Document: FRI-3-35-38

Time lags in plant invasions in heterogeneous habitats.

GREVSTAD, F.*

Oregon State University, Corvallis, OR 97331 USA ¹

Abstract:
A common observation in exotic plant invasions is a long delay between the time of first introduction and the time when the population becomes noticeably invasive. These time lags can be surprisingly long up to hundreds of years and the transition between latent and invasive phases is often abrupt. Explanations tend to enlist changes in habitat, climate, or genetic make-up the population. However, I present a simpler explanation for time lags of this magnitude in invasions occurring in heterogeneous habitats. Using a stochastic simulation in the form of an interacting particle system, I show how the chance configuration of habitat in the vicinity of the introduction can often stall the progress of an invasion. Invasions may be stalled even further if the population has either an Allee effect or seed dormancy. The implication is that many "non-invasive" introduced plants may be time bombs for future invasions. The model can also be used to identify human-assisted disturbance events that have the potential to trigger a population to switch from a latent to invasive phase.

Keywords: biological invasions, time lag, interacting particle system, heterogeneous

This abstract is being presented at: 11:15 AM in session:
Oral Session #60: Forest Restoration.