Post-dispersal seed predation of three major pasture weeds in southern Australia
M.J. NeaveA and R.K. HuwerA,B
A CSIRO Division of Entomology and CRC for Weed Management Systems. GPO Box 1700, Canberra, ACT 2601, Australia.
B NSW Agriculture, NSW Centre for Tropical Horticulture, Alstonville, New South Wales 2774, Australia.
The weed species, Echium plantagineum L. (Boraginaceae), Carduus nutans L.(Asteraceae)and Onopordum illyricum L. (Asteraceae) are major problems of pastures in southern Australia. This study investigates the importance of post-dispersal seed predators and their contribution to weed control. The results are supported by pitfall trapping of potential arthropod seed predators. The study showed that significant numbers of seeds from these weed species are not being incorporated into the seed bank. Rodents were found to be responsible for the largest seed loss (Echium 36%, Carduus 22% and Onopordum 40%) while arthropods were also found to be responsible for significant seed destruction (Echium 13%, Carduus 8%). The study of arthropod activity revealed a range of potential seed predators including; carabid beetles, field crickets and ants in the genera Rhytidoponera and Pheidole. Both E. plantagineum (47%) and C. nutans (18%) seed were lost in the treatment fully protected from predators, suggesting that rotting and soil micro-organism attack may be responsible, while Onopordum (0.1%), did not appear to be susceptible. For all three weed species under study, birds played no role in seed predation.
Plant Protection Quarterly (2003) 18 (3) 102-106.