Fig. 5: Future variation in average macrophyte area of occupancy.
From: Projected loss of brown macroalgae and seagrasses with global environmental change
Brown macroalgae (purple; 185 species) are predicted to lose a higher percentage of their present area of occupancy than seagrasses (pink; 22 species) but expand less than seagrasses. Solid lines represent the mean variation in the macrophyte current area of occupancy (assuming no expansion beyond the species’ extent of occurrence); dashed lines represent the mean expected change in the macrophyte area of occupancy assuming the current ratio between occupied and climatically suitable range will remain constant (proportional expansion; see Methods); this allows for expansion beyond the limits of a species’ extent of occurrence. The shaded area represents a 95% confidence interval (not shown for proportional-expansion trajectories in the upper panel). The upper panel shows the expected change in km2; the lower panel shows the average percentage variation relative to 2015. Columns correspond to different emissions scenarios. We calculated habitat suitability for 2015–2100 using a machine-learning approach (see Methods), and area-of-occupancy trajectories by clipping individual habitat suitability maps with the species’ present-day extent of occurrence obtained using a α-hull method (see Methods). We computed average trajectories over all macrophyte species and aggregated them every 5 years.
