Variable vegetation cover and episodic sand movement on longitudinal desert sand dunes

Geomorphology ◽  
2006 ◽  
Vol 81 (3-4) ◽  
pp. 276-291 ◽  
Author(s):  
Paul P. Hesse ◽  
Rebecca L. Simpson
Keyword(s):  
Vegetation Cover ◽  
Sand Dunes ◽  
Desert Sand ◽  
Sand Movement

The utility of desert sand dunes as Quaternary chronostratigraphic archives: evidence from the northeast Rub' al Khali

2013 ◽  
Vol 78 ◽  
pp. 303-318 ◽  
Author(s):  
Carly L. Leighton ◽  
Richard M. Bailey ◽  
David S.G. Thomas
Keyword(s):  
Sand Dunes ◽  
Desert Sand

Leaf demography and decline of Panicum racemosum populations in coastal foredunes of southern Brazil

1991 ◽  
Vol 69 (7) ◽  
pp. 1593-1599 ◽  
Author(s):  
César S. B. Costa ◽  
Ulrich Seeliger ◽  
César V. Cordazzo
Keyword(s):  
Population Biology ◽  
Sand Dunes ◽  
Salt Spray ◽  
Nutrient Status ◽  
Southern Brazil ◽  
Leaf Demography ◽  
Growth Vigour ◽  
Sand Movement ◽  
Mobile Dune ◽  
Sand Deposition

We studied the effect of nutrient status and sand movement on the population biology of Panicum racemosum Spreng. over a 5-year period (1982–1986) on mobile, semifixed and fixed coastal foredune habitats in southern Brazil. The soils were deficient in nitrate, phosphate, and potassium (<0.5, 0.2–1.2, and 3–5 mg/kg, respectively) in all habitats, and a gradient of decreasing availability existed from the mobile to the fixed dunes. Half-lives of leaves were shorter in the fixed dune as compared with the mobile dune. Similarly, half-lives of leaves were shorter in summer than in winter. Experiments using cuttings of P. racemosum tillers showed that as P. racemosum plants grew, so did the deposition of sand on mobile foredunes. The mechanical deposition of sand itself did not stimulate P. racemosum growth. The deposition of saline sand provided a substrate that supported vertical growth of P. racemosum rhizomes and tillers and was a source of adsorbed nutrients. Also, active sand deposition limited the invasion of frontal dunes by other species. Panicum racemosum populations changed from "invader" to "mature" to "regressive" age states over a 5-year period, apparently in response to the spatial patterns of sand deposition and salt spray input. Key words: Panicum, leaf demography, growth vigour, sand dunes, temporal changes.

On the Observation of Desert Sand-Dunes

1908 ◽  
Vol 31 (4) ◽  
pp. 400 ◽  
Author(s):  
Vaughan Cornish
Keyword(s):  
Sand Dunes ◽  
Desert Sand

scholarly journals MONITORING DESERTIFICATION IN SOME REGIONS OF IRAQ USING GIS TECHNIQUES

2021 ◽  
Vol 52 (3) ◽  
pp. 620-625
Author(s):  
Y. K. Al-Timimi
Keyword(s):  
Remote Sensing ◽  
Environmental Economic ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Marked Decrease ◽  
Social Systems ◽  
Sand Dunes ◽  
Rate Of Increase ◽  
Remote Sensing Techniques

Desertification is one of the phenomena that threatening the environmental, economic, and social systems. This study aims to evaluate and monitor desertification in the central parts of Iraq between the Tigris and Euphrates rivers through the use of remote sensing techniques and geographic information systems. The Normalized difference vegetation index NDVI and the crust index CI were used, which were applied to two of the Landsat ETM + and OLI satellite imagery during the years 1990 and 2019. The research results showed that the total area of ​​the vegetation cover was 2620 km2 in 1990, while there was a marked decrease in the area Vegetation cover 764 km2 in 2019, accounting for 34.8% (medium desertification) and 10.2% (high desertification), respectively. Also, the results showed that sand dunes occupied an area of ​​767 km2 in 1990, while the area of ​​sand dunes increased to 1723 km2 in 2019, with a rate of 10.2%) medium desertification (and 22.9% (severe desertification), respectively. It was noted that the overall rate of decrease in vegetation cover was 21.33 km2year-1 while the overall rate of increase in ground erosion in the area is 10.99 km2year-1.

scholarly journals Development of Desertification Indicators for Desertification Monitoring from Landsat Images Using Python Programming

2022 ◽  
Vol 8 (2) ◽  
pp. 99-114
Author(s):  
Lamyaa Gamal EL-Deen Taha ◽  
Manar A. Basheer ◽  
Amany Morsi Mohamed
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Landsat Images ◽  
Image Differencing ◽  
Layer Stacking ◽  
Southern Side ◽  
Sand Movement ◽  
Dune Migration ◽  
Desertification Assessment ◽  
Python Programming

Nowadays, desertification is one of the most serious environment socioeconomic issues and sand dune advances are a major threat that causes desertification. Wadi El-Rayan is one of the areas facing severe dune migration. Therefore, it's important to monitor desertification and study sand dune migration in this area. Image differencing for the years 2000 (Landsat ETM+) and 2019 (OLI images) and Bi-temporal layer stacking was performed. It was found that image differencing is a superior method to get changes of the study area compared to the visual method (Bi-temporal layer stacking). This research develops a quantitative technique for desertification assessment by developing indicators using Landsat images. Spatial distribution of the movement of sand dunes using some spectral indices (NDVI, BSI, LDI, and LST) was studied and a Python script was developed to calculate these indices. The results show that NDVI and BSI indices are the best indices in the identification and detection of vegetation. It was found that mobile sand dunes on the southern side of the lower Wadi El-Rayan Lake caused filling up of large part of the lower lake. The indices results show that sand movement decreased the size of the lower Wadi El-Rayan Lake and there are reclamation activities in the west of the lower lake. The results show that a good result could be achieved from the developed codes compared to ready-made software (ENVI 5).

Sign in / Sign up

Export Citation Format

Share Document