Seaside arrowgrass facilitates plant diversity in salt marshes by creating elevated rings with its rhizomes.


"Many organisms modulate the availability of resources to other species by causing state changes in biotic or abiotic materials (ecosystem engineering), in the process frequently changing the selection to which the ecosystem engineers and other organisms are exposed (niche construction) [. . .] A final example is seaside arrowgrass (Triglochin maritima), which facilitates plant diversity in salt marshes. By creating elevated rings, maintained structurally by its rhizomes, T. maritima supports both a greater abundance of species and the growth of species not present in the adjacent substratum (Fogel et al. 2004). Experimental analysis revealed that the primary mechanism underlying enhanced plant species diversity was the physical increase in height afforded by the T. maritima rings,which increased reductive potentials and habitat heterogeneity and reduced salinity for neighboring plants (Fogel et al. 2004)." (Boogert 2006)

"Sometimes being left high and dry is a good thing. Seaside arrowgrass, which inhabits saline habitats such as salt marshes, avoids waterlogging by forming raised clumps. Not only does it protect itself, it also creates drier habitats for other species, thus increasing species diversity in a habitat otherwise dominated by a few competitive, clonal species. Seaside arrowgrass forms clumps up to 2 m wide and 60 cm high. Waterlogging of the plants’ roots stimulates production of shallow roots that spread out at or above the surface, resulting in outward expansion of the clumps. As a clump expands outward beyond about 40 cm, the interior shoots die out, resulting in a ring of seaside arrowgrass around a decomposing center. This center initially provides habitat for species such as Salicornia spp., Aster tripolium and Limonium humile. As more dead growth piles up, this creates even drier habitats for species like Plantago maritima and Armeria maritima. The rings have higher organic content and lower water content than the surrounding substrate. The increased height of the rings is the main mechanism behind the increased species diversity because with greater height, there is greater reductive potential, reduced salinity, and increased habitat heterogeneity." (Courtesy of the Biomimicry Guild)

Journal article
The Implications of Niche Construction and Ecosystem Engineering for Conservation BiologyBioScienceOctober 23, 2016

Utah ArrowgrassTriglochin maritimaSpecies