What matters: Conservation values in invasion science

Invasive alien species (IAS) are globally considered major drivers of biodiversity loss. Because invasion science—the field studying IAS—informs policy and management, its normative underpinnings have become a subject of controversy. Historically, invasion science has aligned with traditional conservation, which is an ecocentric approach to conservation that recognises intrinsic value in natural collectives. This article examines debates surrounding the field's normative assumptions—focusing on the concepts of ‘origin’, ‘harm’ and ‘naturalness’—and explores three alternative conservation approaches that challenge them: new conservation, convivial conservation and compassionate conservation. New conservation highlights the ecosystem services IAS may offer in novel ecosystems. Convivial conservation stresses the interconnectedness of humans and nature. Compassionate conservation focuses on individual animal welfare, regardless of native or invasive status. Each of these approaches questions rigid native-alien distinctions. They argue that invasion science's focus on nativeness and undisturbed environments overlooks contemporary ecological challenges, urging a re-evaluation of how these categories influence conservation decisions. Discussing these approaches highlights the interplay between scientific evidence and diverse value systems in IAS debates, and reveals controversies often stem from ingrained normative assumptions rather than purely scientific disagreements. The article argues that explicitly addressing these assumptions is crucial for managing the ethical and practical challenges of IAS effectively. It identifies potential convergence among different conservation approaches while acknowledging unavoidable incompatibilities. Accommodating various viewpoints involves recognising a plurality of legitimate concerns and values, promoting interdisciplinary collaboration and inclusive deliberation, balancing short-term actions with long-term objectives, and considering both human and non-human rights.