A one-of-a-kind research station for climate change

A team of Israeli scientists is experimenting with changes in rainfall patterns to determine how native vegetation will adapt to new climatic conditions.


The only experimental research station focusing on climate change in the Middle East is located in the heart of the Judean Hills in central Israel. Its unique location, surrounded by nature, allows for a rare look at the changes and challenges the future most likely holds for the natural Mediterranean ecosystem.

The experimental research station, which is supported by the Science and Technology Ministry, is located on four hectares of state land and is a part of the Long-Term Ecological Research Network (LTER). This facility, founded 18 years ago by scientists from Tel Aviv University, is one of the oldest of its kind in the world studying the effects of rainfall changes on natural ecosystems and the landscape. Moreover, it is the only research station investigating these effects in the framework of climate change in the Middle East.

Changes in precipitation are much more difficult to predict for climate models compared to changes in temperature. Many models worldwide disagree as to what future trends in precipitation will be. However, there are some regions, particularly the Mediterranean, where nearly all models agree with a decrease in rainfall.

Many regions in the Middle East, Asia and Africa predict higher temperatures, drier air and more severe and frequent droughts. One recent NASA study reveals that the drought that has been affecting the eastern Mediterranean Levant region since 1998 is likely to be the worst drought in the past 900 years.

The perfect storm is coming
“Climate change is a strategic issue for Israel,” says Prof. Marcelo Sternberg, head of the Plant Ecology Lab at the School of Plant Sciences and Food Security at Tel Aviv University and responsible for the experiment. “The confluence of severe climate change impacts, deep environmental crisis and a web of conflicts is reason for serious concern when it comes to the future of the wider Mediterranean region. The perfect storm is approaching; therefore, proposals must reach the rooms where policy decisions are taken.”

Precipitation is characterized by two components: the amount and frequency of the rainfall. Such experiments that include both components like the one led by Sternberg are rare around the world. The findings obtained from this research are not only useful for Israel but the whole region, and even the rest of the world.

Sternberg, who set up the research station several years ago says, “Research and knowledge give the foundation for decision-making, that is why it’s so essential to support the research of climate change.” The threat of increasing temperatures and decreasing precipitation, with longer gaps between rainfall events, will elevate the risk of forest fires. “Our facility here is all about these issues,” he says.

The vegetation surrounding the research station is native to the region, which creates an excellent environment to study how it reacts to different climate change scenarios with changing rainfall patterns. To test this, field studies are conducted that manipulate either precipitation amount or frequency by using rain-out shelters to simulate a reduction in precipitation as well as changes in rainfall patterns.

The experimental options for precipitation change are the simulation of a reduction of rainfall by 60% (meaning extreme drought – only 180 mm. of rain per year) or by 33% (350 mm.) The experimental options for precipitation frequency change are regular frequency distribution (nine rain events of 20 mm. each) versus lower frequency but higher amounts (three rain events of 60 mm. each) as expected by increasing extreme events.

An extreme drought scenario experiment with a variation of rainfall frequencies began this year, and the goal is to continue to do that in the long term (at least 15 years). “The greatest challenge in this type of experiment is to obtain data over an extended period to determine a trend and thus reach conclusions based on long-term data,” Sternberg stresses.

34 species per square meter

While in Europe there is an average of three to four different herbaceous plant species per square meter, in this unique experimental field, there is a range of 21 to even 34 plant species per square meter. According to Sternberg, the high spatial heterogeneity makes difficult to find effects of drought on the experimental plots. “But if we can effectively establish sampling methods, we can be precise and answer one of the most important questions: How will this ecosystem look in the future subjected to extreme drought?” Sternberg states.

Sternberg’s previous findings indicate that this ecosystem is relatively resistant to small rainfall decrease. However, future climate change scenarios predict a more significant reduction in rainfall, causing winters in Israel to have fewer rainfall events and higher soil water deficit. Therefore, in Sternberg’s new experiment, he hopes to find out how the system will respond to these predicted changes.

The examined vegetation at the station looks stable even under the current precipitation conditions. This is because the plants disperse their seeds not only spatially but also over a specific period of time. For example, in a previous study, when Sternberg controlled seed germination in soil samples, he found that only some of the seeds germinated after one year, while others stayed dormant for a few years. He concluded this was a type of “ecosystem insurance” in case environmental conditions did not favor seedling survival, which shows that drought adaptation is already part of the system.

Between deserts and humid ecosystems
“It is not easy conducting this type of experimental research outside the lab,” Sternberg says. The research station is confronted with several problems, one being the lack of budget. The research funding ends next year, and despite the experiment’s progress, the high maintenance costs (technicians, researchers, students, lab analysis, equipment, etc.) make further operation uncertain. Many of the procedures are done with few to no resources. “All is done ‘in-house’ to save money such as repairing the fences to prevent unauthorized people from trespassing, among other activities,” Sternberg says.

Sternberg notes, “people sometimes cut the fence of the research station to shorten the way to a nearby spring, grabbing sensors from the floor out of curiosity and damaging the experimental system.” The station has regrettably experienced theft. “The solar panels that powered the meteorological research station were stolen, and ironically, the fence to prevent theft was also stolen,” Sternberg adds.

The research station is an issue of national and international interest given its uniqueness and the fact that Israel is located on the transitional zone between deserts and humid ecosystems.
“In this country, everything is so condensed that the boundaries between natural and urban areas are disappearing. We are losing many open green areas, and the urbanization rate is increasing at an unprecedented rate,” says Sternberg, while explaining why it’s so important to study the effects of climate change on the natural environment.

What will these hills look like in the future? How will Israel’s natural ecosystem react when precipitation in the region changes? The observations and manipulations in the Judean Hills may very likely hold the answer to those questions and also the necessary means to mitigate the effects of climate change. Support for these types of experiments all over the world is critical for understanding what expects us in the future. “National funding agencies should join forces in an effort to secure the continuity of this unique and essential research,” Sternberg concludes.