Scientists challenge wildlife conservation methods

Study challenges costly practice of killing ‘non-native’ animals

Conservation agencies worldwide spend millions of dollars annually killing healthy wild animals deemed “non-native” to protect local ecosystems. New research from Oxford University and Aarhus University in Denmark suggests that this common practice may be fundamentally flawed.

Research reveals surprising similarities

Scientists analyzed 221 studies comparing how native and introduced large mammals affect plant communities across the globe. Their findings challenge decades of conservation thinking.

Both native and non-native large herbivores showed remarkably similar impacts on plant abundance and diversity. The research demonstrates that an animal’s ecological effects relate more to individual traits than origin.

“We do not find evidence to support the claim that native large herbivores have different impacts on ecosystems, specifically plant communities in this case, than their non-native counterparts,” explained Dr. Jeppe Kristensen from Oxford’s Environmental Change Institute.

Body size matters more than origin

The study uncovered a crucial element that conservation planners frequently ignore: individual animal body mass matters more than collective weight or native status.

Small-bodied selective feeders like deer tend to reduce plant diversity regardless of whether they’re native or introduced. Meanwhile, larger nonselective feeders such as buffalo typically enhance biodiversity by preventing any single plant species from dominating an area.

“One elephant can push over a mid-sized tree, but 50 red deer cannot achieve the same landscape-altering effect,” noted Dr. Kristensen.

Conservation paradox exposed

This research exposes a troubling conservation paradox. While many of these same species face extinction in their native habitats, agencies spend enormous resources removing animals from areas where they are considered invasive.

The contradiction raises serious questions about current conservation priorities and resource allocation. Eradication efforts put many targeted “invasive” animals at risk of further population declines within their home ranges.

“This interpretation suggests that functional niches vacated by extinctions and extirpations in recent prehistory, often due to humans, are better refilled with animals with similar functional traits as the ones that were lost, even if these new species are non-native,” suggested Professor Jens-Christian Svenning from Aarhus University.

Functional ecology over cultural belonging

The research advocates for a fundamental shift in conservation strategy. Rather than making decisions based on cultural notions of belonging, scientists should evaluate all animals through the lens of functional ecology.

“Our findings suggest it is time to start using the same standards to understand the effects of native and introduced organisms alike and to consider seriously the implications of eradication and culling programs that are based on cultural notions of ‘belonging,'” said lead author Dr. Erick Lundgren from Aarhus University.

This approach could enhance biodiversity conservation while fostering a more nuanced understanding of how species contribute to ecosystem health and resilience.

Study limitations and future research

The authors emphasize that their study specifically assessed large mammal herbivores. Nativeness may remain important for understanding other ecological interactions, particularly with specialized introduced species like tree pests that native species didn’t co-evolve with.

The research opens new avenues for conservation biology, suggesting that functional traits should guide management decisions rather than species origin alone.

The study was published in the journal Science.

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