Feed back indirect effects of deer on the plant-animal interactions

Abstract

Mammalian herbivores can directly and/or indirectly affect ecosystems. Here, we review an indirect effect of mammalian herbivores, which affects plant reproduction by changing the relationships between plants and animals. As an example of this feed back indirect effect, we introduced a case study which detected the effect of Cervus nippon on the reproduction of Aucuba japonica Thunb. The success of seed production of A. japonica largely depends on the degree of pollination and seed parasitism. In the wild population of A. japonica, C. nippon decreased the density of A. japonica individuals causing the decrease in parasitism, but not in pollination. These result indicated that the effects of C. nippon on the plant animal interaction such as pollination and parasitism to seeds depended on the degree of decrease of A. japonica density. Such density dependent interactions can determine the degree of feed back indirect effect of mammalian herbivores on plants.