Does evidence of saltwater exposure explain recent changes in the tree communities of North Carolina’s Coastal Plain?

Coastal plant communities globally are highly vulnerable to future sea-level rise and storm damage, but the extent to which these habitats are affected by the various environmental perturbations associated with chronic salinization remains unclear. In this study, Ury et al. examine the relationship between North Carolina wetland tree community composition and basal area change and indicators of salinization such as soil salt ion content and elevation.

View of North Carolina
(A) The Atlantic coast of the USA, the state of North Carolina and inset of our study region. (B) Photograph of a coastal forest retreat taken by Steve Anderson on the Albemarle Sound. (C) The Albemarle–Pamlico Peninsula and study sites (concentric dots are sites that have historic survey data). Source: Ury et al. 2019.

Ury and colleagues surveyed 34 forest plots in forested, freshwater wetlands across the Albemarle–Pamlico Peninsula. A subset of their study sites had been sampled during the previous decade as part of the Carolina Vegetation Survey, enabling them to investigate the environmental effects on current community structure, and community change over time.

The key factors associated with chronic saltwater intrusion (soil ion content) likely explain recent changes in tree biomass, and potential shifts in community composition in low-elevation sites along the North Carolina coast. Not only is it probable that other coastal forest ecosystems worldwide will experience similar stressors and shifts in community biomass and structure as sea levels rise, but the ability of these habitats to deliver key ecosystem services like carbon sequestration and flood defence will be compromised as a result.

Further reading

Ury, E. A., Anderson, S. M., Peet, R. K., Bernhardt, E. S., & Wright, J. P. (2019). Succession, regression and loss: does evidence of saltwater exposure explain recent changes in the tree communities of North Carolina’s Coastal Plain? Annals of Botany. https://doi.org/10.1093/aob/mcz039