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Northern Tallgrass Prairie
(Area - 15,399,005 ha)
Location and physiography - This is the easternmost and
lushest region of the Great Plains at this latitude. It includes north-central Iowa, south-
central and western Minnesota, the Red River Valley of North Dakota, and extends into south-
central Manitoba. Tallgrass prairie grades into savannah on its eastern boundary. The transition
zone has doubtlessly shifted over time with changes in the patterns of fire, drought, and
herbivory that maintain the prairie. Similar forces affect the boundary with Aspen Parkland to
the northeast and north. Drier conditions result in shorter grasses as the tallgrass gives way to
the Mixed Grass Prairie at the western edge of the Red River Valley. The entire Northern
Tallgrass was subjected to recent glaciation, resulting in a dense distribution of wetland
depressions away from the geologically younger river valleys. The southernmost border of this
glaciation created the boundary between this physiographic area and the Dissected Till Plains.
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Conservation issues and recommendations - The Northern Tallgrass has been radically transformed since European settlement: what was formerly grassland is now largely an agricultural landscape. Woodland acreage has increased appreciably due to fire suppression, extirpation of bison, and human occupancy.
Maintenance of grassland/wetland complexes across the landscape is the most important factor necessary to maintain populations of birds in this suite. The Northern Tallgrass is the eastern portion of the Prairie Pothole Joint Venture, where a significant degree of wetland protection and restoration has occurred. Continuing these efforts will benefit priority non-game wetland- associated birds. Due to the fragmented nature of grassland bird habitat, grassland conservation objectives involve the provision of large blocks of habitat. Proposed Bird Conservation Areas consist of a 2000 acre core of high quality grassland embedded in a 10,000 acre buffer. This buffer includes an additional 2000 acreas of smaller patches of grassland. PIF suggests that such an area is sufficient to support, if managed properly, Prairie-Chickens and all other grassland birds. As many as 60 Bird Conservation Areas could be targeted within this physiographic area. The BCA model currently is being tested in the Northern Tallgrass region.
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