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This review addresses the growth and development of medicinal plants under arid land conditions and the potential use of remote sensing technologies to map their distribution, as well as morphological and physiological responses in Arid lands. Plant morpho-physiological variables including, chlorophyll content, and gas exchange (photosynthesis, transpiration, vapor pressure, and stomatal conductance) are linked to plant water status. Multispectral and hyperspectral remote sensing techniques are promising for detecting morphological physiological changes. Vegetation indices derived from hyperspectral and multispectral imagery makes it possible to assess medicinal plants' health through successful detection of the ground plant physiological variables and canopy cover including chlorophyll, canopy density, gas exchange (red, 600-700 nm, nearinfrared spectrum, 700-1100 nm) as well as water status (shortwave infrared, 1300-2500 nm). Surface reflectance data within the shortwave infrared bands (water bands) revealed significant differences between well-watered and drought-stressed plants. However, the moderate spatial resolution (Sentinel-2: 20 m, Landsat: 30 m) for the space-born free sensors and the need for a cloud-free sky could be limitations. Overall, vegetation indices derived from remotely sensed data are a useful approach for estimating the physiology of plants (medicinal plants) especially those under drought stress. [ABSTRACT FROM AUTHOR]

This paper investigated the impact of land use/cover changes on the flow of the Zarqa River in Jordan over a period of twenty-eight years. The land use/cover maps were derived using a set of medium spatial images with full scenes for the years 1989, 2002, 2011 and 2017. These images correspond to the river flow data for the same hydrological rainy seasons. The component of the river flow consists of the base-flow, flood and contribution of effluent from treatment plants. Base-flow was separated from hydrographs and effluent contribution was obtained. Runoff coefficient was determined as the ratio of flood volume to rainfall volume. The land use/cover maps were classified as urban fabrics, bare rocks, open rangelands and bare soils, agricultural areas, agro-forestry, and water bodies. During the study period, urban areas increased from 4.87% to 16.14%, and agricultural areas increased from 21.69% to 31.66%. The areas of rangelands and bare soil decreased from 34.91% to 22.57% and bare rocks from 35.98% to 27.57%, respectively. The increase in urban and agricultural areas resulted in runoff coefficient improvement from 1.89% in 1989/1990 to 2.72% for 2016/2017. The results could be useful for planners and decision makers for future flow management in the Zarqa River Basin. The approach and results of this study confirm the findings of similar studies for land and water management. [ABSTRACT FROM AUTHOR]