A practical example;
The invasion of exotic species is a great threat to the integrity of aquatic ecosystems. The use of ballast water in large ships to confer stability and maneuverability has been an efficient means for the spread of marine and freshwater organisms.The following is a link to a paper of Invasion by Limnoperna fortunei, a bivalve that has invaded the rivers from Argentina and has been colonizing many other rivers in South America. Limnoperna fortunei (Bivalvia, Mitylidae) was introduced into South America in 1991 in the La Plata River (Argentina). It arrived in the ballast water of ships coming from Asia, where this species is native. It was
first observed in 1998 in the Paraguay River. Limnoperna was introduced into the Pantanal region as hull fouling of vessels using the Paraguay–Parana waterway. Despite low densities, L. fortunei can colonize water cooling systems of boats, obstructing water circulation and causing motor overheating. Accumulation in water supply equipment, such as pumps and pipes has also been observed.
As a consequence of its fast reproductive rate, L. fortunei quickly forms extensive colonies with high population density. If colonies
form on or in industrial water intakes, such ‘biofouling’ can result in clogged pipes and filters, changes in flow at the boundary layer,
accumulation of empty shells, contamination of water from pipes due to mass mussel mortality, as well as disruptions in the water intake of industrial and power-generating plants. Operating costs increase due to lowered pump efficiency, tube corrosion as a result of enhanced bacterial and fungal proliferation, and service interruptions for the cleansing and changing of filters. These impacts are very similar to those caused by the zebra mussel (Dreissena polymorpha Pallas (1771)) in North America
This is a clear example of how a human activities can break the natural dispersal limitation of a species from a suitable habitat and the effects of introducing a new species into a natural habitat where there are not natural predators for it.
How bad management of resources can produce millions in losses.
A practical example;