April 2016

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Is Eucalyptus camaldulensis an Invasive Species in Israel?

Oded Cohen, The The Golan Research Institute of Haifa University in Kazrin, The Department of Land of Israel Studies, the Kinneret College, odedic@gmail.com
Yossi Riov, Robert H. Smith Institute of Plant Sciences and Genetics, Robert H. Smith Faculty of Agriculture, Food and Environment, joseph.riov@mail.huji.ac.il

Kewords: alien plants, invasive plants, nature conservation

This article presents a survey of findings reported in the scientific literature, and findings of field studies for determining the ecological status of the River Red Gum (Eucalyptus camaldulensis) in Israel. The River Red Gum was planted in many countries around the world on a large scale. Nevertheless, reports on the invasion of this species in many countries, in the sense of wide scale spreading, are very few, certainly in relation to the scale of world planting. A similar situation exists in Israel.  Dense tree populations that originated from natural propagation that are distant from the mother plants, were viewed to the present only in the Tabor Wadi.  The data in the literature, as well as that from the field studies, support the notion that the River Red Gum deserves the status of a species that has been naturalized in Israel, and not that of an invasive species.

Full Hebrew version


The Iris Hill in Rishon Letzion as a case study of wild vegetation conservation in small areas within the boundaries of an urban settlement.

Gadi Pollak Kalanit editorial gadpollak@gmail.com
Moshe Perlmutter The Society for the Preservation of Nature in Israel moshep@spni.org.il

Keywords: Iris atropurpurea, red loam, kurkar, endangered species, endemic species, Coastal Plain, southern Coastal Plain, nature conservation, botanical site

The iris Hill in southern Rishon Letzion is an open space of red loam and kurkar (calcareous sandstone), which is entrapped between agricultural lands, and is close to an entertainment compound. Despite the many disturbances, the site is rich in wild plants, including species that are typical for red loam and kurkar, endangered species, and endemic species.  Dozens of colonies of the Coastal Iris (Iris atropurpurea) – the flag species of the hill – grow there. The hill constitutes an example to the importance of using small areas of soil for the purpose of preserving plants.  Recommendations for the conservation of the hill are presented, and its integration in the network of open spaces in the north of the southern Coastal Plain.

Full Hebrew version


Summary of the Kalanit study tour in the Western Galilee and the Galilean Coast, 13 & 14 of April, 2016

Avi Shmida,  Department of Ecology and Evolution and the Center for the Study of Rationality, the Hebrew University of Jerusalem at Givat Ram. avi.shmida@gmail.com
Siko,  nature, plants and environment guide, Naharia siambe17@gmail.com
Gadi Pollak Kalanit editorial gadpollak@gmail.com participated in the preparation of the summary

Keywords: antipastoral vegetation, Gesher Haziv, Mediterranean region, annuals, marl, Galilean coast, beach,  Carex, salt marshes, Esh'har stream, Orchids, Limonium, spring flowering, Mediterranean vegetation, Anthemis, chalk, overgrazing,  Shavei Zion, Tel Kida, botanical site.

The Western Galilee and Galilean coast enjoyed an average rainfall and a good distribution of rain in 2015/16.  The timing of the study tour was in the period of peak diversity, when the peak flowering is over, but it is possible to identify and define the maximal number of plant species from the lower altitude vegetation of the Mediterranean region. Emphasis was placed on typical and special species on the lower mountain ridges of the Western Galilee, and the coastal habitats of the Galilean coast.

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Why is the common gender ratio in nature for most organisms 50:50?

Avi Shmida,  Department of Ecology and Evolution and the Center for the Study of Rationality, the Hebrew University of Jerusalem at Givat Ram. avi.shmida@gmail.com
Amos Kreiner – the Galili secondary school in Kfar Saba, and an associate in the Physics department at the Weitzman Institute for Science amos.kriener@gmail.com
Hamutal Kreiner – the Linguistic Cognition Laboratory, Behavioral Sciences at the Rupin Academic Center. hamutalk@ruppin.ac.il

Keywords: evolution, Pistacia, Quercus calliprinos, altruism, mate selection, dioeciy, monoecy, Darwinism, pollination, sex chromosomes, the Aumann-Maschler selection mechanism,  flexible gender, Juniperus Phoenicea, sexual reproduction,  Ochradenus baccatus, game theory, Phoenix dactylifera

Since in every reproduction cycle of a population in nature, every female reproduces only once while every male can fertilize many females, it seems as though the efficient situation is one of few males and numerous females in every population. However, contrary to this assumption the gender ratio in human populations, and of most species in nature is 50:50 – in other words, an equal number of males and females. In this article we explain, with statistical examples, why there is an equal number of males and females – a situation which seems to be non-optimal, and causes an inefficient balance for biological species populations in nature.  The explanation is based on the Darwinist explanation of natural selection, the rational principle of games theory, and on economic doctrines. Using the equal investment rule, which is derived from the Charnov's gender allocation rule, we are exposed to the Fisher Principle regarding gender ratio, which is implemented to many examples in nature.  The article leads us from the explanation of gender ratio, which appears to be simple to understand, to the explanation of surprising phenomena in nature such as: flexible gender ratios in plants, the illogical incidence of males in nature, and the vast waste of pollen grains in wind pollinated plants.

Full Hebrew version


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