Grasslands cover 35% of earth’s land surface, provide many essential ecosystem services, and play an important role in driving global biogeochemical cycles. One of the greatest current threats to these ecosystems is invasion by non-native species. While the underlying biological mechanisms facilitating non-native species invasion are still unknown, there is growing recognition that alterations in belowground processes may play fundamental roles in their success. Our study was conducted at Konza Prairie Biological Station, Manhattan, KS, USA. The objectives of our study are two fold; 1) assess above- and belowground consequences of invasion by a non-native warm-season grass, Bothriochloa bladhii, and 2) eradicate the invasive and assess restoration management practices. Replicate plots were established in invaded and adjacent non-invaded native grassland. Above- and belowground biomass, plant species composition, and soil biotic (relative abundance of soil microbial functional groups and intra-radical mycorrhizal hyphal abundance), and abiotic parameters (plant-available N/P, soil aggregate distribution) were assessed. Eradication of B.bladhii using solarization was initiated spring 2016. Tarps were removed at the end of the growing season with successful eradication of B.bladhii. We will continue to assess B.bladhii re-establishment, and implement soil microbial inoculations to assess successful restoration of grassland ecosystems this upcoming field season.
Results/Conclusions
Plant species richness of the non-invaded prairie averaged 14 species per m2; significantly greater than invaded sites (1 species per m2: B.bladhii). Invaded plots were fertilized annually for 30 years with N; P; N+P; or not fertilized (control). Soils of P-fertilized plots contained significantly greater levels of plant-available P (PO4), compared to N-amended or control plots, or adjacent prairie. Aboveground and total biomass production were greater in N-amended invaded plots, compared to all other treatments. However, allocation to root production was lowest in N-fertilized plots, resulting in significantly lower root/shoot ratio, compared to P-fertilized, control, or native plots. Our preliminary analyses of soil microbial community assessments indicate invasion by the non-native grass altered total microbial biomass and shifted relative abundance of several microbial functional groups. Following solarization throughout the growing season, eradication of B. bladhii was successful. This upcoming field season, we will establish restoration treatments to assess if inoculation with native AM fungi can improve the establishment of native plant species, suppress re-establishment of the invasive grass, and restore soil aggregation.