Lags between arrival and expansion of invasive species have long been recognized. In some cases, invasive species may remain uncommon for many years before their populations explode. Many biological and management causes for breaking invasion lags have been invoked. Our new paper (free to read version here) models a simple system where we create a change in dispersal that simulates a mechanism for breaking invasion lags. It turns out that even in our artificial system, it is very hard to predict when the lag will actually be broken after the biological or management change arrives. And a lag phase frequently appears as a result of the landscape configuration alone, without any need for an external mechanism. This is a sobering message, because it means that many exotic species we think are benignly fitting in with the landscape may well be the invaders of tomorrow.
The stories we tell ourselves: predicting invasion lags