Prairie Turnips at 15: A Good Model Goes Bad

The prairie turnip (Pediomelum esculentum), an edible legume native to the North American Great Plains, makes a poor model organism for investigating population dynamics.  Individual plants are long lived, slow growing, and only visible for a few weeks each year.  These “challengeing” traits, however, make the prairie turnip a good choice as a conservation model, as the traits are shared with many other wild harvested plants.  Fates of individual plants in three populations were tracked from 2001 to 2004 and used in 2006 to project population size and model level of sustainable harvest under many different harvest regimes.  Plots in the largest and most robust population were re-visted in 2013-2015, at which time the population had crashed, with 80% fewer plants in the plots in 2014 than 2004.  Reasons for and implications of this dramatic decline will be discussed.