Distribution, competitive ability, and seed production of Bidens frondosa L. in the Middle Urals

摘要

AbstractThe distribution, plant size and biomass allocation, leaf traits, and seed production of the invasiveBidens frondosaL. plant in the Middle Urals were studied. This species was found in disturbed riverside habitats in the upper stream of the Iset’ River in habitats extending approximately 100 km (from the city of Aramil’ to the city of Kamensk-Ural’sky). Comparative analysis showed that theB. frondosaplant was 35% taller than the native species of the genusBidens. The dry mass of theB. frondosaplant exceeded the biomass ofB. tripartitaandB. radiataby 1.5 and 4.9 times, respectively. The large size and biomass ofB. frondosaindicated a higher competitive ability of this species than the native species of the genusBidens. Given the same leaf thickness in the three studied species, the smaller leaf density (LD) ofB. frondosadetermined a lower (by 1.2 times) dry leaf mass per unit area (LMA) than that ofB. tripartitaandB. radiata. These structural features ofB. frondosaleaves contributed to the optimization of gas exchange processes within a leaf and made it possible to develop a greater assimilation area per unit plant weight (the leaf area ratio (LAR)), which should provide a high growth rate of this species. Analysis of seed production parameters showed that the number of capitula per plant increased in the seriesB. radiata–B. tripartita–B. frondosa; however, the number of achenes per capitulum and per plant decreased in this sequence. The mass of 100 achenes was 1.6 and 2.3 times higher inB. frondosathan inB. tripartitaandB. radiata, respectively. On the whole, the frequent occurrence ofB. frondosain the extended area (approximately 100 km) in the upper stream of the Iset’ River and the values of production parameters (the size and weight of plants and the mass and number of seeds) indicate a successful naturalization of this species in the Middle Urals.]]>