14 April 2010

Nebraska's Salt Basin ... Going, Going, Nearly Gone

July 1985. Nebraska's Salt Basin. Going, going, nearly gone. Nebraskaland, pages 20-24. This was one of the first modern articles about the saline wetlands of Lancaster County.

IN THE DARK, away from the flickering fires of the Indian encampment, yellowlegs, plovers and sandpipers spread across the mudflats, each bird probing its own bit of soil for food. Newly-arrived shorebirds spiraled down to the shallow waters, racing in knots along the shoreline. Each spring, tremendous flocks of ducks, geese descended on the salt basins to rest on their journey to breeding grounds. Herds of buffalo, pronghorn, elk and deer came to the salt licks along well-worn trails.

Native wildlife and Indian people had been drawn to the naturally occurring salt-water basins around present-day Lincoln for thousands of years before whiteman probed the Great Plains. Neither group knew why this particular place had shallow-water basins saturated with salt; salt concentrations that during dry periods caked the ground with a white crust. To the Indians who came to gather their years supply of salt, and to the waterbirds that paused during migration or lingered to nest, it mattered little how the basins came to be, only that they existed. The flowing springs and groundwater seeps that carried alkaline water to the surface along Salt Creek, the extensive mud flats, and clumps of saline-tolerant marsh plants would all be explained in time.

During the final decades of the 19th century, settlers gathered at the basins to harvest the salt and the city of Lincoln grew, yet the shorebirds and waterbirds continued to gather on the marshes and mudflats during migration. Bare ground or marsh surrounded the openwater basins. Although in places only inches deep, the largest basin reportedly covered nearly two square miles during a wet spring.

During the 1890's, the salt basins drew birders to see "the great numbers of gulls, terns, ducks, geese, wading birds, and waterbirds of all kinds." The local bird club compiled a list of more than 80 species on one occasion. Rare sightings included the trumpeter swan, mergansers, caspian terns and "oddly colored plovers."

The Lincoln Gun Club owned hunting rights to the largest basin, northwest of Lincoln called "Salt Lake." According to ornithologists of the period, their management of the area reduced the disturbance to the flocks of birds gathered there.

"Otherwise, there would have been a continuous fusilade," wrote Erwin Barbour, a University of Nebraska geologist and paleontologist. "The few lakes and marshy area enticed large numbers of waterbirds that could be subjected to indiscriminate shooting." Even so, in the fall of 1899, two men killed "157 ducks of various kinds during six afternoons."

At the turn of the century, development began to have an impact on the salt basins. A dam and connection to Oak Creek were built to enlarge Salt Lake (then better know as Burlington Beach) and stabilize its water level. The area was then developed as a pleasure resort that offered boat rides, a salt-water bathing pool, and carnival rides. And yet, the area continued to attract waterbirds.

An entomologist during the first decade of this century noted that: "Innumerable insects and their larvae by the trillions, have made the salt basin a favored stop-over-point" for migrating birds to feed and rest. In 1904, members of the recently organized Nebraska Ornithologists' Union made a visit to Salt Lake during a spring field trip. Their checklist for the day included 75 different species of birds and noted that the basin's water was: "rich in the minute life which served as food [for] innumerable shorebirds." The "number of species to be observed during a favorable spring or autumn day [was] remarkable for so limited an area."

During the summer, the vegetation of the saline marshes was home for a number of breeding birds. Frank Shoemaker, an amateur naturalist who often visited the salt basins, wrote that songbirds nested in abundance in 25 acres of willows, wild plums, and other trees and shrubs on the east end of the lake nearest town. He described the orchard oriole nests as:

"beautiful structures woven of living grasses, and having the fragrance of new-mown hay."

The anomalous salt basins also were of interest to other naturalists. During the 1920's, Claude Shirk, a university doctoral student, conducted an extensive study of a several-mile-square saline area south of Salt Lake. He found that the concentration of salt in the soil had a direct effect on the survival and growth of the vegetation. Subtle variations in land topography, drainage patterns, or the amount of salt in the soil influenced the plant composition of a particular site. The plant communities responded to the changing degree of salinity in the soil due to moisture from the saline springs and groundwater and fresh water from precipitation.

