Continual expansion of Spartina alterniflora in the temperate and subtropical coastal zones of China during 1985–2020

• Published in: International journal of applied earth observation and geoinformation Vol. 117; p. 103192
• Main Authors: Zhang, Xi, Xiao, Xiangming, Wang, Xinxin, Xu, Xiao, Qiu, Shiyun, Pan, Lianghao, Ma, Jun, Ju, Ruiting, Wu, Jihua, Li, Bo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2023; Elsevier
• Subjects: algorithms; China; Drivers; ecosystems; humans; invasive species; Landsat; Pixel- and phenology-based algorithm; salt marshes; Saltmarshes; Spartina alterniflora; spatial data; Spatiotemporal dynamics; time series analysis; China; Saltmarshes; Pixel- and phenology-based algorithm; Drivers; Spatiotemporal dynamics; Spartina alterniflora
• ISSN: 1569-8432
• DOI: 10.1016/j.jag.2023.103192

•A regionally adapted pixel- and phenology-based algorithm was designed.•Spartina saltmarshes are continually expanding at a worrying rate in coastal China.•Spartina invasion exhibited obvious spatial variations along the latitudinal gradient.•A sample-based driver analysis was used to explain Spartina saltmarsh dynamics. Biological invasions are considerably altering ecosystem structure and functions, especially in coastal ecosystems that are subject to intensive anthropogenic disturbances. Spartina alterniflora has been recognized as the most serious invasive species in coastal China, which has received considerable attention from the government and the public. There is urgent need to control this invasive species at regional and national scales, but such efforts were impeded by lack of time-series data of Spartina spread. Here, we assessed the pixel- and phenology-based algorithm for mapping Spartina saltmarshes, and applied this algorithm to generate annual Spartina saltmarsh maps (30-m spatial resolution) from 1985 to 2020 by using time series Landsat 5/7/8 images. The resulting maps suggest that Spartina has been expanding since 1990 in coastal China, with three noticeable phases (rapid, moderate, and rapid). Along the latitudinal gradient, Spartina exhibited a longer invasion history and more frequent changes at low latitudes. Although human interventions caused the decline of Spartina in certain areas, rapid natural spread was primarily responsible for its extensive and continual invasion. These results provide insights for efficiently managing this invasive species, enhancing the conservation of coastal wetlands, and promoting the sustainability of coastal wetlands.