Abstracts

0006

Native revegetation of previously cultivated land in the dry mixedgrass natural subregion of Alberta, Canada.

Jennifer Richman1, Brad Downey2, Kevin France1, Paul Jones2, Brandy Downey1, Francois Blouin31Alberta Environment and Sustainable Resource Development, Lethbridge, Alberta, Canada, 2Alberta Conservation Association, Lethbridge, Alberta, Canada, 3Prairie Conservation Forum, Lethbridge, Alberta, Canada

MULTISAR is a multiple species conservation strategy that aims to conserve multiple species of wildlife, including Species at Risk, at the landscape level, through a process that integrates range management with fish and wildlife management principles. In the early 1900's a significant amount of native dry Mixedgrass range was ploughed to make way for intensive agriculture. Currently, only 43% of the dry mixedgrass natural subregion remains native and continues to be fragmented by human development. In 2008, the MULTISAR program partnered with a landowner to convert 57ha of marginal cropland back to native grassland. A seed mix for the site was determined by assessing the ecological characteristics of the native grasslands immediately adjacent and identifying the composition of the plant community. Seed was broadcast at 10kg/ha followed by a light harrow in the spring of 2008. In the spring of 2009 the site was sprayed with a broadleaf herbicide to combat weeds and 150 silver sagebrush plugs were planted in low lying areas. In 2010 after the third growing season, species composition equaled 13.4% blue grama (Boutelua gracilis), 13% northern wheatgrass (Agropyron dasystachyum), 10.9% June grass (Koeleria macrantha), 6.7% western wheatgrass (Agropyron smithii), and 4.7% needle and thread grass (Stipa comata). Wildlife present on the site shifted from a community dominated by horned larks (Eremophila alpestris) in 2007, to thirteen species identified in 2010 including species at risk like Sprague's pipit and chestnut-collared longspur. Further research is needed to determine their nesting and rearing success on reseeded native grasslands.

0015

Perennial Grass Establishment Following Cheatgrass Control Using Herbicides

Charlie D Clements, Daniel N HarmonUSDA-ARS, Reno, NV, USA

The introduction and subsequent invasion of Cheatgrass (Bromus tectorum) onto Intermountain rangelands has resulted in increased frequencies of wildfires and severely altered native plant communities.The objective of this study was to test the effectiveness of herbicides [Imazapic (Plateau), Rimsulfuron (Matrix), Sulfometuron Methyl (Landmark)] on controlling cheatgrass and allowing for the establishment of seeded species. Twelve plots, 25m x 50m, were established in fall 2010 and treated with 1) Imazapic @ 6oz/ac, 2) Rimsulfuron @ 4oz/ac, and 3) Sulfometuron Methyl @ 1.75oz/ac rates and replicated 3 times in a completely randomized block design with controls. The treated plots were fallowed for one year and then seeded to Siberian wheatgrass (Agropyron fragilla ssp. sibiricum) at 7 lbs/ac rate.Sulfometuron Methyl yielded the highest control of cheatgrass above ground densities from 24.7/ft down to 0.4/ft (98.7%) followed by Imazapic, 17.6/ft down to 0.8/ft (95.6%) and Rimsulfuron 13.1/ft down to 1.1/ft (91.9%). The control plots averaged 39 cheatgrass plants/ft. Siberian wheatgrass seedlings emerged in March 2012 at fairly high densities (22.5/ft in the Sulfometuron Methyl treated plots) and by mid-June 2012 still yielded excellent results in some of the treatments. Sulfometuron Methyl treated plots yielded 6.5/ft, followed by Imazapic, 4.1/ft and Rimsulfuron, 1.5/ft. Control plots yielded 1.1/ft despite only receiving 6.2" of annual precipitation. These numbers are expected to decline over the hot dry summer months, yet the Sulfometuron Methyl and Imazapic treated plots should result in sufficient long-lived perennial grass establishment to suppress cheatgrass densities in the near future.

