Fig. 5: Species-specific facilitation mechanisms.

Both cordgrass and seagrass increase sediment stability with their root mats, but stiff cordgrass stems also attenuate hydrodynamic energy (blue arrow), while flexible seagrass shoots avoid drag by bending (a, b). Small cordgrass and seagrass transplants cannot self-facilitate, making them vulnerable to uprooting (black arrow). Application of trait-based mimicry allows simulating self-facilitation naturally occurring in mature vegetation stands (c, d). Belowground establishment structures simulate a dense root mat, while aboveground structures mimic dense patches of stiff cordgrass stems. Field measurements in Sweden and Bonaire confirm sediment stabilization by aboveground establishment structures, but even more by belowground structures (e). Flume experiments demonstrate that aboveground structures greatly reduce cordgrass stem movement when subjected to 70-mm-high waves ((f), n = 10). Panel e shows sediment mobility grouped for Sweden and Bonaire (ring burial depth in cm, n = 8). Main effects (S structure, L location) are shown with p values (two sided); significant contrasts with letters (p < 0.05, Tukey corrections for multiple comparisons). Exact p values are shown when p > 0.0001. Data are presented as mean values + SEM. Results of the statistical analyses are presented in Supplementary Table 3. Source data are provided as a Source Data file. Symbols for diagrams courtesy of the Integration and Application Network, IAN Image Library (ian.umces.edu/imagelibrary/).