Density-dependent role of an invasive marsh grass, Phragmites australis, on ecosystem service provision

• Published in: PloS one Vol. 12; no. 2; p. e0173007
• Main Authors: Theuerkauf, Seth J, Puckett, Brandon J, Theuerkauf, Kathrynlynn W, Theuerkauf, Ethan J, Eggleston, David B
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24.02.2017; Public Library of Science (PLoS)
• Subjects: Atmospheric sciences; Biodiversity; Biology and Life Sciences; Carbon; Carbon capture and storage; Carbon content; Carbon sequestration; Carbon storage; Common reed; Communities; Community composition; Community structure; Conservation biology; Conservation of Natural Resources; Earth Sciences; Ecology; Ecology and Environmental Sciences; Ecosystem biology; Ecosystem management; Ecosystem services; Ecosystems; Engineers; Environmental changes; Equivalence; Estuaries; Estuarine environments; Flowers & plants; Genetic aspects; Grasses; Hymenachne; Introduced Species; Invasive species; Marshes; Nonnative species; North Carolina; Phragmites; Phragmites australis; Plant communities; Plant diversity; Planting density; Poaceae; Seeds; Shoreline protection; Shorelines; Soil erosion; Spartina; Spartina alterniflora; Species richness; Wetlands; United States; North Carolina; United States > US; North America; Illinois
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0173007

Invasive species can positively, neutrally, or negatively affect the provision of ecosystem services. The direction and magnitude of this effect can be a function of the invaders' density and the service(s) of interest. We assessed the density-dependent effect of an invasive marsh grass, Phragmites australis, on three ecosystem services (plant diversity and community structure, shoreline stabilization, and carbon storage) in two oligohaline marshes within the North Carolina Coastal Reserve and National Estuarine Research Reserve System (NCNERR), USA. Plant species richness was equivalent among low, medium and high Phragmites density plots, and overall plant community composition did not vary significantly by Phragmites density. Shoreline change was most negative (landward retreat) where Phragmites density was highest (-0.40 ± 0.19 m yr-1 vs. -0.31 ± 0.10 for low density Phragmites) in the high energy marsh of Kitty Hawk Woods Reserve and most positive (soundward advance) where Phragmites density was highest (0.19 ± 0.05 m yr-1 vs. 0.12 ± 0.07 for low density Phragmites) in the lower energy marsh of Currituck Banks Reserve, although there was no significant effect of Phragmites density on shoreline change. In Currituck Banks, mean soil carbon content was approximately equivalent in cores extracted from low and high Phragmites density plots (23.23 ± 2.0 kg C m-3 vs. 22.81 ± 3.8). In Kitty Hawk Woods, mean soil carbon content was greater in low Phragmites density plots (36.63 ± 10.22 kg C m-3) than those with medium (13.99 ± 1.23 kg C m-3) or high density (21.61 ± 4.53 kg C m-3), but differences were not significant. These findings suggest an overall neutral density-dependent effect of Phragmites on three ecosystem services within two oligohaline marshes in different environmental settings within a protected reserve system. Moreover, the conceptual framework of this study can broadly inform an ecosystem services-based approach to invasive species management.