Growth and allocation patterns ofMikania micranthain successional environments after slash and burn agriculture

摘要

The growth and allocation of biomass and nutrients inMikania micranthaHBK., an exotic early successional perennial weed, was studied in seral stages after slash and burn agriculture. Peak vigour of the species was reached in a 3-year-old fallow, with decline in older fallows. In general, allocation of biomass and nutrients to the leaf component and for reproduction was low in a 12-year-old fallow. On the other hand, allocation to the rosette root, which is the perennating organ, increased in older fallows and is a strategy for survival and regeneration after a subsequent perturbation. Lower nutrient-uptake efficiency and higher nutrient-use efficiency in 6- and 12-year-old fallows are adaptations for survival in a nutrient-limiting competitive environment. This ruderal species has an exploitative growth strategy, with weed suppression occurring in older successional fallows dominated by shrubs and trees.