Component loadings of ten variables based on principal components analysis of site-level climatic and soil data.

1<p>Climatic data for the May to October growing season (1910–2010) (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#s2" target="_blank">methods</a>). Potential evapotranspiration (PET); atmospheric water balance (AWB) = precipitation- PET.</p>2<p>Component loadings above 0.400 or below – 0.400 are in bold.</p

Climatological data for the May–October growing season for bioregions in the study area.

<p>Data are based on 1910–2010 averages derived from the enhanced meteorological dataset hosted by The State of Queensland (Department of Environment and Resource Management) 2012 (<a href="http://www.longpaddock.qld.gov.au/silo/" target="_blank">http://www.longpaddock.qld.gov.au/silo/</a>). (a) Total precipitation (mm). (b) Mean temperature (°C). (c) Aridity Index. Abbreviations denote the individual bioregions, See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#pone-0049000-g001" target="_blank">Fig. 1</a> for full names. Bioregions are arranged along the <i>x</i> axis from most westerly (BHC) to most easterly (COAST).</p

Mean scores for each bioregion on first and second principal components derived from PCA of data from ten climatological and soil-related variables collected at each of the 34 study sites (see

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#s2" target="_blank"><b>methods</b></a><b>).</b> a) Mean scores on PC1. b) Mean scores on PC2. Variables with high (>0.40) loadings on PC1 and PC2 are shown beside the <i>y</i>-axis; upward and downward arrows indicate positive and negative loadings respectively. For example, in (a) average annual temperature (Tav) loads positively on PC1 while atmospheric water balance (AWB) loads negatively. The data show that PC1 is primarily related to overall aridity, which increases from the most mesic (South-Eastern Highlands) to most arid (Broken Hill Complex) bioregions, while PC2 primarily distinguishes between COAST and South-Eastern Highland bioregions based on soil characteristics. Abbreviations denote the individual bioregions; see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#pone-0049000-g001" target="_blank">Fig. 1</a> for full names. Bioregions are arranged along the <i>x</i> axis from most westerly (BHC) to most easterly (COAST). Climate and soil variable acronyms defined in the text except %N = percentage soil nitrogen; %C = percentage soil carbon; EC = soil electroconductivity.</p

Distribution of <i>Echium plantagineum</i> in Australia and location of collection sites across south-eastern Australia.

<p>(a) Herbarium records from the periods 1889–1910, 1911–1960 and 1961–2010 based on data obtained from Australia's Virtual Herbarium (2009 Council of Heads of Australasian Herbaria Inc) show the pattern of spread since introduction. (b) Distribution of study sites (depicted by black diamonds) across south-eastern Australia, grouped by IBRA bioregion (coloured). BHC = Broken Hill Complex, MDD = Murray Darling Depression, RIV = Riverina, NSS = NSW (New South Wales) South-Western Slopes, SEH = South-Eastern Highlands, SB = Sydney Basin, SEC = South-East Corner. Note that for all analyses SB and SEC were combined into a single coastal bioregion (COAST). The location of CSIRO Black Mountain Laboratories (S 35.27°, E 149.12°) where the glasshouse experiment was conducted is indicated.</p

Seed mass and seed mass variance derived from plants collected from six bioregions in the study area.

<p>(a) Mean site-level seed mass (g; 100 seeds) across all six bioregions based on the final data set (with small seeds removed). Site means are shown as filled circles while bioregion means (average of all sites within a bioregion) are shown as unfilled circles. (b) Estimated mean seed mass (±1 SE) for each bioregion based on linear mixed model analysis (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#s2" target="_blank">methods</a>) of final data set (square root transformed). Means sharing the same letter did not differ significantly at the 0.05 level. (c) Variance in seed mass for all study sites in each bioregion, determined as the variance in seed mass among seed-producing plants using the final data set. Abbreviations denote the individual bioregions, See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049000#pone-0049000-g001" target="_blank">Fig. 1</a> for full names. Bioregions are arranged along the <i>x</i> axis from most westerly (BHC) to most easterly (COAST).</p