Extended Data Fig. 3: Conceptual approach of DOF calculation, and visualization for a river example.

a, b, The DOF index ranges from 0% (no fragmentation impact) to 100% (completely fragmented) and is shown for the conceptual approach (a) and the river example (b) in the colour coding shown in b. It is calculated for all river reaches connected to the barrier location in both the up- and downstream directions (but tributaries to the mainstem downstream of the barrier are not considered affected). The impact is largest in connected river reaches that are similar in discharge to the barrier site and diminishes as rivers become increasingly dissimilar in size, that is, larger in the downstream or smaller in the upstream direction. c, DOF decay functions, as considered and evaluated by the expert group.