Mediterranean, semi-arid ecosystems resilient to climate change

The Middle East is likely to experience decreased rainfall and even droughts in future climate scenarios. But a new study by Israeli and German ecologists shows that region’s vegetation will not affected.

Climate change predictions for the Middle East, like other arid regions of the world, predict decreased rainfall in the near future. To test how this could affect the functioning of these unique ecosystems, ecologists from Tel Aviv University and the University of Tübingen subjected natural ecosystems to an experimental drought over the course of nine years, simulating predicted future climate change scenarios.

In the course of their experiment, conducted in four different ecosystems ranging from desert to moist Mediterranean woodland, the researchers found that, contrary to predictions, no measurable changes in annual vegetation could be seen. Species richness and composition, density and biomass were largely unaffected by the rainfall manipulations.

“Based on our study, the going hypothesis that all semiarid regions will react strongly to climate change needs to be revised,” states Prof. Sternberg.

The researchers believe that the ecosystems are resilient likely due to the highly variable amounts of annual rainfall for which the regions are known. The experimental climate changes, simulating less than 30 per cent of current rainfall, fall within the natural “comfort zone” of the region’s vegetation. Rather than dying off, the species merely adapted to the new conditions created by climate change.

The researchers conclude that Mediterranean and semi-arid annual plant communities would be little affected by climate change in the short to medium term. However, they don’t rule out the possibility that species composition could change after 20-30 years because natural short-term climatic variations impose a different selection regime on organisms than a long-term trend of changing climate conditions.


Photo credit: Ricardo Tulio Gandelman, flickr/Creative Commons

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