Acta Entomologica Sinica ›› 2017, Vol. 60 ›› Issue (1): 67-83.doi: 10.16380/j.kcxb.2017.01.009

• RESEARCH PAPERS • Previous Articles     Next Articles

Effects of Spartina alterniflora invasion on the structural characteristics and seasonal dynamics of insect functional groups in Jiuduansha wetland of the Yangtze River Estuary, East China

PAN Hui1, CHEN Xiu-Zhi2, WU Jie1,*, ZHANG Jing1   

  1. (1. Shanghai Entomological Museum, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; 2. Shanghai Jiuduansha Wetland National Nature Reserve Administration, Shanghai 200135, China)
  • Online:2017-01-20 Published:2017-01-20

Abstract: 【Aim】 This study aims to explore the effects of Spartina alterniflora invasion on the structural characteristics and seasonal dynamics of insect functional groups in salt marshes. 【Methods】 In 2015, insects were seasonally collected by a sweeping net along a 10 m long transect line in different sample plots of S.alterniflora Phragmites australis and Scirpus triqueter communities in Jiuduansha wetland of the Yangtze River Estuary, East China.  The nonparametric test method was adopted to compare the variations in the species richness, individual abundance and seasonal dynamics of different functional feeding groups of insects between different plant communities. The effects of plant habitats on the assemblage compositions of different insect functional groups were assessed by the nonmetric multidimensional scaling (NMS) ordination analysis. The habitat preferences of insect species were analysed by the indicator species analysis (ISA). 【Results】 A total of 10 338 individuals belonging to 188 species in 72 insect families were collected. Species richness and individual abundance of insects were significantly lower in S.alterniflora than in P.australis. The species richness of insects in Sc.triqueter was not significantly different from that in S.alterniflora.However, the individual number of insects in Sc.triqueter was significantly higher than that in S.alterniflora. As far as different insect functional groups were concerned, Sc.triqueter had the lowest species number but the highest individual number of insect herbivores. Both species and individual numbers of insect herbivores were not significantly different between S. alterniflora and P. australis. The species richness and abundance of predator/parasitoid insects were significantly higher in P.australis than in S.alterniflora and Sc.triqueter. The species and individual numbers of insect detritivores were not significantly different among plants. In addition, it was shown that the richness and abundance of all insect functional groups in S.alterniflora reached their peak values in spring. However, in P.australis and Sc.triqueter, different functional groups reached their species richness and abundance peaks in different seasons. According to the results of NMS ordination analysis, S.alterniflora invasion significantly changed the insect community composition,even when each functional group was individually concerned. According to the results of ISA, the number of insect species preferring S.alterniflora was the lowest. Of these species, most were generalist herbivores. The number of species preferring P.australis was the highest. Among these species, most were predator/parasitoid and specialist herbivore species. Herbivore species preferring Sc.triqueter were all generalists, but with relatively high indicator values. 【Conclusion】 S.alterniflora invasion reduces the insect biodiversity and significantly changes the structural characteristics and seasonal dynamics of insect functional groups in Jiuduansha wetland. In comparison with insect herbivores, natural enemy insects are more sensitive to the effects of S. alterniflora invasion. Some generalist herbivores may have developed adaptation mechanisms to S. alterniflora. Enough attention should be paid to the potential ecological and evolutionary consequences behind these phenomena.

Key words: Spartina alterniflora, insect, functional group, seasonal dynamics, wetland, Jiuduansha