The Influence of Plant Traits on Seed Wind Dispersal of Two Invasive Weeds, Conyza canadensis and Aster subulatus
Seed dispersal by wind was a major process for invasive Asteraceae weeds to occupy new habitats, and quickly spread over their colonies. Internal and external factors, such as plant traits and environmental factors will determine seed dispersal direction, distance and seedling distribution. In this paper, we focused mainly on plant traits, such as release height, terminal velocity, shedding behavior, to study seed wind dispersal patterns of two invasive Asteraceae species, Conyzacanadensis and Aster subulatus. Results showed that the terminal velocity of both C. Canadensis (vt=41.4 cm·s-1) and A. Subulatus(vt=30.7 cm·s-1) were slow, suitable for them to stay aloft in the air for potential long distance dispersal. Seed releasing heights of C. Cmadensis (120±38.48 cm) were higher than A. Subulatus (100±26.97 cm ), with great variance excited among populations. Simulation of potential dispersal distance suggested that the average dispersal distance was 28 m and 19 m longer at the highest releasing height than the lowest for C. Canadensis and A. Subulatus, respectively. The probability of seed release was co-related with the square of horizontal wind velocity for both weeds. Results indicated that seed release of these two species were non-random, which increased the potential dispersal distance for seeds. About 0.015% and 0.002 5% of seeds were able to be long-distance dispersal (>100 m) under non-random and random release condition for C. Canadensis, and was 0.001 5% and almost none for A. Subulatus. This paper suggested that plant traits were important for seed wind dispersal study and provided a way to study spread of other invasive Asteraceae weeds in China.
国家科技期刊平台
NSTL
万方数据
维普
