Sagebrush
Recordings from the February 2016 Sagebrush Ecosystem Conservation Conference co-sponsored by the Great Basin Consortium and the Western Association of Fish and Wildlife Agencies and Utah State University.
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This analysis found that season, plant composition, and ungulate assemblage may all influence dietary competition between wild horses and other large ungulate sharing western North American rangelands; however, the low and nonsignificant heterogeneity values at alpha 0.01 for cattle:horse effect size comparisons suggest that cattle and horses respond to regional and seasonal variation similarly—a result not observed for other ungulate:horse comparisons. Our meta-analysis provides a robust data set for evaluations of diet composition for wild horses, livestock, and wildlife, whereas no empirical studies have assessed all species together.
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Collectively, these results provide clear evidence that local sage-grouse distributions and demographic rates are influenced by pinyon-juniper, especially in habitats with higher primary productivity but relatively low and seemingly benign tree cover. Such areas may function as ecological traps that convey attractive resources but adversely affect population vital rates. To increase sage-grouse survival, our model predictions support reducing actual pinyon-juniper cover as low as 1.5%, which is lower than the published target of 4.0%. These results may represent effects of pinyon-juniper cover in areas with similar ecological conditions to those of the Bi-State Distinct Population Segment, where populations occur at relatively high elevations and pinyon-juniper is abundant and widespread.
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This study found that to retain the shrub, especially sagebrush, components on a site and increase ecosystem resilience and resistance through increases in tall grasses, treatment should occur at low to mid tree dominance index (TDI) using mechanical methods, such as cutting or mastication. Effects of fire and mechanical treatments implemented at different phases of tree dominance create different successional trajectories that could be incorporated into state-and-transition-models to guide management decisions.
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This study estimates that fire has approximately twice the treatment life of cutting at time horizons approaching 100 yr, but, has high up-front conservation costs due to temporary loss of sagebrush. Cutting has less up-front conservation costs because sagebrush is unaffected, but it is more expensive over longer management time horizons because of decreased durability. Managing conifers within sage-grouse habitat is difficult because of the necessity to maintain the majority of the landscape in sagebrush habitat and because the threshold for negative conifer effects occurs fairly early in the successional process. The time needed for recovery of sagebrush creates limits to fire use in managing sage-grouse habitat. Utilizing a combination of fire and cutting treatments is most financially and ecologically sustainable over long time horizons involved in managing conifer-prone sage-grouse habitat.
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This study evaluated nutrient availability and herbaceous recovery following various cutting and prescribed fire treatments in late succession western juniper woodlands on two sites in southeast Oregon from 2007 to 2012. Treatments were untreated controls, partial cutting followed by fall broadcast burning (SEP), cut and leave (CUT), and cut and burn in winter (JAN) and spring (APR). Soil inorganic N (NO3−, NH4+), phosphorus (H2PO4−), potassium (K+), and cover of herbaceous species were measured in three zones; interspace, litter mats around the tree canopy (canopy), and beneath felled trees (debris). Peak nutrient availability tended to occur within the first two years after treatment. The increases in N, P, and K were greatest in severely burned debris and canopy zones of the SEP and APR treatments. Invasive annual grass cover was positively correlated to soil inorganic N concentrations. Herbaceous composition at the cool, wet big sagebrush-Idaho fescue site was generally resistant to annual grasses after juniper treatments and native plants dominating post-treatment even in highly impacted debris and canopy zones of the SEP treatment. The warm dry big sagebrush-bluebunch wheatgrass site was less resistance and resilient, thus, exotic annual grasses were a major component of the understory especially when tree and slash burning was of high fire severity.
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In an experiment replicated at three burned sites in the northern Great Basin, this study compared Wyoming big sagebrush establishment across treatments differing by seed delivery technique, timing, and rate of seed application. Wherever density differed between treatments, it was consistently higher in certain treatment levels (minimum-till > conventional drill, drill-delivery > broadcast-delivery, fall broadcast > winter broadcast, and higher rates > lower rates). Densities declined between years at two sites, but we did not find evidence that declines were due to density-dependent mortality. Results indicate that seeding success can likely be enhanced by using a minimum-till imprinter seeding method and using seeding rates higher than typical postfire seeding recommendations for Wyoming big sagebrush.
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In this study, spectrophotometry was used to quantify chemical differences in the water-soluble compound, coumarin. Ultraviolet (UV) absorbance of A. tridentata subsp. vaseyana showed distinct differences among A.t. tridentata and wyomingensis. Use of spectrophotometry to acquire UV absorbance provides empirical results that can be used in seed testing laboratories using the seed chaff present with the seed to certify A. tridentata subspecies composition.
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This study showed higher levels of resilience to fire than is typically discussed in the sagebrush steppe, in part because the studied ecosystems were in good condition before the fire, but also because the longer post-fire monitoring time (17 years) may be more appropriate to capture patterns of succession in these ecosystems.
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The USGS webpage for Survey Data Series 690 provides access to livestock grazing data from 25 BLM offices in 13 states including spatial and tabular data related to BLM grazing allotments.