Controlling invasive species often involves killing large numbers of animals, creating ethical tensions between ecosystem welfare and individual animal welfare.
Lethal invasive species control raises difficult welfare questions: individual animals — often sentient mammals and birds — are killed to protect population-level biodiversity. The welfare cost to individual invasive animals must be weighed against the suffering of native prey species and the biodiversity loss that undermines future animal wellbeing broadly. More humane control methods like fertility control and trap-neuter-return programs are being developed but remain expensive and less effective at large scales.