Effects of Sediment Application on Nyssa aquatica and Taxodium distichum Saplings
The decline of Taxodium distichum forests along the Gulf Coast of North America is partly due to elevation loss and subsequent flooding. In many coastal wetlands, a common approach for coastal restoration is to rebuild elevation through the application of dredge material, but this technique has not been used widely in coastal forests due to concerns of negatively impacting trees. This experiment explored growth responses of Nyssa aquatica and T. distichum saplings to applications of low salinity dredge material (0.08 ± 0.001 ppt) in a greenhouse setting. Compared to controls, saplings of T. distichum grown in 7 and 15 cm sediment depths had greater final height, and increased stem and total biomass. In contrast, N. aquatica did not respond to sediment application. The absence of a negative response to sediment application in these two species indicates that dredge material application has the potential to improve the ecosystem health of sinking swamp forests by raising their elevation. We recommend that field trials applying sediment additions in coastal forests include careful monitoring of ecosystem responses, including seed bank expression, seedling regeneration, and root and canopy production.
KeywordsSediment application Subsidence Wetland loss
Thanks to Aaron Muirhead for assistance with the project and Mr. Josh Pruett of Geoengineers Incorporated for dredge sediment material used in the experiment. Also thanks to Rebecca Howard and anonymous reviewers for their helpful comments on earlier versions of the manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Compliance with Ethical Standards
Conflicts of Interest
The authors declare no conflict of interest with any data or information provided in this manuscript.
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