Submitted to: Society for Range Management Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/25/2006
Publication Date: 2/12/2006
Citation: James, J.J., Mangold, J.M., Sheley, R.L., Svejcar, A.J. 2006. Nitrogen capture by native and invasive great basin species: The role of root plasticity [abstract]. Society for Range Management Meeting Proceedings. Paper No. 190.
Technical Abstract: Spatial and temporal variation in soil N availability is substantially in arid and semi-arid rangelands. Consequently, the ability of a species to rapidly increase N capture through morphological and physiological root adjustments determines, in part, survival and competitive ability. Little is known, however, about how these root responses differ among dominant species and functional groups in the Great Basin and how these responses differ between native and invasive plants. We applied pulses of 15N homogenously or in patches to nine co-occurring Great Basin species representing three functional groups (native bunchgrass, native perennial forb, invasive perennial forb). Plant 15N capture, root length density, precession in root placement and root uptake capacity per unit root length were quantified. Preliminary analysis suggests the invasive forbs had greater root length density, greater precision in root placement, and greater root uptake capacity than the native forbs when N was applied in patches. The native bunchgrasses also had greater precision in root placement and uptake capacity than the native forbs when N was supplied in patches. All species captured more N when N was supplied in patches but invasive forbs had a lower proportional reduction in N capture when N was supplied homogenously relative to the native species. These results suggest native bunchgrasses may have a greater ability to compete with invasive forbs relative to native forbs when soil N supply is heterogeneous and that N capture by invasive forbs may be impacted less than native plants following disturbances that make soil N supply more uniform.