* Presenters for presentations and posters appear in bold
Ecology
Author(s): Danielle L. Clay, Marcelo D. Serpe, Stephen J. Novak, and James F. Smith
Title:Homoploid hybrid speciation in a rare endemic Castilleja from Idaho
Abstract:
Interspecific hybridization has played a pivotal role driving both extinctions and speciation events within angiosperms. The combination of interspecific hybridization and allopolyploidy has significantly contributed to the evolution of the genus Castilleja. The diploid Castilleja christii is a highly fertile rare endemic species, and widespread on 200 acres at the summit of Mt. Harrison, ID. We provide evidence for the homoploid hybrid speciation of Castilleja christii between congeneric diploids Castilleja miniata and C. linariifolia, using molecular and morphological analyses. Some individuals of Castilleja christii that were initially thought to be hybrids between C. christii and either C. miniata or C. linariifolia were found to be transgressive for several morphological traits based on ANOVA analyses and Cochran-Mantel-Haenszel test statistics. Using the single copy nuclear gene waxy, all Castilleja christii individuals were found to share the genomes of C. miniata and C. linariifolia. All individuals of C. christii, C. miniata and C. linariifolia sampled from Mt.Harrison were identified as diploids using chromosome squashes. Most individuals of C. miniata were also diploid with the exception of one subpopulation that was octoploid. This study is the first to report homoploid hybrid speciation in the genus Castilleja, adding to the understanding of the complex evolutionary history in this group. Further, this research will assist land managers with conservation strategies that may contribute to the species protection of Castilleja christii, which to date has not been explored scientifically.
Author(s): Micah Scholer, Jim Belthoff, andMatthias Leu
Title: Co-occurrence patterns of cavity nesting owls and woodpeckers in the BoiseNational Forest
Abstract:
Flammulated Owls (Otus flammeolus) and Northern Saw-whet Owls (Aegolius acadicus) are small, secondary cavity nesters which require formation of natural cavities or, more commonly, cavities created by woodpeckers for nesting opportunities. We investigated co-occurrence patterns of cavity nesting owls and woodpeckers in the BoiseNational Forest. Specifically, we hypothesized that cavity nesting owl occupancy was conditional on woodpecker presence. To evaluate this hypothesis we located owls by broadcasting conspecific vocalizations during nighttime hours at point-count locations (N=150) during 2009 and 2010. We surveyed for woodpeckers at these same locations during daylight hours in a similar manner playing broadcasts for five common woodpecker species. We simultaneously modeled occupancy as a function of snag characteristics and species co-occurrence while accounting for imperfect detection (i.e., the possibility that an individual may go undetected during surveying even when present) using the software program PRESENCE. We found a negative relationship between the estimated number of snags per hectare (12.5 ± 0.2) and occurrence of both owl species, while owl occurrence was positively related to average (35.17 ± 0.08) diameter at breast height of snags measured within 400 m radius plots centered on point-count locations. There was no support for the hypothesis that cavity nesting owl occupancy was conditional on the presence of woodpeckers. Therefore, despite the potential value in understanding the nocturnal owl community by examining the diurnal woodpecker community, current results indicate that there are not strong enough relationships to warrant such an approach.
Author(s): Matt Schmasow & Ian C. Robertson
Title:Diet selection by Owyhee harvester ants (Pogonomyrmex salinus) and its consequences for slickspot peppergrass (Lepidium pappilliferum), a threatened mustard endemic to southwestern Idaho
Abstract:
Owyhee harvester ants (Pogonomyrmex salinus) are generalist granivores native to sagebrush steppe habitat in the Great Basin and Snake River Plain, including areas occupied by slickspot peppergrass (Lepidium papilliferum), a threatened mustard endemic to southwestern Idaho. Recent studies have shown that P. salinus is a voracious seed predator of slickspot peppergrass in areas where their habitats overlap, and suggest that these ants may pose a threat to the long term viability of the species (White & Robertson 2009). To better understand the importance of L. papilliferum in the diet of P. salinus, we compared the diet of P. salinus relative to the availability of major seed types (i.e., Bromus tectorum, Poa secunda, Sisymbrium altissimum and L. papilliferum) located within 20 m of ant colonies. We found that Owyhee harvester ants exhibited distinct seasonal patterns in seed resource use. Poa secunda seeds were overrepresented in the diet of ants early in the season. However, although Poa remained available throughout the season, ants shifted to smaller seed types (e.g., Sisymbrium, Lepidium) once these seeds became available later in the season. Bromus seeds, despite being abundant throughout the season, comprised only a small component of the ant’s diet. Our results further suggest that the reduced handling time associated with smaller seed types may also play a role in resource selection by P. salinus.
