Invasive warm-season grasses reduce mycorrhizal root colonization and biomass production of native prairie grasses
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Soil organisms play important roles in regulating ecosystem-level processes and the association of arbuscular mycorrhizal (AM) fungi with a plant species can be a central force shaping plant species’ ecology. Understanding how mycorrhizal associations are affected by plant invasions may be a critical aspect of the conservation and restoration of native ecosystems. We examined the competitive ability of old world bluestem, a non-native grass (Caucasian bluestem [Bothriochloa bladhii]), and the influence of B. bladhii competition on AM root colonization of native warm-season prairie grasses (Andropogon gerardii or Schizachyrium scoparium), using a substitutive design greenhouse competition experiment. Competition by the non-native resulted in significantly reduced biomass production and AM colonization of the native grasses. To assess plant–soil feedbacks of B. bladhii and Bothriochloa ischaemum, we conducted a second greenhouse study which examined soil alterations indirectly by assessing biomass production and AM colonization of native warm-season grasses planted into soil collected beneath Bothriochloa spp. This study was conducted using soil from four replicate prairie sites throughout Kansas and Oklahoma, USA. Our results indicate that a major mechanism in plant growth suppression following invasion by Bothriochloa spp. is the alteration in soil microbial communities. Plant growth was tightly correlated with AM root colonization demonstrating that mycorrhizae play an important role in the invasion of these systems by Bothriochloa spp. and indicating that the restoration of native AM fungal communities may be a fundamental consideration for the successful establishment of native grasses into invaded sites.
KeywordsArbuscular mycorrhizas Big bluestem Bothriochloa bladhii Bothriochloa ischaemum Little bluestem Old world bluestems Plant–soil feedback Tallgrass prairie Warm-season grasses
This research was funded by the Oklahoma Agricultural Experiment Station, the National Science Foundation Long-Term Ecological Research Program (Konza Prairie Grant IBN-9632851), and the Oklahoma State University Department of Natural Resource Ecology and Management. We thank the Konza Prairie Biological Station, Fort Hays State University Department of Agriculture and Department of Biological Sciences, and the Oklahoma State University Field and Research Service Unit for permitting us to collect soil at their research sites.
- Harper JL (1977) Population biology of plants. Academic Press, San DiegoGoogle Scholar
- Kiers ET, Denison RF (2008) Sanctions, cooperation, and the stability of plantrhizosphere mutualisms. Ann Rev Ecol Evol Syst 39:215–236Google Scholar
- Reynolds HL, Packer A, Bever JD, Clay K (2003) Grassroots ecology: plant-microbesoil interactions as drivers of plant community structure and dynamics. Ecology 84:2281–2291Google Scholar
- Smith MR, Charvat I, Jacobson RL (1998) Arbuscular mycorrhizae promote establishment of prairie species in a tallgrass prairie restoration. Can J Bot 76:1947–1954Google Scholar
- USDA NRCS (U.S. Department of Agriculture, Natural Resource Conservation Service) (2004) The PLANTS database: national plant data center, Baton Rouge, Louisiana, USAGoogle Scholar
- Vitousek PM, D’Antonio CM, Loope LL, Rejmanek M, Westbrooks R (1997) Introduced species: a significant component of human-caused global change. New Zeal J Ecol 21:1–16Google Scholar
- Vogelsang KM, Bever JD, Griswold M, Schultz PA (2004) The use of mycorrhizal fungi in erosion control applications. Final report for Caltrans. California Department of Transportation Contract no. 65A0070. Sacramento, CaliforniaGoogle Scholar
- Wilson GWT, Rice CW, Rillig MC, Springer A, and Hartnett DC (2009) Soil aggregation and carbon sequestration are tightly correlated with the abundance of arbuscular mycorrhizal fungi: results from long-term field experiments. Ecol Lett 12:452–461Google Scholar