Most notorious are the floating water weeds that infest lakes, rivers, swamps and floodplains and the introduced fish and molluscs that affect many water bodies. To assist in this matter, this workshop will identify guidelines for effective identification, risk assessment, incursion management, control programmes and communication to prevent and mitigate the impact of pest species on wetland ecosystems. Alien species are species that have been introduced intentionally or accidentally outside their natural range and dispersal potential, directly or indirectly by human agency. Many alien species are valuable to humans, and are cornerstones of economic activities. The costs of bio-invasion include changes to the ecosystem, reduction of future opportunity, costs of ongoing management of invasives, and direct and secondary impacts on people through the impact on economic and social activities or values.
Invasions cause loss of biodiversity within species, between species, and of ecosystems.
In the case of wetlands, invasives threaten the wise use of wetlands as well as their natural values and water quality and quantity. Increased international travel and trade are two of the major reasons for the increase in invasions. It is now thought that on a global scale invasive species are responsible for more extinctions of species than habitat loss. The irreversibility of extinction and the insidious nature of invasions leads to a high degree of urgency in responding to invasives. Many presentations stressed that public awareness raising is difficult yet crucial in the effort to prevent invasions, as it is essential to implement practical measures relating to prevention, detection, eradication or control.