Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/19/2012
Publication Date: N/A
Technical Abstract: As a riparian invader, Tamarix spp. often leads to native species (e.g., plains cottonwood and willows, grasses) decline and lower habitat quality. Since Tamarix excretes excess salt and has high salt tolerance, negative soil feedback via high soil salinity may negatively affect native plants. However, flooding and other factors cause large spatial and temporal variability in whether Tamarix affects native plants. Also, Tamarix may alter soil properties beside salts, including microbial activity and N, which may benefit or harm native plants. Soil was collected underneath and away from 10 Tamarix shrubs, for 20 soil samples collected from sites near Lovell WY (2), two MT sites (confluence of the Yellowstone and Bighorn Rivers, and along the Musselshell River). Soil from the Musselshell River site had the highest levels of total salts, salinity (moderate), sodium absorption ratio, cation exchange capacity, soil respiration, inorganic C, nutrients (Na, Mg, Fe, Cu, B), and silt content; these parameters were usually lowest (e.g., negligible salinity) at the Confluence site and intermediate at the two Lovell sites. Yet, for one Lovell site’s soil profile several aspects were more similar to the Confluence site. Half of the soil of each sample was autoclaved. For each of 160 autoclaved (or not) soil samples, seeds of three native grasses (western wheatgrass (Pascoryrum/Agropyrum smithii), prairie junegrass (Koeleria macrantha), and Sandberg’s bluegrass (Poa secunda/sandbergii)) were planted into 5-7 conetainers for each species. Germination success, phenological stage, and 2 month root and shoot biomass will be measured. Whether grass performance is affected by site, soil location (under Tamarix shrub or not), and autoclaving, or PCA factors on soil parameters, will be tested using GLM. Multiple regression analysis will also examine plant growth along gradients of several soil parameters. Our results should provide insights about factors limiting native grass recruitment near Tamarix sites.