Invasion patterns of Pinus pinaster in south-west Australia in relation to fire, vegetation type and plantation management.

• Pinus pinaster has not spread widely into terrestrial vegetation in the Perth region Australia. • Spread into wetlands near plantations is however serious, and is promoted by fire. • Pinus pinaster wildings commonly establish after plantation clearing and/or burning. • Feeding activities of black cockatoos are likely to reduce seed dispersal of pine seed. Pinus pinaster is a common plantation species in many Mediterranean-climate regions of the world and has become invasive in several of these, but little is known about its invasive potential, with no studies regarding its invasion potential and patterns being carried out in Australia. It has been widely planted over many decades in the Perth region of southwest Australia. Here we used plots to measure the density, size and approximate age of P. pinaster wildings in native vegetation adjacent to pine plantations and in areas of cleared plantations. Results demonstrated that densities of P. pinaster wildings were highest at edges and varied widely with vegetation type, being much greater in dense, wetland vegetation compared to more open sclerophyllous woodlands, which was contrary to that experienced in other regions. Wilding regeneration following clearing was also highly variable. Local populations of black cockatoos, which fell cones to ground for feeding, are likely to have contributed to low levels of spread into native bushland by curtailing wind dispersal of seeds from tree canopies, as well as providing an ample seed source for regeneration of wildings at cleared sites. Wildfires, which can lead to mass regeneration of P. pinaster elsewhere, did not promote spread of wildings into adjoining bushland, but did enhance wilding densities in wetland vegetation within the plantation matrix. [ABSTRACT FROM AUTHOR]