Fig. 4.

Effects of split spawning on reliability of larval supply from external sources. Number of years with external supply failure observed in the models (a) with, and (b) without, split spawning for reefs across sectors. Reefs with fewer supply failures would tend to have more reliable supply of coral larvae from external sources. (c) Additional years of supply failure the reefs would experience without split spawning. (d) Map showing locations of reefs that would experience more supply failure events if coral populations on the GBR did not undergo split spawning. The maximum number of years in all analyses was 7. The colours of the boxes in (a), (b), and (c) correspond to the colour scheme of the GBR sectors shown in the inset in (d). In boxplots, the centre line represents the median, the upper and lower limits of the box represent the third and first quartile respectively, the notches in the boxes represent the confidence interval around the median (equal to ±1.58 times interquartile range divided by square root of the sample size), the whiskers extend up to 1.5 times the interquartile range from the bounds of the box, and the points represent outliers beyond the limits of the whiskers. In (d) blue hues show reefs that would not have additional years of supply failure without split spawning, and red hues show the reefs that would have up to 5 additional years of supply failure without split spawning