Dynamic Study of Farmland Ecosystem Based on Lotka-Volterra Model with Human Intervention Factors

Abstract

Addressing the ecosystem dynamics during forest-to-farmland conversion and human intervention impacts, this study establishes a multi-species biomass dynamic differential equation model based on the Lotka-Volterra framework. By incorporating seasonal periodic functions and agricultural management measures (e.g., herbicides, insecticides) as disturbance factors, combined with MATLAB numerical simulations, this study simulated biomass variation curves under different intervention conditions. The simulation results revealed several key dynamics: seasonal variations and agricultural cycles were found to significantly dictate crop growth rhythms, inducing a biomass fluctuation amplitude of approximately 30%. The application of herbicides provided a temporary boost to crop biomass accumulation, increasing the growth rate by 20%. Conversely, insecticides triggered a sharp decline in insect populations, raising mortality by 40%, which in turn produced cascading effects evidenced by a 3-to-5-month lag in the decline of bird populations. Predators at higher trophic levels, such as eagles, exhibited a dampened response to these interventions, showing a 60% reduction in sensitivity compared to lower trophic levels. These findings emphasize the necessity of considering trophic level differences and time lags in ecological impact assessments of agricultural interventions, offering valuable insights for sustainable land-use planning and ecosystem management in converted landscapes.