Mycorrhizal associations of an invasive tree are enhanced by both genetic and environmental mechanisms

Abstract

Biotic interactions involving exotic plants in their introduced ranges may differ from those of co‐occurring plant species and from interactions in their native ranges. When interactions are less negative, or more positive compared to native plant species, this may increase invasion success, and differences among ranges may cause changes in exotic plant traits. Here, we investigated arbuscular mycorrhizae (AM) associated with Triadica sebifera seedlings from populations in native (China) and introduced ranges (US) and with seedlings from US and China species within three co‐occurring genera (Liquidambar, Ulmus, Celtis) grown in multiple common gardens in both ranges. No general pattern of higher or lower AM colonization was found in the introduced range for China and US Celtis, Liquidambar, or Ulmus species. However, AM colonization was significantly higher for Triadica than for other genera, particularly in the introduced range, suggesting AM may improve Triadica's invasion success. Triadica AM colonization was higher in US than China gardens, decreased with increasing soil nitrogen in China, but was independent of soil nitrogen in the US. This might reflect a different effect of soil fertility on this mutualism among ranges. Introduced Triadica populations had higher AM colonization than native populations, particularly in US gardens, implying a possible advantage from greater AM association in the introduced range. This is the first field study demonstrating post‐introduction changes in mycorrhizal colonization of an invasive species. It indicates that there are ecological and evolutionary components to the effect of positive interactions on plant invasions.

Interactive effects of elevated CO2 and nitrogen deposition accelerate litter decomposition cycles of invasive tree (Triadica sebifera)

“…Indeed, invasive T. sebifera has been demonstrated to have higher rates of mycorrhizal colonization, greater N or P exploration ability, more rapid growth, higher foliar C:N, and lower R:S and so typically have greater responses to increased soil resources than do T. sebifera from native populations (Siemann and Rogers, 2003;Zhang et al, 2013;Yang et al, 2015). However, in this study we found that litter production was greater for native populations with N deposition which was unexpected based on these other studies.…”

“…For instance, invasive Triadica sebifera populations create more biologically active soils that mineralize more N than soils associated with T. sebifera plants from native populations (Zou et al, 2006;Zhang et al, 2013). In addition, plants from invasive T. sebifera populations have higher rates of mycorrhizal association than plants from native T. sebifera populations which may impact soil physical and chemical properties (Yang et al, 2015). Moreover, litter and soil C:N may interact to determine litter decomposition rates (Finn et al, 2015).…”

The effects of fertilization on plant-soil interactions and salinity tolerance of invasive Triadica sebifera

“…A previous study in the introduced range with Triadica showed a different result in that fertilization increased mycorrhizal colonization and (Nijjer et al 2007). A comparative study also found that soil nitrogen was negatively correlated with arbuscular mycorrhizal colonization of Triadica in the native range but they had no significant relationship in the introduced range (Yang et al 2015b). Together these suggest consistent differences in the role of soil fertility in determining the effects of the soil biota on plant performance in the native vs. introduced ranges that might facilitate Triadica invasion in the USA.…”

“…Previous studies have shown that Triadica mycorrhizal colonization decreases with soil nitrogen in its native range but is unaffected in the introduced range (Yang et al 2015b) and that fertilization has larger positive soil effects for Triadica than for co-occurring native tree species in the introduced range (Nijjer et al 2008). Triadica's salinity tolerance is higher in the introduced range in part due to aboveground enemy release and more beneficial biotic interactions (Yang et al 2015a).…”

Mechanisms of Chinese tallow (Triadica sebifera) invasion and their management implications – A review

“…In addition, invasive ecotypes have lower levels of defense chemicals such as tannins (Huang et al, 2010(Huang et al, , 2012b(Huang et al, , 2013Wang et al, 2012bWang et al, , 2016Yang et al, 2013;Li et al, 2016). These patterns are thought to underlay the greater damage and/or higher performance of numerous herbivores from the native and introduced ranges (including candidate biocontrol agents, aboveground and belowground herbivores, and generalist herbivores from the native and introduced ranges) when they feed on Chinese tallow from invasive populations versus native populations (Siemann and Rogers, 2003d,c;Lankau et al, 2004;Huang et al, 2010;Wang et al, 2011bWang et al, , 2012bWang et al, , 2016Yang et al, 2015b;Li et al, 2016). Invasive ecotypes of Chinese tallow were also found to have more rapid compensatory regrowth following herbivory and greater herbivore tolerance (Rogers et al, 2000(Rogers et al, , 2003Siemann, 2002, 2004;Zou et al, 2008;Wang et al, 2011bWang et al, , 2016Carrillo et al, 2014;Carrillo and Siemann, 2016).…”