Environmental activists, scientists and green organizations, first and foremost the Society for the Protection of Nature in Israel (SPNI), have over the past few years been making an effort to protect the remaining natural assets in urban areas. Apparently there is no clear worldview about the characteristics of urban nature, its importance and the means of preserving it.

Now the Deshe (Open Landscape) Institute, which operates as part of the SPNI, has published a paper, "Urban Ecology," on the subject by Inbal Brikner Brown from the Jacob Blaustein Institute for Desert Research at Ben-Gurion University of the Negev. It deals with, among other things, what is worthwhile and possible to preserve on the basis of existing scientific knowledge.

Scientists tend to define five types of scenery creating a continuum from a natural environment to the typical urban center.

This starts with natural scenery and continues to the "managed natural landscape" in which man is involved in various ways, including the planting of greenery or the feeding of wild animals.

After that, there are agricultural landscaps and suburban landscapes characterized by low or medium density of homes, backyards and roads. Finally there is the urban landscape in which one finds high-density home construction, commercial buildings and paved and tiled areas that are broken up occasionally by parks, gardens or remnants of natural fields locked within the confines of the city.

Research has pointed to a clear decline in the wealth of animal species in urban scenery. Nevertheless there are still many species known as "urban adaptables" that thrive in places offering somewhere to hide, sources of food and available water as well as comfortable temperatures.

The key question is whether there is a basis for assuming that preserving and nurturing urban nature can contribute concretely to preserving the world of flora and fauna on a countrywide level and not only locally. If proven incorrect, this could lead to increased pressure to extend building into open fields.

Most research indicates the answer to this question is no. Urban scenery is indeed interesting in its own right and deserving of being protected and nurtured, especially in cases involving rare species, but it does not contribute directly to preserving the general diversity of the species.

The adaptable species inside urban areas are generally those that do not require preservation since they are part of a large population in nature. There are urban areas, such as large parks, in which a particularly great diversity of species exists, but these are generally foreign species. In the Yarkon Park, for example, there is a great abundance of bird species, but these are mainly foreign species that escaped from zoological gardens and multiplied. Today they are considered a serious ecological hazard that drive out local bird species.

Sometimes there are isolated populations of wild animals in the city, like the deer that have remained alone in Deer Valley in Jerusalem, which has been surrounded by buildings. A population of this kind has no significance from the point of view of preserving the general population of that particular species, and they are no different from populations that can be found in zoological gardens since they cannot keep up a connection with the world outside.

Efforts to preserve rare species in the city and the deliberate attraction of different species by the creation of places to nest and feeding sites can create a dangerous ecological trap, according to Brikner Brown. Red Falcons have found an abundance of nesting places in the roofs and attics of Jerusalem homes, but for many the city has become a death trap.

There are sites like the Winter Pool in Netanya where extremely rare species have succeeded in surviving. Brikner Brown contends these are examples of how the city has rudely invaded nature and harmed it. "Those who protect nature should try as far as possible to keep the influence of the city from these unique assets of nature and not allow them to become integrated into the urban texture," she says. As for Netanya's Winter Pool, that is what environmental activists in that city tried to do but as the pool is being surrounded by buildings and roads, it is not clear which of the rich world of fauna and flora found there will survive.