Don’t judge species on their origins

Background

This commentary suggests that the long-standing “native versus non-native species” debate has created a widespread bias in conservation as it encourages the idea that introduced species are inherently harmful, despite limited quantitative evidence supporting broad claims of catastrophic biodiversity loss. As global changes (such as climate change, nitrogen eutrophication, increased urbanization, and other land-use changes) cause ecosystems to be unable to restore to their historical states, categorizing species based on their origin increasingly mismatches ecological reality, influencing policy, funding, and management priorities.

Goals and Methods

The authors seek to replace origin-focused thinking with an impact-based, context-specific framework that evaluates species according to measurable effects on biodiversity, ecosystem services, human health, and economies. Rather than presenting new data, the paper synthesizes historical, ecological, and policy literature to build a normative but evidence-grounded argument, drawing on published studies and well-known management cases, including devil's claw eradication in Australia, tamarisk control on US rivers, and shifting policy toward non-native honeysuckles. These illustrate how expensive eradication programs often lack evidence showing significant harm and may ignore benefits such as habitat provision or seed dispersal.

Conclusions and Takeaways

This commentary concludes that nativeness is not a reliable indicator of evolutionary fitness, ecological benefit, or risk: some natives, such as the mountain pine beetle, drive severe impacts, while many non-natives increase local diversity or support threatened species, like the southwestern willow flycatcher in tamarisk stands. The authors urge agencies and practitioners to prioritize empirical assessment of function and impact, accept that many alien species are permanent components of novel ecosystems, and reallocate effort from blanket eradication to targeted management of demonstrably harmful species.