Interspecific and intraspecific trait variability differentially affect community‐weighted trait responses to and recovery from long‐term drought

Abstract

Plant traits are useful proxies of plant strategies and can influence community and ecosystem responses to climate extremes, such as severe drought. Few studies, however, have investigated both the immediate and lagged effects of drought on community‐weighted mean (CWM) plant traits, with even less research on the relative roles of interspecific vs. intraspecific trait variability in such responses. We experimentally reduced growing season precipitation by 66% in two cold‐semi‐arid grassland sites in northern China for four consecutive years to explore the drought resistance of CWM traits as well as their recovery 2 years following the drought. In addition, we isolated the effects of both interspecific and intraspecific trait variability on shifts in CWM traits. At both sites, we observed significant effects of drought on interspecific and intraspecific trait variability which, in some cases, led to significant changes in CWM traits. For example, drought led to reduced CWM plant height and leaf phosphorous content, but increased leaf carbon content at both sites, with responses primarily due to intraspecific trait shifts. Surprisingly, these CWM traits recovered completely 2 years after the extreme drought. Intraspecific trait variability influenced CWM traits via both positive and negative covariation with interspecific trait variability during drought and recovery phases. These findings highlight the important role of interspecific and intraspecific trait variability in driving the response and recovery of CWM traits following extreme, prolonged drought. Read the free Plain Language Summary for this article on the Journal blog.

Trade‐offs in rooting strategy dimensions along an edaphic gradient in a grassland ecosystem

“…Intraspecific trait variation, including genotypic variation and phenotypic plasticity, can also cause a change of community‐level trait values (Russo & Kitajima, 2016; Zheng et al., 2022). The effects of species turnover and interspecific trait variation can outweigh the effects of intraspecific trait variation (Ryser & Eek, 2000), but intraspecific effects on community‐level trait variation are often not negligible, especially under environmental stress (Luo et al., 2023; Niu et al., 2020; Zheng et al., 2022).…”

Field experiments have enhanced our understanding of drought impacts on terrestrial ecosystems—But where do we go from here?

“…plastic adjustment and/or changes in population genetics; Pritzkow et al., 2020) and/or shifts in the abundance of species with certain traits (e.g. Jung et al., 2014; Luo et al., 2021; Luo, Griffin‐Nolan, et al., 2023).…”

“…This may be, in part, because intraspecific and interspecific trait responses to drought can oppose each other. In other words, species with high SLA can increase in abundance (a population response) in communities during drought, yet SLA for individual species already present may decrease with drought (Luo, Griffin‐Nolan, et al., 2023, Figure 4b). Perhaps a more promising alternative for linking traits to drought responses at the ecosystem scale is to focus on the response of hydraulic traits of dominant species to experimental drought, an approach that prioritizes more direct, mechanistic plant responses (Brodribb et al., 2020; Griffin‐Nolan, Bushey, et al., 2018; Reich, 2014) and can be integrated into existing trait frameworks (Díaz et al., 2016, Figure 4c).…”

“…desiccation tolerance, Volaire, 2018) might be expected to increase in abundance in ecosystems. This prediction has some support (Barbeta et al., 2013; Harrison et al., 2015; Linares & Tíscar, 2010; Martínez‐Vilalta & Lloret, 2016; Metz & Tielbörger, 2023), but several recent drought experiments suggest an intriguing alternative response—that as drought becomes more extreme in either magnitude or duration, drought tolerance traits actually decrease and drought avoidance and escape traits increase in plant communities (Figure 4d, Blanco‐Sánchez et al., 2022; Griffin‐Nolan, Blumenthal, et al., 2019; Luo et al., 2021; Luo, Griffin‐Nolan, et al., 2023; Kramp et al., 2022). This may occur, in part, because demographic shifts and trait acclimation cannot keep pace with increasing drought stress (Quetin et al., 2023).…”

Variations in the plasticity of functional traits indicate the differential impacts of abiotic and biotic factors on the structure and growth of trees in tropical dry forest fragments

“…Recently, for understanding the resistance of plant species to drought stress and for the maintenance of biodiversity ( Violle et al., 2012 ; Kramp et al., 2022 ), research interest in inter- and intra-specific drought-resistance trait variations has increased ( Choat et al., 2007 ; Cornwell and Ackerly, 2009 ; Luo et al., 2023 ). These studies have mainly evaluated the influence of abiotic (e.g., Valladares et al., 2006 ; Bongers et al., 2018 ) and biotic (e.g., Callaway et al., 2003 ; Díaz et al., 2007 ; Metlen et al., 2009 ; Li et al., 2021 ) factors on plasticity in functional traits separately, whereas a few studies have also reported mixed results of the effects of biotic and abiotic factors for the plastic responses to plant competition (e.g., Semchenko et al., 2007 ; Cahill et al., 2010 ).…”