Ecotoxicological effect of invasive Solidago canadensis L. and hybrid Solidago x niederederi Khek derived extracts toward selected aquatic, semi-aquatic and soil invertebrates.

Allelopathy is associated with biodiversity loss and assemblage changes in Solidago invaded plots. Although plant-allelopathic effects are well documented, little is known about the toxicity of goldenrod allelochemicals to invertebrates, despite its high biomass production and release of bioactive compounds via volatilization, root exudation or during decomposition, whereas the lack of information is especially evident for the new hybrid S. × niederederi. We conducted a laboratory experiment to assess the effect of water extracts and essential oils derived from the invasive Solidago canadensis and hybrid Solidago × niederederi against larvae of the blood-feeding, invasive Asian bush mosquito (Aedes japonicus), glass worms (larvae of non-hematophagous Chaoborus mosquitoes), sludge worms (Tubifex tubifex), and earthworms (Eisenia fetida), which represent aquatic, semi-aquatic and soil-dwelling invertebrates. Impact was determined on the model organism's mortality and lethal concentration values (LC50/LC90). Except for the content of phenolic acids and saponins in the water extracts, and the representation of dominant compounds in the essential oils plus their acetylcholinesterase and butyrylcholinesterase inhibition activity were determined too. Subsequently, possible link to the toxicity was evaluated as well. Used invertebrates exhibited various sensitivities, depending on the extract type: essential oils from both goldenrod species caused high mortality of A. japonicus larvae. We also observed pronounced toxicity of S. canadensis essential oil toward glass worms. In contrast, the essential oils from invader and hybrid had no harmful effect on the earthworms or sludge worms, while both goldenrod's water extracts caused certain mortality of T. tubifex and total mortality of E. fetida. Our analyses suggest that the toxicity of goldenrod's allelochemicals against invertebrates may be linked to the presence of specific phenolic acids and saponins in water extracts, and the inhibitory activity of essential oils against acetylcholinesterase and butyrylcholinesterase consequently. The study thus indicates possible ecological consequences of goldenrod invasion on the impacted faunal communities. Possible usage of Solidago representative's biomass for the bio-based pesticide development, as part of the practically focused plant invasion management, can be deduced as well.