Restoration of metals-contaminated environments requires a functional microbial community for successful plant community establishment, soil development, and biogeochemical cycling . Our research measured microbial community structure and carbon-utilization diversity in treatment plots from a mine waste revegetation project near Butte, Montana. Treatments included two controls (raw tailings) either (1) with or (2) without tilling, (3) shallow-tilled lime addition, (4) deep-tilled lime addition, (5) lime slurry injection, (6) topsoil addition, and (7) an undisturbed area near the tailings. Microbial community structural differences were assayed by plate counts of heterotrophic bacteria, actinomycetes, fungi, and bacterial endospores, and quantification of arbuscular mycorrhizae colonization. Metabolic diversity differences were assessed by carbon-utilization profiles generated with Biolog microtiter plates. Heterotrophic bacteria counts were significantly higher in the limed and topsoil treatment plots than the control plots, and the actinomycete and fungal counts increased in the tilled control plot as well. Endospore counts were significantly higher in the topsoil addition and the undisturbed plots than the other treatment plots. Carbon-utilization activity was very low in untreated plots, intermediate in lime-treated plots, and very high in topsoil and undisturbed plots. Arbuscular mycorrhizae (AM) colonization levels of two grass species showed low levels of colonization on control, shallow-limed, and lime slurry-injected plots, and high levels on the deep-limed and topsoil-addition plots. Plant and soil system components increased across the treatment plots, but individual components responded differently to changing environmental conditions.

The effects of intensive recreation impacts and restoration amendments on soil parameters were assessed at four campsites in the Eagle Cap Wilderness, northeastern Oregon. Sites (2,215‐ to 2,300‐m elevation) are characterized by shallow granitic soils, an Abies lasiocarpa/Pinus albicaulis overstory, and a Vaccinium scoparium understory. In fall 1995, plots were established at four campsites on three subalpine lakes in which soils were scarified, compost amended, and planted to native species. In summer 1998, we sampled surface soils (0–15 cm) on undisturbed sites (between and under vegetation) and unamended and compost‐amended campsite soils. Samples were analyzed for total organic C, total N, potentially mineralizable N (PMN), NH4, soil moisture, microbial biomass, basal 5‐day respiration rates, and microbial community carbon utilization profiles. Unamended campsite soils had significantly lower levels of PMN, microbial biomass, basal respiration, and number of substrates metabolized in carbon utilization profiles. Compost addition elevated all these impacted parameters on campsite soils, although the increase in basal respiration rate was neither statistically significant nor sufficient to approach rates found underneath vegetation on undisturbed soils. Only the number of substrates metabolized in the carbon utilization profiles was significantly higher on compost‐amended soils than on undisturbed soils. Levels of PMN indicate that campsite soils may lack sufficient N for rapid plant regeneration, whereas amended and undisturbed soils contained adequate quantities of available N. This work suggests that compost amendments can ameliorate impacts to soil chemistry and microbial populations caused by camping, without exceeding the N fertility found on undisturbed soils.