Impacts Of The Spartina Alterniflora Invasions On Benthic Nematode Communities In Coastal Wetlands In China

Mangrove and salt marsh are the two important types of coastal wetland, which have the strong function of ecological service. They play important support roles on estuarial and coastal fishery. However, the wetland ecosystems are suffering serious damage in recent years, when the exotic species Spartina has invaded and expanded in the coastal area of China. In this study, we choose a combinative method of morphological classification and PCR-DGGE. And we are aimed at comparing the difference of genetic lineages structure, species diversity and the trophic groups of benthic nematodes communities those who live in Spartina communities and in native plant communities (salt marsh wetland or mangrove wetland) along the different latitude of our country, to reveal the effect of Spartina on nematode communities in coastal wetland in China. It will provide the scientific basis for environmental protection of coastal wetlands and its sustainable utilization, and also provide the important basic data for further perfecting the theoretical system of global biodiversity distribution.Based on PCR-DGGE fingerprinting analysis, we found that the lineages diversity?richness and evenness of benthic nematodes showed no significant differences between in the exotic species Spartina community and the local species Mangroves or Phragmites community. However, the phylogenetic structure was significantly different between invasive plants and native plant communities. It suggested that the invasion of Spartina had an influence on the genetic lineage structure on nematode community.Through the traditional morphological study, we found 66 species of soil nematode on the coastal wetlands, belonging to 7 orders 40 families. The difference of diversity of the benthic nematode between in Spartina and native plant communities were not obvious. But the TD and MI were significantly lower than the natives. It showed that the invasion of Spartina didn't affect species diversity of nematode, but it could reduce the diversity of nematoid trophic groups. The genus richness and Shannon-weaver index of native plant communities in the high latitude were significantly lower than those in the lower latitudes. But the species diversity of nematode in Spartina community didn't exist the corresponding difference of latitude, indicating that the invasion of Spartina at different latitudes would weaken the latitude difference of species diversity.