Climate and Fire

Climate is the engine of evolution. Prairie and savanna habitats are by definition, dry environments that are dependant on periodic fire to maintain the conditions necessary for their continuance. Rapidly draining soils, left after the last glaciation and a warming climate, resulted in an extension of conditions suitable for the migration of prairie and savanna species into this part of Ontario. They migrated from the south and west approximately 5,000 years ago. The plants of this demanding environment have developed survival strategies to cope with exposure, fire and drought.

Prairies are defined as grass dominated landscapes with less than 10% tree cover. In this region of Ontario, surrounding forests would soon encroach upon these open spaces and reclaim them. Fire acts to retard this process and results in a patchy mosaic of habitat dominated by fire resistant tree and grass species as well as flowering prairie plants. Habitats with between 15% and 50% tree cover are called savannas. The forested lands have more complete overhead tree canopy coverage.