0016

Combustion dynamics of cattle fecal pats

John Derek Scasta, Dave M. Engle, John R. WeirOklahoma State University, Stillwater, OK, USA

The combustion of cattle fecal pats could have implications on focal micro-disturbances and production issues associated with cattle parasites. In 2011 and 2012, we geospatially identified fifty cow pats in six pastures (n = 300) and assessed combustion of each pat in relation to multiple variables, including: fire weather (relative humidity, temperature, hours since precipitation); fecal pat characteristic (index of age, volume); four time-lag fuel classes (1 hr, 10 hr, 100 hr and 1000 hr) and fuel load (at each pat). Multiple linear regression using AIC was applied to determine the best combustion models, and stepwise selection was used to select the best multiple regression model. Combustion of pats ranged from 3% to 62%. None of the fire weather variables were significant. Of the fecal pat characteristics, only the age score index was significant, and of the fuel variables, only 100-hr fuel moisture and fuel load were significant. The suggested regression model (r2 = 0.4266; p < 0.0001) was comprised of a three way interaction (100-hr fuel moisture age score index fuel load). Simple linear regression of pat combustion averaged for each pasture (n = 6) and 100-hr fuel moisture was highly correlated (r2 = 0.9587). These data suggest that grazing and fuel characteristics could be managed to optimize combustion of pats for a variety of ecological or production oriented goals.

0017

Perceptions of Drought: How Ranchers in Arizona Prepare for and Respond to Drought

Greg Butler, George Ruyle, Mitch McClaran, Diane AustinUniversity of Arizona, Tucson, Arizona, USA

Ranchers and land managers in Arizona must respond quickly to drought in order to employ the most effective management practices for maintaining forage utilization without degrading livestock or range conditions. I determined relationships between rancher perceptions of drought, practices used in preparation for and response to drought, drought preparedness and sources of drought management information. In order to evaluate these relationships, I sent a mail survey to ranchers and land managers in eastern and southeastern Arizona. Respondents consider the most important practices used both to prepare for and respond to drought to be rotational grazing, reducing herd size, adding more drinking water sources and purchasing additional feed. Sixty eight percent of respondents believe they are more prepared for drought now than they were 10 years ago in spite of worsening drought conditions. They understand they cannot control the weather, but they can control how they manage their operation in response to changing weather conditions.

0036

Development of South Texas Germplasm sideoats grama and comparison to previous releases

Keith Pawelek1, Forrest Smith1, Anthony Falk1, John Lloyd-Reilley2, Shelly Maher2, William Ocumpaugh11South Texas Natives, Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, TX, USA, 2United States Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS), E. Kika de la Garza Plant Materials Center, Kingsville, TX, USA

Sideoats grama is a widespread native bunchgrass in North America, which is often used in reclamation plantings. Eleven seed releases of Bouteloua curtipendula have been made through the work of the USDA NRCS Plant Materials Program and their collaborators. In addition to these tested materials, a number of wild-harvested seed sources of sideoats grama are offered for sale by commercial seed companies, however, no regionally adapted or locally originating (e.g. ecotypic) seed source of sideoats grama has been available for restoration projects in the region known as south Texas. As a result, we began work to collect, evaluate, and develop a seed release of a blend of ecotypic populations for use in the area.

South Texas Germplasm sideoats grama (Bouteloua curtipendula [Michx.] Torr. Var. caespitosa Gould&Kapadia) was cooperatively released in 2012 as a Texas Selected Native Plant Germplasm. This germplasm is a blend of six selected native populations originating from the Rio Grande Plains and Edwards Plateau Ecoregions of south Texas. Following initial evaluation, selection, and isolated seed increase of each component, South Texas Germplasm was compared to sideoats grama cultivars originating from nearest the area of intended use of the germplasm: Haskell', Premier' and Vaughn', in a 6-site variety trial utilizing transplanted and seeded experimental plots. South Texas Germplasm exhibited significantly higher 90-day seedling emergence than available cultivars at planting sites within the area of intended use, as well as superior performance in the transplant experiment at 2 of 3 experimental sites in south Texas.

0038

Who can take the heat: Caespitose grass response to increasing fuel loads

Ryan LimbOregon State University, Corvallis, Oregon, USA

Fire is a natural disturbance that frequents most landscapes globally and produces varying disturbance intensities depending on several factors. Likely the most easily understood and manipulated factor affecting fire intensity on rangelands is the herbaceous fuel load. Alterations in plant community composition and structure in addition to decreased grazing intensities have led to relatively high fuel loads on many western North America caespitose grass rangelands. Increased fuel loads directly increase fire intensity, but also increase other factors that may be more critical to plant survival including residual flame time, burn duration and total heat transfer. Numerous reports suggest that increased fire intensity reduces bunchgrass survival, but often these studies were conducted in wildfire situations where exact fuel loads and fire conditions were not knows. We planted four bunchgrasses native to western North America (Achnatherum thurberianum, Elymus elymoides, Festuca idahoensis, Psuedoroegneria spicata) in 2.5 L pots and maintained them in a climate controlled greenhouse. At 20 weeks old, we burned individual plants under controlled conditions with herbaceous fuel loads ranging between 2000 kgha-1 to 4000 kgha-1. An additional cohort of plants was clipped to 2-cm height to simulate a grazing event. We compared survival of individual plants among the different fuel load and clipping treatments and a non-treated control 21 days post-treatment and tracked the length of time to produce green biomass among the surviving individuals.

