Document Type


Publication Date

Spring 5-1-1969


Three quadrats, one hundred meters to the side, were located at the plains-foothill border region southwest of Boulder, Colorado, near Bluebell Canyon. One quadrat was in a wooded area, another in a meadow, and the third in an ecotone, half-meadow, half-wooded area. Ants were intensively collected in these quadrats for three summers, from 1965 through 1967. The summer of 1968 was utilized for soil moisture and temperature determinations, as well as for actual counts of ant colonies. A total of 25 species and subspecies was discovered. Of these 25 species, nine were species found in two quadrats, which provide evidence of a distinct boundary between the lower edge of the foothill zone and the plains, since eight of these nine were found in the ponderosa pine forest and the ecotone, but did not penetrate the meadow. The other species was found in the meadow and ecotone, but did not penetrate the ponderosa pine forest. There were two additional species in the meadow and five in the forest which did not penetrate the ecotone. The Lincoln Index was utilized in this study to determine its efficacy in estimation of the size of selected ant colonies. It was found to be inaccurate, since use of this index results in great underestimation of ant colony size. Individual nest stability and nest number constancy were also examined. The majority of the 25 species and subspecies are quite unstable in their nesting habits, and nest number was somewhat inconstant. Total counts of ant nests were made, and these, plus the number of nests of the various species, made it possible to determine the ecological dominants in each quadrat for each year. It was also found that there were more species of ants in this study in the wooded quadrat, which had a slope facing north by northwest, than in the ecotone or in the meadow. Observations were also made with reference to compound nests, polydoraous nests, and species which have nuptial flights in late summer.