Ido Izhaki – Previous Research Projects

 

Establishing an optimal management tools to reduce man –crane conflict in the Hula Valley, Israel

 

(with Dr. Yossi Leshem, Dr. Nir Beker, Dan Alon, Yifat Davidson and Naama Lindman)

 


 

                      

                 Yifat & Crane                                Eurasian cranes (Grus grus) in the Hula Valley, Israel (Photos by Zadok                                                   Machiev (left) and Amir Aloni (right))

        

Project description (Yifat Davidson's M.Sc.'s Abstract): Examination of crane-agriculture

management model in the Hula Valley

 

In the beginning of the 90's the Hula Valley underwent many changes, as a part of a project for water and soil management rehabilitation: many water canals were dug, a small lake was created and many new crops were introduced to the valley. All of this and especially the introduction of peanuts brought about a drastic increase in the wintering crane (Grus grus) population in the valley. In order to deal with the large scale crop damage caused by the cranes, the crane project was established in 1999. The project, incorporates agricultural and environmental organizations, aimed at preventing crane damage along with protection of the population. The management includes protection of the fields against the cranes by variety of tools, expulsion of the crane population at the end of the fall and feeding wintering cranes with corn in a feeding station.

Management for preventing wild life damage, specially those using feeding stations, might have a negative impact on the population ecology, such as behavioral changes, alteration of ecological characteristics, disruption of life cycles (migration, wintering and nesting periods) and physiological problems. The research which was conducted in the Hula Valley in the winters of 2002-2004 was intended to deal with the following questions:

- Does the management have multi-seasonal impact on the wintering crane population regarding population size, behavior, (habitat selection and time budget) and demographic characteristics?

- What is the effect of the management on the number of cranes, percentage of returning ringed cranes, habitat selection, time budget and presence of other avian species in the valley?

- What are the nutritional and energetic characteristics of the Euro-Asian crane in the winter?

- How can the management be improved and made more efficient?

- What is the effect of tourism on the crane population?

 

Study of the characteristics of the crane population and their comparison with those in the years 1996-1999 (based on Dan Alon's study) found that:

1. Monthly crane numbers increased since the beginning of the crane project, although not significantly. The trend of change in the crane numbers also changed – instead of a gradual departure from the valley as of the end of January the population increased and the departure to the north took place only at the end of February. These changes in the population size result from the operation of the feeding station in the valley, which cause the wintering and passing cranes to stay longer. An increase in the availability of food in the valley caused a shift in wintering sites northward, and hence the shortening of the migration route. This trend is reinforced by the crane project and the feeding station: if the feeding station continues to operate in the present format (100 days) a year, the danger will be that an undesirable large wintering population will establish a winter base.

2. Habitat selection in the years of the crane project operation is dictated by the level of field protection rather than by the type of crop. This proves the efficiency of the field protection.

3. More breeding adult cranes and more small families (with just one offspring) where observed during the years of the project. It is not known whether this change in demographic characteristics reflects the whole crane population from this migration route or it is a local change, pertaining to the crane population which chooses to stay in the valley.

 

Study of the efficiency of the different management activities, and their impact on the crane population found that:

1. Human presence is most efficient in protecting the fields, and can not be replaced by other devices (such as scar-crows or fireworks); focused protection of seeded fields is more efficient in preventing crop damage than an overall protection of the whole agricultural fields in the valley.

2. The expulsion operation at the end of the fall affects crane decision to leave the valley south (most of them leave at night) and thus reduce crane population in the valley. The expulsion operation in December 2003 took place at a time when the feeding station was already operating, and consisted of drastic actions. This caused a change in the population composition (evident through low return percentage of ringed crane) and in the demographic characteristics that year.

3. The feeding station starts opening at the beginning of December and precedes the 100 mm accumulated precipitation threshold (a threshold that proved to affect the food availability in the valley, and to cause departure of passing cranes, Alon 2001). Therefore it eliminates the natural pressure that a reduction in food availability has on cranes. Closing the feeding station late in the spring causes the cranes to stay longer in the valley and therefore delays the migration waves north. A few ideas were examined as a part of the effort to improve the attraction of the feeding station for cranes and to make it more efficient: digging a water canal in the feeding station reduced the number of cranes in nearby agricultural fields; the allocation of an additional ground area as a feeding station was not successful in increasing the number of cranes that visited the station every day; Changing the time of the food distribution, from night to early morning, reduced the number of seed-eating birds (pigeons, ducks) which use the feeding station; distributing the food inside the soil ("seeding") instead of spreading it on the ground also reduced the number of seed-eating birds in the feeding station.

