水保所知识产出(1956---)知识库

To explore the primary factors affecting the ecological niches in a plant community, four dominant shrub species
(Sophora viciifolia, Periploca sepium, Buddleja alternifolia, Clematis fruticosa) and six dominant grass species
(Bothriochloa ischaemum, Artemisia sacrorum, Stipa bungeana, Cleistogenes squarrosa, Stipa grandis, Lespedeza
bicolor) were selected from a stable grassland community in the Loess Plateau (China). The relative importance
value and niche breadth were used as comprehensive quantitative indices to characterize the status, role, and
degree of dominance of plant species in the community. We found that relative importance value and niche
breadth were higher overall in shrub species than in most grass species, except B. ischaemum. Meanwhile, the
relative importance value was significantly correlated with plant phosphorus concentration, plant carbon:ni-
trogen ratio, rhizosphere soil organic carbon, rhizosphere soil total nitrogen, rhizosphere soil total phosphorus,
rhizosphere bacterial α -diversity. A stepwise regression analysis indicated that, among the plant and rhizosphere
characteristics of these species, only their rhizosphere bacterial α -diversity and plant root carbon concentration
primarily influence ecological niche patterns of these plant species in the community. In summary, our study
reveals that shrub species occupy more advantageous ecological niches than grass species in a stable community
due to the active rhizosphere interactions, providing a new opportunity to disentangle the mechanisms under-
lying the plant community assembly in grassland.