Managing Species Diversity in Tallgrass Prairie: Assumptions and Implications

Conservation and restoration ecology efforts may conserve or restore a particular image of a community, a variety of plausible images, or maximum biological diversity. The choice is a policy decision that should reflect relevant history and sound science. Here I argue that common methods of conserving and restoring tallgrass prairie have a weak scientific rationale, are not consistent with plausible history, and threaten prairie biodiversity. Dormant‐season burns and grazer exclusion are human interventions that may promote artificially consistent dominance of large grasses utilizing the C 4 photosynthetic pathway, thereby relegating hundreds of other prairie plants to small populations that are vulnerable to local extinction. I recommend an experimental approach to large remnant conservation and restoration in which varied conditions alter dominance, thereby increasing short‐term species richness. I also recommend prescribed burning during the summer, to simulate the timing of lightning fire, and light‐to‐moderate grazing by different ungulates, to simulate historical grazing history. Both should favor plants that are consistently infrequent or rare in many managed prairies. Varied regimes of burn season, burn interval, and large‐mammal grazing should promote greater overall species diversity and should more realistically represent varied conditions under which grassland taxa evolved.