0039

Impact of High Stocking Density Grazing on Livestock Walking and Resting Behavior

Alexander Smart, George Perry, Julie Walker, Cody Wright, Megan Mortellaro, Kevin Vander WalSDSU, Brookings, SD, USA

High stocking density "mob" grazing is a recent phenomenon that is being promoted by a few practitioners, but has not undergone rigorous scientific testing. The objective of this study was to determine the walking and resting behavior of cattle grazing at high and low stocking densities. The study was conducted in 2012 on smooth bromegrass (Bromus inermus L.) pasture near Brookings, South Dakota. Two replicate treatments consisting of livestock grazing at a high stocking density (200,000 kg of live weight per ha moved three times per day) or a low stocking density (3,600 kg of live weight per ha moved once per week) were compared. Pedometers were put on three heifers for each replication of the high stocking density treatment and two heifers in each replication of the low stocking density treatment. Pedometers recorded number of steps, the number of laying bouts, and time laying down in one second intervals. Number of steps taken per day in the high stocking density treatment (3103 steps) was 40% more (P=0.02) than the low stocking density treatment (2218 steps). Daily laying bouts was 50% fewer (P=0.01) for high stocking density (10) than for low stocking density (15). Daily resting time was 10.5 hours for heifers in the high stocking density treatment compared with 11.1 hours in the low stocking density treatment (P=0.03). It would appear that high stocking density grazing might cause cattle to do more walking and expend more energy compared with low stocking density rotational grazing.

0054

Long-term alfalfa and clover recovery dynamics in northern temperate pastures sprayed with residual broadleaf herbicide.

Amanda Miller1, Edward Bork1, Linda Hall1, Patrick Forsythe2, Bill Summers01University of Alberta, Edmonton, Alberta, Canada, 2DuPont, Wetaskawin, Alberta, Canada

Beneficial legumes such as alfalfa (Medicago sativa) and white clover (Trifolium repens) increase the productivity of pastures and quality of forage, and are important features of northern temperate pastures. When pastures are sprayed for the control of broadleaf weeds existing legumes are removed from the plant community. Although prompt re-establishment of legumes in sprayed pastures is a goal of many land managers, this process depends on a number of different factors. Current re-cropping guidelines for many herbicide bioactives are based on data from areas with different soil and climatic conditions relative to western Canada. This study used long-term plots to track the degradation of herbicide bioactives (aminopyralid and aminocyclopyrachlor) via the performance of key forage legumes: alfalfa and white clover. Five long-term field sites were established to assess the ongoing recovery of legumes by investigating changes in legume biomass for 3 years following herbicide application. Each experimental site was organized into 4 replicate blocks of a randomized strip-split plot design. Mowing main plots were randomly assigned to of each block, herbicide subplots assigned to each plot, and seeding sub-subplots (alfalfa, clover, or non-seeded) repeated between the mowed and non-mowed portions of herbicide sub-plots. Herbicide bioactives were applied at two rates (0x or 1x) to herbicide subplots. Legume performance differed modestly between plots sprayed with the two different bioactives, and more markedly between mowing regimes. As re-establishment of legumes is an important goal, this information provides insight into the expected return of legumes under field conditions.

0057

Impact of High Stocking Density Grazing on Litter Decomposition

Megan Mortellaro, Alexander Smart, Jiyul Chang, Michelle Ohrtman, Sharon Clay, David ClaySouth Dakota State University, Brookings, SD, USA

High Stocking density mob grazing is a recent phenomenon that is being promoted by a few practitioners, but has not undergone rigorous scientific testing. The objective of this study was to determine the decomposition of litter from cattle grazing at high and low stocking densities. The study was conducted in 2011-2012 on smooth bromegrass (Bromus inermus L.) pasture near Brookings, South Dakota. Two replicate treatments consisting livestock grazing at a high stocking density (200,000 kg of live weight per ha moved two times per day) or a low stocking density (5,800 kg of live weight per ha moved once per week) for 2consecutive years were compared. A 2x2x2x2 factorial treatment design was used to examine litter decomposition by stocking density treatment (high or low), liter type (fresh or old), placement (surface or buried at 7.5 cm), and origin (high or low stocking litter) in-situ from August 2011 until mid-May 2012. After collection, samples were washed, dried and weighed. Fresh litter decomposed 17% more than old litter (55% vs. 47%; P