Elucidation of the factor to bring the Legacy effect in processes from high density of the sika deer to low density

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06151
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: Meijo University
• Principal Investigator: Hino Teruaki 名城大学, 農学部, 教授 (80212166)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: ニホンジカ / ミヤコザサ / ジプシー効果 / 森林再生 / 森林生態系 / 土壌動物相 / オサムシ群集 / 周期的変動

Outline of Final Research Achievements

The objective of this study was to determine changes from high density conditions by examining vegetation, soil, and fauna under conditions of reduced densities of Japanese sika deer as a result of population adjustments. The estimated average density of deer decreased by one-fourth, but the relationship with sasa abundance changed from a positive linear relationship to a bell-shaped curvilinear relationship with a maximum around a density of 10 deer/km2. As a result, the survival rate of tree seedlings increased at sites with high deer density and low sasa abundance, whereas the decrease in sasa abundance decreased seedling survival due to a decrease in soil nutrient supply. Therefore, due to these complex relationships between deer density, sasa abundance, and seedling survival, reforestation through deer reduction is expected to be a slow process.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

本研究では，シカの高密度状態から低密度状態への変化にともなう林床植生，樹木実生，土壌，動物群集の変化の調査によって，シカ密度とササ現存量との間の平衡関係の崩壊とそれにともなう実生生存率の変化，ササが実生におよぼす被圧による負の影響とリター供給による正の効果などの複雑な相互関係を明らかにした．また，シカ密度とササ現存量との間には，遅れをともなう周期的な変動があることを，植食者と植物との間で初めて明らかにした．これらの研究成果は申請者が現地で２５年間にわたって行ってきた長期的なデータの蓄積によって初めて可能になったものであり，学術的および保全生物学的な意義は高い．