TY  - JOUR
A1  - Kurze, Susanne
A1  - Bareither, Nils
A1  - Metz, Johannes
T1  - Phenology, roots and reproductive allocation, but not the LHS scheme, shape ecotypes along an aridity gradient
JF  - Perspectives in plant ecology, evolution and systematics
N2  - This study tested systematically at two spatial scales for key traits shaping within-species ecotypic differentiation under increasing aridity. It assessed different plant strategy theories and considered potential implications for climate change. We studied the widespread Mediterranean grass Brachypodium hybridum. At large scale, we tested 14 populations along a steep natural aridity gradient (114-954 mm annual rainfall). At small scale, we tested the microclimatic contrast between plants originating from corresponding north (more mesic) and south (more arid) exposed hillslopes. Fifteen traits were measured in the greenhouse, including the popular traits of the LeafHeight- Seed scheme (SLA, plant height, seed mass), several traits on phenology, architecture, growth, fitness, and rarely measured root traits. Clear trait shifts indicated ecotypic differentiation along the large-scale gradient. Earlier phenology, higher reproductive allocation and reduced root investment characterized arid ecotypes. Surprisingly, no trait of the Leaf-Height-Seed scheme shifted with aridity and root responses were opposite to the theory of optimal resource partitioning. Trait differences between north and south exposures were small, often inconsistent between sites, and poorly matched the trends across the large-scale gradient. South exposures thus appeared unlikely to harbour distinct ecotypes better adapted to aridity. Our findings highlight ecotypes as a crucial way how species span environmental gradients, yet underpinning their restriction at small spatial scales. In combination, this possibly renders populations more vulnerable to climate change. We draw attention to specific, partly unexpected traits and pose the question whether the LeafHeight- Seed scheme has limited applicability for intraspecific investigations in drylands.
KW  - Brachypodium hybridum
KW  - Local adaptation
KW  - Rainfall gradient
KW  - Seed mass
KW  - SLA
KW  - Slope exposure
Y1  - 2017
U6  - https://doi.org/10.1016/j.ppees.2017.09.004
SN  - 1433-8319
VL  - 29
SP  - 20
EP  - 29
PB  - Elsevier
CY  - Jena
ER  - 
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  -