NTU Undergraduates' research April 2014 - Biosciences | Page 58

Abstract
North American freshwater has some of the most species rich fauna in the world, but this biodiversity
is on the decline (Ricciardi 1999). This literature review looks into the increasing rate of extinction of North
American freshwater fauna, specifically that mussel species (particularly Uniodoida and D. polymorpha) of
which almost half are already extinct or listed as threatened or endangered (Ricciardi 1999).
The reasons for the increasing declines in native mussel populations and extinctions can be linked to
human interactions being the cause of many abiotic stressors such as pollutants and silt accretion. Much of
North American freshwater systems have been modified in some way and very few now follow their natural
course, through channelization, dams and flood protection, this is may be having detrimental effects on the
biodiversity of freshwater fauna. Furthermore, the introduction of the Eurasian zebra mussel (Dreissena
polymorpha) has proven to be an extremely invasive species, causing the extirpation of many native species of
mussel.
Ways in which to reduce the effects of both abiotic and biotic factors increasing the rate of extinction
of native mussels have been addressed through the review of papers contributing to conservation techniques to
counteract the invasion of zebra mussels, pollutants, silt accretion and alterations of the watercourse.