Responses of Temperate Grassland Plants to Recurrent Heatwaves

ABSTRACT Heatwaves are an often‐overlooked aspect of current climate change in plant research. However, projections of future scenarios show an increase in their frequency and intensity in most temperate‐climate regions. The effects of heatwaves on crop and woody species are well known. In contrast, for wild herbaceous species, no overview is available. Moreover, negative or neutral effects on temperate grassland species are found in the literature, raising the complexity and diversity of responses to heatwaves. To disentangle this diversity, we review research articles on the impact of heatwaves on plant growth and survival in temperate grasslands. The mechanisms and factors mentioned in these articles are discussed to better understand this diversity of responses. We highlight the importance of the timing of a heatwave relative to phenology, as heatwaves can occur in spring, summer or early autumn. We also propose to classify plant mechanisms according to their utilisation, that is, before, during and after the heatwave, which is considered a disturbance. We emphasise the overall effects (whether positive or negative, small or large) on different molecular, physiological and whole‐plant mechanisms; the resilience or tolerance after heatwaves and not only resistance during heatwaves; the interactions with abiotic factors, such as drought, but also with biotic factors as plant–plant interactions; and the effects of recurrent heatwaves, which can trigger priming effects or cumulative negative effects. Solutions for grassland management in the face of current climate change, with more frequent heatwaves in temperate‐climate regions, are also explored.