Fig 1.
Bifurcation diagrams illustrating model output metrics.
In (a), ΔdV <0 and there is only a single coral steady state for each value of dV. In (b) ΔdV >0 and alternative stable states exist for the values of dV between critC and critM, and an unstable equilibrium (dashed black line) exists between the two stable equilibria.
Table 1.
Default parameters and parameter ranges.
Fig 2.
Histograms showing the distribution of values of ΔdV, for 20,000 random combinations of parameters for (a) the unstructured macroalgae model, and (b) the stage-structured macroalgae model (the * includes all parameter combinations for which ΔdV ≥ 12).
Fig 3.
Bifurcation diagrams for (a) the unstructured macroalgae model, and (b) the stage-structured macroalgae model, showing the steady-state coral cover (C*) as a function of the death rate of vulnerable macroalgae (dV). Solid lines represent stable equilibria, and dashed lines represent unstable equilibria. The default parameters in Table 1 were used.
Fig 4.
(a) and (b) Results of local sensitivity analyses on ΔdV for the Stage-structured Macroalgae Model. (a) Bifurcation diagrams showing the effects of a one-at-a-time 10% increase in the parameters from the default set (with ω = 2, black line; ϕM and gTV lines are indistinguishable from the default set). (b) Change in ΔdV resulting from a one-at-a-time 10% increase in each parameter. The stem-and-whisker plots show the median (horizontal black lines), the 25th and 75th quantiles (boxes), and the 5th and 95th quantiles (lower and upper bars) of the change in ΔdV resulting from a 10% one-at-a-time increase using 1000 randomly sampled “default sets”. The red diamonds indicate the default set listed in Table 1. (c) and (d) Comparison of two methods for Global Sensitivity Analysis showing the importance of the parameters in the Stage-structured Macroalgae Model in determining ΔdV: (c) comparing the Random Forest method and the first-order sensitivity index (i.e., Sobol’s Index; Si), and (d) comparing the Random Forest method and the total importance metrics from Sobol’s method, St,i.