Invasive species and pathogens reduce native animal populations

The IPBES Assessment of Invasive Alien Species identifies invasive alien species as one of the five major direct drivers of biodiversity loss. Introduced predators, competitors, parasites, pathogens and disease vectors can cause mortality, reduce reproduction and alter food webs.

The risk is especially acute for island species and small populations that evolved without particular predators or have limited immunity and little demographic capacity to absorb losses. Disease can also spread through wildlife trade, domestic animals, environmental change and conservation movements that lack adequate biosecurity.

This issue covers biological threats that directly suppress threatened native animal populations. It excludes habitat conversion and direct human exploitation as separate mechanisms.