The Arava is a long and narrow valley running from the southern tip of the Dead Sea to the Bay of Eilat and it divides the Edom Mountain Range in the east from the Negev and Eilat Mountains in the west. The Arava is located in the Saharo-Arabian Region and has an extreme desert climate. The most prominent feature of the region is the continuous lack of water, which stems from the low level of precipitation and very few permanent sources of water. The level of precipitation changes every year as does the timing and dispersion. Because there has been so little rainfall for tens of thousands of years, the process of rock erosion and development of the soil is very slight and very slow resulting in little and shallow soil. The high summer temperatures and the strong radiation cause evaporation, and in many places, the saline content of the soil is very high. There is also a huge variation between night and day temperatures and between summer and winter.
These conditions make it very difficult for the flora and fauna in the Arava. Hence, the flora covering the surface is quite sparse. Most of the plants live in the dry riverbeds where floods occasionally occur. Because of the exposed surfaces, the winds cause sandstorms that spread over vast areas.
Given that the environment is allegedly not friendly to animals, we would expect that these difficulties would limit the number of animals and species that can live in the desert. However, a comparison with the number of animal species that live on a regular basis in Galilee, provides interesting results. Tests reveal that out of 98 mammal species that live in Israel, in the Upper and Lower Galilee there are 53 species, while 46 species of mammals live in the Arava on a regular basis. Out of 91 species of reptiles that live in Israel, 33 are found in the Galilee and the same number of reptile species are found in the Arava. These two examples show that relative to the harsh climate conditions in the Arava, the diversity of species is broad, and this phenomenon necessitates explanation.
Article by Dr. Ostreicher from the book Arava Ein Ketz, The Endless Arava