Plant–soil feedback in native vs. invasive populations of a range expanding plant

Abstract

Background and aims Although plant-soil feedback has been suggested as a mechanism that drives the success of invasive plants, studies that investigate differences in the intensity of plant-soil feedback among native and invasive populations of the same species are still lacking. However, such knowledge is important because it can provide an understanding of the mechanisms responsible for the spread of a species. Rorippa austriaca is a potentially invasive species -a successful range expander in Europe.Methods We compared the plant-soil feedback of R. austriaca in populations from its native and invasive range. We explored both intraspecific feedback as well as feedback on a co-occurring grass species. Results Our results revealed a strong negative feedback effect as a consequence of soil conditioning by R. austriaca from the native range. On the contrary, a negative feedback effect was not observed for invasive R. austriaca. Interestingly, R. austriaca from the invasive range had a higher biomass than native R. austriaca. Conclusion Our results might be explained by pathogen accumulation and soil modification by native R. austriaca, which had strong intra-and interspecific effects that seemed to be lost in the invasive R. austriaca. The loss of negative intraspecific plantsoil feedback and the increased growth of the invasive population may contribute to its successful range expansion. In spite of its increased growth, the co-occurring grass species is expected to successfully coexist with the invasive R. austriaca.

Range-expanding plant species and their belowground neighbours : digging into novel interactions

“…Climate warming-induced range-expanding plant species can experience weaker negative impact in soil from the new than from the original range (van Grunsven et al 2010;De Frenne et al 2014;Dostálek et al 2015;Van Nuland, Bailey & Schweitzer 2017). This may be caused by the loss of belowground natural enemies, such as root-feeding nematodes and soil-borne pathogens, as a result of plants having higher dispersal capacities than soil biota (Berg et al 2010;Morriën et al 2010).…”

“…Such a disruption of plant-enemy interactions due to intra-continental range expansion may not be as strong when compared to intercontinental introductions, as some natural enemies of range-expanders may have wider distributions and will therefore already be present at higher latitudes (Menendez et al 2008). Yet, an increasing number of studies show that some range-expanding plant species are less affected by soil communities in their new range compared to their original range, suggesting a degree of enemy release (van Grunsven et al 2010;De Frenne et al 2014;Dostálek et al 2015;Van Nuland, Bailey & Schweitzer 2017). However, comparisons between the compositions of soil communities from the original and new range of rangeexpanding plant species so far have rarely been made (Van Nuland, Bailey & Schweitzer 2017).…”

“…Through plant range-expansions, interactions between plants and specific rhizosphere communities can be disrupted with functional consequences for plant performance in the new range (Morriën et al 2010;van der Putten 2012). Indeed, several rangeexpanding plant species seem to be less negatively affected by soil communities in their new than in their original range, suggesting that range expansion enables release from natural enemies from the original range (van Grunsven et al 2010;De Frenne et al 2014;Dostálek et al 2015;Van Nuland, Bailey & Schweitzer 2017).…”

“…Range-expanders that are phylogenetically more distinct from native flora can be expected to have even stronger suppressive effects on these native natural enemies, but such evidence is lacking so far. Moreover, it is still largely unknown if the interactions between range-expanding plant species and their natural enemies differ between their original and new range as only a couple of studies (van Grunsven et al 2010;Dostálek et al 2015;Macel et al 2017) have addressed these questions experimentally.…”

“…As not all species expand their range at similar rates (Berg et al 2010), coevolved interactions between plants, aboveground and belowground organisms are likely to become disrupted, whereas novel interactions can be developed in the new range (Lavergne et al 2010;van der Putten 2012). Range-expanding plant species might benefit from these new biotic conditions when they do not encounter coevolved natural enemies in the expanded range (De Frenne et al 2014;Dostálek et al 2015). At the same time, range-expanders will become exposed to non-coevolved natural enemies that are native to these new areas.…”