Predator induced dispersal can create indirect linkages between habitat patches with different top predator communities

Background/Question/Methods

Dispersal is a central process determining community structure in heterogeneous landscapes, and species interactions within habitats can be an important determinant of dispersal.  Although the effects of species interactions on dispersal within habitats have been well studied, how species interactions affect the movement of individuals between habitats in a landscape has remained understudied.  These movements, however, have the potential to generate indirect connections between habitats that vary in their predator composition and to shape patterns of regional connectivity.  Predator-induced dispersal is therefore a question of central interest in understanding landscape connectivity.  We used mesocosm experiments to examine the extent to which predation risk affects dispersal by a flight-capable semi-aquatic insect (Notonecta undulata). 

Results/Conclusions

Exposure to non-lethal (caged) fish that were fed conspecific notonectids, increased dispersal rates in N. undulata.  Moreover, dispersal rate was positively correlated with the level of risk imposed by the fish; the greater the number of notonectids consumed by the caged fish the greater the dispersal rate from the habitat.  These results indicate that risk within a habitat can affect the behavioral decision to disperse out of that habitat.  Our results suggest that prey can exhibit finely-tuned behavioral responses to predation risk that can shape patterns of landscape connectivity.  This behavior creates indirect interactions between habitat patches that differ in their predator communities.  Our findings suggest that prey behavioral responses to predators have the potential to affect community structure on a much larger spatial scale than the direct effect of predation itself.