A new strategy for controlling invasive weeds: selecting valuable native plants to defeat them.

Weihua Li,Wah Soon Chow,Taijie Zhang,Jianning Luo,Zhongyu Sun,Changlian Peng,Xingshan Tian,Shaolin Peng

doi:10.1038/srep11004

Abstract

To explore replacement control of the invasive weed Ipomoea cairica, we studied the competitive effects of two valuable natives, Pueraria lobata and Paederia scandens, on growth and photosynthetic characteristics of I. cairica, in pot and field experiments. When I. cairica was planted in pots with P. lobata or P. scandens, its total biomass decreased by 68.7% and 45.8%, and its stem length by 33.3% and 34.1%, respectively. The two natives depressed growth of the weed by their strong effects on its photosynthetic characteristics, including suppression of leaf biomass and the abundance of the CO2-fixing enzyme RUBISCO. The field experiment demonstrated that sowing seeds of P. lobata or P. scandens in plots where the weed had been largely cleared produced 11.8-fold or 2.5-fold as much leaf biomass of the two natives, respectively, as the weed. Replacement control by valuable native species is potentially a feasible and sustainable means of suppressing I. cairica.

Highlights

Ipomoea cairica (L.) Sweet (Convolvulaceae) is an extremely fast growing, sprawling, perennial liana, believed to have originated from a rather wide area: Africa, Asia, Pacific Islands and South America[13]
There was no significant difference between the total biomass of P. scandens when it was grown with I. cairica and when it was under intraspecific competition (Table 1)
As compared with intraspecific competition, the root mass ratio (RMR) of I. cairica increased significantly when it was planted with one of the two native species, whereas the root mass ratio (RMR) of P. lobata decreased significantly when it was planted with I. cairica or P. scandens (Table 1)

Summary

Introduction

Ipomoea cairica (L.) Sweet (Convolvulaceae) is an extremely fast growing, sprawling, perennial liana, believed to have originated from a rather wide area: Africa, Asia, Pacific Islands and South America[13] It is recognized as the second worst invasive weed in southern China following M. micrantha[14,15], occurring widely in thickets, roadsides, waste places, cultivated areas and sunny meadows in Guangdong, Guangxi, Hainan, Fujian, Taiwan and Yunnan[13,14]. P. scandens (Chinese feverine), native to China, is a rapidly growing vine, widely distributed in provinces south of Chang Jiang (the Yangtze River) as well as in the riverside areas This plant has medicinal properties and a decoction of the whole plant is used in the treatment of abdominal pain, abscesses, arthritis, over-eating and more[19]. We expected the natives to be less affected by interspecific or intraspecific competition than the alien. (2) Replacement control through planting the valuable native species could prevent recruitment of the invasive weed, I. cairica

Methods

Results

Conclusion