Probably present by 1875-1880, based on surrounding records.

Wells National Estuarine Research Reserve/ME/Webhannet and Little Rivers (Tyrrell et al. 2008)

Level	Vector
Alternate	Natural Dispersal
Alternate	Hull Fouling

Ecological Impact		Herbivory
In marsh environments in the Wells National Estuarine Research Reserve, ME, removal experiments showed that in a stressed site (long inundation, poor drainage), Littorina reduced the growth of the marsh grass Spartina alterniflora (Smooth Cordgrass), but had no effect at a benign site (Tyrrell et al. 2008).

Ecological Impact		Habitat Change
In marsh environments in the Wells National Estuarine Research Reserve, ME, removal experiments showed that in a stressed site (long inundation, poor drainage), Littorina reduced the growth of the marsh grass Spartina alterniflora (Smooth Cordgrass), but had no effect at a benign site (Tyrrell et al. 2008). Grazing by this introduced snail could reduce the biomass of Spartina at stressed sites, increasing rates of erosion, particularly as a response to sea-level rise (Tyrrell et al. 2008)

Species Regional Summary Littorina littorea Wells Bay ( N120 )