In recent years, some large mammals have expanded their distribution to human-made landscapes, including roads and artificial forests. Therefore, it is necessary to understand the ecological role of large mammals in anthropogenic landscapes. On Hokkaido's Shiretoko Peninsula, since 2000, when the herbaceous layer was drastically reduced due to foraging pressure from deer, brown bears have begun to actively dig up artificial forests and eat cicada larvae. In this study, we investigated the effect of brown bear digging on tree growth in order to clarify the ecological role of brown bears in human-made landscapes, including artificial forests.

　Brown bears dig up larch plantations more frequently than other plantations. Soil, larch leaves and tree rings were collected from the larch forest targeted for investigation. We then compared soil nutrients, fine root biomass, leaf traits, and tree ring data with and without digging.

　Tree ring analysis showed that tree growth has deteriorated since 2000 due to digging, and nitrogen availability in the soil and nitrogen concentration in larch fine root biomass and leaves have decreased. In addition, although it was shown that soil moisture decreased due to digging, it did not affect the moisture stress index (LMA, carbon stable isotope ratio) of trees, and the negative impact on trees was due to a decrease in nitrogen availability. thought to be causing it.

　This study suggests that by changing the behavior of brown bears, the creation of plantations has also changed the role they play in the ecosystem. The role of wild animals in human-made landscapes needs to be evaluated while taking into account the differences in their behavior and ecology from those in the wild.

Paper information:【Ecology】Brown bear digging decreases tree growth: Implication for ecological role of top predators in anthropogenic landscapes