نتایج جستجو برای: high vegetation

تعداد نتایج: 2095458  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده علوم انسانی 1391

this research is a study on indicators of listening instruction in iranian english as a foreign language (efl) curriculum at guidance school and high school educational levels. this thesis aims at determining: a) the indicators of listening instruction at guidance school and high school efl curriculum. b) the indicators of listening instruction in irans guidance school and high school efl curri...

2013
Miguel L. Villarreal Laura M. Norman Robert H. Webb Raymond M. Turner

Vegetation and land-cover changes are not always directional but follow complex trajectories over space and time, driven by changing anthropogenic and abiotic conditions. We present a multi-observational approach to land-change analysis that addresses the complex geographic and temporal variability of vegetation changes related to climate and land use. Using land-ownership data as a proxy for l...

2013
Sarina Macfadyen Warren Muller

Agricultural landscapes can be characterized as a mosaic of habitat patches interspersed with hostile matrix, or as a gradient of patches ranging from suitable to unsuitable for different species. Arthropods moving through these landscapes encounter a range of edges, with different permeability. Patches of native vegetation in these landscapes may support natural enemies of crop pests by provid...

2002
Joan S. Thullen James J. Sartoris William E. Walton

The impact of three vegetation management strategies on wetland treatment function and mosquito production was assessed in eight free water surface wetland test cells in southern California during 1998–1999. The effectiveness of the strategies to limit bulrush Schoenoplectus californicus culm density within the cells was also investigated. Removing accumulated emergent biomass and physically li...

Journal: :Journal of environmental quality 2007
P K E Campbell E M Middleton J E McMurtrey L A Corp E W Chappelle

Current methods for large-scale vegetation monitoring rely on multispectral remote sensing, which has serious limitation for the detection of vegetation stress. To contribute to the establishment of a generalized spectral approach for vegetation stress detection, this study compares the ability of high-spectral-resolution reflectance (R) and fluorescence (F) foliar measurements to detect vegeta...

2005
M. W. Straatsma

The determination of hydrodynamic vegetation density of floodplain forests in the Netherlands is currently based on manually delineated vegetation types and a lookup table to convert these into vegetation density. In this paper a method is presented to extract vegetation density from high-density airborne laser scanner data. Field reference data were collected on 45 plots in three different flo...

2015
Niti B. Mishra Kelley A. Crews Jennifer A. Miller Audrey L. Mayer

Savanna ecosystems are geographically extensive and both ecologically and economically important; they therefore require monitoring over large spatial extents. There are, in particular, large areas within southern Africa savanna ecosystems that lack consistent geospatial data on vegetation morphological properties, which is a prerequisite for biodiversity conservation and sustainable management...

Desertification phenomenon is not devoted to an especial climate, although its role in arid and semi-arid areas is clearer than other regions. In this research, four criterions of the wind erosion, soil, vegetation cover and climate have been considered for evaluating desertification potential and mapping of desertification intensity using to IMDPA model in ZAHAK Sistan region. Considering to e...

Journal: :Remote Sensing 2015
Martin Kappas Pavel Propastin Jan Degener Tsolmon Renchin

Long-term global datasets of the Leaf Area Index (LAI) are important for monitoring global vegetation dynamics and are an important input for Earth system models (ESM). The comparison of long-term datasets is based on two recently available datasets both derived from AVHRR (Advanced Very High Resolution Radiometer) time series. The LAI3g dataset is developed from the new improved third generati...

2016
Craig P. Paukert David W. Willis Richard S. Holland CRAIG P. PAUKERT DAVID W. WILLIS RICHARD S. HOLLAND

—We assessed the precision of visual estimates of vegetation and substrate along transects in 15 shallow, natural Nebraska lakes. Vegetation type (submergent or emergent), vegetation density (sparse, moderate, or dense), and substrate composition (percentage sand, muck, and clay; to the nearest 10%) were estimated at 25–70 sampling sites per lake by two independent observers. Observer agreement...

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