Recently, considerable debate has been heard about the control or elimination of introduced or "exotic" animals on publicly held U.S. lands. Species introductions, whether intentional or unintentional, seem to be an inevitable result of human activities, but they may result in both economic and ecological problems: It has been estimated that over 90 percent of all such introductions have been harmful in some respect. Control of exotics can be accomplished through containment, shooting, poisoning, reintroduction of native predators, introduction of disease organisms, live capture and removal, and reproductive inhibition.
Those who must make decisions about the fate of introduced species need to seek a balance between the rights of the individual animals and preserving the viability of whole ecosystems. One important consideration is that, although the control of exotic animal populations may adversely affect individual sentient beings, inaction may cause widespread suffering to many species and consequent loss of biological diversity.
Hutchins, M., Stevens, S., & Atkins, N. (1982). Introduced species and the issue of animal welfare. International Journal for the Study of Animal Problems, 3(4), 318-336.