Print PageEcotypes are genetic variations of a plant species adapted to local environmental conditions. Andropogon gerardii Vitman is a dominant C4 grass across the North American prairie and is represented by many local ecotypes. Forage quality analyses quantify digestibility and nutrition of a plant sample and allow an assessment of suitability for grazers. The variability in forage quality among A. gerardii ecotypes is unknown. This study aims to quantify forage quality variation in A. gerardii collected across a precipitation gradient from eastern Colorado to Illinois in the North American grassland. Four distinct precipitation regions and three-remnant grassland populations within each region were sampled in July 2010 to assess differences in forage quality.
Results/Conclusions
Results of the field experiment show there were significant differences in digestibility between precipitation regions (p<0.0001), and significant differences within eastern and western populations but not within Illinois or Colorado sources. A Principal Component Analysis (PCA) of forage quality variables shows an east to west gradient of source populations within precipitation regions (p<0.0001, PC1 79.4%). Digestibility was highest in Colorado sources and subsequently declined moving east across the gradient. These findings have implications for management of prairie remnants and the collection of plant materials for restorations that seek to incorporate large grazers.
