Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

Hydrobiologia
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Abstract

Higher atmospheric concentrations of CO2 can offset the negative effects of flooding or salinity on plant species, but previous studies have focused on mature, rather than regenerating vegetation. This study examined how interacting environments of CO2, water regime, and salinity affect seed germination and seedling biomass of floating freshwater marshes in the Mississippi River Delta, which are dominated by C3 grasses, sedges, and forbs. Germination density and seedling growth of the dominant species depended on multifactor interactions of CO2 (385 and 720 μl l-1) with flooding (drained, +8-cm depth, +8-cm depth-gradual) and salinity (0, 6% seawater) levels. Of the three factors tested, salinity was the most important determinant of seedling response patterns. Species richness (total = 19) was insensitive to CO2. Our findings suggest that for freshwater marsh communities, seedling response to CO2 is species-specific and secondary to salinity and flooding effects. Elevated CO2 did not ameliorate flooding or salinity stress. Consequently, climate-related changes in sea level or human-caused alterations in hydrology may override atmospheric CO2 concentrations in driving shifts in this plant community. The results of this study suggest caution in making extrapolations from species-specific responses to community-level predictions without detailed attention to the nuances of multifactor responses.
Publication type Article
Publication Subtype Journal Article
Title Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?
Series title Hydrobiologia
DOI 10.1007/s10750-011-0946-3
Volume 683
Issue 1
Year Published 2012
Language English
Publisher Springer
Publisher location Amsterdam, Netherland
Contributing office(s) National Wetlands Research Center
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Hydrobiologia
First page 123
Last page 133
Country United States
Other Geospatial Mississippi River Delta
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