Plant community response to switchgrass (Panicum virgatum) population source in establishing prairies

Abstract

Ecological restoration and revegetation efforts entail the translocation of native plant populations. Risks associated with these efforts include failure of translocated populations to establish or, conversely, such strong establishment that they excessively dominate the recipient community. The role that selective breeding plays in mediating these risks is unclear but of increasing importance as efforts to restore and establish multifunctional grasslands also increase. In a three-year, spatially replicated study, we seeded experimental prairie communities with either domesticated (cultivar) or undomesticated strains of Panicum virgatum (switchgrass), a North American C species under development as a biomass crop. We evaluated the composition, performance, and diversity of the recipient plant communities and compared the performance of cultivar and undomesticated switchgrass in those communities. We found little evidence that switchgrass population source affected community response. Switchgrass cultivars modestly exceeded undomesticated strains with respect to stand establishment, third-year stand density, and aboveground biomass; effect size and significance differed among sites. Our results suggest that including cultivars in ecological restorations and multifunctional grasslands may enhance success of switchgrass establishment with little risk of impairing the composition or diversity of plant communities for up to three years, as reflected in the measures used here. However, the incorporation of undomesticated switchgrass into multifunctional grasslands may enhance landscape-scale genetic variation and mitigate risks associated with gene flow between translocated and local wild switchgrass populations; more research on these dynamics is needed.

Effects of Selection Regime on Invasive Characteristics in an Emerging Biomass Crop, Switchgrass (Panicum virgatum L.)

“…This conclusion aligns with reports of similar values in both upland cultivars and wild switchgrass populations for at least some invasiveness-related traits during the first one or two growing seasons [33,34]. Additionally, we ran a concurrent experiment at the same evaluation sites with the same switchgrass strains and found no evidence of differential effects of cultivars versus commercial ecotypes on species diversity or yield in developing prairie communities [76]. It bears noting, however, that switchgrass stands generally require three years or longer to mature fully and that characteristics such as rooting depth and tiller number increase with age [24,77]; therefore, invasivenessrelated traits in mature switchgrass stands may differ from those in younger ones.…”

Population source affects competitive response and effect in a C4 grass (Panicum virgatum)

“…Efforts to establish multifunctional grasslands-polycultures of perennials in which some species function as biomass crops and others provide different ecosystem services (Vink et al 2017)-could be informed by examination of this potential biomass species in terms of its response to, and effect on, competitors. The prospect of expanded switchgrass presence has motivated comparisons among population sources with respect to effects on community diversity and composition (Wilsey 2010;Flint et al 2018), molecular diversity (Mutegi et al 2014), and agronomic traits (Parrish & Fike 2005). However, we are aware of only two published studies relating population source to intraspecific competitive differences in switchgrass (Palik et al 2016;Eckberg et al 2018).…”