Chin J Plan Ecolo ›› 2017, Vol. 41 ›› Issue (4): 409-417.DOI: 10.17521/cjpe. 2016.0338

Special Issue: 红树林专题 入侵生态学专辑

• Orginal Article • Previous Articles     Next Articles

Effects of Spartina alterniflora invasion on enrichment of sedimental heavy metals in a mangrove wetland and the underlying mechanisms

Quan CHEN1,2, Ke-Ming MA1,*()   

  1. 1State Key Laboratory of Urban & Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;
    and
    2University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-11-03 Accepted:2017-02-28 Online:2017-04-10 Published:2017-05-19
  • Contact: Ke-Ming MA

Abstract:

Aims The cordgrass Spartina alterniflora is one of the highly successful invasive plants in coastlines worldwide. Although the S. alterniflora invasion is threatening mangroves and the increasing heavy metal pollution of oceans and coasts are of growing concerns, especially in China, the effects of S. alterniflora invasion on the enrichment of sedimental heavy metals in mangrove wetlands are not known. The objectives of this study are to determine the effects of S. alterniflora invasion on enrichment of sedimental heavy metals in the mangrove wetland and the underlying mechanisms.
Methods We investigated differences in the contents of sedimental heavy metals, including As, Cd, Cr, Cu, Ni, Pb, Zn, and Mn, for two pairs of comparisons (unvegetated shoal vs S. alterniflora monoculture and Avicennia marina monoculture vs A. marina + S. alterniflora mixture), and their relationships with environmental factors in Zhanjiang Mangrove National Natural Reserve, Guangdong, China.
Important findings Spartina alterniflora invasions in mangrove wetlands increased the contents of sedimental heavy metals, with the effects being significant on Cr, Ni, Cu, Zn, and Mn. The intermediate level of pollution was only detected in the sedimental Cd. The presence of S. alterniflora resulted in enrichment in the sedimental heavy metals in the mangrove wetland in Zhanjiang, but not to the degree of concerns for contaminations. The contents of sedimental organic matter, total C, total N, total S and total K were strongly related to the contents of sedimental heavy metals in the invaded mangrove wetland. Ultimately, the dense above-and below-ground architectures of the invasive S. alterniflora likely play a predominant role in causing enrichment of sedimental heavy metals.

Key words: Spartina alterniflora, Avicennia marina, heavy metals, sediment physicochemical property, vegetation characteristics, Zhanjiang, China