PARENT SESSION
Poster Session #75: Nutrient Cycling II.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Nitrogen enrichment in ant mounds varies across a prairie restoration chronosequence.

Lane, Diana^*,1, BassiriRad, Hormoz¹, ¹ University of Illinois-Chicago, Chicago, IL

ABSTRACT- We compared soil properties on ant mounds (built by Formica subsericea) and on adjacent bulk soil from three prairie restoration sites of different ages at FermiLab outside of Chicago, IL. In particular, we were interested in assessing whether physical and chemical properties of ant mound soil varied as a function of restoration age. We also measured the relative basal area of ant mounds at five restoration sites (1, 4, 8, 16 and 26 years old), an old field site, and a nearby prairie remnant. The total basal area of ant mounds increased significantly (from 0.25% to 1% of ground area) with increasing restoration age (r²=0.97, F_1,3=91.1, p=0.002). At the native prairie, however, ant mounds covered only 0.02% of ground area. Bulk density was significantly lower on- versus off-mound at all sites, despite no changes in the soil texture. Soil moisture was significantly higher on-versus off-mound at the 8-year old site only. Ant mounds had a significantly higher inorganic N concentration compared to the bulk soil at the youngest restoration site, but not at the older ones. Ant mounds also had higher total N and C and a greater concentration of dissolved organic N and amino acids compared to the bulk soil, but these differences disappeared with restoration age. The results suggest that compared to bulk soil ant mounds initially provide highly altered microsites for plant establishment, but those differences diminish with restoration age.

KEY WORDS: tallgrass prairie, restoration, ant-mound, soil