The Initial Effects of Community Variables on Sand Prairie Restoration: Species Establishment and Community Responses

We established a sand prairie restoration experiment in northern Lower Michigan’s pine-oak barrens to analyze the effect of different community variables (vegetative cover, species richness, biomass, diversity, and floristic quality) when comparing: (1) how our restoration efforts (seeded treatments) compare to natural community succession (control plots), (2) how different seeding treatments affect these community variables, specifically when evaluating (2a) the effect of grass seeding densities; and (2b) the effect of different forb guilds (early flowering, late flowering, and legumes) during the initial two growing seasons of restoration establishment. In general, a comparison between seeded treatments and non-seeded control treatments indicates that our efforts may be more successful in the restoration of native sand prairie than would have resulted from succession alone. Restoration attempts displayed a significant decrease in invasive, resident species richness and increased diversity compared to succession. Treatments that included a high concentration of grass and/or an early season forb component had the greatest overall impact on plant community development. These treatments exhibited significantly higher plant biomass, diversity, and floristic quality than most other treatments. Conversely, these seeded treatments displayed less nonnative or invasive cover than other treatments. The benefit of high concentrations of grasses and early season forbs may play a critical role in initial species establishment of a sand prairie restoration due to the facilitative and competitive advantages they may provide in these harsh environments. However, it remains to be seen if these initially successful communities will have continued success over long periods of time