Seedling predation of Quercus mongolica by small rodents in response to forest gaps

Although the importance of gaps in forest dynamics has been well documented, the influence of gap size on the foraging behavior of small rodents and seedling predation has received little attention. In this study, we explored the foraging behaviors of seedling predators and seedling survival in the artificial gaps with different sizes and the associated closed canopy forest, to see the influence of rodent predation on seedling establishment of Quercus mongolica. Our results showed that small rodents (Apodemus peninsulae, Clethrionomys rufocanus, Tamias sibiricus and Sciurus vulgaris) tended to avoid recently created gaps in comparison with the associated closed canopy forests. As a consequence, lower levels of seedling predation (i.e., cotyledon removal and shoot clipping) and higher levels of seedling survival were observed in the gaps than in the closed canopy forests. In addition, gaps with large size tended to provide a better shelter for seedlings of Q. mongolica, possibly due to higher predation risks on small rodents in large gaps than in small gaps and the associated closed canopy forests. Our one-year study indicates that small rodents exert strong impacts on the recruitment of Q. mongolica through clipping young seedlings both in the gaps and closed canopy forests. Our study also implies that seedling predation by small rodents is regulated by gap size.