Composition and spatial distribution of main species in grassland community of Baiyinhua mining area, China

Abstract

We analyzed composition and spatial distribution of main species in the surrounding grassland of Baiyinhua mining area in Inner Mongolia. The results showed that there were 55 plant species in the grassland, with dominant species being Stipa grandis, Carex korshinskyi, and Cleistogenes squarrosa, and common species being Leymus chinensis, Agropyron cristatum, and Anemarrhena asphodeloides. The accumulative relative importance value of those six species was 79.6%, with their densities being 26.6, 204.7, 105.4, 107.1, 68.2 and 55.1 individuals·m-2, respectively. The population density of those six species was modeled by the semi-variance function. The population distribution was in accordance with the exponential model, exponential model, exponential model, spherical model, linear model and Gaussian model, respectively. Through analyzing the spatial distribution pattern, structure ratios were 59.2%, 97.2%, 89.1%, 94.5%, 62.6% and 72.1%, respectively. The spatial autocorrelation of C. korshinskyi, C. squarrosa and L. chinensis populations was mainly affected by structural factors, whereas S. grandis, A. cristatum and A. asphodeloides were mainly affected by random factors. According to results from the fractal dimension analysis, population distribution patterns of S. grandis, C. korshinskyi, C. squarrosa and A. cristatum were simple, and the spatial dependence was strong. Both L. chinensis and A. asphodeloides showed contrasting patterns with those four species. From 2D and 3D images, S. grandis and A. asphodeloides showed gradient diffusion, while C. korshinskyi, C. squarrosa, L. chinensis and A. cristatum showed patch distribution. The results showed that the spatial distribution of the main species in this grassland community did not correlate with mining.