Woodland/Grassland Boundary Changes in the Middle Niobrara Valley of Nebraska Identified by δ13C Values of Soil Origanic Matter
Steuter AA, Jasch B, Ihnen J, Tieszen LL. 1990. Woodland/Grassland Boundary Changes in the Middle Niobrara Valley of Nebraska Identified by δ13C Values of Soil Origanic Matter. The American Midland Naturalist. 124(2):301-308
Recent studies document that woodland species are expanding out of the middle Niobrara River canyon and into the adjoining Sandhills Prairie. Stable carbon isotope ratios of soil and root samples from valley contours are used to contrast the past vs. present configuration of grassland and woodland boundaries. Carbon isotope ratios for samples obtained beneath the canopies of known-age ponderosa pine (Pinus ponderosa Laws.) trees are used to provide evidence of the time associated with community change. Carbon isotope differences between root and bulk soil samples indicate that in the past woodlands were more narrowly restricted to the lower slopes of the Niobrara canyon and its short tributary streams. Analysis of samples collected beneath aged ponderosa pines suggest that isolated patches of woodland vegetation existed within a grassland matrix on the upper canyon slopes prior to European settlement. These patches now occur within the expanded woodland matrix.
- Type
- Journal Article
- Authors
- Steuter, Allen; Jasch, Bruce; Ihnen, Joel; Tieszen, Larry
- Units
- NIOB
- Keywords
- Carbon (C), Forest, Grassland, Isotopes, Niobrara River NE, Niobrara Valley Preserve, Plant Communities, Plant Studies, Soil Chemistry, Vegetation Change