January 2018

A new method for dealing with the eradication of the invasive Tree Tobacco

Jean-Marc Dufour-Dror – Ecologist, advisor and researcher in Applied Ecology,  expert in invasive plants, advisor to the Israel Nature and Parks Authority, and to the Kishon River and Drainage Authority.  jmdd@netvision.net.il

Keywords: introduced xenophyte, alien species, Solanaceae, herbicides, invasive plants

In the course of the last year a new method for dealing with the Tree Tobacco (Nicotiana glauca) – one of the most common invasive plants along the river channels and wadis in the Judean Desert and the Negev – has been developed. The treatment is based on principles of focused chemical treatment, and meets all the conditions required for the applicable successful treatment in Israel. This method of treatment raises hopes for reducing the presence and damage caused by this invasive plant in the natural eco-systems of the river channels in the arid region of the country.

Full Hebrew version

Summary of the Kalanit study tour in the Western and Upper Galilee – January 3, 2018

Avi Shmida,  the Department of Evolution and Econology, and the Center for the Study of Rationality at the Hebrew University in Jerusalem, Givat Ram, avi.shmida@gmail.com
Mimi Ron – Open Landscape Institute, and the Society for the Protection of Nature in Israel.  mimiron47@gmail.com
Editing: Gadi Pollak – Kalanit editorial board. gadpollak@gmail.com

Keywords: Acer obtusifolium, Rhamnus punctata, geophytes, Ba'ana lime, Mandragora autumnalis, Platanus orientalis, Centaurea speciosa, Chaparral, Terra rossa, moss, forest, limestone, winter bloomers, phenology, flowering, cliff vegetation, Calendula, Carlina lanata, Polypodium cambricum, cattle grazing, ferns

The winter blooming in the Western Galilee was delayed in this season, apparently because of the paucity of rain in the beginning of the winter.  Typical flora for the red loam and limestone of the coastal plain was studied at the Gesher Haziv and Liman Reserve.  At the stations of  Ein Hardalit in Nahal Kziv , and Hurvat Eirav in the Admit ridge, the trees that are typical of the Western Galilee were observed, such as the Syrian Maple (Acer obtusifolium) and the Oriental Plane Tree (Platanus orientalis). in the Nahal Kziv channel, the Dotted Buckthorn  (Rhamnus punctata) and additional trees growing in an area with extensive grazing, as well as rock and cliff plants were observed. The differences in the vegetation and flora of the Mediterranean Chaparral  and the slopes  with a southern and northern exposure were demonstrated  along the course from the Goren Park through Nahal Kziv, to the Hila lookout.  Various types of fern that are typical of rocks grow on the southern slopes, while the northern slopes house the Common Polypody Fern  (Polypodium vulgare).

Full hebrew version

Tuvia Kushnir – one of the 35

Uri Rosenberg agron@netvision.net.il

Keywords: Iris regis-uzziae, Colchicum tuviae

The death of Tuvia Kishnir, as one of the 35 fighters who went out to assist Gush Etzion during the War of Independence, was not only a tragedy for his family and acquaintances, but also a heavy loss to the scientific world. Tuvia's name, that was also commemorated in the names of several plants, is known to every botanist and scientist to the present day, seventy years after his death. Tuvia was 24 years old when he was killed, but already managed to contribute a lot to the study of the vegetation of Eretz Yisrael in his observations and studies, which he began as a youth. This article describes his short life, and contribution to science.

Full Hebrew version

The Desert Rhubarb – a plant that irrigates itself

Simcha Lev-Yadun, The Department of Biology and the Environment, Haifa University, Oranim. levyyadun@research.haifa.ac.il
Gadi Katzir, , The Department of Biology and the Environment, Haifa University, Oranim. gkatzir@research.haifa.ac.il
Gidi Neeman, The Department of Biology and the Environment, Haifa University, Oranim. gneeman@gmail.com

Keywords: evolution, adaptation to drought, Polygonaceae, the Negev Highland, desert, irrigation, morphology, water, Arod pass,  leaf rosette

The Desert Rhubarb (Rheum palaestinum) of the Polygonaceae family, is a rare perennial hemicryptophyte, which grows in the Negev Highland and Jordan, in locations that receive around 75 mm of rain per annum.  Following the rainfall, it produces one to four large, round leaves that create a leaf-rosette, which is tightly attached to the ground and whose surface can reach up to one square meter. The large leaves are not flat, but have a three dimensional morphology, resembling the relief map of a steep mountainous area, with the leaf's veins forming deep wadis.  These leaves are very different to the small leaves that characterize most of the desert plants.  This fact raises the question whether it is possible that the large leaves provide the plant with an advantage, despite the fact that it grows in the desert, and if so, what is the cause for their evolutionary development through natural selection? We raise the assumption that the large leaves collect rainwater that then drain to their base, where they seep into the soil close to the plant's vertical root. In order to check this assumption we followed the growth of the leaves, measured the wet soil around the root after actual and simulated rain.  From these data and the average weekly quantity of rain, we developed a model in which we calculated the quantity of rain water collected by the plant.  The results show that after vey light rain, that hardly wet the soil in the desert, the drops of rain that fall on the leaves roll into balls, run along the leaves' sunken veins to their base, and from there they flow into the soil and irrigate the soil around the vertical root.  According to the calculations, an average Desert Rhubarb can collects around 4,100 cubic centimeters of water in an average year, and thus enjoys a water regime of around 427 mm of rain per annum – a quantity that is typical of  a Mediterranean climate.  This is the first case of self-irrigation by large leaves in a desert plant, creating a leaf-made mini oasis, to be described.


This article is based on the following article that appeared in the sientific literature:

Simcha Lev-Yadun, Gadi Katzir, & Gidi Ne’eman, 2009, "Rheum palaestinum (Desert Rhubarb), a self-irrigating desert plant", Naturwissenschaften, 96: 393-397.‏

Full Hebrew version


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