BayCEER Workshop 2016

Quantifying plant drought tolerance of temperate grasslands plants: a comparative experimental approach

P 3.2 in Water and the environment: From biosphere to geosphere

Introduction

Drought is well known to be an important driver for shaping community composition and diversity, and ecosystem function. An understanding of the mechanisms conferring species differential drought tolerance and of the role of drought for community assembly and ecosystem resilience is needed for projections of climate change.

Material and Methods

Towards this goal, we comparatively quantified whole-plant drought performance for 41 common grassland species in a common garden drought experiment. Plants were kept in a dry and an irrigated treatment, and growth and survival were assessed.

Results and Discussion

Although drought conditions in the experiment were very severe, in general most plants survived and even maintained shoot growth. Drought survival ranged from 28 % to 100%, but more than half of the species had a drought survival greater than 90%. Consistently, growth did not differ between the dry and the irrigated treatment. Our results confirm that temperate grassland species are overall very drought tolerant, nevertheless, species differed considerably in drought tolerance with potential pervasive consequences for species distribution and community composition. Unexpectedly, drought tolerance of individual species was unrelated to Ellenberg's moisture index, emphasizing the role of plant interactions for species distribution and abundance across moisture gradients.

Conclusions

This first data set on comparative drought tolerance of temperate grassland species will for the first time allow (1) to rigorously test the relative importance of various physiological and morphological traits (and their combinations) for differential drought tolerance of grassland species (see poster and talk Sun et al.), and (2) to address the importance of differential species drought tolerance for grassland community assembly and ecosystem resilience across moisture gradients. These aspects will be further explored within the DFG priority program Biodiversity Exploratories.

Keywords: Drought, temperate grassland, survival, drought tolerance