Rewilding with keystones: Using bison and fire to restore North American grasslands

Authors:
Cristina Eisenberg

Publication Date:
2019

Abstract/Summary:
Native grasslands have been declining in North America since the 1880s, attributed to elimination of bison (Bison bison) and wildfire, introduction of non-native agronomic grass species, and suppression of fires set by Indigenous people. Since less than 3% of historic grasslands remain in North America, restoring a keystone species linked to grassland resiliency is a conservation priority. Restoring native grasslands (also called prairies) is a powerful climate-change adaptation strategy, because native grasslands sequester more carbon more rapidly than non-native, agricultural grasslands. Extensive paleoecological evidence of bison use of North American prairies and Indigenous burning exists. Bison, primarily grass-eating species, increase prairie ecological resiliency and biodiversity. Bison are a keystone species and an ecosystem engineer because their grazing patterns, which include several hundred-mile seasonal migrations, intensively alter the biophysical environment. Bison fertilize the soil with their urine and horn-up saplings and shrubs, keeping prairies open. Bison presence improves soil resources, changes plant and animal composition, and increases biodiversity and energy cycling, thereby creating communities more resilient to climate change. However, to be ecologically effective, bison must be wild and free-ranging. Captive bison have similar impacts as domestic cattle, producing over-grazed, ecologically degraded pasture conditions, damaging even large ranges. Fire improves native grass communities’ vigor, including their resiliency to climate change. While Indigenous people long have seen the bison as central to their world, Euro-American scientists and managers only recently acknowledged this species’ full importance. Subsequent management and legislative actions, including bison reintroductions and prescribed burning, may facilitate prairie restoration.

Resource Type:
Audio/Video, Conference Presentation, SER2019

Pre-approved for CECs under SER's CERP program

Source:
Society for Ecological Restoration