Electronic Supplementary Material 1. R Statistics and P-Values from ANOSIM Analyses Based

Electronic Supplementary Material 1. R statistics and p-values from ANOSIM analyses based on Euclidean distances and using monthly nutrients concentrations and -3 DIN/P-PO4 ratio as variables. The combination island-type is used as single grouping factor. Significant p-value is set to α = 0.0056 after applying Bonferroni correction. MA: Majorca, MI: Minorca, IB: Ibiza and FO: Formentera

Factor (island-type) R Statistic p-value MA-oligohaline, MA-mesohaline 0.231 0.073 MA-oligohaline, MA-euhaline 0.231 0.026 MA-mesohaline, MA-euhaline 0.168 0.108

MI-mesohaline, MI-oligohaline -0.025 0.494

MA-oligohaline, MI-oligohaline 0.073 0.213 MA-mesohaline, MI-mesohaline -0.109 0.750

FO-euhaline, MA-euhaline 0.053 0.151

IB-euhaline, MA-euhaline 0.063 0.339

IB-euhaline, FO-euhaline 0.362 0.018