Changes in yearly mean average taxonomic distinctness (Δ⁺) and taxonomic variability (Λ⁺) over 35 years in the Chicago Area Waterway System indicate a more taxonomically diverse ecosystem in 2019 than 1985. Lines represent significant piecewise regressions (minimum of 3-yr spans; α = 0.05). Different shapes represent groups with significantly different (A = circles vs. B = squares) or shared (AB = diamonds) means (α = 0.05) within each index.