The role of nutrients for the variability of drought effects on community composition and productivity across land use gradients in grasslands: a trait based approach

Picture: The photograph shows an unmown meadow containing numerous large, grey, rectangular, open-topped containers for mesocosms containing grassland plants. The containers are under open semi-circular tunnel-shaped metal poles that can presumably be covered with foil. Shrubs and deciduous trees can be seen in the background.

Background

Drought is important in grasslands worldwide. Temperate grasslands experience years with low rainfall and are subject to extreme drought events that lead to plant drought stress. With global climate change, temperatures are projected to increase and water availability to decrease in temperate grasslands during the growing season. At the same time, the intensity and frequency of drought events is expected to increase. The importance of drought in driving community structure and ecosystem function in grasslands is therefore expected to even increase in the future.
However, although we have plenty of evidence for the importance of drought in grasslands we still lack a thorough understanding that enables us to predict which species/traits will benefit or suffer from drought, and therefore the effects on community composition and on ecosystem function and resilience.

Hypotheses

In this research project we will address the following main questions:

how does drought tolerance vary among grassland species in the Exploratories?
what traits are important for determining differential drought tolerance of grassland species?
to what extend is drought important in shaping community composition and diversity across space and time, and what is the role of neutral vs. deterministic processes (and habitat filtering vs. niche differentiation)?
does the importance of drought for community assembly change with land-use?

Methods

We will conduct common garden drought experiments on the most important species in the Exploratory grasslands to comparatively assess species drought responses and potentially underlying traits. We will combine the results with Biodiversity Exploratory data on vegetation composition and moisture variation in the experimental plots to evaluate the relative importance of drought for community assembly.

Picture: The photograph shows a table in a greenhouse on which there are twenty-five long black tube-like containers in each of seventeen racks, filled with soil and containing various grassland plants. In all the containers are strip-like labels, each rack either yellow, blue, white or red in colour

In the greenhouse we investigate the effect of different nutrient availability on drought resistance traits of grassland species

In these mesocosms we study the effect of drought and nutrient availability on grassland species

Publications

Drought survival is positively associated with high turgor loss points in temperate perennial grassland species

Sun S., Jung E., Gaviria J., Engelbrecht B. M. J. (2020): Drought survival is positively associated with high turgor loss points in temperate perennial grassland species. Functional Ecology 34 (4), 788-798. doi: 10.1111/1365-2435.13522

Comparative drought resistance of temperate grassland species: testing performance trade‑ofs and the relation to distribution

Jung E., Gaviria J., Sun S., Engelbrecht B. M. J. (2020): Comparative drought resistance of temperate grassland species: testing performance trade-offs and the relation to distribution. Oecologia 192, 1023–1036. doi:10.1007/s00442-020-04625-9

Comparative drought resistance of temperate grassland species: mechanisms, prediction and relation to species distribution across moisture gradients

Sun S. (2019): Comparative drought resistance of temperate grassland species: mechanisms, prediction and relation to species distribution across moisture gradients. Dissertation, University Bayreuth. doi: 10.15495/EPub_UBT_00004322

Datasets

Public Datasets

High turgor loss point promotes drought survival of temperate grassland species, experiment, 2015 – 2016.

Engelbrecht, Bettina (2018): High turgor loss point promotes drought survival of temperate grassland species, experiment, 2015 - 2016.. Version 2. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de/ddm/data/Showdata/23026?version=2/ddm/data/Showdata/23026?version=2

Drought resistance of grassland species, common garden experiment, 2015

Engelbrecht, Bettina; Jung, Eunyoung (2017): Drought resistance of grassland species, common garden experiment, 2015 . Version 3. Biodiversity Exploratories Information System. Dataset. https://www.bexis.uni-jena.de/ddm/data/Showdata/20846?version=3/ddm/data/Showdata/20846?version=3