A new Israeli study examined how the presence of wolves affects the activity of large mammals. The findings reinforce the importance of the predator in maintaining the integrity of the ecosystem
by Reut Alon. Angle - a news agency for science and the environment
In 1920, the last wolf pack was hunted in Yellowstone National Park in the United States. Following the extinction of the wolves in the park, the moose population grew to huge proportions and their overgrazing damaged the variety of plant and tree species in the area. This imbalance ended when in 1995 ecologists returned the gray wolf to Yellowstone. This case shows the importance that top predators have in maintaining a healthy ecosystem. We have an example of this in Israel as well, as can be seen from a new study that examined the effect of wolves on other large mammals in the Golan Heights, the findings of which will be presented this year In the 52th Annual Conference on Science and the Environment, which will be held on September 25-26 at Ben-Gurion University in the Negev.
Israel is a meeting point between two subspecies of wolves that even breed together in the country - one is the Indian wolf that is common from Israel eastward to India, and the other is the Arabian wolf that is common in desert areas such as the Arabian Peninsula and its distribution reaches as far as northern Israel. In Israel, the distribution of wolves is wide, but most of them are found in the Golan Heights and the Arabah. You can also see them in the Negev, the Judean Desert, the Galilee and in recent years also in Carmel.
A map of fear
"The population of wolves in Israel is considered small but stable and they reproduce relatively easily," says Shlomo Pricebloom, a doctoral student in the laboratory of Prof. Tamar Dayan, from the School of Zoology at Tel Aviv University. According to him, the wolves adapt and are less sensitive to disturbances, unlike the super predators that lived in the Golan 50 years ago and became extinct - such as the tigers and the bears. "Their diet is also varied. In the Golan they feed on large mammals such as young wild boars and deer, and eat plant food such as dates in the prairie, melons and even cherries.'
In his doctorate, under the guidance of Dayan and Dr. Dror Ben Ami, zoologist and nature conservation expert, he examined how the presence of wolves affects three large mammal species in the Golan Heights - jackals and wild boars, which are outbreak species, i.e. species that thrive due to human activity, down the food web. and an Israelite deer which is globally endangered.
To examine the activity of the various species, Priceblom placed 60 cameras with a motion sensor throughout the Golan, which yielded hundreds of observations. "At each photo point I checked whether the wolf activity was high or low, and in relation to it I checked the activity level of the other species, and I counted how many photos were taken of each species in order to quantify the different activity levels," he explains. "That way I could check whether in an area with high activity of wolves we see, for example, high activity of jackals or perhaps low activity of deer that are afraid of being eaten. Some of the findings were surprising.'
Pricebloom explains that the wolves create a "Landscape of Fear" for Pigs and jackals "Despite the human disturbances in the Golan and the fact that jackals and pigs are being thinned there (controlled hunting, RA), we still see that the presence of wolves affects these species," he says. according to him, the jackals Stay away from areas where there are wolves because they don't want to share territory with a predator that could endanger their pups. "Adult wild boars do not have natural predators in Israel today, but their young are eaten by jackals and wolves, so the pigs also stay away from the areas where the super predators roam."
The most interesting finding was the reaction of the deer to the presence of the wolves. "We hardly saw deer in places where there was a high presence of jackals, but surprisingly we saw that the deer preferred to stay in the areas where the wolves roamed," says Priceblum. "We estimate that the reason for this is that in the area where there are wolves, there is a low density of other predators, because the wolves crowd out the jackals that pose a threat to the sheep."
The wolf as a balancing factor
It is interesting to see that although wolves prey on deer, it is precisely the suppression of the jackals that helps the Haaretz-Israeli deer. "In a study conducted by the Nature and Parks Authority in the Golan, it was found that thinning jackals did not reduce their activity, so thinning jackals does not appear to be an effective method to protect deer," he says. According to him, a normal pack of wolves in the Golan controls an area between 100-50 square kilometers. If you look at the overall density of deer predators, it is "safer" for deer to be in an area with one wolf pack that keeps jackals away, compared to a similar area without a wolf pack where the jackal density will probably be much higher. "It is better to keep whole packs of wolves that will naturally reduce the density of the jackals because the jackals are an explosive species and the wolves curb their outbreak."
In addition, predation of piglets by wolves can slow the outbreak of wild boar. "Even ten piglets can be born in one litter and they multiply very quickly," explains Priceblum. "Predation can mean that instead of ten piglets, only four will reach adulthood, for example, which means there is balance and control." According to him, if for example in a certain period there are more piglets than ofrem, the wolves will prefer to devour the piglets because for them this is an energetic consideration - they invest less effort for the food.
The populations of jackals and wild boars in the Golan are at a high outbreak due to the availability of water sources, the high availability of food from plantations, fields, dumps and carcasses of farm animals, as well as due to their loss of fear of humans and the way they have adapted to living alongside us. "They are indeed protected species, but since they are also harmful to agriculture, the Nature and Parks Authority has thinning programs in order to provide a response to farmers," says Pricebloom. According to him, even in Europe these species have become explosive due to human activity - especially the jackals that have started to spread on the continent in recent years. "In Europe as in Israel, wolves were hunted almost to extinction in the past, but the recovery of wolves in our country is ahead of Central and Western Europe by about 30 years," he says. "What is happening here is a case study for the continent, and the research can be an inspiration for the Europeans on how to stop the wave of jackal invasion."
Even in the case of efforts to preserve the Haaretz-Israeli deer, the research may be useful. "There are a lot of pressures on deer. They adapt less and are more sensitive to disturbances, are preyed upon by jackals, stray dogs and wolves, suffer from the fragmentation of their habitats and are susceptible to diseases," explains Priceblom. According to him, due to this set of pressures, their numbers in Israel have dropped drastically and this is very worrying. "Jackals, wolves and wild boars are widely distributed in Europe and Asia, but the Haaretz-Israeli deer can only be found here and in Turkey, where there is only a small population. The deer is in danger of global extinction and therefore it is urgent to preserve it here.'
In conclusion, these findings are important in the context of nature conservation - both in terms of preserving the Haaretz-Israeli deer and as a case study that can be useful in similar cases in Europe. "The top-down effect of wolves as a predator on the mirror shows its important role in maintaining a balanced ecosystem," says Pricebloom.
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