The impacts of invasive African olive on native Australian legumes via altered soil conditions do not persist as legacy effects

Can the impacts of invasive African Olive on native Cumberland Plain Woodland plants be mitigated through bioinoculation?

“…Our previous DNA barcoding study on the rhizobia associated with Australian Indigo and Hickory Wattle grown in the same CPW and IS soils analysed here, as well as soils from a nearby restored site that was mechanically cleared in 2005 and kept free of African Olive ever since, showed that distinct rhizobium strains characterised each soil type (Le Roux et al 2023a). Le Roux et al (2023a) found that nodulation in both legumes was negatively correlated with the abundance of rhizobia characteristic of African Olive-invaded soils and positively related to the abundance of those characteristic of CPW and restored soils. The negative impacts of African Olive invasion on the nodulation of Hickory Wattle that we observed in the current study were partially mitigated through the addition of inocula.…”

“…The invasion of African Olive into CPW may negatively impact native species through the reduction of effective mutualists (Lankau et al 2014;Le Roux et al 2017, 2023a. These impacts on the rhizobium symbionts of Hickory Wattle may underlie the lower growth and nodulation we observed for this species when grown in IS soils compared to CPW soils (also see Le Roux et al 2023a).…”

“…These impacts on the rhizobium symbionts of Hickory Wattle may underlie the lower growth and nodulation we observed for this species when grown in IS soils compared to CPW soils (also see Le Roux et al 2023a). Our previous DNA barcoding study on the rhizobia associated with Australian Indigo and Hickory Wattle grown in the same CPW and IS soils analysed here, as well as soils from a nearby restored site that was mechanically cleared in 2005 and kept free of African Olive ever since, showed that distinct rhizobium strains characterised each soil type (Le Roux et al 2023a). Le Roux et al (2023a) found that nodulation in both legumes was negatively correlated with the abundance of rhizobia characteristic of African Olive-invaded soils and positively related to the abundance of those characteristic of CPW and restored soils.…”

“…The invasion of African Olive into CPW may negatively impact native species through the reduction of effective mutualists (Lankau et al 2014;Le Roux et al 2017, 2023a. These impacts on the rhizobium symbionts of Hickory Wattle may underlie the lower growth and nodulation we observed for this species when grown in IS soils compared to CPW soils (also see Le Roux et al 2023a). Our previous DNA barcoding study on the rhizobia associated with Australian Indigo and Hickory Wattle grown in the same CPW and IS soils analysed here, as well as soils from a nearby restored site that was mechanically cleared in 2005 and kept free of African Olive ever since, showed that distinct rhizobium strains characterised each soil type (Le Roux et al 2023a).…”

“…Nevertheless, sites cleared of African Olive almost 15 years ago at The Australian Botanic Garden, Mount Annan, harbour unique rhizobia that benefit the nodulation of Australian Indigo. Thus, despite the generalist rhizobium requirements of Australian Indigo, inoculation with certain rhizobia may still benefit its performance during restoration (Le Roux et al 2023a).…”