Low recruitment of native trees in a deciduous forest associated with Japanese barberry (Berberis thunbergii) invasion

Invasive plants may dramatically impact forest ecosystems by establishing dense populations and suppressing the recruitment of native tree species. One invasive shrub currently spreading throughout eastern deciduous forests of North America, Japanese barberry (Berberis thunbergii DC), may be limiting tree recruitment in stands where it invades. Once established, B. thunbergii becomes densely populated within forest understories and suppresses native plants by competing for limited resources, altering soil conditions, and changing the understory microclimate. To quantify native seedling inhibition caused by B. thunbergii invasion, we conducted an observational study on seedling abundance within forest plots that were either invaded or not invaded by B. thunbergii and used survey data to generate Bayesian models of native seedling densities along gradients of increasing B. thunbergii stem counts and aboveground plant dry mass. Model outputs predicted that B. thunbergii–invaded plots had 8...