Evolutionary rescue with interspecific interactions: Theory and experiments

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18618
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Ecology/Environment
• Research Institution: The University of Tokyo (2017-2018); Kyoto University (2016)
• Principal Investigator: Yamamichi Masato 東京大学, 大学院総合文化研究科, 講師 (70734804)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 絶滅 / 適応 / 進化的救助 / ヒドラ効果 / 個体群動態 / 種間相互作用 / 繁殖干渉 / 捕食

Outline of Final Research Achievements

We examined how population and community dynamics are affected by complex feedbacks between “rapid evolution” (i.e., allele frequency changes in populations in short timescales), environmental changes, and interspecific interactions by using mathematical models.
First, we developed the theoretical framework of “indirect evolutionary rescue,” where prey adaptation prevents predator extinction. We revealed conditions where predator-prey coevolution promotes or prevents predator extinction as well as the paradoxical “hydra effects,” where increasing predator mortality results in increased predator abundance. Second, we examined conditions where intermediate generation overlaps (due to e.g., seed dormancy) can maximize the speed of evolution. Finally, we revealed how environmental fluctuations and positive frequency-dependence in community dynamics influence species coexistence and extinction.

Free Research Field

生態学・進化生物学

Academic Significance and Societal Importance of the Research Achievements

人間活動により地球環境が大きく変化していく中で、多くの種が絶滅し生物多様性が減少しつつある一方で、新しい環境に適応することで絶滅を免れる種もいる。そのため、生物の絶滅過程を理解するためには、迅速な進化と環境変動を理解することが重要とされている。本研究は、それらに加えて種間相互作用を考慮することで、個体数と進化の間に複雑なフィードバックが起こり、結果として直感に反する動態が生じうることを示した。