Fig. 4. Discontinuities detected by HCA, BCART, CART, and GRI approaches for boreal forest birds (top left), firm size SIC 226 (top right), SW cities 1890 (middle left), boreal forest mammals (middle right), Everglades mammals (bottom left), and Mediterranean mammals (bottom right). Dots at bottom represent data used in each analysis, dashed lines depict gaps (discontinuities).