Effects of different scenarios of temperature rise and biological control agents on interactions between two noxious invasive plants

Abstract

Aim: An increasing number of exotic plants and their biological control agents are being introduced into new regions. Therefore, it is necessary to study their interactions and to manage the future directions of plant invasions under different scenarios of temperature rise. Location: China. Method: We investigated the distribution patterns of the two most prevalent invasive aquatic plants in the world, Alternanthera philoxeroides and Eichhornia crassipes, at a large scale and studied the interactions of both invasive plants with their respective biological control agents, Agasicles hygrophila and Neochetina eichhorniae, in response to different scenarios of temperature rise. Results: Both plants performed better in warmer climates in common garden experiments. However, large populations of A. philoxeroides occurred only in the temperate zone because this species experienced competitive exclusion from E. crassipes and suppression due to A. hygrophila herbivory in tropical and subtropical areas. Moreover, in both subtropical zones, where the two plants and A. hygrophila cooccur, and the temperate zone, where only A. philoxeroides occurs at present, A. hygrophila herbivory and the competition from E. crassipes hindered the performance of A. philoxeroides. Moreover, in the extreme high-temperature environment, A. philoxeroides performance improved, while E. crassipes performance worsened. In addition, the combination of N. eichhorniae herbivory and competition from A. philoxeroides also reduced the performance of E. crassipes, but E. crassipes still dominated when in competition with A. philoxeroides. Main conclusions: Our results indicate that climate warming and the introduction of herbivores do not alter the interspecific relationship between E. crassipes and A. philoxeroides. Moreover, our study suggests that under climate warming, E. crassipes will replace A. philoxeroides as the dominant species in some communities in | 2301 ZHANG et Al.

Effects of Warming, Phosphorous Deposition, and Both Treatments on the Growth and Physiology of Invasive Solidago canadensis and Native Artemisia argyi

“…A study found that native plants benefit from warming more than invasive plants, and this asymmetry, in effect, may decrease the relative abundance of invasive plants [ 29 ]. Another study found that regardless of warming conditions, invasive and native plants were similar in their responses in terms of total biomass, leaf and root areas, biomass allocation, temperature sensitivity, and phenotypic responses [ 30 ]. However, a study found the opposite result, where warming was generally more beneficial to invasive plants than native plants [ 31 ].…”

Competitive exclusion from native plants and co-occurring exotic plants was the most important factor influencing plant invasion in freshwater ecosystems

“…Therefore, specialist herbivores may lower the population expansion speed of invaders but cannot eliminate or reduce the developed population. What's more, in multi-invader communities, it is rare that specialist herbivores of each invasive plant appear and all plants are effectively controlled (Zhang et al 2021b). Even if enemies can successfully control one invasive plant, the co-occurring invasive plants can still dominate the communities (Center et al 2005, Hill et al 2020.…”

“…Whereas climate warming can facilitate the establishment and dispersal of exotic aquatic plants by altering streamflow and thermal regimes, reducing ice cover in waterbodies, and increasing water development activities (Rahel and Olden 2008). In addition, climate change has the potential to influence plant invasions by influencing native communities and co-occurring exotic plants (Li et al 2017, Zhang et al 2021b. Given the complexity of the effects of climate change on biological invasion, the study on predicting biological invasion under climate change should involve numerous invasive species, multiple measures of invaders, and the interactions between native and invasive plants, as well as among invaders.…”

“…Additionally, in communities with multiple invasive plants, an invader is influenced by cooccurring invaders (Kuebbing and Nuñez 2015). The invasive plants may facilitate each other by suppressing shared resident competitors, increasing resource availability, providing protection from herbivores, enhancing pollinator visitation rates as magnet species, and promoting their dispersal and establishment as nurse species (Simberloff 2006, Tecco et al, 2007, Molina-Montenegro et al 2008, Cushman et al, 2011, Flory and Bauer, 2014, or interfere with each other by competing for resources and pollinators (Belote and Weltzin 2006, Yang et al 2011, Zhang et al 2021b.…”

“…Furthermore, because the living environment of four lifeforms of aquatic plants (emergent, submerged, floating-leaved, and free-floating) varies greatly (Gallego et al 2015, Hussner et al 2021, Hu et al 2021, the effect and relative importance of the same factors on different life-form exotic plants may differ. Additionally, freshwater ecosystems often experienced multiple invasions (Zhang et al 2021b), a general understanding of the relative importance of various factors in the invasion process necessitates taking into account the overall performance of all invasive plants, as well as the performance of single invaders.…”