Helping the Delicate Balance of Nature

This unique occurrence has been studied in the Zoology Department of Tel Aviv University by researchers headed by Gilad Friedman with Sameh Darawshi, with KKL-JNF funding. Gilad Friedman presented his findings at a special day-seminar on KKL-JNF's latest R&D projects.

March 3, 2010 13:18
Helping the Delicate1

Helping the Delicate1. (photo credit: kkl)


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Something weird has been happening in the last few years among Israel's population of long-legged buzzards. This big and imposing predator used to nest in the cliffs above water courses in the Judean Mountains. But in recent decades they have gradually ceased nesting in these places, and have transferred their preference to a location that is very unconventional for this bird: on the crowns of trees in forests in the Judean lowlands. This nesting on trees by long-legged buzzards is a phenomenon that is unique to Israel.

This unique occurrence has been studied in the Zoology Department of Tel Aviv University by researchers headed by Gilad Friedman with Sameh Darawshi, with KKL-JNF funding. Gilad Friedman presented his findings at a special day-seminar on KKL-JNF's latest R&D projects. His research concludes that KKL-JNF's work in afforestation and in the rehabilitation of natural woodlands is the cause of this remarkable phenomenon. The forests and natural woodland cover almost 60% of the open areas where the long-legged buzzard hunts for its food, such as rodents and lizards. Since these food sources hide among the trees, the buzzard has relocated into a nearby area where, on the one hand, there are many open farmed fields, and nesting sites are available on mature forest trees, on the other hand.

However, since moving its nests to the trees, the buzzard now lives in closer proximity to the eagle owl (bubo bubo) and this closeness is affecting the buzzard's nesting success. The eagle owl likes to devour the buzzard's chicks out of the nest: nature is endlessly challenging.

Fifty-one buzzard nests were investigated during 2006 - 2008, using photography, marking of hatched chicks, and collecting disgorged pellets and uneaten remains of food. All these data are used to determine the type and quantity of the food that these magnificent birds consume. In addition, tracking transmitters were attached to some of the adults. Twenty-two nests were located on trees in KKL-JNF forests. One of the facts brought out by the research is the delicacy of the natural balance that allows the long-legged buzzard to prosper: the shortage in its food supply during the drought in 2008 caused a significant decline in its nesting success.

This investigation was only one in a whole series of studies presented at the annual KKL-JNF seminar day, held in the Ministry of Agriculture's premises at Beit Dagan. It was attended by senior researchers in the sphere of land use, mainly KKL-JNF staffers from all round the country, as well as personnel from the Volcani Agricultural Research Institute.

In his opening remarks, the director of KKL-JNF's Land Development Authority Gershon Avni voiced his anxiety about the future fate of the research studies, which are such a vital primary tool when deciding on policies for land use. The worldwide economic crisis is now threatening the principal sources of KKL-JNF's income from land and from donations worldwide. "We are endeavoring to engage in research that is applicable and practical, the very opposite of purely academic research. Recently we've taken part in several international meetings where it was made very clear just how greatly KKL-JNF's research work also contributes on the international level, and how great the demand is from many countries around the world for the assistance that our accumulated knowledge provides.

"Dr. Avi Gafni, who moderated the first session of the seminar, pointed out that "In 2008, KKL-JNF supported around 70 different research projects, most connected with forestry. This is a very respectable number, and the support for them is significant. This annual seminar is first and foremost a forum for the dissemination and enhancement of knowledge through the research results, while at the same time also serving us as a platform for discussion and clarification, and to bring up research issues.

"Professor Yuval Eshdat, the chief scientist of the Ministry of Agriculture and Rural Development, spoke of two crises confronting the world at the present time: the energy crisis and the food crisis. And hovering over both of these is the enormous financial breakdown. "The lack of credit and the drop in prices will affect the scope of new plantings and the extent of agricultural crops, and that will have an effect on the directions when planning land use. I expect dramatic changes to take place in the allocation of ground for crops, including industrialized agriculture for producing energy that should not be at the expense of food crops.

