Rodent-Mouse long-term monitoring survey in the Tomakomai Experiment Forest (compartment 202,204) since 1995. The surveys have been held in the two plots (50m x 100m, distance between the plots is around 300m) in the natural deciduous broadleaved forest: (1) the plot in which lower layer vegetation was dominated by bamboo in 1995 (i.e., bamboo plot) and (2) the plot in which lower layer vegetation was not dominated by bamboo in 1995 (i.e., non-bamboo plot). The surveys were held for 3 days in spring (mainly May) and autumn (mainly October) every year. In each plot, 50 Sherman traps were settled in grid patterns with 10-m interbals (5 Rows x 10 Columns). The captured mise and rodents were recorded their species identity, sex, mass, and were also marked individually by toe-clipping. After these processing, the individuals were released at their captured location immediately. Note: Abundance of bamboo in the bamboo plot have decreased since around 2014 and, thus, lower vegetation in the non-bamboo plot became richer than that in the bamboo plot since around 2020. (ja) 北海道大学苫小牧研究林（202, 204林班）での野ネズミの個体数動態。1995年の時点でのササ優占プロット（Bamboo plot, 50m×100m）とササ非優占プロット（Non-bamboo plot, 50m×100m）の2か所で、50個のシャーマントラップを10mおきに設置（5列×10行）。毎年、春（5～6月）と秋（9～11月）の2季節に3日間ずつ実施（各プロットの合計ワナ数は150個）。捕獲したネズミは種同定、雌雄判定、体重測定、個体識別（指切り法）を施した後、放逐した。注意：XXXX年ごろより、ササ優占プロットにおいてササが枯死し、ササ密度が低い状態が続いている（2021年現在）。