Effects of Rudbeckia laciniata on the soil seed bank
Rudbeckia laciniata (Asteraceae) is a rhizomatous perennial originating from the Eastern USA and was introduced into the EPPO region as an ornamental plant at the beginning of the 17th century. It prefers moist habitats, rivers streams and drainage ditches, ruderal habitats along transportation networks. In invaded areas, it can form dense monocultures which can alter the species composition of the habitat. The study was conducted in Southern Poland in two types of abandoned meadows. The first location was outside a river valley in a fresh meadow, and the second was within a river valley in a wet meadow. In each meadow, the soil seed bank was sampled from sites dominated with R. laciniata (sites where it exceeds 70% of the vegetation cover), sites of intermediate invasion (less than 70% cover but greater than 0% cover), and sites where R. laciniata was absent. Soil samples were taken from each site from the upper soil layer (0-5 cm) and the lower layer (5-10 cm) in early spring. The soil seed bank was estimated using the seedling emergence method. Soil was placed on trays in a greenhouse and emerging seedlings were identified. In the wet meadow, the seed bank of R. laciniata in the invasion zone was 17 476 seeds/m2, and in the fresh meadow, it was 4132 seeds/m2. The majority of the R. laciniata seeds were located in the surface layer of soil. The results showed that 47 % (in fresh meadow) and 56 % (wet meadow) of recorded species occurred only in the soil seed bank, and were absent in aboveground vegetation. Emergence of native plants from the soil seed bank is low due to rapid shading of the soil surface by R. laciniata seedlings. However, as native seeds persist in the seed bank regular management may act to promote the restoration of the invaded sites.
Sources
Jędrzejczak E, Klichowska E, Nobis M (2022) Effect of Rudbeckia laciniata invasion on soil seed banks of different types of meadow communities. Nature Scientific Reports https://doi.org/10.1038/s41598-022-14681-1