to the associated habitat disturbance and potential for regrowth if viable plant matter is not completely removed, which could facilitate the spread of Spartina (Bo Li, pers. comm). Furthermore, sediment consolidation from heavy machinery can negatively impact benthic invertebrates (David Melville, pers. obs.). Covering: Spartina can be covered over temporarily with fabric to prevent photosynthesis and deter plant growth. Care should be taken to ensure the cloth is not washed away (Lyu et al ., 2023). Alternatively, Spartina can be covered with inter- or sub-tidal soils, but this can increase the height of the treated areas. This may trigger an increased vegetation cover. Where this is carried out in the upper intertidal areas, it risks reducing the width of open tidal flat areas that are extremely important for feeding of migratory shorebirds (Mu & Wilcove, 2020). Burning: Prescribed fire can be used to kill invasive plants, including Spartina . Studies where removal by burning has been successful at controlling salt marsh vegetation (including Spartina ) used backfires, whereby the fire goes against the prevailing wind (de Szalay & Resh, 1997; Gabrey et al. , 1999). This exposes the plant to higher temperatures for longer (DiTomaso & Johnson, 2006). Burning while the seeds are still on the plants can increase the chances of seed mortality (DiTomaso & Johnson, 2006); however, seed production can be quite variable – in the UK, it was found that flowers emerging in July/August will seed in November, but those emerging in September may not set seed (Mullins & Marks, 1987).
Smooth Cordgrass Spartina alterniflora is highly invasive in China and there are ongoing efforts to control it. The photo on the left shows an area of Spartina at Nanhui New Town, Pudong New Area, Shanghai in July 2022. The photo on the right shows the same location in September 2022, after the Spartina mown, leaving a stubble height of 20 cm. The soil was thoroughly turned over after mowing. Photos taken by Tianyou Li, a PhD student from East China Normal University.
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