Vegetation Trends in Tallgrass Prairie From Bison and Cattle Grazing

Abstract

Comparisons between how bison and cattle grazing affect the plant community are understood poorly because of confounding differences in how the herbivores are typically managed. This 10-year study compared vegetation changes in Kansas (USA) tallgrass prairie that was burned and grazed season-long at a moderate stocking rate by either bison or cattle. We held management practices constant between the herbivores and equalized grazing pressure by matching animals so that the total body mass in all pastures was similar each year. Trends in species cover and diversity indices in the bison and cattle pastures were compared with ungrazed prairie that also was burned annually. We found that little bluestem (Schizachyrium scoparium) cover decreased over time in bison pastures, and big bluestem (Andropogon gerardii) cover increased over time in cattle pastures. Grazing by either herbivore increased the canopy cover of annual forbs, perennial forbs, and cool-season graminoids, but both annual and perennial forb cover increased at a greater rate in bison pastures than in cattle pastures. Missouri goldenrod (Solidago missouriensis) and heath aster (Symphyotrichum ericoides) were primarily responsible for the increased forb cover in grazed pastures. Species richness at both small (10 m 2 ) and large (200 m 2 ) spatial scales increased at a greater rate in bison pastures than in cattle pastures, but richness did not change through time in ungrazed prairie. The number of annual forb species was significantly higher in bison pastures than in pastures grazed by cattle. Residual graminoid biomass at the end of the grazing season was lower in bison pastures than in cattle pastures, whereas forb residuum increased over time at a greater rate in pastures grazed by bison than in pastures grazed by cattle. Although bison and cattle differentially altered some vegetation components, the plant communities in bison and cattle pastures were 85% similar after 10 years of grazing. We conclude that most measurable differences between bisongrazed and cattle-grazed pastures in tallgrass prairie are relatively minor, and differences in how the herbivores are typically managed may play a larger role in their impact on prairie vegetation than differences between the species.

Farming Practices Influence Wild Pollinator Populations on Squash and Pumpkin

“…Although previous work found bison and cattle grazing sites were 85% similar in plant community, the observed small scale differences in plant richness and diversity (Towne et al 2005) could significantly affect bees that have low mobility. Bison grazing can help increase rare plant species (Wilsey and Martin 2015), as well as landscape level heterogeneity (McMillan et al 2011;Kohl et al 2013), which could be important to bee diversity.…”

Effects of grassland management practices on ant functional groups in central North America

“…Grazing, like fire, is a disturbance that can affect the abundance and diversity of fauna (Andresen et al 1990, Sutter and Ritchison 2005, Warui et al 2005) and flora (Towne et al 2005). Fire and grazing have also interacted for millennia Engle 2001, Archibald et al 2005), a process labeled as pyric herbivory (Fuhlendorf et al 2009) because fire alters distribution and foraging behavior of large ungulates in space and time.…”

The role of herbivores in Great Plains conservation: comparative ecology of bison and cattle

“…In the Great Plains of North America, ecologists, conservation biologists, and land managers have studied and debated the effects of grazing by bison and domestic cattle (Bos taurus), often without including other interacting factors (Hartnett et al 1997, Steuter andHidinger 1999). Common managerial differences associated with bison and cattle also confound differences in effects between the two species (Towne et al 2005). Cattle herds are often associated with ranches that are based on commodity production, where animals are commonly separated for most of the year based on sex or age (e.g., cows and calves, bulls).…”