TY - JOUR A1 - Bergholz, Kolja A1 - May, Felix A1 - Ristow, Michael A1 - Giladi, Itamar A1 - Ziv, Yaron A1 - Jeltsch, Florian T1 - Two Mediterranean annuals feature high within-population trait variability and respond differently to a precipitation gradient JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Intraspecific trait variability plays an important role in species adaptation to climate change. However, it still remains unclear how plants in semi-arid environments respond to increasing aridity. We investigated the intraspecific trait variability of two common Mediterranean annuals (Geropogon hybridus and Crupina crupinastrum) with similar habitat preferences. They were studied along a steep precipitation gradient in Israel similar to the maximum predicted precipitation changes in the eastern Mediterranean basin (i.e. -30% until 2100). We expected a shift from competitive ability to stress tolerance with decreasing precipitation and tested this expectation by measuring key functional traits (canopy and seed release height, specific leaf area, N-and P-leaf content, seed mass). Further, we evaluated generative bet-hedging strategies by different seed traits. Both species showed different responses along the precipitation gradient. C. crupinastrum exhibited only decreased plant height toward saridity, while G. hybridus showed strong trends of generative adaptation to aridity. Different seed trait indices suggest increased bet-hedging of G. hybridus in arid environments. However, no clear trends along the precipitation gradient were observed in leaf traits (specific leaf area and leaf N-/P-content) in both species. Moreover, variance decomposition revealed that most of the observed trait variation (>> 50%) is found within populations. The findings of our study suggest that responses to increased aridity are highly species-specific and local environmental factors may have a stronger effect on intraspecific trait variation than shifts in annual precipitation. We therefore argue that trait-based analyses should focus on precipitation gradients that are comparable to predicted precipitation changes and compare precipitation effects to effects of local environmental factors. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved. KW - Climate change KW - Functional ecology KW - Plant height KW - Drought stress KW - Rainfall gradient KW - Trait-environment relationship KW - Local adaptation KW - Phenotypic plasticity Y1 - 2017 U6 - https://doi.org/10.1016/j.baae.2017.11.001 SN - 1439-1791 SN - 1618-0089 VL - 25 SP - 48 EP - 58 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Albert, Cécile H. A1 - Grassein, Fabrice A1 - Schurr, Frank Martin A1 - Vieilledent, Ghislain A1 - Violle, Cyrille T1 - When and how should intraspecific variability be considered in trait-based plant ecology? JF - Perspectives in plant ecology, evolution and systematics N2 - Trait-based studies have become extremely common in plant ecology. Trait-based approaches often rely on the tacit assumption that intraspecific trait variability (ITV) is negligible compared to interspecific variability, so that species can be characterized by mean trait values. Yet, numerous recent studies have challenged this assumption by showing that ITV significantly affects various ecological processes. Accounting for ITV may thus strengthen trait-based approaches, but measuring trait values on a large number of individuals per species and site is not feasible. Therefore, it is important and timely to synthesize existing knowledge on ITV in order to (1) decide critically when ITV should be considered, and (2) establish methods for incorporating this variability. Here we propose a practical set of rules to identify circumstances under which ITV should be accounted for. We formulate a spatial trait variance partitioning hypothesis to highlight the spatial scales at which ITV cannot be ignored in ecological studies. We then refine a set of four consecutive questions on the research question, the spatial scale, the sampling design, and the type of studied traits, to determine case-by-case if a given study should quantify ITV and test its effects. We review methods for quantifying ITV and develop a step-by-step guideline to design and interpret simulation studies that test for the importance of ITV. Even in the absence of quantitative knowledge on ITV, its effects can be assessed by varying trait values within species within realistic bounds around the known mean values. We finish with a discussion of future requirements to further incorporate ITV within trait-based approaches. This paper thus delineates a general framework to account for ITV and suggests a direction towards a more quantitative trait-based ecology. KW - Comparative ecology KW - Functional ecology KW - Genetic variability KW - Intraspecific functional variability KW - Phenotypic plasticity KW - Plant functional hairs KW - Within-species variability Y1 - 2011 U6 - https://doi.org/10.1016/j.ppees.2011.04.003 SN - 1433-8319 VL - 13 IS - 3 SP - 217 EP - 225 PB - Elsevier CY - Jena ER -