4. The influence of tourism on cranes in the valley has was studied: intensive presence of vehicles and visitors close to the lake caused the crane to avoid that roosting site, and to prefer the roosting site at the reserve; The presence of visitors inside the feeding station (in a covered wagon harnessed to a tractor-"mobile hide") was a disturbance only during after noon hours, when cranes gathered in the station to pre-roost. Cranes also drew away from the northern part of the feeding station, at the boarding site of the wagon.

 

In order to find out which type of food is better for using in the feeding station- corn, barley or peanuts- the cranes' daily food consumption and food preference were

checked in cages:

1. The cranes preferred peanuts and barley over corn, there was no obvious preference between peanuts and barley.

2. The daily food consumption was 180 (±60) gr per crane. The daily energy consumption was 595 (±230) Kcal per crane. Both values did not differ significantly between the 3 food types. All three food types provide the daily energy requirement for the cranes but lack nutrient component (macroelements and trace elements) that are necessary for the crane winter diet. These components are present in natural foods that are found in the agricultural fields such as the rhizome of Nutsedge (Cyperus rotundus) and other sources (vegetal and animal). Therefore it is expected that, for any food type chosen for use in the feeding station, cranes will exit the station to search for food that contains those components that are missing in the main food source.


 

 

Project description (Naama Linndeman's M.A.'s Abstract): Ecological and economic aspects of the "Crane Project" in the Hula Valley

The Common Crane (Grus grus) is a migratory bird living in large flocks (up to some tens of thousands), which arrives in Israel in autumn and winters in the region. Cranes cause heavy agricultural damage while feeding on crops such as maize, peanuts, sunflowers, peas and wheat. Damage was especially severe in the last decade in the Hula Valley in the north of Israel.  Two main reasons for the multitude of cranes in the Hula Valley were identified:  (a) re-flooding of an area of approximately 1,000 dunam in 1993 creating a shallow lake (Hula Agmon) which is used as a roost site and attracts large numbers of cranes and (b) modification of the agricultural cultivars, mainly increase of areas of groundnut which is a preferable food for cranes.

          In the last 5 years a “Crane Project” has been conducted in the area, aimed at preventing the cranes damage to agriculture while maintaining the bird population. The project is funded by the local farmers as well as supported by public finance and donations. The main concept of the “Crane Project” is regional cooperation between farmers, nature conservation activists and the project implementers. The principals are guarding and eviction of the cranes to prevent damage while correspondingly feeding them in a specially allocated nearby area. To date, the economic profitability of this project has not been examined.

          This examined the economic efficiency of this project as a public project aimed at dealing with the farmers-cranes conflict while considering the Common crane as a unique environmental resource. I checked cost and benefits of the project and performed a general evaluation, while comparing three alternative management methods used in the past and a new theoretical possible method. Out of the previous methods, eviction was found most economically efficient. In addition, I checked the farmers positions and their ability to cooperate, as they are bearing the main burden. According to the results, the main cost of the project (2/3) is funded privately by the Hula Valley agriculturists – the main victims of the crane population, while the public funding to the project is minor (1/3) and comes from the potential beneficiaries of the crane population as an environmental  resource.

          Despite the aforesaid, the local farmers seem to support the project and give precedence to the inferior economic alternative, by agreeing to the existence of cranes in their vicinity. They are willing to cooperate and bear the costs, as vast regional insight acknowledging the crane being a positive resource, on top its being a pest.

          The study also checked the ecological and agricultural factors that influence the crane dispersal and the project costs: available food amounts in the fields, sowing time and characterizing and estimating the crane damages during the research period. The results show that some of the farmer’s activities such as guarding and tilling, affect the crane dispersal and the available food quantities in the farmland. Guarding and crane eviction were found as significant factors on the farmer’s costs and their willingness to cooperate as well as on the crane dispersal in the area. The most effective factors on crane dispersal in November and December are the type of the former summer crops, and in December and January is the guarding policy taken by the farmers. In the agricultural areas a 150-400% surplus of food relatively to the estimated crane requirements was observed. In December and January the amount of food wasn’t found as an influential factor on their dispersal in the fields. In February and March, while reduction of available food occurs, a significant positive correlation was found between the amount of available peanut and nut grass (Cyperus rotundus) and the crane numbers in the fields.

          The “Crane Project” is a rare opportunity for exploitation of the total benefit to society, as an agricultural area combined with a unique birding site. The research shows that since farmer’s policy and acts have the main effect on the crane dispersal in the fields, there are actions to be executed to reduce the farmer’s private cost and by that minimize the agriculture-cranes conflict. The research also proves that by proper management it can be made sustainable and beneficial for agriculturists and naturalists.