Story of the Plains

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Story of the Plains

North America’s Great Plains cover an area that extends from the panhandle of Texas north to Saskatchewan and from the shortgrass prairies of the Rocky Mountain foothills east to the tallgrass prairies of Illinois. This region is largely characterized by grasslands or prairies, with the exception of the riparian forests associated with streams and rivers, and tree clusters that dot savannahs and shrubland steppes. Denizens of the Great Plains include large grazing mammals and associated predators, as well as burrowing mammals, numerous bird species, and a diversity of insects. As many as 300 different plant species can grow on less than 3 acres of North American tallgrass prairie, which also supports more than 3 million individual insects per acre.

These vast grasslands once dominated the center of North America and supported the massive migration of bison that populated these prairies. Other mammals, such as wolves, grizzly bears, and even a subspecies of the Rocky Mountain Bighorn Sheep also foraged and grazed across these rich grasslands. Today, these large tracts of prairie have since been partitioned into agricultural land tracts. By the twentieth century, massive dam projects not only repressed the free-flowing Missouri River, but provided extensive mechanical irrigation, and as a result, millions of acres of grasslands were rapidly transformed to croplands.

Agricultural practices such as plowing, grazing, excessive burning, fire suppression, loss and degradation of riparian habitats and water sources of grasslands, savannahs, and shrublands drastically alter species compositions and the restoration potential of natural communities. As a result, these areas now suffer from significant landscape changes, such as erosion and soil degradation and the loss of keystone species.

Many vagile species of the Great Plains require large natural landscapes of contiguous grasslands to track seasonal or patchy resources. These expansive natural areas are needed to maintain natural fire regimes that sustain community structure and composition. The presence of water and riparian vegetation is also important for many species.

Most of the remaining grasslands in the Great Plains today tend to occur as small, scattered pockets, serving as mere remnants of the vast expanses of prairie that once existed. Many species, especially birds, are just as vulnerable to fragmentation effects as they are to overall habitat loss. Fragmentation reduces the size of habitat patches, increases exposure to negative edge effects, and isolates habitat patches from one another. These influences affect the occurrence or density of birds using a habitat patch, reproductive success, predation rates, and competition with other species.

Today, the grassland prairies of the Great Plains are one of the most degraded and imperiled ecosystems on the continent. In response, land trusts have been created to hold easements, non-profit conservation organizations have increased land acquisitions, wildlife species are being surveyed and/or monitored regularly, Conservation Reserve Programs (CRP) have been initiated, and management practices have shifted to sustain grassland composition and structure. While these initiatives and other innovative approaches have not been able to reverse the habitat degradation suffered by the Great Plains, they are a step in the right direction.