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., S Mr. Robert Liddle May 11, 1982 '~. Page Two N ., However, we feel that measuring the number, or frequency of occur- . rence, of species per "minimal area" would provide data more objective i,;, and precise than measuring b,y cover. To begin with, a proposal by the +" Division has been made to set standards on the basis of cover; yet that basis is derived from the frequency data of Table 2.04.10(4). In addi- ' tion, we feel cover data by individual species is always weak in both precision and objectivity. Our samples on Valent Sand [Tables 2.05.4(1) and (3)] were derived from 320 placements of the one-square-foot quadrat (l6 per observation), and the samples on Osgood Sand were derived from 240 placements of the quadrat. Even with such intensive sampling, ~~' precision was reasonable for only 2 species in two of the samples, for 3 • species in one sample, and for 4 species in one sample. The problems ~(~ with cover are: (1) herbaceous cover is a moving target, (2) even at • peak standing crop, the cover of an individual species never exceeded ••~'`., 4,7%, and (3 cover estimates are not highly objective and accurate even -~ when estimated on a small quadrat. "~' We suggest the follo~+ring in replacement for the second and third ' sentences in the Division proposal: "To be measured using frequency of occurrence data with the follow- ,. ing minimum number of perennial herbaceous species per 'minimal' sampling area-- at least 2.4 r+ann-season grass seecies at least 1.3 cool-season grass species at least 0.2 forb species at least 4.3 total perennial herbaceous species" The numbers are obtained by applying to the 4.3 total species per area the percent determined for each type of vegetation as found in Table 2.04.10(4). That is, 55Y wann-season grass species, 30X cool- season grass species, and 15Y forb species. The number of forb species per sampling area has been adjusted to 0,2 from 0.6 to pennit a condition in whicfr some grasses could he sub- stituted for forbs, thereby remaining consistent with our approved goal of obtaining good range conditions. All perennial forbs found at the site, except for western ragweed, are, by average, very scarce. Because it isn't healthy or wise to deliberately replace western ragweed, we have included alfalfa, ricer milkvetch, and hractless stickleaf in the seeding plan. One could not expect such a large component of perennial weeds on good condition range and should therefore not expect to obtain as much as 0.6 good forbs per minimal area.