نتایج جستجو برای: total vegetation cover decreased by 362

تعداد نتایج: 7530927  

According to the National Park Bamoo protection, land use in and around the park area that have direct and indirect effects and impacts on the park. It is necessary to examine changes in the use and management plan appropriate to the region. To evaluate the quantitative and qualitative changes occurred in the national park Bamoo ecosystem and environmental conservation and management of this ar...

Maryam Moradnezhadi Sahar Delpasand Yousef Askari, Zahra Hossaini

The preparation of vegetation cover maps by used the land inventory and a traditional method has a lot of cost and time. But today, remote sensing is one of the main sources of data collection and information production for study and monitoring land resources, and was efficient tools for providing quickly and timely data and information needs for program planning in the natural resource filed. ...

Journal: :Remote Sensing 2014
Xiaohui Yang Xulin Guo

Spectral vegetation indices have been the primary resources for characterizing grassland vegetation based on remotely sensed data. However, the use of spectral indices for vegetation characterization in grasslands has been challenged by the confounding effects from external factors, such as soil properties, dead materials, and shadowing of vegetation canopies. Dead materials refer to the dead c...

2007
Marilyn D. Walker Donald A. Walker Kaye R. Everett Susan K. Short MARILYN D. WALKER

The hypothesized presence of large regions of grass and forb-dominated "steppe tundra" across Alaska and Siberia during the Pleistocene glacial epochs has led to a search for modern analogs. Evidence is presented for the presence of steppe vegetation on south-facing slopes and summits of pingos within the central Arctic Coastal Plain of Alaska. Vegetation, floristics, soils, and climatic factor...

2013
Huifeng Hu Benjamin O. Knapp G. Geoff Wang Joan L. Walker

We installed a field experiment to support the development of protocols to restore longleaf pine (Pinus palustris Mill.) to existing mature loblolly pine (P. taeda L.) stands at Camp Lejeune, NC. Seven canopy treatments included four uniform and three gap treatments. The four uniform treatments were defined by target residual basal area (BA) [control (uncut), BA9, BA4.5, and BA0 (clearcut) m2/h...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2007
L Gillson K I Duffin

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 ...

2003
Jenny Bergfur A. Lisa M. Carlsson Per Milberg

Phenological changes within a growth season were investigated in two grazed, seminatural grasslands in southern Sweden. On four occasions during the growth season, two independent observers recorded plant frequency and percentage cover. The vegetation data sets were analysed with ordination methods. The temporal changes were highly significant, but accounted for only a small part of the total v...

2017
Dongwook W. Ko Dasom Kim Amartuvshin Narantsetseg Sinkyu Kang

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it c...

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...

Plant species distribution, composition and diversity in deserts of arid and semi-arid areas, especially saltland; depend on soil physical and chemical gradients. The aim of this research was to investigate changes in the plant species diversity and richness along a soil salinity gradient in the margin rangelands of Petregan Playa. After vegetation zoning in relation to soil salinity, random-sy...

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