Long Term Changes in the Fish Fauna of the Platte River: A Comparative Study
Beth Goldowitz, Aquatic Ecologist, Platte River Whooping Crane Maintenance Trust, 2550 N. Diers Ave. Suite H, Grand Island, Nebraska 68803, (308) 384-4633 (4634), goldowitz@hamilton.net
In the midwest, the human activities that have the greatest and most widespread impact on rivers often are related to agriculture. Impoundments and diversions of water have resulted in precipitous reductions in fish species diversity in some midwestern rivers. In the Platte River system, hydrologic alteration caused by the operations of Kingsley Dam and associated facilities has had a profound impact on the morphology of the river, causing extensive encroachment of woody vegetation and shrinking of the channel. R.E. Johnson's study (1939-1941) of the fishes in Nebraska, conducted before the dam was completed, offers a rare opportunity for a comparison of long term changes in the fishes of the Platte system. At five sites between Kingsley Dam and Grand Island that were sampled by Johnson in 1939-40, I repeated fish collections in 1992-95. I compared these recent collections with Johnson's descriptions of habitat and fish species composition. Species richness decreased at three sites, increased at one site, and remained the same at one site. However, species composition changed at all sites; only 64% of the species collected by Johnson were also collected by me. The largest differences occurred at the sites with the greatest amount of hydrologic alteration.
Population Structure, Distribution, Habitat Use, and Food Habits of Shovelnose
Sturgeon in the Lower Platte River, Nebraska
Robin L. Hofpar and Edward J. Peters, Department of Forestry, Fisheries and Wildlife, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0814, (402) 472-0825
Shovelnose sturgeon (Scaphirhynchus platorynchus) have been documented in Nebraska from the Missouri and Platte rivers and lower reaches of the Niobrara, Loup, Elkhorn, and Nemaha rivers. To study their populations in the lower Platte River, we established six sampling sites between the confluence of the Platte and Missouri rivers and the mouth of the Loup River at Columbus, Nebraska, approximately 160 km upstream. Fish populations are sampled at each site using drifted gill nets, beach seines, and drift nets. All sturgeon captured receive a PIT tag, stomach contents are sampled using pulsed gastric lavage, and pectoral fin rays are removed for age and growth determination. Radio transmitters are implanted into selected fish to study movement patterns and habitat use. Depth, mean column velocity, bottom velocity, substrate, cover, dissolved oxygen, water temperature, and turbidity are measured to describe each habitat sampled. At locations where shovelnose sturgeon were collected, depths have ranged from 15-212 cm, mean column velocities from 9-75 cm/sec, bottom velocities from 3-75 cm/sec, water temperatures from 5.9 to 30.9 C, and turbidities from 15 to >500 NTU. Comparisons of the numbers of sturgeon captured per hectare of river sampled at each site by month indicates that they are migrating upstream in the spring and downstream in the fall. Radio telemetry during June and July has shown that they tend to stay within a two to four km reach of river. Chironomids are the major food item in their diet throughout the year.
Notes on the range and population size of the American burying beetle (Nicrophorus
americanus) in the dissected hills south of the Platte River in Central Nebraska
Mark M. Peyton, Central Nebraska Public Power and Irrigation District, P.O. Box 188, Gotthenburg, NE 69138, (308) 537-3582 (3582), mpeyton@nrcdec.nrc.state.ne.us
In 1994 Central Nebraska Public Power and Irrigation District (Central) conducted a preliminary survey for the American burying beetle (Nicrophorus americanus) at 11 locations between North Platte, Nebraska and Lexington, Nebraska. These locations were along the Platte River and the Central Supply Canal.
After trapping and releasing 36 beetles at sites along the supply canal, Central developed a study plan to determine the range and population size of American burying beetles in the dissected hills which border the supply canal.
In 1995, 384 trap nights at 25 different locations resulted in the collection of 201 specimens of American burying beetles. These collections, along with work being done through the University State Museum, identified the 3,264 square mile area of dissected hills south of the Platte River between Lexington and North Platte, Nebraska, as the range for this population of beetles.
In 1996, 187 trap nights at three locations resulted in the collection of 241 individual American burying beetles. From these collections an estimated population of approximately 2,000 beetles is derived.
Prior to the collection of 481 individual American burying beetles by Central, a total of 18 specimens of American burying beetles had been collected in Nebraska. With the discovery of the population present in the dissected hills south of the Platte, and with collections in the Sandhills and along the Nebraska - South Dakota border, it is now evident that Nebraska has, if not the largest, one of the largest remaining populations of this species in the world. Our data would indicate this population far exceeds the minimum of 500 individuals as outlined in the U.S. Fish and Wildlife Service's recovery plan for this species.
A Comprehensive Study of the Middle Loup River Basin
Patrick C. Larsen, L. Cody Cohn, and Darla E. Eisenhauer, University of Nebraska at Kearney, Biology Department, Kearney, NE 68847, (308) 865-8549 (8157), plars@KDSI.net
Of all of the major rivers in Nebraska, one of the least studied is the Loup River. The Loup River is an important part of the Platte River Ecosystem. It is one of the Platte River's principal tributaries. It originates in the Sandhills and flows southeastward across central Nebraska. The Loup Basin contributes about 60% of the Platte's flow at North Bend Gage.
We are currently involved in a two year study to locate and evaluate high quality sites in the Loup flood plain and also to locate rare plants and animals. Thirty-three sites along the Middle Loup river from Dunning, NE southeast to Columbus, NE were sampled. These areas consisted of wet meadows and riparian forests. Both one by one meter and ten by ten meter quadrants were sampled for percent plant species composition. Seven rare plant species were found. Despite the project being incomplete, much has been learned about the impressive state of the basin. The project is a multi-factor investigation including invertebrates to small mammals and mycorrhizae. A hypothesis to be tested is; does the ground water level and invertebrate communities affect plant diversity.
Return to 1997 Platte River Basin Ecosystem Symposium
Last updated by Darren A. Jack on 4/30/97