Causes of differences in the distribution of the invasive plants Ambrosia artemisiifolia and Ambrosia trifida in the Yili Valley, China

Abstract

Ambrosia artemisiifolia and Ambrosia trifida are two species of very harmful and invasive plants of the same genus. However, it remains unclear why A. artemisiifolia is more widely distributed than A. trifida worldwide. Distribution and abundance of these two species were surveyed and measured from 2010 to 2017 in the Yili Valley, Xinjiang, China. Soil temperature and humidity, main companion species, the biological characteristics in farmland ecotone, residential area, roadside and grassland, and water demand of the two species were determined and studied from 2017 to 2018. The area occupied by A. artemisiifolia in the Yili Valley was more extensive than that of A. trifida, while the abundance of A. artemisiifolia in grassland was less than that of A. trifida at eight years after invasion. The interspecific competitive ability of two species were stronger than those of companion species in farmland ecotone, residential, and roadside. In addition, A. trifida had greater interspecific competitive ability than other plant species in grassland. The seed size and seed weight of A. trifida were five times or eight times those of A.artemisiifolia. When comparing the changes under simulated annual precipitation of 840 mm versus 280 mm, the seed yield per m2 of A. trifida decreased from 50,185 to 19, while that of A. artemisiifolia decreased from 15,579 to 530. The differences in the distribution of the two species are mainly due to differences in interspecific competitive ability, seed size, and water dependence. The two species have stronger interspecific competitive ability than that of companion species, but A. artemisiifolia has a smaller seed size and stronger drought tolerance, which allows A. artemisiifolia to spread farther than A. trifida. The reason for wider distribution of A. trifida in grassland is that A. trifida has stronger interspecific competitive ability than A. artemisiifolia under sufficient water.

Phenotypic plasticity and exotic plant invasions: Effects of soil nutrients, species nutrient requirements, and types of traits

“…Under high‐nutrient environment, the invasive species X. strumarium and A. trifida showed significantly higher growth plasticity than their respective related native species, contributing to their growth advantage and, therefore, to their invasions. These two invaders have posed a serious threat to the agricultural production of soybean, cotton, maize, sunflower, peanut, and so on, causing huge economic losses (Danuso et al, 2012; Dong et al, 2020; Follak et al, 2013; Iqbal et al, 2020). They have high‐nutrient requirements and prefer to invade fertile habitats such as farmlands (Feng, 2020), where fertilizers are applied regularly.…”

“…However, Solanum rostratum and Erigeron canadensis usually invade nutrient‐limited habitats such as sandy soil, having low‐nutrient requirements (Đurđević et al, 2015; Juan et al, 2013; Thébaud et al, 1996; Zhang et al, 2017; Zhao et al, 2013). Bidens frondosa , Xanthium strumarium , and Ambrosia trifida generally invade nutrient‐rich habitats with regular nutrient addition, such as farmlands and wetlands, having high‐nutrient requirements (Danuso et al, 2012; Dong et al, 2020; Follak et al, 2013; Iqbal et al, 2020; Ronzhina, 2017). The native species Bidens tripartita and Solanum nigrum are often found in fertile habitats (Jagatheeswari & Ali, 2013; Särkinen et al, 2018) with high Ellenberg's nitrogen indicators (Hill et al, 1999), exhibiting high‐nutrient requirements.…”