Zostera marina
The extinction of "Lottia alveus" does not seem to have been caused directly by human interference. This small limpet disappeared from the fauna because of a sudden catastrophic collapse of the populations of the eelgrass plant, "Zostera marina", which was its sole habitat and food source. In the early 1930s, the seagrass beds all along that part of the coastline were decimated by "wasting disease", which was caused by a slime mold of the genus "Labyrinthula". Some colonies of "Zostera marina" lived in brackish water, and these areas served as refugia for the eelgrass since the wasting disease did not spread to brackish water. The eelgrass was thus able to survive the catastrophic impact of the disease. The limpet however was unable to tolerate anything but normal salinity seawater, and therefore it did not live through the crisis.