Control of an invasive alien species, Ambrosia trifida with restoration by introducing willows as a typical riparian vegetation

Abstract

We evaluated the restoration effect by introducing willows as a means of controlling invasions of giant ragweed (Ambrosia trifida L.) on a riparian site. Our preliminary survey demonstrated that a problematic exotic species, giant ragweed and the representative riparian species, Salix koreensis are in competitive exclusive relationship. We planted willows at 1 m intervals on the bank of the Dongmun stream at Munsan, Paju, in Central Western Korea as an experimental restoration practice. We installed two 50 m ⅹ 5 m sized restored and non-restored for this experimental study. The non-restored plots were located on river banks, which were covered with concrete blocks and left in itself without any treatment. The height of willow was measured after each of three consecutive growing seasons and compared with the height of the giant ragweed. Although the height of Salix gracilistyla did not achieve the height of the giant ragweed, the height of S. koreensis surpassed that of giant ragweed in the third year after introduction. The results were also reflected in the relative light intensity on the herb layer of willow stand, and thereby the relative light intensities of stands, which were dominated by S. koreensis or restored by introducing S. koreensis, 1.99 ± 0.33 (%, mean ± SD) and 1.92 ± 0.50 (%, mean ± SD), respectively were lower than those in the stands treated by S. gracilistyla, 3.01 ± 0.43 (%, mean ± SD). The giant ragweed stands receive full sunlight as there are no any vegetation layers higher than the herb layer formed by the giant ragweed. As the result of Detrended Correspondence analysis ordination based on naturally established vegetation, the stands dominated by willows and giant ragweed showed different species composition between both stands. The species composition of the restoratively treated sites resembled the reference sites more than the non-treated sites. The species diversity (H') of the sites restored by introducing S. koreensis and S. gracilistyla was higher than the non-restored site dominated by A. trifida. On the basis of our results, the restoration of riparian vegetation equipped with integrated features could contribute not only to the control of exotic plants including giant ragweed but also to ensure the diversity and stability of riverine ecosystems.

Effects of cutting and sowing seeds of native species on giant ragweed invasion and plant diversity in a field experiment

“…Only one study has reported the use of native plant restoration to suppress A. trifida invasion (Lee et al 2010). The introduction of willow (Salix sp.)…”

Antioxidant potential of ragweeds: Ambrosia artemisiifolia, A. trifida and Iva xanthifolia

“…Giant ragweed has remained largely restricted to ruderal habitats, which might be one of the reasons for its slow spread in Central and Eastern Europe (Follak et al, 2013). Outside of this region, A. trifida occurs in several (semi-) natural habitats (Lee et al, 2010). As for A. artemisiifolia and I. xanthifolia, they have both undergone a habitat shift and expansion during their invasion, which may have contributed to their more extensive colonization of Central and Eastern Europe (Follak et al, 2013;Essl et al, 2009).…”

Ambrosia trifida L

“…In Japan, A. trifida can be found predominantly along riverbanks, mostly in disturbed locations (artificial banks, bridges and quarries) but also in the riverine vegetation (Miyawaki & Washitani, 2004). In South Korea, it occurs in the riparian systems of streams and rivers and around agricultural fields, on road edges and landfill sites and, recently, it has also invaded forest edges and interiors (Lee et al , 2010). In Japan and South Korea, A. trifida grows also in semi‐natural areas (Miyawaki & Washitani, 2004; Lee et al .…”

“…In Japan and South Korea, A. trifida grows also in semi‐natural areas (Miyawaki & Washitani, 2004; Lee et al . , 2010).…”

“…Miyawaki and Washitani (1996) found that plant species diversity was negatively correlated with the abundance of A. trifida in a nature reserve of moist tall grasslands along the Arakawa River, near Tokyo/Japan. Lee et al (2010) demonstrated that the vegetation dominated by A. trifida in South Korea differed with regard to the composition and diversity of the species to that of the uninvaded riparian vegetation.…”