Search results for "VEGETATION"
showing 10 items of 1069 documents
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…
The effect of vegetation structure on seasonal density of Sylvia warblers in the eastern Iberian Peninsula
2021
Vegetation characteristics determine seasonal habitat selection by Eurasian Blackcaps Sylvia atricapilla, Dartford Warblers Sylvia undata, and Sardinian Warblers Sylvia melanocephala, and changes i...
New Data on Orthotrichum gigantosporum Lewinsky (Orthotrichaceae, Bryophyta), a Widespread Northern Andean-Patagonian Endemic Moss
2021
The moss family Orthotrichaceae is still poorly known in the southern extreme of South America. This is especially true regarding the morphological variability, geographical distribution, and ecological affinities of the species restricted to the Andean-Patagonian area. These deficiencies are addressed for Orthotrichum gigantosporum Lewinsky, one of the least known and most interesting endemics of the area. After examining the rich collections made by our team in southern Chile and Argentina, we have found numerous new localities for the species. Orthotrichum gigantosporum has proven to be a widespread moss in the forests and scrublands of the northern sector of the Andean-Patagonian area. …