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Bernik BM, Pardue JH, Blum MJ
Soil erodibility differs according to heritable trait variation and nutrient-induced plasticity in the salt marsh engineer Spartina alterniflora
The salt marsh grass Spartina alterniflora is used extensively in coastal management to stabilize soil. Though such ecosystem engineers are prized tools for habitat restoration, unanticipated outcomes are not uncommon. Departures may arise by overlooking within-species variation in traits and their effects. To evaluate how trait variation affects erodibility of restored soil, S. alterniflora individuals from different populations were grown by Bernik and colleagues under control and high-nitrate conditions. Nitrate induced trait changes that increased soil strength, but heritable differences among populations had an even larger effect. Together, plastic and genetic effects explained 70% of the variation in soil shear strength. This highlights the importance of considering population composition and local environment in the application of engineer species.