2025 Volume 71 Issue 3 Pages 159-163
In this study, we examined the effects of runway formation on pasture surface by small mammals inhabiting grasslands in the Tohoku region on soil composition and vegetation in the pasture the following spring. One hundred and sixty locations (1 m×1 m each) were established in an orchardgrass-dominant pasture, and the area percentage of runway traces and the content of moisture, nitrate nitrogen, and ammonia nitrogen of the soil surface layer at each location were measured. Plant species emerged and their coverage were measured in the central area (0.5 m x 0.5 m) of each location, and plant species diversity was evaluated using the Simpson index. In addition, the height and coverage of orchardgrass were also recorded. Based on these results, a path analysis was conducted with a hypothesis to estimate the effects of disturbance on the grassland. The results indicated that small mammal runway formation contributed to the increase in plant species diversity and orchardgrass height through an increase in inorganic nitrogen, especially nitrate nitrogen concentration.
