Domestic goat grazing disturbance enhances tree seed removal and caching by small rodents in a warm-temperate deciduous forest in China

Abstract

Context. Grazing by large herbivores may have a considerable influence on ground vegetation as well as on the species composition and abundance of granivors (e.g. small rodents) and this may affect forest regeneration. Very few studies have focussed on the effects of herbivore disturbance on forest regeneration by looking at the modified seed-hoarding behaviour of small rodents. Aims. To test the indirect effects that grazing disturbance by domestic animals has on seed dispersal through the modified seed-hoarding behaviour of small rodents. Methods. We looked at the differences in seed removal and caching of Liaodong oak (Quercus liaotungensis) by small rodents between a plot that was grazed and a plot that was ungrazed by domestic goats in a warm-temperate forest in northern China in 2006 (a non-mast-seeding year) and 2008 (a mast-seeding year). Key results. Seed removal and caching by small rodents were significantly higher in the grazed plots, especially in the mast-seeding year (2008). Significantly more seeds were buried in soil during the mast-seeding year (2008) compared with the non-mast-seeding year (2006). Conclusions. Grazing-induced disturbance might stimulate hoarding efforts by seed-caching rodents. Mast seeding benefits seed survival and forest regeneration. Implications. The presence of large herbivores is likely to benefit early seed dispersal in forests by increasing the hoarding activities of rodents.