@article {KNZ001555, title = {Population origin and genome size do not impact Panicum virgatum (switchgrass) responses to variable precipitation}, journal = {Ecosphere}, volume = {4}, year = {2013}, pages = {37 -}, abstract = {

Population-level adaptation to broad-scale regional climates or within-population variation in genome size of the genetically and phenotypically diverse C4 grass, Panicum virgatum (switchgrass), may influence the responses of this species to future precipitation variability associated with climate change. Therefore, we investigated P. virgatum responses to water variability between natural populations collected across a latitudinal gradient and among individuals spanning a range of genomes sizes within these populations. P. virgatum plants from natural populations originating from Kansas, Oklahoma, and Texas, U.S.A, received frequent, small precipitation events (\“ambient\”) or infrequent, large precipitation events (\“altered\”) to simulate contrasting rainfall variability expected for this region. We measured leaf-level physiology, aboveground biomass and genome size for each individual. Gas exchange rates and aboveground biomass varied significantly by population origin but did not differ by genome size. Altered precipitation treatments reduced leaf-level physiological rates; however this result did not vary by population or genome size. Our results suggest that trait variation in P. virgatum is primarily attributed to population-level adaptation across a latitudinal gradient, not genome size, and that neither population-level adaptation nor genome size may be important predictors of P. virgatum responses to future climatic conditions.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES12-00339.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES12-00339.1}, author = {O{\textquoteright}Keefe, K. and Tomeo, N. and Jesse B. Nippert and Springer, C.J.} } @article {KNZ001500, title = {Ecotypic responses of switchgrass to altered precipitation}, journal = {Functional Plant Biology}, volume = {39}, year = {2012}, pages = {126 -136}, abstract = {

Anthropogenic climate change is projected to alter precipitation patterns, resulting in novel environments for plants. The responses of dominant plant species (e.g. Panicum virgatum L. (switchgrass)) to climate changes can drive broader ecosystem processes such as primary productivity. Using a rainfall mesocosm facility, three ecotypes of P. virgatum (collected from Kansas, Oklahoma and Texas, USA) were subjected to three precipitation regimes (average, \–25\%, +25\%) to determine the physiological and growth responses to altered precipitation in a common garden setting. Results showed mean maximum photosynthetic rates, stomatal conductance, transpiration, midday water potential and dark-adapted chlorophyll fluorescence were lowest in the Kansas ecotypes. Increased precipitation treatments raised the mean midday water potentials and lowered water-use efficiency. Aboveground biomass responded positively to changes in precipitation, but flowering initiation was later and rates were lower for Texas ecotypes. In general, ecotype origin was a better predictor of differences in physiological responses and flowering, whereas the precipitation treatments had greater control over biomass production. Depending on the growth variable measured, these results show responses for P. virgatum are under varying ecotypic or environmental control with few interactions, suggesting that future predictions to climate change need not inherently consider localised adaptations in this economically important and widely distributed species.

}, keywords = {LTER-KNZ}, doi = {10.1071/FP11229}, url = {http://www.publish.csiro.au/fp/FP11229}, author = {Hartman, J.C. and Jesse B. Nippert and Springer, C.J.} } @article {KNZ001503, title = {Potential ecological impacts of switchgrass (Panicum virgatum L.) biofuel cultivation in the Central Great Plains, USA}, journal = {Biomass and Bioenergy}, volume = {35}, year = {2011}, pages = {3415 -3421}, abstract = {

Switchgrass (Panicum virgatum L.) is a broadly adapted warm-season grass species native to most of the central and eastern United States. Switchgrass has been identified as a potential biofuel species because it is a native species that requires minimal management, and has a large potential to sequester carbon underground. Since the 1990\’s, switchgrass has been bred to produce cultivars with increased biomass and feedstock quality. This review addresses potential ecological consequences of widespread switchgrass cultivation for biofuel production in the central United States. Specifically, this review address the ecological implications of changing use of marginal and CRP land, impacts on wildlife, potentials for disease and invasions, and changes in soil quality through reductions in erosion, decomposition rates, and carbon sequestrations. A central theme of the review is the utility of maintaining landscape heterogeneity during switchgrass biofuel production. This includes implementing harvest rotations, no till farming, and mixed species composition. If negative ecological consequences of switchgrass cultivation are minimized, biofuel production using this species has economical and environmental benefits.

}, keywords = {LTER-KNZ, Carbon sequestration, Crop rotation, CRP land, Landscape heterogeneity, Marginal land, SOC}, doi = {10.1016/j.biombioe.2011.04.055}, url = {https://www.sciencedirect.com/science/article/pii/S0961953411002935?via\%3Dihub}, author = {Hartman, J.C. and Jesse B. Nippert and Orozco, R.A. and Springer, C.J.} }