Biological invasions negatively impact global protected areas

Protected areas underpin global biodiversity conservation and sustainability agendas. Biological invasions increasingly threaten the ecological functioning and long-term conservation value of protected areas, while a lack of information on impact impedes management decisions. We collated data from effects of biological invasions in protected areas to provide the first quantitative analysis of their global impacts. Based on 300 reported effects from 44 invasive species, we show that there are overall negative impacts from invasive species on both biotic and abiotic characteristics of protected areas globally. Impacts were pervasive across population, community, and ecosystem scales, and for the vast majority of invasive taxa with sufficient data. Negative impacts have been incurred around the world, with National Parks and World Heritage Sites in the Neartic and Neotropical regions the most studied. Notwithstanding context-dependencies and uneven research efforts, the recurrent negative impacts of invasive species indicate that current efforts are insufficient to curb current stressors and meet conservation and sustainability targets on land and in water. To address the risk of biological invasions in protected areas, it is imperative to prioritise fundamental research on ecological interactions, establish robust monitoring and prevention programs, and raise awareness through global initiatives. [Display omitted] •Metanalysis reveals invasive species have widespread negative impacts on protected areas.•Data from 44 invasive species and 300 effects highlight the global scale of the problem.•Impacts across population, community, and ecosystem scales highlight broad ecological implications.•Neartic and Neotropical regions, including National Parks and World Heritage Sites, show significant impacts.•Urgent need to strengthen research, monitoring, and prevention to mitigate invasive species threats and achieve conservation goals.