Biophysical and anthropogenic influences on the status of Tonga’s coral reefs and reef fish fishery
Fig 5
Top left: Map of hard coral cover at sites sampled across Tonga. Light blue represents reef, green land, and black outlines villages. Each provincial capital is marked by a black star. Bottom left: Relative influence of the 11 predictor variables included in the Boosted Regression Tree. The dashed vertical line represents a reference point of relative influence that would be expected if all predictors were equally influential. Top right: Partial dependency plots with 95% confidence intervals for the most influential variables predicting hard coral cover. The plots show the effect of each predictor on the repsonse while all other variables were at their mean values. Relative influence of each predictor is reported in parentheses. Grey tick marks across the top of each plot indicate observed data points. Bottom right: Plots of the strongest pairwise interactions between influential variables. Contour lines indicate model predictions and points represent observed data. Units are as follows: SST−OCelcius, distance from provincial capital–km, rugosity– 1–5, reef density–km2, log wave energy–Joules per m2.