Herbivory can reduce plant fitness, and its effects can be increased by competition. Though numerous studies have examined the joint effects of herbivores and competitors on plant performance, these interactive effects are seldom considered in the context of plant invasions.

To address this issue, Prof. DING Jianqing and his research group at Wuhan Botanical Garden, Chinese Academy of Sciences examined variation in tolerance to both specialist and generalist herbivores of native and invasive populations of Chinese tallow (Triadica sebifera) while competing with either a strong or weak conspecific competitor. They found that when no herbivory was imposed, invasive populations always had higher total biomass than natives, regardless of their neighbours. Defoliation by either generalist or specialist herbivores suppressed plant growth but the effects of specialists were generally stronger for invasive populations. Invasive populations had their lowest biomass when fed upon by specialists while simultaneously competing with stronger neighbours. The root/shoot ratios of invasive populations were lower than those of native populations under almost all conditions, and invasive plants were taller than native plants overall, especially when herbivores were present, suggesting that invasive populations may adopt an “aboveground first” strategy to cope with herbivory and competition.

These findings may provide insights into an effective biological control program against invasive plants. The results suggest that release from herbivores, especially specialists, improves an invader’s performance and helps to increase its competitive ability. Therefore, increasing interspecific competition intensity by planting a stronger neighbour while simultaneously releasing a specialist herbivore may be an especially effective method of managing invasive plants.

The research result has been published in Oecologia entitled “Interactive effects of herbivory and competition intensity determine invasive plant performance”.

Article link: http://www.springerlink.com/content/274745pm27863187/ 

Author contact: Prof. DING Jianqing

Tel: +86-27-87510970

Email: ding@wbgcas.cn