The Effect of Bison Grazing on Soil Respiration on the Konza Prairie

It has recently been thought that large mammals such as bison have substantial influence over ecosystem processes such as nutrient cycling and may serve as a keystone species in tallgrass prairie. The focus of this research was to explore the effects of bison grazing on soil respiration at Konza Prairie Research Natural Area. Konza Prairie Research Natural Area, located in the Flint Hills of northeastern Kansas, has been a National Science Foundation Long Term Ecological (LTER) site since 1981. Data indicates that grasses often preferentially allocate carbon resources for aboveground growth following defoliation (or grazing). Therefore, it was hypothesized that soil respiration rates would decrease under grazed conditions. The N4D grazing lawn on Konza served as the study site. Soil temperature and moisture were measured simultaneously with respiration. Microbial respiration under both moderately and heavily grazed conditions were analyzed through controlled incubations. Results indicated that bison grazing did significantly decrease soil respiration and significantly increase soil temperature. Grazing had no significant effect on soil moisture or microbial respiration.