Figure 1.
Spatial distribution of P. aculeata and survey design according to climate and habitat.
A) Current distribution of P. aculeata across Australia (>800,000 km2) and the survey design across a 1,000 km rainfall gradient. B) Australian locations climatically similar to surveyed sites, as determined using climate-matching function in CLIMEX™ [70]. Within each climate region, populations were surveyed where possible between 2001 and 2007 in three habitat types (defined according to inundation patterns), for a total of 23 populations and more than 3,000 individuals at different life-stages.
Figure 2.
Rainfall anomaly histories for the different regions surveyed during the study period (2001–2007).
The rainfall anomaly is the departure from average rainfall conditions (1961–1990). Details on the 23 sites and associated rainfall history can be found in Table S1.
Figure 3.
Life-cycle and life-stages of Parkinsonia aculeata.
Nodes represent the three main demographic stages: seed bank (SB), juvenile (Juv: non-reproductive) and adult (Ad). Nodes (continuous lines) represent stages that can be stratified at an annual time step. The adult stage (dashed line) was stratified into 7 sub-stages according to canopy volume: Ad1.5, Ad5, Ad20, Ad50, Ad100, Ad200, Ad300 m3: for instance in the volume class A1.5, trees have a volume between ]1.5 m3–5 m3], and Ad300 have volume larger than 300 m2. Arcs that link nodes represent the flow of individuals that transit from one stage to another. Self-loops represent the capacity for individuals to delay the transition to the next stage.
Figure 4.
Tree-level plastic response between the mass of individual seeds and the number of seeds produced across the rainfall gradient.
A) Reversible plastic tree-level response of the seed mass-seed number trade-off to rainfall. B) Reconstruction of seed mass distribution across the rainfall gradient from 1930 to 2007, using the observed plastic response. C) The most parsimonious tree-level trade-off between seed production and seed mass across the rainfall gradient. Nomenclature - colours correspond to climate regions, as in Figure 1A. Error bars represent s.e.
Figure 5.
Benefits of plasticity on fitness components.
A) on seed survival rate (Sseed), and B) on seedling survival rate (Ssg). A, SA, SWT, WT refer to the climate regions (see nomenclature in Fig. 1). For SWT, the Ord site (SWTOrd) and Auvergne site (SWTAuv) were analysed separately to account for the difference in Ssg.
Figure 6.
Average individual-level fitness benefits of plasticity.
A) The log-normal distribution between annual rainfall and observed fitness (continuous line, average ± s.d) and fitness if there had been no plasticity (dashed line). B) The Jack-of-All-Trades (JT) strategy as predicted from the distribution between annual rainfall and observed probability of extinction (continuous line) and probability of extinction if there had been no plasticity (dashed line). C) Fitness gain provided by plasticity (average ± s.d). D) The Jack-&-Master (JM) strategy as predicted from the correlation between the reduction of probability of extinction and the average fitness benefits. The probability of extinction was calculated as the proportion of the populations with rs-value<0.
Figure 7.
Selection pressure on the plastic trade-off across the annual rainfall gradient, calculated as the sensitivity of average fitness to potential change in the slope (α) and intercept (β) of the trade-off between seed mass and seed number.
Error bars represent s.d. For the riparian habitat in the semi-arid hot and semi-wet tropical region, sensitivities are not stochastic and s.d. represents the variation between years at those sites.