Impatiens glandulifera reduces soil fungi biomass in deciduous forests
Impatiens glandulifera (Balsaminaceae: EPPO List of Invasive Alien Plants) has been shown to have a number of negative effects on the ecosystems it invades, including outcompeting native plant species, and thereby reducing the associated invertebrate population. It also has negative impacts on ecosystem services, e.g. by restricting access to water bodies and increasing the amount of sediment intake into river systems. The potential impact of invasive alien plants on the soil mycobiota has received increased attention in recent years, particularly the effect of alien invasive plant species on arbuscular mycorrhizal fungi – where the effect can be both positive and negative depending on the species and system studied. The impact of I. glandulifera on the ectomycorrhizal (fungi which colonize around the root structure) community was studied in deciduous forests in Switzerland. Areas of the forest invaded by I. glandulifera were compared with areas where the species was removed, and the ectomycorrhizal biomass was estimated by placing mesh bags within the soil and measuring the ectomycorrhizal community which colonised the bags. Fungal genetic diversity was measured using terminal restriction fragment length polymorphism (T-RFLP). I. glandulifera reduced ectomycorrhizal biomass by between 30 – 80 % and the largest negative effect was in the centre of invaded stands. Fungal genetic diversity was not affected by I. glandulifera but the composition of the fungal community was and is most likely an effect of decreased ectomycorrhizal fungi and an increase of saprotrophic fungi. Such changes in biomass and community composition of the soil mycobiota could potentially have effects on forest nutrient and carbon cycling and therefore, can impact on forest ecosystem functioning.
Gaggini L, Rusterholz HR, Baur B (2019) The annual invasive plant Impatiens glandulifera reduces hyphal biomass of soil fungi in deciduous forests. Fungal Ecology 39, 242-249.