Why grasses grow better after drought: Mechanisms driving post-drought recovery and productivity outperformance in temperate grasslands
Schärer, M.L . 2025.
Abstract
When back in the 1990s, climate change was predicted to hit us soon, it has not yet been
confirmed to be already happening. Now, 30 years later, it affects our everyday lives with
unmistakable evidence. Despite 2023 being with a 1.4 K higher global surface temperature
compared to the 1850-1900 average the warmest year ever recorded, it will likely once be
among the coldest years measured in this century. According to the Intergovernmental Panel
on Climate Change (IPCC), the increase in earth's surface temperature will reach 1.4 K to 4.4
K compared to the 1850-1900 reference period by 2100, depending on the future emission
scenario (IPCC, 2023)1. With every temperature increment, the capacity and demand of the
atmosphere to hold water increases. Increased amounts of water vapor in the atmosphere will
affect large-scale atmospheric circulation processes and ultimately lead to more frequent
extreme climatic events such as drought (IPCC, 2007). Drought has been a common threat to
terrestrial ecosystems. Nonetheless, the projected increase in its frequency and intensity will
doubtlessly transform our ecosystems and pose new challenges to human societies. Yet, certain
ecosystems seem to cope better with drought than others. Some grasslands have a remarkable
capacity to regrow after drought with formerly drought-stressed grasslands even outperforming
non-stressed controls once drought is released (Hahn et al., 2021; Hofer et al., 2016; Ingrisch
et al., 2018; Ru et al., 2023). The processes and factors underlying this capacity have, however,
not yet been identified. In this PhD thesis, I delve into drought recovery mechanisms in
temperate perennial grasslands and identify the key drivers that lead to post-drought
outperformance in plant aboveground productivity.
