نتایج جستجو برای: vegetation cover
تعداد نتایج: 148562 فیلتر نتایج به سال:
In Australia, remotely sensed Landsat TM data is routinely used for mapping and monitoring the change in extent of woody perennial vegetation cover providing information for conservation, land management and for modelling carbon flux and water use. For a variety of reasons including land cover definitions and sensor spectral limitations, studies have tended to focus on reporting changes in land...
Detecting land cover change over semi-arid rangeland is important for monitoring vegetation responses to drought, population expansion, and changing agricultural practices. Such change can be detected using vegetation indices, but these do not represent non-green vegetation and are dominated by seasonal changes. An alternative is to observe spatial changes in thermal emissivities, a measure tha...
negative impacts of gully erosion in marly areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. the objective of this research was to evaluate gully thresholds related to plant vegetation cover and landuse change in the agriculture (ag), fair rangeland (fr) and weak rangeland (wr) areas of ghaasr-e-shirin, kermanshah, i...
It is generally believed that there is an inverse relationship between population growth and vegetation cover. However, reports about vegetation protection and reforestation around the World have been continuously increasing in recent decades, which seems to indicate that this relationship may not be true. In this paper, we have taken 21 cities in Guangdong Province, China as the study area to ...
Land cover changes significantly influence vegetation greenness in different regions. Dense Landsat time series stacks provide unique opportunity to analyze land cover change and vegetation greenness trends at finer spatial scale. In the past three decades, large reclamation activities have greatly changed land cover and vegetation growth of coastal areas. However, rarely has research investiga...
Comparison of several recent, publicly available and widely used land-cover products for the Eurasian Arctic revealed important differences in their representations of vegetation distribution. Such disparities have important implications for models that use these products as driving data sets to monitor vegetation and its role in carbon dynamics. The differences between GLC-2000 and MODIS.PFT a...
In the Kruger National Park (KNP), South Africa, ecosystem managers use a series of monitoring endpoints, known as thresholds of potential concern (TPCs), to define the upper and the lower levels of accepted variation in ecosystems. For woody vegetation, the current TPC suggests that woody cover should not drop by more than 80% of its 'highest ever' value. In this paper, we explore the utility ...
Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sed...
The goals of this paper are to assess feasibility of using total concentration (TPC) of phytoliths in modern soils and morphotypes in soil assemblages to infer paleovegetation cover and composition. We sampled from undisturbed grassland sites with different values of shrub and grass cover in the Columbia Basin, interior Pacific Northwest, USA. Phytolith concentration in soils were measured and ...
The West Virginia Department of Environmental Protection, in a cooperative agreement with the Office of Surface Mining’s Charleston Field Office, is evaluating the utility of high resolution satellite images for characterizing vegetation patterns on reclaimed surface mines. This paper details the results of the first phase of this project, which sought to determine whether satellite images coul...
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