Dynamic analysis of niche and diversity of populations in the early stage of dump reclamation

In order to study the community succession characteristics in the early stage of land reclamation in surface coal mine dump, the method of space replacing time was adopted. The important value of main plant species, niche breadth, niche overlap among species and the change of plant diversity index in three years of land reclamation in surface coal mine dump were studied. The results show that the importance value and niche breadth of alfalfa, bromus inermis and elymus dahuricus increased year by year, while the important values and niche breadth of rape and oat grass, and other plants decreased. Compared with the first year, the niche overlap value (O_ik) in the second year of land reclamation increased by 0.297, and decreased by 0.065 in the third year. The similarity and competitiveness of species in resource utilization first increased and then decreased. In the first three years after land reclamation of the dump, the plant species increased from 29 to 74, and the Margalef richness index increased by 1.10 times. In general, the succession rate of the reconstructed ecosystem in the mining area was rapid in the early stage, and the community structure began to stabilize in the third year after land reclamation.