Reversed Desertification on Sand Dunes Along the Sinai/Negev Border

Changes in the Israeli/Egyptian border since 1948 have affected the land use patterns of the Bedouin tribes inhabiting these areas. These changing patterns are clearly discerned from aerial photographs and satellite images in this area of extensive linear dunes. The most recent change occurred after Israel’s withdrawal from the Sinai in 1982. Field observations show that the vegetation in the Negev recovered from overgrazing in a very short time, with a 180% increase in the number of Negev shrubs, coincident with a continued decrease in the number of shrubs on the Sinai side of the border. Analysis of the reflectance of the Landsat-MSS for the recovery years (1984, 1987, and 1989) shows a statistically significant difference between the two sides of the border for the four MSS bands. However, the spectral brightness curves of the four bands failed to reveal any specific “signature” typical for vegetation. Field measurements with a spectrometer indicate that the curve shape of the reflectance of the Landsat-MSS images is swayed by the biogenic crust in the Negev that makes the well known contrast in albedo with Sinai.