Search results for "Cover"
showing 10 items of 5959 documents
Comparison of cloud-reconstruction methods for time series of composite NDVI data
2010
Land cover change can be assessed from ground measurements or remotely sensed data. As regards remotely sensed data, such as NDVI (Normalized Difference Vegetation Index) parameter, the presence of atmospherically contaminated data in the time series introduces some noise that may blur the change analysis. Several methods have already been developed to reconstruct NDVI time series, although most methods have been dedicated to reconstruction of acquired time series, while publicly available databases are usually composited over time. This paper presents the IDR (iterative Interpolation for Data Reconstruction) method, a new method designed to approximate the upper envelope of the NDVI time s…
Short-Term Vegetation Recovery after a Grassland Fire in Lithuania: The Effects of Fire Severity, Slope Position and Aspect
2016
In Lithuania, fire is frequently used by farmers as a tool to remove dry grass, improve soil nutrient status and help soil tilling. However, little is known about the ecological impacts of these fires, including vegetation recovery. The objective of this work is to study the impacts of a spring grassland fire on vegetation recuperation on an east-facing (A) and a west-facing slope (B), considering fire severity and slope position, 10, 17, 31 and 46 days after the fire. Because of their effects on fire behaviour, aspect, steepness and heterogeneity of topography favoured higher fire severity on slope B than on slope A. Three different slope positions were identified on slope A – flat top, mi…
Assessing and Modeling Soil Detachment Capacity by Overland Flow in Forest and Woodland of Northern Iran
2020
Land use has significant effects on the erosion process, since it influences the soil detachment capacity by causing an overland flow (Dc). The effects of different land uses on the rill detachment capacity have not been explained in depth, and the hydraulic parameters providing accurate estimates of this soil property have not been completely identified. This study quantifies Dc at low flow rates in woodland and forestland, compared to two other land uses (cropland and grassland), in the Saravan watershed (Northern Iran), and develops prediction models of Dc and rill erodibility (Kr). Dc was measured on undisturbed soil samples, collected in the four land uses, and characterized in terms o…
Holocene land-cover reconstructions for studies on land cover-climate feedbacks
2010
The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover – CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene…
Monitoring elevation variations in leaf phenology of deciduous broadleaf forests from SPOT/VEGETATION time-series
2011
International audience; In mountain forest ecosystems where elevation gradients are prominent, temperature gradient-based phonological variability can be high. However, there are few studies that assess the capability of remote sensing observations to monitor ecosystem phenology along elevation gradients, despite their relevance under climate change. We investigated the potential of medium resolution remotely sensed data to monitor the elevation variations in the seasonal dynamics of a temperate deciduous broadleaf forested ecosystem. Further, we explored the impact of elevation on the onset of spring leafing. This study was based on the analysis of multi-annual time-series of VEGETATION da…
Topographic descriptors and thermal inversions amid the plateaus and mountains of the Jura (France)
2018
Sixteen temperature measurement sites under forest cover are distributed across the plateaus and mountains of the Jura (France). They are composed of pairs of stations located, one at the bottom of a topographic trough, the other at least 50 m higher in altitude. Three descriptors (station elevation, altitudinal difference (amplitude) between the two stations of each site, and topographical context) are used to explain how the frequency, intensity, and duration of inversions are spatially structured. Depending on whether one considers: 1) tn (minimum temperature) or tx (maximum temperature), 2) frequency or intensity, the sign of the correlation values changes. This reflects the fact that n…
Analysis of the radar vegetation index and assessment of potential for improvement
2018
The Radar Vegetation Index (RVI) is widely applied to indicate vegetation cover. The index includes the backscattering intensities of co- and cross-polarization that do not only contain information coming from vegetation scattering at longer wavelength (L-band), but also from the soil underneath. A forward modelling approach using active and passive microwave-derived parameters to obtain the scattering contribution of the soil is pursued. The idea of this research study is a subtraction of the attenuated soil scattering contribution from the measured backscattering intensities, to provide a clean vegetation-based solution, called improved RVI (RVII). For latter analysis, the vegetation volu…
Prehistoric palaeodemographics and regional land cover change in eastern Iberia
2019
Much attention has been placed on the drivers of vegetation change on the Iberian Peninsula. While climate plays a key role in determining the species pools within different regions and exerts a strong influence on broad vegetation patterning, the role of humans, particularly during prehistory, is less clear. The aim of this paper is to assess the influence of prehistoric population change on shaping vegetation patterns in eastern Iberia and the Balearic Islands between the start of the Neolithic and the late Bronze Age. In all, 3385 radiocarbon dates have been compiled across the study area to provide a palaeodemographic proxy (radiocarbon summed probability distributions (SPDs)). Modelled…
Advances in Cretaceous palaeontology and stratigraphy – Christopher John Wood Memorial Volume; editors' preface
2018
Abstract In the last week of January 2016, the ‘Cretaceous community’ lost another of their prominent members, Chris Wood. During recent decades, Chris had been active in the United Kingdom as well as in mainland Europe, particularly in Germany and Poland. Several years ago he had been forced to leave the ranks of Associate Editors with Cretaceous Research , due to a severe illness that he was adamant to overcome. Later in 2016, two of us, fellow editors with that journal for a number of years, with the help of Rory Mortimore, approached former colleagues and friends of Chris's to contribute to a special issue. From the start, the idea has been to cover all aspects of Cretaceous stratigraph…
What are the effects of even-aged and uneven-aged forest management on boreal forest biodiversity in Fennoscandia and European Russia? : A systematic…
2019
Abstract Background Biodiversity is vital for human well-being, but is threatened by human actions world-wide. In the boreal zone, harvesting and management of forests on an industrial scale is the most important factor driving habitat change and degradation. Over time different forest management regimes have been implemented but their impact on biodiversity at different spatial and temporal scales has not been systematically reviewed although non-systematic reviews on the topic exist. The aim of this article is to describe a protocol for a systematic review to synthesise and compare the impacts of two different forest management systems on biodiversity at different spatial and temporal sca…