Dr. Oded Cohen

Ecology and Management of Invasive Plants
Research Interests
Photos

Invasion Ecology

My research focuses on ecology of invasive species, particularly relating to invasive woody plants. During the recent years, I have been working on species risk assessment, management and restoration following invasion. I lead the largest projects of conservation and restoration of invaded ecosystems in Israel, these include: a) conservation of Judean Mountains following invasion of A. saligna; b) Restoration of Einot-Gibton following invasion of A. saligna; c) Restoration of the Issahar stream following invasion of Parkinsonia aculeata.  Currently, my team is collaborating with other research groups in estimating the risk assessment of Eucalyptus camaldulensis and Tetraclinis aculeata. Our laboratory specializes in the heat-response of seeds, a major mechanism that determines the seed bank persistency and the success of invasive plant colonization.   

 

Current Research Projects

The effect of soil warming on the invasion success of woody plant invaders

Current evidence-based research estimates that summer heat waves are becoming more frequent, longer, and more intense. We study the effects of soil warming and heat waves on invasive plants, focusing on the spatiotemporal distribution of seed germination. Our methodology is based on laboratory and field experiments in understanding the heat-response of seeds; comparing natural and invasive populations. Our research will improve understanding on the relation between  climate change, soil disturbance and plant invasion.

 

Assessing the invasiveness of Eucalyptus camaldulensis in Israel

Eucalyptus camaldulensis is one of the most common planted trees in Israel. The species is native to Australia and was recently declared an invasive species in Israel, a status with both local and global implications. The invasion status of this species in Israel is a controversial issue, the conversation surrounding this has taken an emotional tone rather than factual. Our group is developing quantity and quality data regarding the magnitude of the spread of this species outside the planted boundaries. The symbiotic relation of this species with Australian ectomycorrhizal is also studied. Our studies will improve the ability to recognize the current status of this species in Israel and to assess the future risk of invasion. Research supported by the Ministry of Agriculture and Rural Development.

Co-researchers: Efrat Shefer, The Hebrew University; Hagai Shemesh, Tel-Hay College.

 

 

Assessing the invasiveness of Tetraclinis articulata In Israel

Tetraclinis articultata is an evergreen coniferous tree native to the southern west Mediterranean basin. This species was planted in Israel as a forest tree, mainly in semi-arid regions. Lately, it was found that T. articulata spread outside the planted boundaries far from the mother plants and grew in both disturbed and undisturbed habitats. The main goal of our group is to provide empirical data for understanding the environmental factors that determine the distribution of growth. Study supported by the Jewish National Fund.

Co-researchers: Efrat Shefer, The Hebrew University; Yagil Osem, Agricultural Research Organization

 

 

Developing chemical control tools for reducing the spread of T. articulate

The high density of the T. articula offspring has reduced the cultural services of the forests and altered the natural landscape outside the forests. T. articulata is not considered an invasive plant in the majority of the world as it has only been a known problem in South Africa and Israel. Therefore, there has been no data on effective strategies to deal with the high-density regeneration. Our team is developing protocol for chemical control. The research focuses on the comparison between treatments including application techniques, chemicals and different climates and seasons. Study supported by the Jewish National Fund.

 

Restoring the Issachar stream following the invasion of Parkinsonia aculeata

Parkinsonia aculeata is one of the most invasive woody plants in Israel. This species has widely invaded moist habitats producing highly dense stands and suppressing the local plant species and the value of grazing land. Our group is working on providing protocol for restoring habitats following the invasion in Issachar stream reservation (North of Israel), which has been highly invaded by this species. Research supported by the Israel Nature and Parks Authority.

 

Threats to Platanus orientalis in Israel and conservation possibilities

Platanus orientalis is among the few big size riparian tree species indigenous to Israel. The tree could become endangered for three main reasons: degradation or loss of habitats mainly due to water over-exploitation, invasion of an aggressive ambrosia beetle Euwallacea nr. fornicatus and genetic pollution. The main goal of our group is to study the population sustainability of this species by surveying trees that are growing along 15 streams in the Galilee and the Golan.  Data will fill the gap of knowledge in developing a holistic approach for the conservation plane. Study supported by the Ministry of Science and Technology of Israel.

Co-researchers: Zvi Mendel, Agricultural Research Organization; Yuval Sapir, The Hotanical Garden, School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv Israel; Oded Barshalom, Sharmir Research Institute.