In many cases, the biological control organisms do not survive well in the new environment and usually do not eradicate the pest species. Sometimes the biological control agent becomes a pest if it attacks or displaces the native biota. The Issues History shows that invasive organisms usually harm the native biodiversity. In many cases, the alien invaders will take over the niche of native species, causing the extinction of previously established organisms. Controlling or trying to eradicate the invasive organism in most cases causes worse environmental damage than the invasive organism.
Some environmentalists argue that much of the damage of invasive plants is economic.
They propose using only environmentally friendly ways to control invasive plants and only in cases when the invader is creating significant environmental damage. Others feel that a new biodiversity is being created. They use the constantly changing evolutionary history of the world to support a view that all ecosystems decline and change naturally. In the case of water hyacinth, some people have evidence that the plant can be beneficial if managed properly. Researchers doing initial investigations to control kudzu are considering managing and overharvesting the plant for commercial purposes.