Comprehensive Effects of Sex Ratio Changes in Lampreys on Ecosystem Based on the Integration of Population Dynamics Model and Multi-Factor Assessment Model

This study focused on the effects of sex ratio changes in lampreys on the ecosystem, and comprehensively used a variety of models to investigate. First, a dynamic model of lampreys population was established by Lotka- Volterra equation and population dynamics equation to analyze the impact of sex ratio changes on lampreys population, and it was found that it affected the population growth trend and fluctuation, which laid the foundation for subsequent research. Then, the paper studies the impact of sex ratio change on the stability of ecosystem, discusses its impact on parasite transmission and food chain structure from the perspective of ecology, and analyzes its impact on fishery economy from the perspective of sociology, and finds that the imbalance of sex ratio will interfere with the stability of ecosystem. Then, TOPSIS multi-attribute decision analysis method was used to evaluate the impact of sex ratio change on other species in the ecosystem, and an evaluation system including competition relationship, parasite population change and food web complexity was constructed. It was found that sex ratio change would reshape the species relationship in the ecosystem and bring advantages to some species. This study provides a theoretical basis for understanding the role of lampreys in ecosystem and ecosystem management.