Survival of Rumex obtusifolius L. in an unmanaged grassland

Survival of broad-leaved dock (Rumex obtusifolius) plants exposed to grass (mainly Festuca rubra and Elymus repens) competition in unmanaged grassland in Central Europe was investigated. Individual plants (n = 244) were marked in a 35 x 28 m experimental plot divided into 20 quadrats. The mortality of the dock plants was recorded twice a year, and plant size (number of flowering stems) recorded for 8 years (2000-2007). Half of the plants died within 4 years and 4% survived to the end of the experiment. On average, winter mortality (October-April, 60%) was greater than summer mortality (May-September, 40%) but both varied between years. The plants decreased in size as they approached death. The survival of dock plants in particular quadrats was negatively correlated with the biomass of grass roots and rhizomes. Intensity of below-ground competition and possibly water deficiency contributed most to dock mortality.