Study of ecological niches of plant species in different abandoned arable land in desert grassland areas of Inner Mongolia

Ecological niche characteristics can accurately reflect the interrelationships among plant populations. To study the influence of abandonment years on the ecotone characteristics of plant species, three treatments of 5, 15, and 20 years of abandonment were selected in the desert grassland in Inner Mongolia. Natural grassland was used as the control. Shannon-Wiener ecotone width index and Pianka ecotone overlap index of plant populations were analyzed to explore the succession pattern of plant community composition in the abandoned cropland. The succession pattern of plant community composition in the abandoned crop was investigated by analyzing these indices. Species with a higher importance in the succession stage of abandoned plowing gradually changed from first- and second-year plants to perennial grasses. Species with the largest ecotone width also changed from annuals to perennials but still differed from those with the largest ecotone width in natural grassland. The overlap of ecological niches between 20 years of abandonment and natural grassland was higher than between 5 and 15 years of abandonment. The overlap of ecological niches between 15 years of abandonment was mainly between Artemisia scopari and Neopallasia petinata. The largest overlap of ecological niches between natural grassland and 20 years of abandonment was between species pairs Stipa breviflora and N. petinata.