Testing for the weed control potential of seed predators in agroecosystems (GA CR)

• Applicant: Dr. Paula R. Westerman
• Subject Area: Ecology of Land Use
• Term: from 2012 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 232633309

Post-dispersal seed predation can cause severe seed losses in plant populations. However, it is unclear whether such losses can help to lower weed densities, as an aid in weed control in agroecosystems. Seed predators could be removing seeds that would have died anyway, that would never have germinated or whose seedlings would never have reached reproductive maturity. It leads back to the paradigm whether a plant population is seed or microsite limited, which can be tested by the classical seed addition experiment. If seed additions lead to higher plant densities, a population is said to be seed limited; if they do not, it is said to be microsite limited. The proportion of added seeds that germinates and gets established is indicative of the degree of seed limitation. The main objective of this proposal is to examine if and to what extent weeds in maize are seed limited; granivory only matters if weeds are predominantly seed limited. The fate of seed cohorts, in terms of seedling recruitment and establishment, in the absence and presence of granivores will be monitored in maize fields over the course of three years. A range of seed densities will be applied to assess the degree of seed limitation. The relationship between seed and plant densities will be corrected for density dependent granivory. The results of this study should clarify whether granivory is an ecosystem service and, thus, whether it is worthwhile to invest in measures to preserve and enhance granivory.

• DFG Programme: Research Grants
• International Connection: Czech Republic
• Partner Organisation: Czech Science Foundation
• Participating Person: Dr. Pavel Saska