The Invasive Plant Impatiens glandulifera Manipulates Microbial Associates of Competing Native Species

Abstract

Impatiens glandulifera or Himalayan balsam is one of the most invasive weeds across Europe and can seriously reduce native plant diversity. It often forms continuous monocultures along river banks, but the mechanisms of this arrested succession are largely unknown. Here, we investigated the effect of arbuscular mycorrhizal (AM) fungi on balsam competitive ability with two native plant species, Plantago lanceolata and Holcus lanatus. We also studied how competition with Impatiens affects colonisation by foliar endophytes and mycorrhizas of two other co-occurring native species, Urtica dioica and Cirsium arvense. Mycorrhizal colonisation reduced balsam growth when the plants were grown singly, but appeared to have little effect when balsam experienced intra- or interspecific competition. Competition with balsam together with the addition of mycorrhizas had no effect on P. lanceolata biomass, suggesting that the fungi were beneficial to the latter, enabling it to compete effectively with balsam. However, this was not so with H. lanatus. Meanwhile, competition with Impatiens reduced endophyte numbers and mycorrhizal colonisation in U. dioica and C. arvense, leading to enhanced susceptibility of these plants to insect attack. Himalayan balsam is known to degrade soil fungal populations and can also reduce foliar beneficial fungi in neighbouring plants. This allows the plant to compete effectively with itself and other native species, thereby leading to the continuous monocultures.

Variability of <i>Puccinia komarovii</i> var. <i>komarovii</i> isolates from <i>Impatiens parviflora</i> DC. and its occurrence in the Drawa and Wigry National Parks in Poland

“…Most scientific reports concern the invasive species Impatiens glandulifera (Ab Razak et al, 2023;Coakley & Petti, 2021;Tanner et al, 2015a), which is infected by P. komarovii var. glanduliferae.…”

“…Most scientific reports concern the invasive species Impatiens glandulifera Royle, known as Himalayan balsam, which is invasive throughout Europe and can also seriously reduce native plant diversity (Ab Razak et al, 2023;Coakley & Petti, 2021;Tanner et al, 2015a;Tanner & Gange, 2020). It negatively affects whole ecosystems where the native biodiversity of invertebrates and microbial communities is disturbed (Coakley & Petti, 2021).…”

Impacts of Soil Properties on Species Diversity and Structure in Alternanthera philoxeroides-Invaded and Native Plant Communities

“…These four soil factors all gradually increased from bottom to top along axis 2 (Table 3; Figure 5A). O. articulata (1) tended to be distributed in areas with high NCP and ORG; C. dactylon (2), Digitaria sanguinalis (9), and Imperata cylindrica (15) were distributed in areas with high CP but low N-NO3; E. indica (3) was distributed in areas with low ORG and N-NO3; Duchesnea indica (5) was distributed in areas with high N-NO3; and many species, including G. odoratum (4), tended to be distributed in areas with low FWC and TP (Figure 5A).…”

“…Increased Lupinus polyphyllus invasion coverage intensifies the biohomogenization of native plant communities [8]. Impatiens glandulifera can enhance its invasive competitiveness by reducing the number of beneficial epiphytic fungi on native accompanying plants [9]. Due to its great niche breadth, long flowering period, large seed quantity, and high root-shoot ratio, Gaillardia aristata can transform from an alien ornamental species into an invader under stressful environmental conditions, and it decreases the plant richness and diversity indices in invaded habitats [10].…”