Search results for "VEGETATION"

Application and evaluation of biomagnetic and biochemical monitoring of the dispersion and deposition of volcanically-derived particles at Mt. Etna, …

2010

article i nfo Article history: Received 6 August 2009 Accepted 4 January 2010 Available online xxxx Biomagnetic monitoring, using tree leaves as passive surfaces for particle collection, has been shown to be a promising technique for assessing the dispersion and deposition of particles in the context of anthropogenic pollution. By comparing leaves' magnetic properties with trace metal levels measured in the leaves, we here assess the utility of the biomagnetic technique as a sensitive, fast and inexpensive method for assessment of volcanic plume deposition. Samples of sweet chestnut leaves (Castanea sativa) were collected from the area surrounding Mt. Etna volcano in Sicily during the 2008 …

Pampa Biome Environmental Particularities Regarding to Energy Balance

2020

Ecosystem evapotranspiration (ET) has been quantified around the world by different methodologies to understand the energy balance, especially to control the evolution of climate change. It is known that the vegetation of the pampa biome is natural grasslands, it has a large variety of species (flora and fauna), however is it different in the environmental aspects related to the energy balance when compared to the grassland cultivated? In this study the objective was to analyze the environmental differences of the Pampa Biome related to the energy balance in comparison with the pastures cultivated in Barrax, Spain. In the first one the minimum daily ET is 0.99 mm/day, while in the second is…

Conservation of threatened habitat types under future climate change – Lessons from plant-distribution models and current extinction trends in southe…

2015

A higher risk of future range losses as a result of climate change is expected to be one of the main drivers of extinction trends in vascular plants occurring in habitat types of high conservation value. Nevertheless, the impact of the climate changes of the last 60 years on the current distribution and extinction patterns of plants is still largely unclear. We applied species distribution models to study the impact of environmental variables (climate, soil conditions, land cover, topography), on the current distribution of 18 vascular plant species characteristic of three threatened habitat types in southern Germany: (i) xero-thermophilous vegetation, (ii) mesophilous mountain grasslands (…

Grasslands and Shrublands of Kazakhstan and Middle Asia

2020

Abstract Kazakhstan and Middle Asia comprise 4 million km2 of plains, uplands and tall mountain ranges in the core of the Eurasian continent. The region's semi-arid climate, grazing pressure by wild and domestic ungulates, and long pastoral tradition, have given rise to a variety of open habitat types and a distinct flora and fauna. Grasslands and shrublands are a natural and dominant vegetation type in the forest-steppe and steppe zone of northern and central Kazakhstan, as part of the Eurasian grassland biome. In Middle Asia, grasslands and shrublands are widespread habitat types in the Tian Shan, Pamir-Alai and Pamir—mountain systems that have been recently acknowledged as a global biodi…

Testing GIS-morphometric analysis of some Sicilian badlands

2014

Abstract Calanchi badlands are erosion landforms characterized by areas with scarce or absent vegetation, steep slopes, knife-edge divides and high erosion rates. They are originated by a combination of morphogenetic processes, partly similar to those shaping bigger fluvial landforms, and therefore can be considered as field “laboratories.” This paper presents the results of an investigation carried out in two badland sites located in Sicily, where the geometry of 25 calanchi has been characterized using Digital Elevation Models having a mesh size equal to 2 m. For each landform, a power length–volume relationship is established. This relationship demonstrates that length of calanchi channe…

A new empirical model for estimating calanchi Erosion in Sicily, Italy

2015

Abstract Calanchi (plural of calanco) are typical badland landforms of the Italian landscape. They consist of dense networks of V-shaped valleys, with a sparse or absent vegetation cover, which frequently develop on unconsolidated or poorly consolidated clayey deposits. In this paper, the dimensional analysis and the incomplete self-similarity theory were used to deduce a model relating the volume of sediments eroded from the calanchi area to a set of geometric attributes of their tributary areas. The morphometric characteristics of 209 calanchi basins were used to calibrate and validate the model. The predictive skill of the model was assessed by calculating the mean square error and the N…

2021

Abstract. Lignin oxidation products (LOPs) are widely used as vegetation proxies in climate archives, such as sediment and peat cores. The total LOP concentration, Σ 8, provides information on the abundance of vegetation, while the ratios C / V and S / V of the different LOP groups also provide information on the type of vegetation. Recently, LOP analysis has been successfully applied to speleothem archives. However, there are many open questions concerning the transport and microbial degradation of LOPs on their way from the soil into the cave system. These processes could potentially alter the original source-dependent LOP signals, in particular the C / V and S / V ratios, and thus compli…

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…