Competitive interactions between native Spartina alterniflora and non-native Phragmites australis depend on nutrient loading and temperature

• Published in: PloS one Vol. 13; no. 2; p. e0192234
• Main Authors: Legault, 2nd, Rene, Zogg, Gregory P, Travis, Steven E
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.02.2018; Public Library of Science (PLoS)
• Subjects: Analysis; Anthropogenic factors; Biology and Life Sciences; Biomass; Climate change; Closed experimental ecosystems; Coastal marshes; Common reed; Comparative analysis; Competition; Earth Sciences; Ecology and Environmental Sciences; Environmental aspects; Flowers & plants; Global temperature changes; Global temperatures; Greenhouse effect; Greenhouses; Growing season; Growth; Human influences; Influence; Invasive plants; Mesocosms; Nutrient enrichment; Nutrient loading; Nutrients; Phragmites australis; Physical Sciences; Poaceae - chemistry; Pollution load; Research and Analysis Methods; Salt marshes; Spartina; Spartina alterniflora; Species Specificity; Stems; Temperature; Temperature effects; Wetlands; New England; United States > US; North America
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0192234

We explored the nature and impact of competitive interactions between the salt marsh foundational plant Spartina alterniflora and invasive Phragmites australis in New England under varying levels of anthropogenic influence from nutrient loading and temperature warming. Plants were grown with and without competition in mesocosms over a four-month growing season. Mesocosms were split evenly among three levels of nutrient additions and two temperatures varying by an average of ~3° C, manipulated using small greenhouses. We measured aboveground productivity as total biomass, numbers of new stems, and mean stem height. Nutrient enrichment increased all growth parameters, while competition generally reduced aboveground biomass and the production of new stems in both species. Most importantly, smooth cordgrass suffered no negative consequences of competition when no nutrients were added and temperature was elevated. The results of this study suggest that minimizing nutrient loading into coastal marshes could be an important factor in slowing the spread of common reed into the low marsh zone of New England salt marshes as global temperatures continue to warm.