Persistent loss of animal diversity on a rocky shore over nine decades and across multiple investigators

). Relative to the historical baseline in the 1930s, there was no evidence for change in richness but strong evidence for change in diversity metrics. On average, Hill-Shannon diversity declined by 41-61%, Hill-Simpson diversity declined by 32-56%, and species evenness declined by 41-68% since the 1930s. Declines in diversity were associated with several taxonomic and functional changes in species composition. On average, species with a southern geographic range increased in abundance more than coastwide species, reinforcing previous work on the historical transect that demonstrated a fingerprint of seawater warming. Taken together, this case study emphasizes the value of marine stations in providing a venue for sustained periodic ecological monitoring at small spatial scales, long duration, and fine taxonomic resolution.