How biological invasions affect animal behaviour: a global, cross-taxonomic analysis

1. In the Anthropocene, species are faced with drastic challenges due to
rapid, human-induced changes, such as habitat destruction, pollution and
biological invasions. In the case of invasions, native species may change
their behaviour to minimise the impacts they sustain from invasive
species, and invaders may also adapt to the conditions in their new
environment in order to survive and establish self-sustaining populations.
2. We aimed at giving an overview of which changes in behaviour are
studied in invasions, and what is known about the types of behaviour that
change, the underlying mechanisms and the speed of behavioural changes. 3.
Based on a review of the literature, we identified 191 studies and 360
records (some studies reported multiple records) documenting behavioural
changes caused by biological invasions in native (236 records from 148
species) or invasive (124 records from 50 species) animal species. This
global dataset, which we make openly available, is not restricted to
particular taxonomic groups. 4. We found a mild taxonomic bias in the
literature towards mammals, birds and insects. In line with the enemy
release hypothesis, native species changed their anti-predator behaviour
more frequently than invasive species. Rates of behavioural change were
evenly distributed across taxa, but not across types of behaviour. 5. Our
findings may help to better understand the role of behaviour in biological
invasions as well as temporal changes in both population densities and
traits of invasive species, and of native species affected by them.