Species richness improves grassland recovery after drought, but only in low-productive environments

Date: 3 October 2017

Introduction: Ivan Nijs, Sigi Berwaers and Hans De Boeck (UAntwerpen) participated in the first multisite international experiment to uncover how biodiversity affects resistance and recovery of grassland ecosystems after drought.

Biodiversity is declining in many places, while climate change increases the prevalence of extreme weather events. But how do both environmental challenges interact? Higher biodiversity has often been pinpointed as a potentially important aspect in protecting ecosystems from the impacts of climate extremes. Biodiversity is like an insurance: if one species fails to cope with the extremes, there are multiple others around that can take over its role in the ecosystem.

Surprisingly however, experiments on this topic were all relatively small-scale so far, which prevents to define which observed effects of biodiversity on coping with drought stress are general, and which effects are peculiar to specific localities.

Sigi Berwaers, Hans De Boeck and Ivan Nijs (Global Change Ecology Centre, Research group Plants and Ecosystems) therefore participated in a large scale experimental setup in 5 different countries, from Belgium to Turkey. Drought was imposed on both temperate and Mediterranean grasslands.

Hans De Boeck explains the most important results: “Imposed drought led to a decline in grassland biomass production regardless of the number of species in the ecosystem. However, recovery after the drought was improved in more diverse grasslands, but only in low-productive environments.        Our research shows that biodiversity may indeed help in buffering negative aspects of climate extremes, although this protective role is not ubiquitous, but context dependent.”

The results were published in the scientific journal Ecology Letters.

Biodiverse grasslands are better protected against climate extremes, but only if productivity is low. Fertilisation may thus negatively affect this natural insurances against droughts (
Photo: Fotolia/ J. Fälchle).