Pyric-herbivory: Re-wilding through the re-coupling of the fire-grazing interaction

Recent suggestions of re-wilding North America through the introduction of charismatic African herbivores to replace extinct Pleistocene fauna have led to discussions of the roles of specific species in ecosystem management. In addition, previous discussions have focused on the role of native species, such as the American bison, as keystone herbivores that are critical to maintenance and conservation of the North American Great Plains. These competing conservation objectives are important options for the conservation of these herbivore species but provide minimal understanding of the grazing process or the importance of grazing to conserving grassland ecosystems. I suggest that ecosystem management of grasslands is more dependent on pyric-herbivory (herbivory promoted through fire) in complex landscapes than on the presence or absence of specific species of grazing animal. Our recent experiments demonstrate that the fire-grazing interaction is critical in maintaining heterogeneity of grassland ecosystems and that heterogeneity increases biodiversity and maintains system sustainability. I will present an overview of the logic and results of experimental evaluations of the fire-grazing interaction in maintaining heterogeneity and biodiversity. Response of native plant and animal species are used as an indicator of restoration of historical patterns in grassland ecosystems. A focus on introducing specific species may have important conservation implications to charismatic fauna, but will likely have minimal impact on the conservation of grassland landscapes unless interactive influences of fire, grazing and drought are considered.