Fire in a Prairie
Fire on the Southern Ontario Landscape
At a landscape level, fire is an important mechanism in the maintenance of wildlife diversity by creating younger, early successional habitats that contain a range of preferred and nutritious plant foods. Fire is important in the development and maintenance of grasslands, forests, and wetlands throughout history. Tall grass prairies and open brushlands have been kept free of trees by the occasional wildfires. These fires were caused by lightning, or set intentionally by humans.
While fires occurred historically in southern Ontario, they were less common than areas further north on the Precambrian Shield. However, certain physiographic regions in the south experienced higher than normal levels of fire, particularly on the flat to gently rolling sand plains, where the pre-European settlement vegetation consisted of open prairies, savannahs, and oak and oak-pine woodlands. The distribution and extent of this fire-adapted and maintained vegetation has a strong correlation to sandplains (Bakowsky, unpublished). Additionally, fires historically maintained the drier oak-maple-hickory forests which occurred on sands and coarse loams (Van Sleeuwen, 2006).
Fires also occurred in other forest types, albeit less frequently, including white pine-red pine, successional poplar-white birch, white birch-poplar-conifer, deciduous oak, and white pine-maple-oak mixed woods, again on sands and coarse loams (Van Sleeuwen, 2006).
With conversion of natural vegetation to agriculture and settlements, natural landscape level disturbance by fire ceased, and fire-adapted vegetation, including prairies, savannahs and woodlands, quickly succeeded into forest. However, in specialized sites, with severe drainage and/or southern exposure, or which continue to experience fire on a periodic basis, this vegetation still persists, with good examples remaining at Walpole Island, Windsor, and the Pinery-Port Franks area (Bakowsky, 1988).
In an effort to protect property values and human health and safety, active fire suppression activities have largely removed fire from the southern Ontario landscape.
In the absence of wildfire, ecosystems change over time, often becoming less productive and hosting a diminishing variety of flora and fauna. Without fire, many of the tallgrass prairies and savannahs that were not converted to other uses eventually changed to shrub thicket and dense forests of oak, ash, maple and elm. Fire is needed to restore and maintain most of these rare communities.
In order to achieve the positive ecological effects of fire, prescribed fire or prescribed burns are used today by resource managers to renew and sustain ecosystems and maintain habitat on a local scale. Prescribed burns are identified as a management tool in recovery strategies for several species at risk. Prescribed fire is the application of fire to a specific land area to accomplish pre-determined objectives. This could include managing a fire that was started by lightning to accomplish specific, ecosystem-based, management objectives.
For more information download Tallgrass Paper 2003 – Dr. Brent Tegler
Norfolk County changes open-air burning bylaw to accommodate prairie management. Prairie managers can now burn their own prairie under certain conditions.