Determining Range Condition from Frequency Data in Mountain Meadows of Central Idaho

Abstract

Although a useful method for monitoring changes in species composition, frequency sampling does not provide herbage production or cover data needed to use existing range condition guides. Responding to this need, frequency sampling procedures were investigated for determining range condition. Eighteen mountain meadow sites were sampled with 100 nested frequency quadrats. These quadrats had 5 plot sizes contained (nested) within 1 frame: 5×5 cm, 10×10 cm, 25×25 cm, 25×50 cm, and 50×50 cm. Rooted frequency of occurrence within each plot size was recorded by species. Discriminant analysis related a site's frequency data to its known range condition class, resulting in 2 range condition guides for mountain meadows based on frequency data. One guide was formulated with data from the 10×10-cm quadrat size, and a second guide was based on summed data from the 4 largest plot sizes. Both guides had equal resolution, correctly classifying 15 of 18, or 83%, of sites examined. Our procedures should prove valuable in developing condition guides based on frequency data in other areas and in other vegetation types.