Kentucky bluegrass (Poa pratensis L.) has been increasing rapidly on rangelands in the northern Great Plains. Despite the rapid increase, relatively little is known about the impact of Kentucky bluegrass (POPR) invasion on ecosystem services. A study was initiated at the Northern Great Plains Research Laboratory (USDA-ARS) near Mandan, ND to investigate POPR invasion effects on plant species diversity and aboveground biomass nitrogen (N). Four sites (4.9 x 4.9m) within a long-term moderately grazed pasture were selected with half the area being dominated by POPR and half dominated by other species (Control). Two 1/8 m2 quadrats were clipped by species to ground level on each half in July 2013. All standing dead and detached litter was also removed and placed in a litter category. Nitrogen and carbon were determined on the green biomass and litter components. Species richness was similar in POPR and control areas. However, Simpson's Diversity index was greater on the Control (D=0.379 and 0.666 for POPR and Control, respectively; P=0.0005). Percent N in all the aboveground biomass components was similar between POPR and Control areas, but total g N m-2 was greater in the POPR area (9.2 vs. 4.0 g m-2 for POPR vs Control, respectively; P= 0.0011) because of greater biomass in POPR. The increased N in the POPR dominated area may drive the POPR increase. However, while species diversity was greater in the Control, the lack of differences between the two areas may suggest potential for re-establishing dominance of native grasses afflicted by POPR invasion.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.