Upland vegetation removal as a potential tool for facilitating landward salt marsh migration
Citation:
Raposa, K., R. Weber, D. Durant, J. Mitchell, S. Rasmussen, R. McKinney, AND C. Wigand. Upland vegetation removal as a potential tool for facilitating landward salt marsh migration. RESTORATION ECOLOGY. Blackwell Publishing, Malden, MA, 32(8):e14242, (2024). https://doi.org/10.1111/rec.14242
Impact/Purpose:
Rising sea level in the northeast US threatens the sustainability of coastal salt marshes. The one-time removal of upland vegetation adjacent to a coastal marshes might be a technique to facilitate landward migration of a drowning marsh. However, implementation of this method had little benefit on enhancing landward migration of the salt marsh. Repeated removals of upland vegetation or more intensive vegetation control methods might be required to facilitate landward migration of salt marshes. Upland habitat manipulations to benefit salt marshes may have adverse effects on upland bird and wildlife habitat and needs to be considered when upland vegetation removal is undertaken.
Description:
To increase the resilience of salt marshes subject to sea-level rise impacts, managers can focus on interventions within current marsh footprints or in adjacent uplands to facilitate landward marsh migration. The latter approach may be more appropriate when degradation is severe and in situ intervention options are limited. Strategies for facilitating marsh migration include removing artificial barriers, soil grading to reduce steep topography, and manipulating adjacent upland vegetation that can hinder migration, but experiments testing the effectiveness of these activities are limited. We therefore conducted a field experiment to determine if physically removing three upland vegetation types (forest, shrub, and Phragmites australis) adjacent to a Rhode Island salt marsh facilitates short-term marsh migration. Upland vegetation removal led to increased ambient light in all habitats, significantly enhanced marsh plant cover, extent, and elevation in shrub habitat, and declines in total bird abundance in forest and shrub habitats. Enhanced migration did not occur in forest or Phragmites habitats, and in shrubs, marsh plants only colonized where Baccharis halimifolia, common in upper marsh borders, had been removed. Five years after removal, all upland habitats and associated vegetation were indistinguishable from initial conditions. Our study suggests that upland plant removal might provide a limited window for facilitating salt marsh migration and that more intensive methods may be needed for sustained, longer-term benefits. It also demonstrates that there may be ecological trade-offs to consider when altering upland habitats to enhance landward marsh migration.
URLs/Downloads:
DOI: Upland vegetation removal as a potential tool for facilitating landward salt marsh migration