Oecologia (2011) 165, 797-807

Rong Hao Peng, Chang Ming Fang, Bo Li and Jia Kuan Chen (2011)
Spartina alterniflora invasion increases soil inorganic nitrogen pools through interactions with tidal subsidies in the Yangtze Estuary, China
Oecologia 165 (3), 797-807
Abstract: Invasive alien plants increase both plant N and soil inorganic N pools in many terrestrial ecosystems. This is believed to be the result of altered plant-soil-microbe feedbacks that accelerate N cycling. However, it may also be due to the greater ability of invasive species to uptake lateral N subsidies that can modify ecosystem N dynamics. We conducted manipulative field experiments to determine the impact of smooth cordgrass (Spartina alterniflora) invasion on the N cycling of salt marsh ecosystems in the Yangtze Estuary, China. The results showed that the aboveground plant N and soil inorganic N pools in S. alterniflora marshes, 14.39 and 3.16 g N m⁻², were significantly higher than those in native common reed (Phragmites australis) marshes, 11.61 and 2.29 g N m⁻². These increases after invasion were explained by a significantly higher uptake of dissolved inorganic N (DIN) from tidal subsidies in S. alterniflora marshes (6.59 g N m⁻²) than from those in P. australis marshes (1.61 g N m⁻²), and not by soil organic N mineralization, which was not significantly different between S. alterniflora (6.45 g N m⁻²) and P. australis marshes (6.84 g N m⁻²) during the growing season. Our study indicated that the ecosystem engineering effects of S. alterniflora, which increases the interception of external N input, can be an alternative mechanism that increases plant N and soil inorganic N pools-especially in ecosystems with ample anthropogenic N subsidies, such as the coastal wetlands of China.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Bo Li

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sporobolus alterniflorus (weed)		China (south)