PMC

(A and B) Relationships between the coral cover variables (log-SD and mean of coral cover) and the relative importance of variance components that underlie patterns of fish species commonness and rarity across reefs. The relationships are plotted using parameter estimates for the lowest-AIC models, with interactive effects of the coral cover volatility and mean coral cover as explanatory variables and variance components of fish assemblage as response variables (n = 40 reefs; table S2). To illustrate the interactive relationships, coral cover volatility (log-SD of coral cover) is plotted on the horizontal axis, with points color-coded according to levels of mean coral cover on the corresponding reef. The light-, medium-, and dark-colored lines represent the estimated relationship between the variance component and coral cover volatility for the first (21% cover), median (27% cover), and third (41% cover) quartiles of long-term average coral cover, respectively.

a, Woody cover derived from MSAVI at 1.7 m resolution (Supplementary Figs 2-5). b, The woody cover map at 1.7 m resolution was validated with in situ data from northern Senegal (MAE of 3.2, r=0.87, slope=0.98, n=144). Woody cover >10% (r=0.76); woody cover <10% (r=0.77). c, The predicted woody cover map (100 m) was validated with independent in situ data from Senegal (n=24), Mali (n=23) and Niger (n=25) (MAE=0.8, r=0.9, slope=1.01) both for woody cover >10% (r=0.75) and woody cover <10% (r=0.86).

Chao-1 species richness (±s.e.) in areas of low nodule percent cover (<15% cover) is represented by the black line, Chao 1 species richness (±s.e.) in areas of medium nodule percent cover (15–50% cover) is represented by the grey line. Ugland (UGE) species accumulation in areas of low nodule percent cover (<15% cover) is represented by the light green line and Ugland (UGE) species accumulation in areas of medium nodule percent cover (15–50% cover) is represented by the dark green line. Bootstrap species richness in areas of low nodule percent cover (<15% cover) is represented by the dark blue line, Bootstrap species richness in areas of medium nodule percent cover (15–50% cover) is represented by the light blue line. Jacknife 2 species richness in areas of low nodule percent cover (<15% cover) is represented by the yellow line, Jacknife 2 species richness in areas of medium nodule percent cover (15–50% cover) is represented by the orange line. High nodule percent cover (>50% cover) was not observed during this study.

Black curve: mean cover proportions that were used to generate cover class simulated data (averaged within each time). Black dots: cover classes in the simulated data (dots are on the medians of the classes and are jittered vertically). Red curve: estimated overall cover proportion without spatial variations. Red region: 95% credible intervals of the estimated cover proportion.