Seed dynamics of the invasive geophyte Lachenalia reflexa Thunb. in south-west Australia
Kate Brown and Grazyna Paczkowska, Department of Environment and Conservation, Swan Region, PO Box 1167, Bentley Delivery Centre, Western Australia 6983, Australia.
Geophytes from South Africa’s Cape Province are a particularly serious group of invasive plants in south-west Australia. They threaten natural biodiversity across the region, invading relatively undisturbed habitat and displacing native plant communities. Their success as invaders has been linked to rapid and profuse seedling germination, however studies on a number of species have documented short lived soil seed banks. This study investigates seed viability and soil seed bank persistence of the Cape geophyte, Lachenalia reflexa Thunb. where it is invading Banksia woodlands on the Swan Coastal Plain, Western Australia.
Seed was collected from naturalized populations in the summer of 2004/2005 and placed in nylon mesh bags buried at two different soil depths, in replicated plots across field sites (February 2005). Samples were retrieved and assessed in May, July and September 2005, September 2006 and September 2007.
Initial tests found 95% seed viability. More than 90% germinated or rotted in the first autumn/winter. No viable seed remained at the 10 cm depth by September 2006 or at the 1 cm depth by September 2007. The results show that L. reflexa seed have high initial viability but do not persist in the soil seed bank for more than three years.
Keywords: Invasive, geophyte, germination, viability, soil seed bank, Lachenalia reflexa.
Plant Protection Quarterly (2011) 26 (2) 47-49.