Taxonomy and Ecology Of Inland Sand Dune ... - Mycorrhizae

44and pH (r 2 = 0.015); and moisturepercent had a positive correlation withan increase in pH (r 2 = 0.200).FIG. 12 Regressions of mycorrhizalinoculum potential (MIP) and percentcover, moisture percent, and pH for thecombined data from June, July, andAugust transects as measured bymycorrhizal formation in Zea maysbioassay plants.The undisturbed vegetation in areas inwhich transects were established wasdominated by sagebrush, and bitterbrushwith significant amounts of graminoidspecies. The vegetation in the June,July, and August transects wererepresented by 7, 11, and 8 species,respectively. TABLE 7 gives themycorrhizal inoculum potential (MIP),percent cover, and frequency for eachplant species in each transect. Thehighest MIP values were obtained fromAugust soil samples that supportedArtemisia tridentata (25.3), Purshiatridentata (29.0), and Oryzopsishymenoides (32.7).In the June transect, Artemisia tridentatahad the highest percent cover (35.7) andfrequency (68.4). In the July transect,Purshia tridentata had the highestpercent cover (28.6), and Agropyronsmithii var. molle had the highestfrequency (63.2). As in the Junetransect, Artemisia tridentata had thehighest percent cover (19.8) andfrequency (73.7) in quadrats along theAugust transect.Regression of MIP values and initialpercent cover and regression of MIPvalues and initial frequency of plantspecies in quadrates along the June, Julyand August transects are illustrated inFIG. 13 through FIG. 18. A positivecorrelation was found between MIPvalues and initial percent cover (R 2 =0.744) and species frequency (R 2 =0.624) along the June transect (FIG. 13and FIG. 14). There is also a positivecorrelation between MIP values andinitial percent cover (R 2 = 0.140) along