The research of Dr. Shirk also determined that the saline wetlands he studied were a result of groundwater seeping to the surface from a geologic outcrop below the soil surface. The Dakota Formation was formed millions of years ago when a vast inland sea covered the interior plains of the North American continent. At the bottom of this sea, river and stream sediments trapped saline water as these deposits became sandstone. Near Lincoln, saline soil conditions occur where the water trapped within this outcrop reaches the surface.

Interest in the salt marshes continued through the decades since the beginning of the century. Occasional, but regular, notes and articles on the birdlife have described sightings of rare plovers, sandpipers, and ibis at Capitol Beach (as the Salt Lake, later Burlington Beach, came to be known) and the wetlands north of the city of Lincoln. In August, 1927 the Bruner Bird Club of Lincoln counted over 2,500 individual birds of 14 different species on Capitol Beach. The concentrations of waterbirds also continued to attract hunters. Bird club notes mention that one man shot seven yellowlegs, seven stilt sandpipers, seven pectoral sandpipers, and two long-billed dowitchers in one day. Three days later, eared grebes and three golden plover were taken.

Today, the shallow water, marsh and mud flats that have not been drained or filled, or surrounded by developments of a growing city are only a small remnant of what was once present. But there is still a variety of waterfowl and waterbirds that continue use the limited habitat that is available although not in the numbers common in historic times. During migration, ducks and grebes forage in the open water; small peeps, yellowlegs, and plovers probe the mudflats and shorelines while emergent cattails and sedge still provide cover for rails and blackbirds. During the last 90 years, more than 230 species of birds have been reported from the saline wetlands near Lincoln, more than half of the species reported for the entire state. Rare migrants like the whooping crane and trumpeter swan are no longer seen but an impressive variety of unusual species including the black rail, black-necked stilt, and black-legged kittiwake have been sighted. Recently common moorhens and least bitterns have nested.

Not only birds have been of interest to visitors to the salt marshes. The vegetation that exists has been described by botanists that have identified nine distinct plant communities. As the water level and degree of salinity fluctuates there is a nearly continual movement in these plant communities as they seek the conditions suitable for growth. A number of salt-tolerant plants have been identified in the Lancaster County basins that do not occur elsewhere in the region- sea blite, saltwort and seaside heliotrope.

Today the salt basin wetlands are only a shadow of what they once were, and those that have not been drained or filled are encircled by developments. Yet the variety of waterbirds continue to use the remaining habitat, though not in the numbers common at the turn of the century or earlier. During migration, ducks and grebes forage in the open water; sandpipers, yellowlegs, and plovers probe the mudflats and shorelines; aquatic vegetation still provides cover for rails and blackbirds. During the last 90 years, more than 230 species of birds have been reported from the saline wetlands near Lincoln, more than half the total number reported for the entire state. Rare migrants like the whooping crane and trumpeter swan are no longer seen, but unusual species such as the black rail, black-necked stilt, and black-legged kittiwake have been sighted, and recently, common moorhens (common gallinules) and least bitterns have nested in the remnant salt marshes.

In recent years, botanists have identified nine distinct plant communities. As the water level and degree of salinity fluctuate, there is an ebb and flow of these plant communities as they seek conditions suitable for growth. A number of salt-tolerant species have been identified in the Lancaster County basins that do not occur elsewhere in the region - seablite, saltwort and seaside heliotrope. These plant names alone are an indication of the uniqueness of the salt basin environment.

Only a few relict alkaline plant communities remain around Lincoln. Railroad yards and industry have replaced much of the saline flats studied by botanists and ornithologists only a half century ago. The large "Salt Lake," has a housing development on three sides but the woods and marsh on the east shore is still a haven used by migratory and breeding birds. Oak Park and Lagoon Park, owned by the City of Lincoln, also shelter some native vegetation. Small saline marshes and mud flats along Little Salt Creek by landowners and waterfowl hunters have maintained othr marshy basins.

The large flocks of waterbirds that once gathered on the extensive open water and miles of saline wetlands are now represented by small flocks of waterfowl and smaller gatherings of shorebirds. As native bluestem prairie and meadows that once surrounded the basins have been converted to agricultural, industrial, or residential land, prairie birds have declined in number and variety.

The small tracts of saline wetlands continue to attract naturalists. From the native Indian tribes to modern man, the marshes have been a resource that provides the many needs of both man and wildlife. The salt basins that remain today are only enough to remind us of unique wetland habitat, the wildlife it once supported, and our own early history. Enough remains, though, to encourage us to preserve the remnants.

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