Post-dispersal seed predation can limit the number of seedlings of Echinochloa crus-galli

Abstract: To shift weed management from the reliance on herbicides to ecological based approaches, post-dispersal seed predation may contribute to the regulation of weed populations. There is clear evidence that seed predators can reduce the density of seeds on the surface but it is unknown if they also limit the number of seedlings emerging from these seeds. To test the effect of seed predators on the number of seedlings of the weed Echinochloa crus-galli, we installed a seed addition experiment in three fields that differed in landscape complexity. Seed predators where excluded from half the experimental plots by exclosures. We identified the predominant seed predators, and measured over-winter predation rates and the number of emerged seedlings in the following spring. The composition of seed predators varied per field. In our study, over-winter seed predation rate varied from 38 to 72% in one year. Seedling emergence varied from 58 to 70% and was major in the most simplified landscape. Seed predations seem to have an impact on the number of seedling emerging from a fresh seed rain. The results should be tested and verified in long-term studies.