MONITORING STANDING HERBAGE OF THE SANDS AND CHOPPY SANDS ECOLOGICAL VEGETATION TYPES IN THE NEBRASKA SANDHILLS

摘要

A modified Robel pole with white and gray alternating bands (2.54 cm) was used to measure vegetation on sands and choppy sands ecological types in the Sandhills of Nebraska. Objectives were to determine the relationship between visual obstruction readings (VOR) and clipped standing herbage, develop guidelines for monitoring standing herbage, and provide sample size estimates. Visual obstruction measurements of standing herbage were linear, and regression coefficients were significant (P 0.001) for 125 transects (R2 = 0.60, SE = 496 kg/ha). Clipped standing herbage ranged from 293 to 4389 kg/ha with a mean of 1,559 kg/ha. A minimum of four transects (20 stations/transect with four readings/station) is required for monitoring key areas or small areas up to 259 ha in size. Cluster analyses (ISODATA) applied to VOR and standing herbage resulted in four resource categories: short, short intermediate, intermediate, and tall. Band 3 corresponded to approximately 40% utilization of herbage. The protocol and guidelines developed provide managers with a tool that is cost effective, accurate, and reliable for management and monitoring standing herbage.