"In his talk, Professor Gabriel Schiller raised many questions about the future of interface management of forests in Israel, and the present trend of changing the composition of the planted forests that already exist. He warned that the lack of detailed knowledge about the source of seeds and saplings in past periods led to the creation of forests whose trees are genetically not the best. Therefore, Schiller emphasized, it is essential that each forest be managed by its own "forest book" that will include all possible data, starting with its biology, taking into account its water and rainfall and noting the source of all the trees planted in it. Schiller urged that research must continue on specific topics relating to the condition of the natural vegetation that grows in a planted forest. "For most of our forests, the seeds were gathered from a low source (a relatively low tree is easier for climbing on) and not from 30-meter high upright trees. That's why we haven't yet managed to grow a multi-purpose forest, and why we haven't been successful in maintaining our forests' health and stability.

"This was precisely a point made in the research of Assaf Tsur, one of the winners of a scholarship from the René Kershon Fund, named in memory of one of the leading scientists in the sphere of forestry worldwide. This is the tenth year that these scholarships have been awarded to students studying for their master's degree in different aspects of forest research. Assaf Tsur's research aims to identify the best sources for seeds of the Calabrian pine, in order to locate the seeds that will grow best in arid conditions. His research focuses on identifying the most suitable sub-species for the desert conditions and aridity that prevail in Israel, in order thereby to create a forest that will respond to the changing climatic conditions and that will be resistant even during years of total drought or of little rainfall.

The other beneficiaries of the Kerson scholarship are Omer Golan, Efrat Sheffer and Nitai Zacharia, whose researches address interface forest development (for the wood and paper industry), the effect of human intervention on the development of natural woodland in the coming decades, and the likelihood of natural renewal in pine forests.

Dr. Jean-Marc Dufour-Dror presented his research on the kermes oaks that grow within the present pine forests. He declared that without human intervention the oaks will not be able to close up the bald patches that are going to form in the pine forests as they reach the end of their lives, towards the year 2050. His research focused on KKL-JNF's forests in the center of the country, and showed that oaks within pine forests are subject to different kinds of pressures, such as the amount of light that penetrates into them, and the effect of animals' eating the acorns and preventing natural germination. Dr. Dufour-Dror said that only meticulous, consistent implementation of interface activities will be able to bring about long-term planning for mixed forests, to replace the first generation of planted pine forests.

Dr. Yosef Sapir's research is on the condition of one-year and multi-year vegetation in arid regions. Carried out in and around the Yatir Forest, it shows that the forest is having a beneficial effect on the propagation of one- and multi-year low plants on the forest edges over significant distances - from between hundreds of meters and up to five kilometers from the forest's outskirts. Dr. Sapir also gave his recommendations on how to safeguard the plants and rare flowers that bloom in the forest's environment. These included transferring and increasing the number of sternbergia (autumn crocus) bulbs and planting them in new concentrations, so as to reduce the pressure caused by the many visitors at the present sternbergia sites.

A fascinating research study described at the seminar is that of Shmuel Arbel from the Soil Erosion Research Station of the Ministry of Agriculture. Arbel's research is aimed at deciding, once and for all, whether trees should be planted in the stream beds of wadis. Even though his work did not have a budget for comprehensive research, it nevertheless has shown that the traditional mind-set on the question of planting trees in wadi channels has been wrong. Before Arbel's research, the Ministry of Agriculture's Soil Preservation and Drainage Department opposed planting trees in drainage channels and river beds for the purpose of stabilizing the soil and preventing erosion. Most of this opposition stemmed from concern about disturbing the proper flow of the water, creating spots of turbulence and eroding the channels' banks.

Shmuel Arbel's research was carried out during three years in different river beds around the country, and also included channels where enormous floods have taken place. And it transpired that in not one of these sites did any trees planted in a wadi have any sort of negative effect at all: indeed, in many cases the trees had a positive effect because they slowed down the water's flow and stopped the deluge from speeding-up when flowing down slopes. The trees made a conspicuous contribution to the amount of energy in large floods: at its peak the largest torrent swept 160 cubic meters of water per second! All the trees stood up very well to the pressure from the deluge, and their roots were not ripped out. The height of the flood's flow, that was sometimes over 2 meters high, could be clearly seen on the trees, as the vegetation that had been swept along in the water ended up clinging to the trunks.

KKL-JNF's research continually provides new findings to help Israel's nature thrive. And this knowledge is disseminated worldwide, to help improve the global environment.

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