Pinaceae

Pinus contorta is one of Aotearoa’s worst weeds. Evidence suggests that its spread and growth rates in Aotearoa are greater than in its native range in North America, yet the underlying drivers remain poorly understood. In this study, we examine cone and seed traits of P. contorta across several major invasion sites in Aotearoa and compare their traits with values from the native range.

Pathogen accumulation on an invasive plant species can occur over time, through co-invasion, or adaptation of native pathogen species. While accumulated pathogens can reduce the success and spread of an invasive species, they can also spill-over into native plant communities or valuable non-native populations. Transmission of pathogens may be density-dependent, with dense invasive populations creating better opportunities for pathogen spread than scattered individuals.