The role of mallard ducks (Anas platyrhynchos) in distribution and germination of seeds of the submerged hydrophyteNajas marina L.

The effect of passage ofNajas marina L. seeds through the digestive system of the common mallard duck (Anas platyrhynchos) on their germinability was investigated. Most of the seeds (∼70%), which were consumed by the birds were digested. However, germination of the remaining seeds was remarkably improved. Germination of seeds whose seed coats were mechanically cracked was also higher than that of the controls and equalled the germination percentage of the mallard-treated seeds. Seeds ofNajas are retained in the diegestive tracts of mallards for over 10 hours. Thus, as mallards are strong flyers, the seeds ofNajas may be distributed over long distances.