| Beihai in Guangxi was facing a severe threat from smooth cordgrass Spartina alterniflora invasion and urgently necessary to be eradicated and restored to natural status. Research on the impact of Spartina alterniflora control by chemical analysis method on intertidal animal communities provides scientific prevention and control of Spartina alterniflora. The project was settling three concentrations of herbicide-spraying groups (i.e 50.0 g a.i./L, 62.5 g a.i./L, 75.0 g a.i./L of imazapyr herbicide) and CK (Control Check) group, a field trial to eliminate S. alterniflora was conducted from April to August 2022 on the intertidal flat of Dandou Bay, Guangxi province, China. The intertidal macrobenthos on the trial flats were quantitively sampled seven times on 0 d, 1 d, 3 d, 6 d, 30 d, 60 d, 120 d respectively, and some community indexes were applied to analyze the ecological effect on the macrobenthos. Totally 7 phyla, 8 classes and 49 species of macrobenthos were captured, in which the mollusks and arthropods dominated in species abundance. The imazapyr herbicide did not show a significant regular effect on the community indexes of macrobenthos. The composition of dominant species in the CK group was relatively stable throughout the trial, however significant changes occurred in the all three herbicide-spraying groups, the number of dominant species in the three herbicide-spraying groups fluctuated in the short and middle term, but showed an upward trend in the later stages, with population densities tending to concentrate on the main dominant species. The replacement rate of dominant species in the CK group (71.4%) was not much different to those in herbicide-spraying groups (57.1%～80.0%). The macrobenthos pollution indexes was negative at all sampling times, and the habitat qualities in vast majority of sampling times were non-polluted. Overall, based on a comprehensive assessment, the ecological impact of using the imazapyr herbicide solution with a concentration of 50.0 g·L-1 and a dosage of 60 L·hm-2 to remove Spartina alterniflora on the macrobenthic community was acceptable. |
