Environmental Engineering Reference
In-Depth Information
There is a large suite of invasive aquatic plant species creating severe problems
in many water systems throughout the world. Not every species has invaded and
established on all continents, and some of these species could pose an even greater
threat to aquatic environments than those weeds already present. Increased global
trade and travel have created many new routes for the intentional and acciden-
tal spread of these invaders, signifi cantly increasing the threat of both new and
recurring invasions (Ielmini and Ramos 2003). The best defence against the threat
imposed by invasive aquatic weeds is prevention, followed by the second line of
defence, early detection and rapid response (EDRR). New Zealand, Australia, and
many states in the USA have developed EDRR programmes, particularly prevent-
ing the introduction of aquatic invasives (e.g. Champion and Clayton 2000, 2001).
These could be adopted by other countries around the world, such as Botswana,
which is the only country in southern Africa where water hyacinth has not invaded
(Navarro and Phiri 2000). An EDRR system could ensure that it remains free of
this scourge.
