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Natural Resources Survey
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 Geographical and Historical-Ecological Overview
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Jerusalem is in the Judean Hills, on the national watershed between the Mediterranean Sea and the Dead Sea, at an elevation of 650-840 meters above sea level. The Old City is located on Mount Moriah, on the eastern side of the city, in a region that reflects the sharp transition between the coastal strip of the Mediterranean Sea and the desert frontier. In this respect there are differences in the amounts of precipitation and the nature of the flora on the western and the eastern sides of the Old City, even though the distance between them is just one kilometer. Nahal Kidron and Gai Ben Hinnom, which drain the Old City and Mount Moriah to the south and east, flow in a generally eastward direction to the northern Judean Desert and the Dead Sea.
The wall surrounding the Old City of Jerusalem serves as a buffer element between the Old City and the New City. Ecologically speaking it constitutes a barrier affecting the movement of animals and plants to and from the Old City. Because it delimits the Old City it also dictates the building density and the kind of construction inside it, as well as the nature of the transportation, access roads, garbage removal and drainage, all of which have a decisive effect on the functioning of the Old City as an ecosystem.
In the past, in the absence of a city outside the wall, the wall was the interface between nature and the city. At the time the wall was built nature in the region of Jerusalem was both powerful and undisturbed.
The construction of the city wall, which utilized indigenous stones set on top of the natural rock with none of the intensive development work that is customary today, certainly facilitated the rapid integration of organisms into man-made infrastructures. Since its construction the city wall has been a kind of open laboratory in which fauna and flora meet the urban infrastructure and "attempt" to integrate into it. Those that succeeded in creating the initial contact remained on the city wall and became established in it, gradually adapted themselves to living alongside man, penetrated beyond the walls into the city itself, and later, by various means of transport and distribution, into adjacent settlements and other cities in the region as well.
An Ecological System Built in the Form of a Stepped-Pyramid. On the first tier are the primary creatures; these are flora, algae and photosynthetic bacteria that carry out the transduction processes by means of solar energy and assimilating the carbon molecules. On the next tiers are the secondary creatures, the herbivores followed by the carnivores and the apex carnivores that feed on everything. To the best of our knowledge there still does not exist a model that describes the order in which the various tiers are established on an urban platform. Was the habitat organized according to the ecological pyramid, that is flora first, and only later insects, mammals and seed-eating birds and finally the carnivores?
We do not believe that is the case. Presumably the more intact and undisturbed nature was on the interface along the wall, the easier it was for the upper tiers in the ecosystem to settle, to establish themselves not only in the faunal and floral system of the wall, but rather that of its surroundings, whereby the wall is used in this instance as a vantage point and a site for perching and nesting. In other words, we believe it is unreasonable that the common kestrel for example, an apex carnivore that was found during the survey nesting on the city wall, needed to "wait" for vegetation and insects to establish themselves on the wall, in order that it too could settle and nest on it. It seems more likely that the kestrels began using the wall for rest, observation and nesting shortly after the wall appeared, when they were hunting on the exposed slopes in the vicinity. Unfortunately, we do not have many sources that describe the inhabitation processes of organisms in the city of Jerusalem and none at all in urban infrastructures.
Almost certainly many of the animals and plants that were identified during the survey of the wall originally populated cliffs and natural stone walls. For example such was the case of house sparrows which in the past roosted in the cliffs and between the rocks, and already in antiquity adopted man-made structures as a substitute for their original living habitations. The Sages discuss this saying, "The free bird (i.e. house sparrow) refers to a wild bird which does not submit to taming" and add "Why is it called a free bird? Because it dwells in the house as in the fields" (Shabbath 106b).
There is no information regarding the time when most of the other organisms established themselves on artificial infrastructures. The first reliable sources that describe nature in Jerusalem are from the late nineteenth century, a time when a number of pilgrims and naturalists visited the Land of Israel. Two such researchers are the Reverend Henry Baker Tristram who was in the country in 1863-1864 and described his findings in two volumes, and Selah Merrill, the American consul in the Land of Israel at the end of the nineteenth century, who published a number of books and articles. The descriptions these two provide refer to the kinds of fauna and flora from which we learn that nature in the region of Jerusalem at this time was still wild and pristine. The animals they hunted included leopards, hyenas, wolves, honey badgers and Ruppell's foxes, none of which are seen in the vicinity of the city today. Also among the birds there are many species in their collections that are extremely rare today such as the Lanner falcon, Bonelli's eagle, Egyptian vulture, Peregrine falcon and tawny owl (Merrill 1890, Kark 2000).
Their descriptions teach us about the juxtaposition of nature in all its glory with the city, but it is difficult for us to draw conclusions from them regarding nature's integration within the city. A description by Merrill is therefore interesting, "In the autumn there were multitudes of different species of crows that came down to sleep on Jerusalem's city walls, more than any other bird". According to Tristram, in the past the common raven was widespread throughout Jerusalem and the Judean Hills, including on the city wall, whereas today it is extremely rare in the country and is not seen in this region.
He also described the western jackdaw as numbering in the thousands in the Old City and on top of the walls (Tristram 1884). This description is important because in the current survey the western jackdaw was found nesting on top of the city walls; however, on the basis of our observations and those of others, we know it has been absent from the city and almost all of Israel from the mid twentieth century until the 1990's. The current inhabiting is therefore a second settling after the species was harmed by pesticides that were scattered against the insects which it fed on. One of the qualities that seem to have enabled the western jackdaw to live on the wall and in artificial structures is its ability to learn and its rapid acclimatization and flexibility in selecting nesting sites. For example, in recent years enormous lampposts with round tops have been erected along the country's roads. Within a short period of time the western jackdaws learned that these lampposts are suitable for nesting, and today they populate them in large numbers.
The process of animal and plant adaptation to man's environment is therefore dynamic and unceasing. In fact, in our world today, when the country is being covered and "clothed in a robe of concrete and cement", it is doubtful if anyplace will remain for organisms that will not integrate in this process.
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