What happens after drought ends: synthesizing terms and definitions

Abstract

Drought is intensifying globally with climate change, creating an urgency to understand ecosystem response to drought both during and after these events end to limit loss of ecosystem functioning. The literature is replete with studies of how ecosystems respond during drought, yet there are far fewer studies focused on ecosystem dynamics after drought ends. Furthermore, while the terms used to describe drought can be variable and inconsistent, so can those that describe ecosystem responses following drought. With this review, we sought to evaluate and create clear definitions of the terms that ecologists use to describe post-drought responses. We found that legacy effects, resilience and recovery were used most commonly with respect to post-drought ecosystem responses, but the definitions used to describe these terms were variable. Based on our review of the literature, we propose a framework for generalizing ecosystem responses after drought ends, which we refer to as 'the post-drought period'. We suggest that future papers need to clearly describe characteristics of the imposed drought, and we encourage authors to use the term post-drought period as a general term that encompasses responses after drought ends and use other terms as more specific descriptors of responses during the post-drought period.

Drought legacies and ecosystem responses to subsequent drought

“…Next to the term ‘drought legacy’ several other terms have been used in the literature, including ‘lagged effects’ (Zhao et al, 2018), ‘stress imprint’ (Bruce et al, 2007), ‘stress memory’ (Fleta‐Soriano & Munné‐Bosch, 2016; Walter et al, 2013) or ‘drought memory’ (Canarini et al, 2021; Ogle et al, 2015; Walter et al, 2011; for a broader discussion see also [Vilonen et al, 2022]).…”

“…Drought legacies are commonly defined as any alterations of an ecosystem state or processes that occur after a drought has subsided (Buttlar et al, 2018; DeBoeck et al, 2018; Delgado‐Balbuena et al, 2019; Griffin‐Nolan et al, 2018; Rousk et al, 2013; Sala et al, 2012; Vilonen et al, 2022; Walter et al, 2013). They refer to changes of intrinsic factors after a disturbance event (see material legacies [Johnstone et al, 2016]) compared to evolutionary adaptions to historical disturbance regimes (see information legacies [Johnstone et al, 2016]).…”

“…In addition to the concurrent effects of drought events on ecosystems, manifold changes can persist after the drought has subsided (Frank et al, 2015). These post‐drought effects are commonly referred to as “drought legacies” (Vilonen et al, 2022) and have been demonstrated for various aspects of ecosystem structure and functioning. Drought legacy effects have been associated with altered carbon (C) cycling (Craine et al, 2013; Kannenberg et al, 2020; Liu et al, 2022; Scott et al, 2010; Wei et al, 2022; Xie et al, 2020), nitrogen (N) cycling (DeLong et al, 2019; DeVries et al, 2012; Legay et al, 2018), growth (Anderegg, Schwalm, et al, 2015; Gazol et al, 2020; Wu et al, 2018; Zhao et al, 2020), phenology (Berwaers et al, 2019; Hoover et al, 2021; Kang et al, 2018; Peng et al, 2019; Sippel et al, 2018; Zeng et al, 2021), species composition (DeBoeck et al, 2018; Griffin‐Nolan et al, 2019; Stampfli et al, 2018; Stampfli & Zeiter, 2020; Winkler et al, 2019), herbivory (Gutbrodt et al, 2011), as well as soil physicochemical properties (Goebel et al, 2011; Sánchez‐García et al, 2019).…”

Mycorrhizas shape the evolution of plant adaptation to drought

“…My study, although based on an evolutionary timescale too coarse to be fully informative at finer ecological timescales, when combined with previous eco-physiological studies (Augé, 2001; Lehto & Zwiazek, 2011), supports the consideration of mycorrhizal strategy when studying the impact of droughts on vegetation to help us fully appreciate the mechanisms underpinning temporal variation and trajectory of responses. This would be particular important when considering vegetation types and larger time scales of post-drought monitoring, as it is increasingly recommended (Martínez-Vilalta & Lloret, 2016; Ploughe et al ., 2019; Vilonen et al ., 2022).…”

Intensive grassland management disrupts below-ground multi-trophic resource transfer in response to drought

“…Despite this knowledge, our understanding of the key components and interactions within food webs that drive the response of C and N fluxes to perturbations is limited. Furthermore, while we have a good understanding of the response of ecosystem processes during drought, comparatively little is known about ecosystem responses, including C and N flux, after these events during a post-drought period 31 . These gaps in our knowledge hamper our ability to make reliable predictions of soil C and N cycling and sequestration in response to dual pressures of agricultural intensification and increased frequency and intensity of climate extremes.…”