Fig. 4: Local management scenarios that support coral reef persistence four years postdisturbance.

a, Percentage cover of reef-building organisms (hard coral + crustose coralline algae) among reefs surveyed (n = 55) in 2019, four years following the marine heatwave. Colours represent low (≤25th percentile), moderate (>25th and <75th percentile) or high (≥75th percentile) cover. b, Probability of low, moderate or high cover of reef-builders shown in relation to variations in scraper biomass and wastewater pollution. Example scenarios show that simultaneously decreasing wastewater pollution and increasing scraper biomass results in a far greater probability of high reef-builder cover (scenario ‘C’) than achieving either management scenario in isolation (scenarios ‘A’ and ‘B’). The upper (250 kg ha⁻¹) and lower (30 kg ha⁻¹) management scenarios for scraper biomass represented the 92nd and 36th percentiles, respectively. We specifically chose 250 kg ha⁻¹ as it approximates the long-term mean (2003–2019; n = 17) scraper biomass in Kealakekua Bay, a marine protected area in our study region where no fishing has been allowed since 1969 (Supplementary Fig. 11). Similarly, the upper (600,000 l ha⁻¹) and lower (2,500 l h⁻¹) management scenarios chosen for wastewater pollution represented the 95th and 36th percentiles of the 2019 distribution, respectively (Supplementary Fig. 12). Probability values and lines were derived from the top model from ordinal logistic regression modelling (Extended Data Table 3, Methods and Supplementary Information). Colours for low, moderate and high in b are the same as those in a. See Extended Data Table 1 for full list of local land–sea human impacts and environmental factors included in the analysis, including those removed that were highly correlated (r > 0.7, Methods and Supplementary Fig. 8). See Supplementary Fig. 9 for predictor variable distributions.