Monitoring the Invasion of Smooth Cordgrass Spartina alterniflora within the Modern Yellow River Delta Using Remote Sensing

Abstract

Ren, G.-B.; Wang, J.-J.; Wang, A.-D.; Wang, J.-B.; Zhu, Y.-L.; Wu, P.-Q.; Ma, Y., and Zhang, J.B., 2019. Monitoring the invasion of smooth cordgrass Spartina alterniflora within the modern Yellow River Delta using remote sensing. In: Jung, H.-S.; Lee, S., and Ryu, J.-H. (eds.), Advances in Remote Sensing and Geoscience Information Systems of the Coastal Environments. Journal of Coastal Research, Special Issue No. 90, pp. 135-145. Coconut Creek (Florida), ISSN 0749-0208.The Smooth Cordgrass, Spartina alterniflora, was introduced into the modern Yellow River Delta in 1989 to protect banks and beaches within the intertidal zone. By 2018, its distribution area had expanded to 4005.89 ha, which was 2557 times its initial colonization area. The distribution of S. alterniflora in the modern Yellow River Delta at given times and its ecological and biological effects have been studied previously; however, its invasion rate and characteristics, which affect its comprehensive management, are not known. Using multi-resolution and multi-platform remote sensing time series data from 1989 to 2018, combined with years of field data, the invasion of S. alterniflora within the modern Yellow River Delta was studied. These data show that S. alterniflora began to expand rapidly in 2011, after a 22-y incubation period within the modern Yellow River Delta. Its expansion mainly occurred via seed reproduction. In addition, S. alterniflora preferentially invaded intertidal deltaic areas, using local seagrass beds as colonization sites. There was a significant correlation between the increase in area of S. alterniflora and the decrease in pollutant concentration of the Yellow River. Clearly, the improvement in water quality of the Yellow River accelerated the invasion of S. alterniflora within the delta.