Biological invasions on Indigenous peoples’ lands

Biological invasions are a growing challenge in a highly interconnected and globalized world, leading to the loss of native biodiversity. Indigenous peoples’ lands (IPLs) play a vital role in biodiversity conservation through activities such as land stewardship and management practices. Similar to protected areas, they are also often remote, with fewer connections to international trade networks. The extent to which IPLs are threatened by the spread of invasive species is still unknown. Here we provide a global study detailing the distribution and drivers of alien species on IPL. On average, IPLs host 30% (in absolute numbers: 11 ± 3.5) fewer alien species relative to other lands, after controlling for sampling intensities. Alien species numbers remained consistently lower on IPLs even after accounting for potentially confounding factors such as differences in accessibility and ecological integrity. The difference may result from land management practices of Indigenous peoples. In the relatively small number of cases where IPLs host disproportionately higher numbers of alien species than other lands, the most likely reason is high alien species propagule pressure arising from proximity to large urban areas. Overall, our results highlight the importance of IPLs in protecting nature in the face of increasing biological invasions.