Prediction of alpine artificial grassland restoration based on an improved Lotka-Volterra interspecific competition model

Combining the quantitative characteristic changes of plant community components in the restoration process of the "black soil patch" degraded alpine meadow in the Qinghai-Tibet Plateau after being converted into artificial grassland, computer simulations based on methods, such as the central difference method, relative error thermography, and ODE algorithm were conducted. A prediction model of competitive effects suitable for alpine meadow restoration succession was established through the nonlinear improvement of the Lotka-Volterra interspecific competition model. The model was compared with the classical Lotka-Volterra interspecific competition model, and the solvability and accuracy of the improved model were demonstrated. Furthermore, the dynamic behavior of the improved Lotka-Volterra model system was analyzed, the competitive outcome of the plant community components in the artificial restoration was predicted, and the restoration succession of the artificial grassland was judged. The results showed that:(1) With the increasing length of vegetation recovery, cultivated plants(Elymus nutans or Poa pratensis) and original plants will gradually tend to be dynamically balanced after undergoing a fierce competition phase. Accordingly, cultivated plants -- Elymus nutans or Poa pratensis can promote the effective restoration of the "black soil patch" degraded alpine meadow in the Qinghai-Tibet Plateau;(2) Synthesizing the characteristics of the restoration succession stage of each group, the competitiveness of edible forage, cultivated plants, and climax plants all showed an obvious downward trend since the 7 th year. In the restoration management of the artificial grassland, we recommend that moderate human interventions, such as fertilization, rodent control, poisonous and harmful weed removal be carried out in the next 7-10 years;(3) Analyzing the prediction results on competition succession of each group synthetically, all of tend to be dynamically balanced from the 20 th year. Consequently, according to the model, from the perspective of ecological restoration, it will take at least 20 years for the artificial restoration of the "black soil patch" degraded grassland to obtain a relatively stable plant community.