An international team of researchers led by Dr. Fernando T. Maestre, ecologist and professor at Rey Juan Carlos University, has finished a global empirical study that suggests that preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.
The study, entitled “Plant species richness and ecosystem multifunctionality in global drylands”, was published in the prestigious journal Science on Friday. The publication of this study is the outcome of a 5-year research effort, which has involved more than 50 researchers from 30 institutions in 15 different countries, including Dr. Bertrand Boeken of the Jacob Blaustein Institutes for Desert Research at BGU’s Sede Boqer Campus and Dr. Eli Zaady of the Gilat Research Center, the Volcani Institute - Agriculture Research Organization. The Israeli researchers contributed research data from two long-term ecological research sites in the northern Negev, in Park Shaked near Ofakim and in the Lehavim hills.
The results of this study indicate that the ability of ecosystems in drylands worldwide to maintain multiple functions, such as carbon storage and buildup of nutrient pools (multifunctionality) is enhanced by the number of perennial plant species, mainly shrubs and dwarf-shrubs, whereas increased average annual temperature reduces this ability.
While small-scale controlled experiments have provided evidence of the positive relationship between biodiversity and multifunctionality over the years, this study is the first in explicitly evaluating such relationship among real ecosystems at a global scale.
The fieldwork of this study has been carried out in 224 dryland ecosystems from all continents except Antarctica, where direct measurements of plant diversity and other biotic and abiotic features of the ecosystem were taken. To assess ecosystem multifunctionality, researchers assessed more than 2,600 soil samples for 14 ecosystem functions related to carbon, nitrogen and phosphorus cycling and storage. The functions measured deliver some of the fundamental supporting and regulating ecosystem services (e.g. soil fertility and climate regulation), and are also used to identify the onset of desertification processes.
Drylands constitute some of the largest terrestrial biomes, collectively covering 41% of Earth’s land surface and supporting over 38% of the global human population. They are of paramount importance for biodiversity, host many endemic plant and animal species, and include about 20% of the major centers of global plant diversity and over 30% of the designated endemic bird areas. However, dryland ecosystems are also highly vulnerable to global environmental change and desertification. “This study provides empirical evidence on the importance of biodiversity to maintain and improve ecosystem multifunctionality in drylands. The quality and quantity of ecosystem services depend on variables such as those we evaluated, and thus the results obtained indicate that increases in the number of plant species could improve the provision of these services. Our findings also suggest that such richness may be particularly important for maintaining ecosystem functions linked to C and N cycling, which sustain carbon sequestration and soil fertility. Because land degradation is often accompanied by the loss of soil fertility, plant species richness may also promote ecosystem resistance to desertification”, says Dr. Maestre.This study emphasizes the need to preserve biodiversity in dryland ecosystems, Dr. Maestre stressed.
In this regard, Boeken says that “Our results also suggest that the increase in average annual temperature predicted by climate change models will reduce the ability of dryland ecosystems to perform multiple functions, which are crucial to support life on Earth. Plant biodiversity enhances this ability, therefore, maintaining and restoring it can contribute to mitigating the negative consequences of global warming and to promoting the resistance of natural ecosystems to desertification.”
Read the article: 
Science Plant Species Richness and biodiversity.pdf
