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Plant invasion impacts on the gross and net primary production of the salt marsh on eastern coast of China: Insights from leaf to ecosystem
Author(s) -
Ge ZhenMing,
Guo HaiQiang,
Zhao Bin,
Zhang LiQuan
Publication year - 2015
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2014jg002736
Subject(s) - spartina alterniflora , phragmites , primary production , salt marsh , growing season , biomass (ecology) , leaf area index , environmental science , ecosystem , canopy , eddy covariance , photosynthesis , marsh , agronomy , forb , ecology , biology , botany , wetland , grassland
The exotic Spartina alterniflora from North America has been rapidly invading the entire Chinese coast, while the impacts of plant invasion on the gross (GPP) and net primary production (NPP) of the coastal salt marshes were less known. In this study, we investigated the photosynthetic performance, leaf characteristics, and primary production of the exotic C 4 grass and the dominant native C 3 grass ( Phragmites australis ) in two marsh mixtures (equipped with eddy covariance systems) in the Yangtze Estuary. The light‐saturated photosynthetic rate and annual peak leaf area index (LAI) of S . alterniflora was higher than that of P . australis throughout the growing season. The leaf nitrogen content of P . australis declined sharper during the latter growing season than that of S . alterniflora . The leaf‐to‐canopy production model with species‐specific (C 3 and C 4 types) parameterizations could reasonably simulate the daily trends and annual GPP amount against the 3 year flux measurements from 2005 to 2007, and the modeled NPP agreed with biomass measurements from the two species during 2012. The percentage contributions of GPP between S. alterniflora and P. australis were on average 5.82:1 and 2.91:1 in the two mixtures, respectively. The annual NPP amounts from S . alterniflora were higher by approximately 1.6 times than that from P . australis . Our results suggested that higher photosynthesis efficiency, higher LAI, and longer growing season resulted in greater GPP and NPP in the exotic species relative to the native species. The rapid expansion rate of S . alterniflora further made it the leading contributor of primary production in the salt marsh.