Nutrient Capital Sequestration in Pioneer Plant Communities on Surface-Mine Spoil

Biomass production and nutrient capital sequestration of four pioneer plant communities on a surface-mine spoil were compared. A Chenopodium album-dominated community (Treatment 4) produced the greatest amount of biomass. Next were a community derived from a forest topsoil seed bank spread over mine spoil (Treatment 2), a seed bank community with common reclamation species seeded into it (Treat­ ment 3 ) , and a mix of grasses and Lespedeza commonly used in reclama­tion (Treatment 1). Treatments 1, 2, and 3 sequestered N in aboveground biomass in an amount approximately equal to that added as fertilizer, but Treat­ment 4 sequestered 237 percent of the amount of N added. Phosphorus in all aboveground vegetation was 14 to 27 percent of the amount added as fertilizer. Amounts of nutrients sequestered in vegetation were not strictly proportional to biomass. Community nutrient con­tents were largely influenced by community biomass and the nutrient uptake characteristics of the species with most biomass. Significant changes in soil chemistry were found after one growing season. Available K, Fe, Cu and K base saturation were greater in topsoils of all treatments. Topsoil pH, buffer pH and available Mn, were greater in Treatments 1, 2, and 4, while Mg and Mg base saturation increased in Treatments 2, 3, and 4. Topsoil H saturation declined. Vegetation significantly affected changes in topsoil available K, K and Mg base saturation, and buffer pH. The top ten cm of spoil showed a significant decrease in available K during the five-month period of the study which was modified by vegetation treatment. The forest soil seed bank produced 84 taxa, of which 65 were identifiable to species. These included five tree species, seven shrubs or woody vines, 14 grasses, and 59 forbs. Addition of the reclamation mix of grasses and Lespedeza to the seed bank resulted in significantly fewer established native species. Native species lost their normal dominance and exhibited stunted growth and phenological delay in Treatment 3. Concentrations of N, P, K, Ca, Mg, Mn, Fe, Cu and Zn varied significantly between species. Community membership and underlying spoil influenced concentrations of some elements within species. Nutrient content niche, nutrient content niche share, and niche breadth (Levins\u27 B) were calculated for important species in each community. Native species generally had reduced niche breadths and niche shares when reclamation species were added to the community. Niche share of the reclamation species generally decreased when they were added to the seed bank community, but their niche breadths generally increased. Community content niche, the sums of species content niches, varied between different types of pioneer communities