Between Grand Island and Kearney, The Nature Conservancy’s Platte River Prairies are a stretch of upland prairie grasslands and wetlands along the Platte River Valley in south-central Nebraska. Active management on the landscape promotes and sustains wildlife and plant diversity on a land that is a matrix of wetlands, river habitat, agricultural fields, and sandpit and gravel mining operations.
It is not without challenges. Agricultural fields can drain wetlands intimately linked with groundwater while mining operations leave scars on the land in the form of deep lakes and steep sandy slopes. These lingering effects often pose conservation challenges to keep wildlife and habitat healthy and functioning.
Restoration efforts are critical in this region. More than 80 percent of native grasslands and wetlands have been tilled, drained and converted to agricultural fields, keeping up with the increasing food and energy demands of a growing human population. The prairies and wet meadows that remain are vulnerable to invasive and non-native plants, shrubs, and trees.
This shift in the ecological makeup of the Platte River and associated habitats has dire implications for the health of native plant and wildlife communities that call this ecosystem home.
To these efforts, in the fall of 2011, the Nature Conservancy worked to restore an open sandpit lake on the Derr Tract of land south of the Platte River near Wood River, Neb., acquired by the organization in 2000. With the financial assistance from the U.S. Fish and Wildlife Service and Ducks Unlimited, the deep sandpit lake was re-graded and re-shaped to create multiple meandering stream channels while the area was seeded with a highly diverse mixture of grassland and wetland seeds.
“We wanted to create a more open habitat in our area, so we cleared out the trees and pushed the spoil piles into the remaining ponds, creating a mixture of meandering channel and shallow side channel and backwater wetlands,” Chris Helzer, The Nature Conservancy’s eastern Nebraska program director, said of the project. An initial phase was done in 2003 and was completed in the fall of 2011.
Following the completed landscape work in 2011, the Derr Tract has gone through two growing seasons. For the first few years, annual weeds are expected to remain the dominant plant species. But after several seasons of growth, the seeded native prairie grasses and forbs will begin to take over.
“Establishment of the plant community on [the] site has been slow, but consistent. We’re seeing a slow conversion of plant species on the sandy uplands from annual weeds to more of a sand prairie plant community,” Helzer said. The 2012 drought further exacerbated the slow recovery of the prairie plants, giving much of the Central Platte valley record low rainfalls.
Despite the 2012 drought, which left nearby Grand Island with a record low rainfall of 12” during the entire year, water remained on Derr site year round, making it a unique wetland habitat closely tied to groundwater. The main channel of the Platte River went dry and, according to Helzer, other wetlands went dry including those just upstream of the Derr Tract.
This consistent groundwater supply is one of the reasons The Nature Conservancy has prioritized this site. “It seems important to take advantage of that kind of consistent moisture and be sure to provide the best wetland habitat possible during very dry times,” Helzer said of the wetland habitat.
Wildlife has responded positively. Ducks, shorebirds, many other grassland bird species like spotted sandpiper and killdeer, spiny softshell turtles, painted turtle, leopard frogs, Woodhouse’s toads, freshwater mussels, and otters have all been recorded in the wetland. The Conservancy’s hope is that sandhill cranes and the endangered whooping crane will begin to use the unique habitat in peak migration periods.
PBT’s time-lapse imagery will assist in documenting and monitoring change on the site for years to come, helping to tell the story of restored wetlands.