Background and Aims In hilly Loess region, Artemisia scoparia is always the dominator in the early abandoned field communities. It may be replaced by Agropyron cristatum or Heteropappus altaicus or Stipa bungeana in next succession stage when no disturbance occurs. In order to study the direction of Artemisia scoparia community succession under different standing conditions, we conducted transplant experiments to test the intraspecfic and interspecfic competition of Artemisia scoparia in river terrace and northern mound land and, at the same time, its morphological traits were investigated.
Methods In the experiments, nine species (three coexisting species, five later sere species and Artemisia scoparia itself) were chosen and transplanted as test species, but due to the low survival of two species, only seven species were analyzed to test the relative competition ability to phytometer Artemisia scoparia under different standing conditions.
Key Results The results show that the individuals tend to be miniaturized, i.e., its communities are composed mainly of small-sized individuals and competition can change the morphological traits. The unit biomass competition intensity is better than total competition intensity in explaining plants' relative competitive ability when local conditions and plant size are considered. Under the northern mound land and the lowest river terrace, late-successional and perennials species have higher competitative ability than early-successional and annual plants, suggesting that the competition of late- against early-successional species is one of the driving force to succession. Comparison of the competition between the seven test species and the unit biomass of Artemisia scoparia, the northern mound land ranks the first, lower river terrace the second and the lowest terrace the third, suggesting that intensive competition occurs more severely in poor growing conditions. There is significant difference in the ability of competition between the test species and Artemisia scoparia from the lowest river terrace to the northern mound land, suggesting that the ranks of the competition ability may vary depending on standing conditions.
Conclusions As competition is one of the decisive factors in constructing plant community, the shift or variation of competition ability between coexisting species and sere species may result in different community structure and dynamics, so it changes the direction and pathway of succession under different standing conditions.