• Heifer Production on Rangeland and Seeded Forages in the Northern Great Plains

      Haferkamp, M. R.; MacNeil, M. D.; Grings, E. E.; Klement, K. D. (Society for Range Management, 2005-09-01)
      Integrating use of seeded perennial cool-season grass pastures with native rangeland can increase available forage and provide a high plane of nutrition for grazing livestock. Our objective was to compare performance of yearling beef heifers grazing native rangeland with those grazing an integrated system that included seeded forages. Twice-replicated, 3-ha pastures seeded to either ‘Rosana’ western wheatgrass (Pascopyron smithii [Rydb.] A. Love), ‘Luna’ pubescent wheatgrass (Elytrigia intermedia [Host] Nevski), or ‘Hycrest’ crested wheatgrass (Agropyron cristatum [L.] Gaertn. ssp. desertorum [Fisch. ex Link] A. Love) were grazed in spring, whereas twice-replicated, 3.24-ha pastures seeded to either ‘Alkar’ tall wheatgrass (Thinopyrum ponticum [Podp.] ZW Liu RC Wang), ‘NewHy’ hybrid wheatgrass (Elymus hoffmannii KB Jensen KH Asay), ‘Bozoisky’ Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski.), or ‘Prairieland’ Altai wildrye (Leymus angustus [Trin.] Pilger) were grazed in autumn. Native rangeland was grazed during summer in the integrated system and spring, summer, and autumn in the rangeland treatment. Heifers exhibited greater weight gains on seeded pastures than on native rangeland in spring and autumn of most years. In 2 out of 3 years, heifers that grazed native rangeland during spring gained more (P = 0.012 for gain head-1 and P = 0.021 for gain head-1 day-1) while grazing native rangeland during summer than heifers that grazed seeded pastures in spring. Spring + summer gains averaged (mean +/- SE) 0.56 +/- 0.01 kg head-1 d-1 and 73.1 +/- 1.6 kg head-1. Livestock managers need to consider their livestock marketing and management strategies when using seeded pastures for seasonal grazing.  
    • Hyperspectral One-Meter-Resolution Remote Sensing in Yellowstone National Park, Wyoming: II. Biomass

      Mirik, Mustafa; Norland, Jack E.; Crabtree, Robert L.; Biondini, Mario E. (Society for Range Management, 2005-09-01)
      This study was designed to determine the utility of a 1-m-resolution hyperspectral sensor to estimate total and live biomass along with the individual biomass of litter, grasses, forbs, sedges, sagebrush, and willow from grassland and riparian communities in Yellowstone National Park, Wyoming. A large number of simple ratio-type vegetation indices (SRTVI) and normalized difference- type vegetation indices (NDTVI) were developed from the hyperspectral data and regressed against ground-collected biomass. Results showed the following: 1) Strong relationships were found between SRTVI or NDTVI and total (R2 = 0.87), live (R2 = 0.84), sedge (R2 = 0.77), and willow (R2 = 0.66) biomass. 2) Weak relationships were found between SRTVI or NDTVI and grass (R2 = 0.39), forb (R2 = 0.16), and litter (R2 = 0.51) biomass, possibly caused by the mixture of spectral signatures with grasses, sedges, and willows along with the variable effect of the litter spectral signature. 3) A weak relationship was found between sagebrush biomass and SRTVI or NDTSI (R2 = 0.3) that was related to interference from sagebrush photosynthetic or nonphotosynthetic branch and twig material, and from the indeterminate spectral signature of sagebrush. This study has shown that hyperspectral imagery at 1-m resolution can result in high correlations and low error estimates for a variety of biomass components in rangelands. This methodology can thus become a very useful tool to estimate rangeland biomass over large areas.  
    • Long-Term Successional Trends Following Western Juniper Cutting

      Bates, Jon D.; Miller, Richard F.; Svejcar, Tony (Society for Range Management, 2005-09-01)
      Western juniper (Juniperus occidentalis spp. occidentalis Hook.) expansion into sagebrush steppe plant communities in the northern Great Basin has diminished shrub-steppe productivity and diversity. Chainsaw cutting of western juniper woodlands is a commonly applied practice for removing tree interference and restoring understory composition. Studies reporting understory response following juniper cutting have been limited to early successional stages. This study assessed successional dynamics spanning 13 years following tree cutting. Total herbaceous standing crop and cover increased significantly in the CUT. Total standing crop was 10 times greater in the CUT vs. WOODLAND. Herbaceous standing crop and cover, and densities of perennial grasses in the CUT did not change between 1996 and 2004 indicating that by the 5th year after cutting, remaining open areas had been occupied. In the early successional stages, perennial bunchgrasses and Sandberg’s bluegrass were dominant. By the 5th year after treatment, cheatgrass had supplanted Sandberg’s bluegrass and was codominant with perennial bunchgrasses. In 2003 and 2004, perennial bunchgrasses dominated herbaceous productivity in the CUT, representing nearly 90% of total herbaceous standing crop. A pretreatment density of 2-3 perennial bunchgrasses m-2 appeared to be sufficient to permit natural recovery after juniper control. Perennial bunchgrass density peaked in the 6th year after treatment and the results suggested that 10-12 plants m-2 were sufficient to fully occupy the site and dominate herbaceous composition in subsequent years. In the CUT, juniper rapidly reestablished from seed and from the presence of seedlings not controlled in the initial treatment. The shifts in herbaceous composition across years suggests that long term monitoring is important for evaluating plant community response to juniper control and to develop appropriate post treatment management to promote continued site improvement.