A study of plant community stability in the lower Tarim River based on MLR and MLP and improved Morneau dynamics model

Abstract

Taking the lower reaches of Tarim River as the research area, drought adaptability and species number of plant communities were studied. Due to the simple, dry and water-scarce topography, the plant community structure in this region is relatively uncomplicated, so it is a good area for analysis. In this paper, Monod model, a macroscopical internal mechanism of long-term interaction between plant community and environment, is proposed. The Monod model is derived from the growth of microorganisms and therefore needs to be optimized when considering plants: self-inhibition characteristics are introduced to obtain an optimized mechanism model. Based on this model, the conditions to be met when the change rate of plant population density is positive are solved in this paper. Combined with the actual number of species, it is considered that the community needs at least three different plant species to benefit, and the situation caused by the increase of species is discussed. Different types of plants have different NDVI, so they have different effects on the model. In this paper, the analysis is divided into three types of plants, and the effect of changing drought frequency is considered. Since there are only two regions with different drought frequency and easy to be divided, this paper introduced multiple linear regression models in the two regions respectively, extracted the general model from the regression coefficient relationship between the two regions, and analyzed the NDVI regression coefficient of the two regions at the same time, to obtain the general rule of the effect of less drought on the number of species. Due to the lack of pollution data and habitat data in the study area, this paper derived a model of negative environmental factors from the mechanism model, and finally combined with the easily available pm2.5 index. Based on the established model, this paper hopes to help ensure community survival in terms of increasing resource growth rates and preserving diversity.