Mollusks account for a largely
unheralded but sobering 40%
of all documented extinctions of
animal species. These extinctions
have resulted from habitat loss, pollution, introduced species, overharvesting, and other human actions.
Many pearl mussel populations, for example, were driven to extinction
by overharvesting for their shells, which were used to make buttons
and other goods. Today, the remaining populations of these and other
freshwater bivalves face threats from pollution and introduced species.
Terrestrial gastropods such as the species pictured above are highly vulnerable to the same threats and are among the world’s most imperiled
animal groups.
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| An endangered Pacific island
land snail, Partula suturalis |
WHY IT MATTERS The extinctions of mollusks represent an irreversible loss of biological diversity and greatly threaten other organisms, too. Land snails, for example, play a key role in nutrient cycling,
while the filtering activities of freshwater bivalves purify the waters of
streams, rivers, and lakes.
 |
| Workers on a mound of pearl mussels killed to make
buttons |
