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Savannas are best described as transitional zones between tall grasslands and heavy forests. As such, they contain a mixture of grasses,
herbs, and shrubs along with an intermittent canopy of mostly oak trees. This two-tiered ecosystem sounds like a pleasant place to build a house, doesn’t it?
And that’s exactly what the early Euro-American settlers thought, not only because the savannas reminded them of their homeland, but also because it was simply easier
to the clear the land and site a dwelling on a savanna than it was on a tallgrass prairie or a hardwood forest.
Photo by Molly McGovern
Thus it was the savanna’s “settler friendly” characteristics that made it the first type of landscape to be disturbed (and nearly eliminated) within Iowa.
Its usefulness led to its disappearance.
A second, related, pressure on disappearing savanna was the human suppression of natural fire. Oak, which was the dominant
tree on a savanna, is a hardy species with a high tolerance to fire due it a deep root system and tough bark. Native prairie plants also rely on deep root systems
and fire-tolerant seeds to survive the flames. Periodic fires, even regular fires, deliberately set by Native Americans, were important to the sustainability of
savannas because it eliminated competing, non-native trees and plants, making more resources (water, sunlight, nutrients) available for the surviving flora, and clearing a
space for new growth. By assuming that all naturally occurring or purposefully set fires are “bad,” we inadvertently arrest nature’s powerful cycle of renewal, and we
discourage the very ecology that created the natural wealth of our Iowa heritage.
More information about savannas:
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