השפעת איקליפטוסים על הצומח בנגב המערבי – השלכות לשיקום: [מתוך המדור: חזית המחקר]

Large areas in Israel’s Western Negev region are planted with Eucalyptus trees. As in other regions, Eucalypti are controversial, as an alien species known for allelopathy – the inhibition of other plant species by producing chemical compounds. Despite intense debates, little is known on the effects of Eucalypti on the vegetation in Israel, especially in the Western Negev. In this study, we examined the effects of Eucalypti on herbaceous plant communities that provide many ecosystem services, such as grazing areas and different cultural services. The study was conducted in the Be’eri forest and near Re’im in the spring of 2023 and focused on three Eucalyptus species: E. camaldulensis, E. loxophleba and E. torquata. We found that in the trees’ southern ‘habitat’, where there is no shading, herbaceous biomass is highly reduced compared to open areas, which may indicate allelopathic effects. In contrast, the difference between the trees’ northern ‘habitat’ (which is shaded) and the southern ‘habitat’ was small, indicating a weak shading effect. Moreover, we found a negative effect of the Eucalypti on the flowering density of red anemones (A. coronaria), but a diversity loss was observed only in E. torquata. Overall, this study shows that despite Eucalypti’s numerous benefits in security-forestation and as nectar providers, they might have a negative influence on ecosystem services. Therefore, we advise caution when planting them in areas that are tourist-designated, especially in the ‘Darom Adom’ (red south) festival context and in areas where rare or protected species are found. Nonetheless, we found large differences between the different Eucalyptus species, and for some of them, the negative effects are minor. Thus, we recommend prioritizing the planting of minimal-effect species in the restoration process after the 7th of October tragedy.