Middle-Eastern plant communities tolerate 9 years of drought in a multi-site climate manipulation experiment.

Katja Tielbörger,Claus Holzapfel,Marcelo Sternberg,Edwin Lebrija-Trejos,Mark C Bilton,Irit Konsens,Johannes Metz,Hadas A Parag,Jaime Kigel

doi:10.1038/ncomms6102

Abstract

For evaluating climate change impacts on biodiversity, extensive experiments are urgently needed to complement popular non-mechanistic models which map future ecosystem properties onto their current climatic niche. Here, we experimentally test the main prediction of these models by means of a novel multi-site approach. We implement rainfall manipulations—irrigation and drought—to dryland plant communities situated along a steep climatic gradient in a global biodiversity hotspot containing many wild progenitors of crops. Despite the large extent of our study, spanning nine plant generations and many species, very few differences between treatments were observed in the vegetation response variables: biomass, species composition, species richness and density. The lack of a clear drought effect challenges studies classifying dryland ecosystems as most vulnerable to global change. We attribute this resistance to the tremendous temporal and spatial heterogeneity under which the plants have evolved, concluding that this should be accounted for when predicting future biodiversity change.

Highlights

For evaluating climate change impacts on biodiversity, extensive experiments are urgently needed to complement popular non-mechanistic models which map future ecosystem properties onto their current climatic niche
The Eastern Mediterranean Basin is a global biodiversity hotspot[1], which has been under human influence for millennia, and harbours valuable genetic resources for some of the world’s most important crop species[2]
Our innovative experiments were designed to test whether such a directional shift in species composition will occur when plant communities are exposed to many years of climate manipulation in the field

Summary

Introduction

For evaluating climate change impacts on biodiversity, extensive experiments are urgently needed to complement popular non-mechanistic models which map future ecosystem properties onto their current climatic niche. They often focus on functional, physiological and ecosystem-level responses rather than variables of community structure[7], which are more relevant for assessing species extinction risk and biodiversity-driven ecosystem services Due to this lack of long-term experimental information, predictions of future species diversity and distributions are commonly based on bioclimatic envelope models (BEMs17), which deduce climatic requirements for individual species from their current geographical range and assume migration of species in parallel with the shifting climate to which they are adapted[6,16,17,18,19,20,21]. This assumption can be tested experimentally if the investigations are conducted along a climatic gradient

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Results

Conclusion