Audubon's $16,000-per-mile fight to keep

The National Audubon Society and its partners have spent millions of dollars over five decades to keep Nebraska's Platte River habitable for migrating cranes. Their work combats changes to the river's flow and landscape caused by human settlement, which began altering the crucial stopover site in the 1970s.

For thousands of years, the wide, braided, and mostly treeless channels of the Platte River provided ideal habitat. European settlers changed that by retiming water flows and removing natural forces. This loss motivated the initial conservation advocacy. Today, non-governmental organizations like Audubon, The Nature Conservancy, and The Crane Trust work with state and federal agencies. Their focus is a 'critical reach' of the river between Lexington and Chapman, Nebraska.

For the last two decades, this effort has been formalized through the Platte River Recovery Implementation Program. It includes power and irrigation districts and the states of Colorado, Wyoming, and Nebraska. Their collective goal is to hold human-caused changes at bay and maintain the river closer to its historic state.

Maintaining the River Channel

Keeping the river suitable is a difficult and expensive task. Historically, scouring spring floods cleared vegetation from sandbars. With those floods now controlled, vegetation must be removed manually. Conservation groups use heavy equipment to disk sandbars, at a cost of up to $16,000 per mile.

An alternative is to use vegetation-suppressing river flows. The U.S. Fish and Wildlife Service can release allocated water from upstream reservoirs to replace missing natural flows. This supplemental water is limited. Often, there is only enough for one or two months of flows at 1,500 cubic feet per second. This is far short of the historic spring flows that could exceed 35,000 cfs.

Invasive species like Phragmites threaten to undo this costly work. The Platte Valley Weed Management Area, a cooperative weed control organization, spends nearly $600,000 annually to control this plant alone. It spreads rapidly and can choke out river channels.

Managing the Surrounding Lands

Beyond the river channel, land management is critical. At the Rowe Sanctuary, managers maintain the property as open, treeless grasslands. They focus on a diversity of vegetation heights and floral diversity to support wildlife and provide food for cranes.

These practices simulate historic disturbance events like grazing and fire to influence prairie plant communities. Trees encroaching on prairies and along the river are removed. This maintains the wide, unobstructed views favored by endangered Whooping Cranes when selecting roost sites.

Each year, the sanctuary aims to have about one-third of its land in open short grasses. This structure is preferred by cranes searching for roots, tubers, and insects. This food offers better nutrition than the waste corn the birds often feed on. The diligent year-round work of controlling invasives, conducting prescribed burns, coordinating grazing, and removing trees is rewarded with thousands of cranes feeding on the sanctuary's grasslands.

Sufficient water in the river remains the best way to keep the Platte healthy. Audubon advocates to keep natural flows in the river and to prevent further development and diversions. The sight of thousands of cranes each spring relies on this ongoing, intensive conservation effort.