they reflect Neolithic cultures and present comparable floral compositions. The reconstruction of past forest communities from the Great Hungarian Plain in the Atlantic period is based on pollen analysis and new anthracological data offer significant complementary information to the established pollen sequences. These data were obtained from more than 5000 charcoal fragments in which 28 taxa were identified. The main contr…
Comparison of social-ecological resilience between two grassland management patterns driven by grassland land contract policy in the Maqu, Qinghai-Ti…
2018
Embraced for decision-making, resilience has evolved as a meaningful term in areas such as ecology, the economy and society. After a policy of grassland contracts was implemented on the Qinghai-Tibetan Plateau, two grassland management patterns evolved: the multi-household management pattern (MMP) and the single-household management pattern (SMP). Within a resilience-driven perspective, this study compared the outcomes of these grassland management patterns by measuring their effects on the resilience of grazing, ecological, economic and social systems. Resilience indicators for each of the four systems were: grazing system (grazing space, transhumance, water source and reproduction); ecolo…