Germination and viability of mesquite (Prosopis pallida) seed following ingestion and excretion by feral pigs (Sus scrofa)

A study in northern Queensland aimed to determine if feral pigs disperse vi able seeds of the invasive woody weed, Prosopis pallida. Thirty-eight dung samples were collected, 19 from within a dense P. pallida infestation and 1 9 from an adjacent area that had been mechanically cleared of P. pallida. A il seeds were removed from the dung and undamaged seed tested for germinati on and viability. Mean (+/- s.e.) dry weight of collected dung samples aver aged 51.1 (+/- 2.9)g, with no difference between infested and cleared sites . Visual estimation of the contents of these samples showed that P. pallida seed pods were the major component of the dung, averaging 69 (+/- 4)% from samples collected within dense infestation and 57 (+/- 4)% for those from the adjacent area. Fifty-eight % and 42% of the pig dung samples collected from within and adjacent to the infestation, respectively, contained viable seed. No significant difference (P>0.05) was found between the number of v iable seeds present in dung samples from the two areas; an average of 2.4 s eeds per sample was recorded with a range of 0-19. The germinability of thi s seed was high, with 70% of all viable seed germinating within 21 days and the remainder germinating immediately after scarification.