Effects of extreme drought on specific leaf area of grassland species: A meta‐analysis of experimental studies in temperate and sub‐Mediterranean systems

Abstract

Here, we conducted a meta-analysis of experimental drought manipulation studies using rainout shelters in five sites of natural grassland ecosystems of Europe. The single studies assess the effects of extreme drought on the intraspecific variation of the specific leaf area (SLA), a proxy of plant growth. We evaluate and compare the effect size of the SLA response for the functional groups of forbs and grasses in temperate and sub-Mediterranean systems. We hypothesized that the functional groups of grasses and forbs from temperate grassland systems have different strategies in short-term drought response, measured as adjustment of SLA, with SLA-reduction in grasses and SLA-maintenance in forbs. Second, we hypothesized that grasses and forbs from sub-Mediterranean systems do not differ in their drought response as both groups maintain their SLA. We found a significant decrease of SLA in grasses of the temperate systems in response to drought while SLA of forbs showed no significant response. Lower SLA is associated with enhanced water-use efficiency under water stress and thus can be seen as a strategy of phenotypic adjustment. By contrast, in the sub-Mediterranean systems, grasses significantly increased their SLA in the drought treatment. This result points towards a better growth performance of these grasses, which is most likely related to their strategy to allocate resources to belowground parts. The observed SLA reduction of forbs is most likely a direct drought response given that competitive effect of grasses is unlikely due to the scanty vegetation cover. We point out that phenotypic adjustment is an important driver of short-term functional plant response to climatic extremes such as drought. Differential reactions of functional groups have to be interpreted against the background of the group's evolutionary configuration that can differ between climatic zones. © 2017 John Wiley & Sons Lt

Compensatory mechanisms to climate change in the widely distributed species Silene vulgaris

“…Our biomass‐related traits were able to confirm this theory but leaf traits, however, were not significantly influenced by the precipitation treatment in our overall model. This contradicts the results of several other studies, where leaf area and SLA decreased under drought (Jung et al., ; Maes et al., ; Wellstein et al., ). Under dry conditions, plants are expected to decrease their leaf surface and SLA to prevent the evaporation of water and thus enhance the water‐use efficiency.…”

“…We measured biomass, plant height, number of flowers, number of branches, number of leaves, leaf area and specific leaf area (SLA) as fitness‐related plant traits. These traits have been shown to negatively respond to drought and temperature stress (Eziz et al., ; Khan, Raza, Farooq, & Jabran, ; Rucker, Kvien, Holbrook, & Hook, ; Wellstein et al., ; Zeiter, Schärrer, Zweifel, Newbery, & Stampfli, ). Thus, we hypothesized that biomass‐related traits will have lower values under drought and increased temperature treatments.…”

Global patterns of intraspecific leaf trait responses to elevation

“…() and Wellstein et al. (), our findings further reinforce the importance of intraspecific variation as important driver of functional plant response to climate changes.…”

Transpiration and water potential of young Quercus petraea (M.) Liebl. coppice sprouts and seedlings during favourable and drought conditions

“…Nonetheless, water availability may also influence the adaptation of leaves, hence the species adapted to a drier conditions tend to show lower values of SLA (Poorter et al 2009). Reduction of SLA is assumed to be a way for plants to increase water use efficiency (Wellstein et al 2017), which is contradictory to our results and expected lower values of seedling SLA as compared to coppice sprouts (Drake et al 2012). However, the detailed physiological regulation of the SLA is still unclear (Poorter et al 2009).…”