Biological characteristics of A.artemisiifolia, A. trifida and companion species (Experiment 3)
Ambrosia trifida was significantly taller than other plant species in all habitats from LS period to MR period, being 3.45 to 8.3 times taller than the companion species in the FR period. Ambrosia artemisiifolia was significantly taller than companion species in the farmland ecotone and residential area from ES period to MR period (Fig. 4).
The density of A. trifida was significantly higher than that of the other species in all habitats, reaching 1.35 to 4.4 times that of the companion species in the FR period. The density of A. artemisiifolia was higher than that of the companion species in the farmland ecotone, residential area, and roadside, at 1.39 to 2.23 times that of the companion species in FR period. However, the density ofA. artemisiifolia was lower than that of the companion species in grassland, at only 0.37 times the density of the companion species in FR period (Fig. 4).
The coverage of A. trifida was significantly greater than that of the other species in all habitats from LS period to MR period, at 1.31 to 2.8 times that of the companion species in FR period, respectively. The coverage of A. artemisiifolia was significantly higher than that of the companion species in the farmland ecotone and residential area from EG period to MR period, at 1.84 and 1.7 times that of the companion species in FR period, respectively. However, the coverage was significantly lower than the companion species in grassland, at 0.53 times that of the companion species in FR period (Fig. 4).
The 100-seed weight and seed size of A. artemisiifolia andA. trifida in roadside habitats were significantly lower than those in other habitats. The seed size of A. trifida was about five times that of A.artemisiifolia , while the weight of A. trifida seeds was about eight times that of A. artemisiifolia(Fig. 5).
The numbers of seeds per plant of A. artemisiifolia and A. trifida in roadside habitat were significantly lower than in other habitats. Ambrosia trifida produced a significantly greater number of seeds per plant in grassland than in other habitats. Meanwhile, A. artemisiifolia produced fewer seeds per plant thanA. trifida in grassland, but more than A. trifida in other habitats (Fig. 5).
Seed yield per m2 of A. artemisiifolia in various habitats was ranked as follows: farmland ecotone> residential area> grassland > roadside. Seed yield per m2 of A. trifida in various habitats differed as follows: grassland > farmland ecotone> residential area> roadside. Seed yield per m2 of A. artemisiifolia was less than that of A. trifida in all habitats (Fig. 5).