Fire as a driver of pine invasions in the Southern Hemisphere: a review

Abstract

Contrasting evidence in the degree of post-fire conifer invasion reported for different regions of the Southern Hemisphere (SH) raises questions about the role of fire as a presumed driver of invasion. We studied the influence of fire on invasion responses (assessing ‘serotiny’ and ‘time’ as key factors to determine invasion) based on a review of case studies performed in natural habitats of the SH. Our work showed that burned environments have no lag time with respect to invasion and are more susceptible to serotinous pine invasion than are unburned environments. Also, serotinous pines reached extremely high densities in burned habitats, exceeding records for the same species in unburned habitats, as well as for non-serotinous pines in any habitat condition. Therefore, burned environments are impacted by conifer invasion earlier and more intensively than unburned ones. Overall, our work indicates that fire is a leading driver of invasion, but only for serotinous pines. This highlights the importance of considering life history traits of introduced species to determine the probability and extent of invasion in relation to disturbance. We discuss the implications of introducing serotinous species in regions of the SH where serotiny is absent from native flora. Lastly, we provide suggestions for prioritizing management and further study.