Search Results (5)

Priority effects—the phenomenon where early-arriving species influence the establishment, growth, and reproduction of later-arriving species during community assembly—play a critical role in determining the invasion success of exotic species. However, how priority effects are influenced by nitrogen (N) availability remains understudied. The invasive species Bidens frondosa has rapidly expanded its range in China over the past few years. Yet it remains unclear how priority effects in B. frondosa versus native species may mediate invasion success, as well as how nutrient levels may alter these effects. Addressing these questions is essential for understanding the mechanisms driving B. frondosa invasion and for developing effective management strategies. In a greenhouse experiment, we manipulated the planting order of B. frondosa and its native congener B. biternata, then measured the growth and competitiveness of B. frondosa and B. biternata in both control and N addition treatments. Planting order greatly impacted the growth and competitiveness of both B. frondosa and B. biternata. Early arrival had more positive effects on B. frondosa than B. biternata, while late arrival more strongly inhibited B. frondosa than B. biternata. For B. frondosa, priority effects lessened with nitrogen addition, but the opposite occurred for B. biternata. Thus, priority effects may favor B. frondosa invasion, while late arrival, particularly under nitrogen addition, may curb its spread. As such, sowing early-germinating native species represents a useful management strategy for controlling B. frondosa invasions. Full article

Global changes, such as atmospheric nitrogen deposition, can facilitate alien plant invasions, which are often attributed to the increase in soil nitrogen availability. However, few studies have considered the effects of global change-driven alterations in soil nitrogen forms, especially under conditions with interspecific competition. In this study, we first determined the differences in growth, biomass allocation, and photosynthesis under different nitrogen forms and addition levels between three noxious invasive species (Xanthium strumarium, Ambrosia trifida, and Bidens frondosa) and their respective related natives grown with and without interspecific competition and then assessed the interspecific difference in nitrogen form preference using the ¹⁵N labeling technique. Interspecific competition significantly decreased the positive responses of growth to nitrogen addition for all three natives, while increasing the responses for all three invaders, particularly under nitrate addition. When grown in competition, all invaders showed significant growth advantages over their related natives in most cases, and responded more positively to the addition of nitrate relative to ammonium, while the natives responded more positively to ammonium addition. These findings indicate that the invaders prefer nitrate, while the natives prefer ammonium. Consistently, the growth advantages are more pronounced for the invaders under nitrate relative to ammonium addition, indicating that nitrate-rich habitats may be more vulnerable to the invaders. When grown in monoculture, however, the growth advantage of the invaders became smaller or even disappeared. Nitrogen form preference also disappeared in Siegesbeckia glabrescens (native) and Bidens frondosa (invasive). Interestingly, the native plant Xanthium sibiricum showed significantly higher total biomass than its invasive congener under ammonium addition in both mixed and monoculture conditions. Our ¹⁵N labeling experiment showed that all six species preferred nitrate over ammonium, although this was not significant for two natives (S. glabrescens and X. sibiricum), which is not completely consistent with the results from our nitrogen addition experiment. Our results indicate that global change-driven alterations in soil nitrogen forms, particularly the shift from ammonium to nitrate, may facilitate alien plant invasions. Planting patterns significantly affect the responses of invasive and native species to nitrogen forms and addition levels, with mixed-culture experiments providing better insights into the invasiveness of alien species. Full article

The aim of the study was to evaluate the impact of European beaver (Castor fiber L.) on vegetation diversity and the expansion of non-native plant species in areas surrounding watercourses in Polesie National Park, Poland. The investigation was carried out within six watercourses inhabited by beavers and four comparison watercourses where beaver were absent. European beaver living in the park had a small excursion range, reaching a maximum distance of 25 m from the watercourse so that effects on vegetation diversity were limited to the immediate vicinity of the watercourse. Beaver significantly influenced diversity of the tall tree and forest floor vegetation, while it did not significantly modify the diversity of the low tree and shrub layer. Five alien plant species were documented. The alien species most strongly associated with beaver activity was devil’s beggartick (Bidens frondosa L.), which occurred in the immediate vicinity of beaver dams. Other alien species most benefiting from the presence of beaver were giant goldenrod (Solidago gigantea Aiton) and black cherry (Prunus serotina Ehrh.). Our study confirmed hypotheses found in literature according to which beaver activities that reduce the proportion of native species can promote the expansion of plant alien species. Full article

To identify habitat conditions, indirect ordination methods on the basis of environmental scales are used widely in Europe. However, many alien plants are absent from those scales. Bidens frondosa (Asteraceae) is an invasive alien species distributed widely in Europe. It is becoming a significant part of natural plant communities, sometimes forming monospecific stands. This study aimed to empirically determine environmental factor values using analysis of the flora accompanying B. frondosa in 22 regions of European Russia collected in a 34-year time span. In European Russia, Tsyganov environmental scales are widely used for such analyses. We determined intervals of values for each environmental factor according to Tsyganov environmental scales, namely thermoclimatic scale (TM: 7.3–9.4), climate continentality (KN: 6.0–9.4), climate aridity/humidity (OM: 6.1–8.6), cryoclimatic scale (CR: 5.3–8.8), soil moisture (HD: 9.9–17.6), scale of the soil salt regimen (TR: 5.1–10.7), soil nitrogen availability (NT: 4.4–8.5), soil pH (RC: 4.8–8.8), habitat shading (LC: 2.0–4.5), and soil-moisture variability (FH: 0.7–5.9). These data on environmental factor values can be further used in ordination analyses of plant communities where B. frondosa appears in the subzone of coniferous-deciduous forests of Eastern Europe. Results of this study demonstrate the ecological preferences of this species and can be used to determine conditions of habitats invaded by B. frondosa. Full article

A new polyacetylene glucoside (3E,5E,11E)-tridecatriene-7,9-diyne-1,2,13-triol-2-O-β-d-glucopyranoside (1), a new phenylpropanoid glucoside 2′-butoxyethylconiferin (2), and a new flavonoid glycoside 8,3′,4′-trihydroxyflavone-7-O-(6′′-O-p-coumaroyl)-β-d-glucopyranoside (3), have been isolated from Bidens frondosa together with fifty-three known compounds 4–56. The structures of these compounds were established by spectroscopic methods. mainly ESIMS, 1D- and 2D-NMR spectroscopic data. and comparison with literature data. Compounds 1–34, 36, 39, 43, 47, 51, and 52 were tested for inhibition of nuclear factor kappa B (NF-κB) in 293-NF-κB-luciferase report cell line induced by lipopolysaccharide (LPS), and compounds 1, 2, 3, 9, 15, 21, 24 and 51 were tested for the production of TNF-α, IL-1β, IL-6, IL-10 in RAW 264.7 macrophages induced by LPS. In conclusion, the isolated compounds 1, 2, 3, 9, 15, 21, 24 and 51 exhibited significant activity in anti-inflammatory activity assays. Full article