Species preference of small mammals for direct-sown tree and shrub seeds

Direct seeding can be a useful method for creating new woodland on former agricultural sites. However, the success of the technique is variable when it is used to restore conifer plantation sites to native species. Seed predation by small mammals, particularly the wood mouse, has been identified as a factor potentially limiting success. Small mammals are known to exhibit preferential predation when presented with a range of tree and shrub seeds. This research demonstrated that, when seeds used in the direct seeding of woodlands were presented on the soil surface, small mammals showed a preference for large-seeded species such as oak, hazel, beech and sycamore. In the case of oak, the removal of seeds by predators was rapid and total, usually in less than 24 hours. Smaller-seeded species and those with greater physical protection were significantly less likely to be taken. The results showed that the pattern of preference remained consistent between several different sites. The burial of seeds is known to reduce predation by reducing the chance of seeds being detected and increasing the time required for predators to find and remove them. In our experiments, burial restricted predation to just the highly-preferred species while less-preferred species were left almost untouched. However, burial also significantly reduced predation risk overall.