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Heavy shade: the effect of eucalyptus trees on anemones in the Western Negev

The many eucalyptus trees planted in the area have become an integral part of the landscape around Gaza. A new study examined their effect on the anemones and other unique plants in the region and suggests reconsidering their planting, as part of the restoration efforts

The Western Negev region abounds in a unique and unusual biological diversity of landscapes, flora and fauna. Photo: Yuval Neuman
The Western Negev region abounds in a unique and unusual biological diversity of landscapes, flora and fauna. Photo: Yuval Neuman

Beyond the many victims in body and soul, the Hamas attack on October 7 and the war that has been going on since then also have disastrous consequences for the nature of the Western Negev. The unique nature of the area suffered irreversible damage - many trees and plants were burned, agricultural areas and farms were abandoned and looted, and the open areas were severely damaged due to the passage of military tanks and the construction of defense batteries. The findings of a new study that examined the effect of the many eucalyptus trees in the area on the unique vegetation may help in rehabilitation processes and the preservation of local nature.

The research was conducted by Yuval Neuman, an undergraduate student at the Robert H. Faculty of Agriculture, Food, and Environment. Smith at the Hebrew University of Jerusalem, under the guidance of Dr. Niv De Malach, a senior lecturer in the faculty. It was held a few months before October 7, and published Recently also in the journal for environmental science and policy "Ecology and environment". The study examined the effect of the three most common eucalyptus species in the region on the flora, and specifically on the density of anemone flowers. Contrary to the common opinion that eucalyptus trees encourage anemones to bloom, the study found that two species of eucalyptus actually harm their blooming, due to the allelopathic property of the trees (more on that later) or due to the shading they create.

An integral part of the surrounding landscape

The Western Negev region abounds in a unique and unusual biological diversity of landscapes, flora and fauna wild animals, including rare and endangered species. The area is also characterized by the abundance of forests that were planted by Keren Kimet for Israel starting with the establishment of the state as part of the forestry enterprise in the country. Most of the trees planted in the area are eucalyptus trees, which over the years have become an integral part of the landscape of the open areas in the Gaza Envelope. The resistance of the trees to drought, combined with their rapid growth and their broad leaf canopy, made them natural candidates for planting in a semi-arid area such as the Western Negev. The planting of trees in this area is intended to provide shade for travelers, as well as to provide security by hiding the settlements close to the fence.

The origin of the eucalyptus tree is in Australia. Of the 800 species of eucalyptus in the world, about 60 species grow in Israel. "Some claim that in Israel there are no local trees suitable for growing in a semi-desert area like the Western Negev, so eucalyptus is an excellent idea," Yuval Neuman, the editor of the study, explains the reason for the large number of eucalyptus trees in the Western Negev region. "also Beekeepers enjoy the eucalyptus Because some species bloom and provide nectar for bees for ten months of the year."

Allelopathy of the collared eucalyptus in the study area near Reim. Photo by Yuval Neuman
Allelopathy of the collared eucalyptus in the study area near Reim. Photo by Yuval Neuman

More shade, less anemones

Like other trees, the eucalyptus trees also shade the herbaceous vegetation (wild grasses and vegetation), and thus may interfere with the penetration of the sun's rays and damage the photosynthesis that is essential for plant growth. In addition to this, some eucalyptus species are attributed a property called allelopathy, which means inhibiting the growth of other plants by releasing chemical substances from the dry leaves on the ground. In view of the massive presence of eucalyptus in the Negev, it is surprising that until now their ecological effects on the vegetation in the area have hardly been examined. Neumann's research was designed to test these effects for the first time, and the timing of its publication made it, unfortunately, more relevant than ever as the area faces restoration. "Our motivation as ecologists is to be as objective as possible, to examine the effect of eucalyptus and give our professional opinion on the subject - does the tree reduce or enrich the diversity of species," he notes.

"It would be good if decisions about planting and preserving nature were made with a broad perspective." The research area near the Ra'im intersection, photo: Yuval Neuman
"It would be good if decisions about planting and preserving nature were made with a broad perspective." The research area near the Ra'im intersection, photo: Yuval Neuman

The study was conducted in the Bari and Ra'im forest area, where there are many eucalyptus trees that were planted in the 90s of the last century. One of the main findings of the study is the essential differences between the different types of eucalyptus, where each affects the plant in a different way. The study found that the three eucalyptus species present in the area reduce the herbaceous biomass by dozens of percent compared to other habitats in the area without trees, and that one of the species, the collared eucalyptus, significantly reduces the density of flowering anemones compared to the other species.

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