Effects of disturbance intensity on seed germination, seedling establishment and growth of Ageratina adenophora
Alien plant invasions are tightly correlated with disturbance.and seed germination and seedling establishment are the most vulnerable plant life-history stages.and also the key stages for alien plant invasions. To evaluate the roles of disturbance in success invasion of noxious Ageratina adenophora, responses to disturbance intensities of seed germination,seedling establishment and growth of this plant were studied by simulating natural invasion process into artificial pasture community after man-made disturbances(remove different area of forage grass). Irradiance under canopy increased with increasing disturbance. Relative irradiance under canopy after 15 cm,20 cm,25 cm,30 cm,and 35 cm(diameter) disturbance were 6% ,9% ,16% ,20%,and 28% respectively. At all disturbance intensities,Ag-eratina seeds were able to germinate,and seedlings were able to survive and colonize. The percentages of seed ger-mination(40%-50%),seedling survive(26%-40%) and establishment(11%-15%)were not significantly different between disturbances. Seedlings successfully established were not found at 100% irradiance. Plant height,crown width,leaf number,leaf length,leaf width,individual leaf area,and total leaf area increased with increasing disturbance. The crown width,leaf number,and total leaf area were the biggest at 100% irradiance. Our results indicated that Ageratina had a strong ability to tolerate shade, and small disturbance might lead to invasion success for this plant. The abilities to grow slowly at adverse environments and to grow fast after environments improved might be a key strategy for Ageratina invasion.
Ageratina adenophora or Eupatorium adeno phorumdisturbancegrowthinvasivenessseed germinationseedling establishment
国家科技期刊平台
NSTL
万方数据
维普
