The downsides of single‐species invasive non‐native mammal control: Competitive release and the need for ecosystem‐wide thinking in invasive species management

Research Highlight discussing: Carpenter, J. K., Puke, T., Monks, A. R. (2025). Competitive release of invasive frugivorous mammals leads to perverse outcomes for native seed abundance, Journal of Applied Ecology , https://doi.org/10.1111/1365‐2664.70165 . Management of invasive non‐native species often focuses on controlling a single species, neglecting the complex ecosystem in which the target invasive non‐native species is embedded. This approach can lead to unintended and adverse consequences for native species, posing a challenge to effective restoration. Carpenter et al. (2025) conducted field experiments to assess the impact of removing invasive non‐native brushtail possums ( Trichosurus vulpecula ) and ship rats ( Rattus rattus ) individually and simultaneously on the seed rain of native tree species in the North Island of Aotearoa‐New Zealand. Their results clearly demonstrate that simultaneous removal of both invasive mammals is required to increase native tree seed rain. Otherwise, the removal of either species alone results in competition release, leading to an increase in detections of non‐removed species and a decrease in native seed rain. In other words, considering interactions between invasive non‐native mammals is crucial to effectively mitigating their negative impacts on native vegetation. Ecosystem‐level thinking is thus required to address the impacts of invasive non‐native species and mitigate the potential unintended consequences of well‐intentioned conservation initiatives.