Lesser celandine (Ranunculus ficaria), an invasive ephemeral buttercup brought over from Europe, is becoming widespread throughout the Northeastern United States. This herbaceous perennial is able to create extensive dense mats that limit native species growth. It takes advantage of an early growing season and rapid reproductive rates, which enable this species to create dense monocultures, threatening native communities and ecosystems. Elimination of native spring ephemerals results in decreased biodiversity.
We examined lesser celandine abundance and reproductive output (seed, bulbil and tuber production rates) in plots spanning a distance away from Rocky River (Ohio). Site characteristics (PAR, aspect, soil pH, texture, nutrient and moisture content) were investigated in order to examine their role in plant performance. We hypothesized that reproductive output and lesser celandine abundance would be highest in moist floodplains at intermediate distances from rivers. We also expected soil characteristics (pH and nutrient availability) to drive lesser celandine plant performance; specifically we expected higher biomass and reproductive output when pH was higher.
There was high variability observed between sample sites, with bulbil production ranging from 0 to as high as 18 per plant (mean = 2.851) and tuber production ranging from 1 to 11 tubers per plant (mean = 2.417). Densities of lesser celandine were found to be as high as 11,425 plants/m2 in some areas with an overall mean of 2,772 plants/m2. Reproductive output and lesser celandine biomass were not significantly greater at intermediate distances from rivers, thus we cannot support our hypothesis. Many soil nutrients and characteristics were significantly related to biomass and reproductive output; specifically phosphorus, calcium and LTI (lime test index) all showed significantly positive relationships with plant biomass and bulbil counts, while soil pH was significantly positively related to biomass. These findings imply that soil characteristics (pH) and nutrients (P, Ca) are strongly linked to plant performance. Understanding where to manage is of vital importance to land managers. These results can inform management decisions, suggesting that limited resources should be focused by land managers on sites matching these characteristics. This study was able to expand on the current limited understanding of lesser celandine, which can prove helpful in more effectively reducing population size and spread.