Fig. 3: The relationship between the maximum density of molluscs and shorebirds across survey years (Supplementary Data 1, noting that years surveyed varied across sites) along the Chinese coast.

a the spatial variation in maximum densities of shorebirds and molluscs at 16 sites where both types of survey were conducted (Supplementary Data 1). The map was produced in R using the sf package⁶⁰. b For the 29 shorebird species with known diet, the correlation coefficient between the maximum density of commercial molluscs and each species’ maximum density increases with the percentage of molluscs in the diet (least-squares regression, two-sided: slope β = 0.32 ± 0.13 (SE), t(df = 27) = 2.54, 95% CI [0.06, 0.58], p = 0.02, R² = 0.23, n = 29 species. c, Relationships between the maximum densities of commercial molluscs and shorebirds by dietary guild, fit with least-squares regressions (two-sided) on log-transformed densities: molluscivorous (red; β = 0.45 ± 0.18 (SE), t(df = 14) = 2.53, 95% CI [0.07, 0.83], p = 0.02, R² = 0.31, n = 16), non-molluscivorous (orange; β = 0.18 ± 0.18 (SE), t(df = 14) = 1.02, 95% CI [−0.20, 0.57], p = 0.32, R² = 0.07, n = 16), and diet unknown (blue; β = 0.42 ± 0.22 (SE), t(df = 14) = 1.91, 95% CI [−0.05, 0.90], p = 0.08, R² = 0.21, n = 16). d Relationship between the maximum densities of commercial and non-commercial molluscs, fit with least-squares regression (two-sided) on log-transformed densities: β = −0.24 ± 0.29 (SE), t(df = 14) = − 0.82, 95% CI [−0.86, 0.38], p = 0.43, R² = 0.05, n = 16. The relationship is significant when the p-value is smaller than 0.05. Solid lines represent significant correlations, and dashed lines represent non-significant correlations. Source data are provided as a Source Data file.