JST01 Juniperus virginiana seedling trial with and without bison at Konza Prairie

We report the results of a 30-year experiment at Konza Prairie, a mesic grassland in the Central Great Plains, under fire suppression (20-year fire return intervals) and experimental presence/absence of bison. Based on remote sensing, the land cover of deciduous trees was lower (6% grazed vs. 16% ungrazed) in bison-grazed areas. There was no difference between shrub land cover (42% grazed and 41%) and herbaceous land cover was higher in the grazed vs the ungrazed (51% grazed and 40% ungrazed). The land cover of evergreen trees (Juniperus virginiana L.)—which disproportionately decreases native biodiversity and increases wildfire risk—was approximately 0% with bison compared to 4% without bison. In a seedling trial of J. virginiana L., we found eight times greater over-winter mortality in the bison treatment. Juniperus virginina seedlings were transplanted with and without bison to compare mortality rates.