A FLORISTIC STUDY AND SPECIES CHECKLIST FOR THE REPUBLICAN RIVER VALLEY IN NEBRASKA, WITH EMPHASIS ON PLANTS OF CONCERN FOR CONSERVATION

摘要

A botanical survey of the Republican River Valley in Nebraska was initiated during the 1995 growing season and continued through 1998. A major objective of this study was to discover and tabulate rare plants (as designated by the Nebraska Natural Heritage Program), but a general floristic study was also completed. Natural areas, selected because of species composition or location, were identified and described. The study area is characterized by a high degree of human disturbance. Most county floras, with the exception of Webster, are poorly represented. Seven species of conservation concern are reported, which is 1.4% of the total collected flora of 499 species. Dominant vegetation types are riparian forest, tallgrass prairie, mixed-grass prairie, sandsage prairie, and wetlands. Most of the floodplain has been cultivated or grazed and is also subject to fluctuating ground water levels, resulting in a general decline in the diversity of native plant species. The loss of wet meadows throughout the valley has contributed to this lack of diversity.