Author(s): Pamela Bond
Title: LiDAR-derived height and cover estimation of sagebrush steppe shrub communities
Abstract:
Light Detection and Ranging (LiDAR) and multispectral imagery are useful tools for studying sagebrush steppe vegetation. My research explored the utility of LiDAR data and LiDAR Landsat 5 Thematic Mapper data fusion for classifying the shrub communities of a sagebrush steppe ecosystem, encompassed by the USDA ARS Reynolds Creek Experimental Watershed in southwestern Idaho. The objectives of my research were to: 1) quantify the correlation between field-based and LiDAR-derived shrub heights, and 2) determine if LiDAR-derived vegetation heights can be used to accurately classify the varying shrub community types within a sagebrush steppe ecosystem into appropriate categories (low, moderate, high, and tree) using linear discriminant analysis, 3) determine if LiDAR data can be used to estimate shrub canopy cover, and 4) determine if LiDAR fusion with Landsat 5 TM data further improves canopy cover estimations. A simple linear regression of field- versus LiDAR-derived maximum vegetation height yielded an R2 of 0.78. Linear discriminant analysis of the categorical classification based on LiDAR-derived height values had an overall accuracy of 0.703. Compared to field-derived estimates, LiDAR generally underestimated shrub canopy cover with an average root mean square error of 17.15 and mean error of -8.71 across all study areas. LiDAR and Landsat 5 TM fusion increases the strength of the relationship between field- and LiDAR-derived shrub canopy cover from R2 0.4028 to 0.523. These results indicate that a LiDAR-based approach to sagebrush steppe classification and canopy cover estimation has the potential to serve useful tool for rangeland managers.
Author(s): Amy C. Ulappa, J.S. Forbey, L. A. Shipley, R. Kelsey, J.L. Rachlow, and A.L. Price
Title:Nutritional and chemical factors shaping the “foodscape” of a dietary specialist herbivore, the pygmy rabbit
Abstract:
Herbivory is a foraging strategy that poses special challenges, which can be partially addressed by selecting high quality forage among plants that vary nutritionally or chemically. Although several studies have demonstrated that herbivores prefer diets with the highest nutrient and lowest chemical constituents, these studies are primarily confined to laboratory feeding trials because observing diet selection in free ranging herbivores is difficult. Our field observations demonstrated that pygmy rabbits (Brachylagus idahoensis), facultative specialists on sagebrush (Artemisia tridentata), forage on specific sagebrush plants more than others within a foraging patch. We used this system to test the hypothesis that sagebrush plants heavily browsed by pygmy rabbits are nutritionally superior and preferred to rarely browsed plants. We collected samples from pairs of sagebrush with high and low levels of browsing at 20 active pygmy rabbit burrows. First, we used a choice feeding trial to validate preference for heavily browsed plants. Captive pygmy rabbits voluntarily consumed 2.4 times more leaves from sagebrush with high levels of browsing. Second, we compared total and digestible crude protein and monoterpene amounts between sagebrush plants exhibiting high and low levels of browsing using a paired design. Amounts of total and digestible crude protein were both higher and several monoterpenes were lower in highly browsed sagebrush relative to the rarely browsed plants. Predictive foraging models generated with this study can be used to map areas of palatable sagebrush across the landscape, termed “foodscapes”.
Geosciences
Author(s):Andrew Austreng, Shawn Benner, Jennifer Pierce, and Marie-Anne de Graaff
Title:Massive changes in the carbon budget associated with sagebrush restoration
Abstract:
Sagebrush-steppe communities of the western U.S. have undergone widespread invasion of non-native cheatgrass, often following wildfire. One reclamation strategy that has shown long-term success in replacing cheatgrass is seeding certain bunchgrass species such as crested wheatgrass. This approach allows the eventual reestablishment of native sagebrush communities. To determine how this remedial strategy impacts the carbon budget, we are currently quantifying the carbon content of biomass and soils associated with each stage of this remedial treatment.The preliminary results of our work indicate that the reclamation strategy of replacing cheatgrass with bunchgrass has significant carbon storage benefits (~20 t C ha-1). Furthermore, our data indicates that significant additional carbon storage benefit will be achieved by the transition from bunchgrass to native sagebrush (~30 t C ha-1). Propagation of these preliminary values toward reclamation of all cheatgrass-degraded sagebrush-steppe ecosystems in the U.S., (~39,000 mi2), implies that sagebrush restoration may have the potential to offset annual carbon emissions for approximately ~100 million people.
Author(s):Jill Glenn, Daniele Tonina, Fritz Fiddler, and Mark Morehead
Title:Effects of cross-section location and interpolation methods on the accuracy of 3D bathymetric surfaces
Abstract:
Accurate representation of river channel geometry is important for any modeling research that utilizes three-dimensional (3d) channel geometry (bathymetry). Whether the scope is to estimate the extent of flood inundation, the effects of dam operations on aquatic habitat, or populating one, two, or three-dimensional parameters for hydraulic models, the accuracy of the bathymetry determines model outcome. The increased availability of geographic information systems (GIS) has improved the efficiency in mapping and spatial analysis there by making the mapping of bathymetry and results of research a standard practice. The generation of surfaces for river bathymetry is relatively new and given the anisotropic trend in these data the method of interpolation between data points plays an important role in the accuracy of the surface. This study investigates the number of cross-sections required to accurately represent geomorphologic features and compares different interpolation methods used in the generation of a bathymetric surface. This is accomplished by using a high resolution 1-meter grid digital elevation model (DEM) to generate a series of different discretizations of cross-sections using geomorphologic feature characteristics as placement criteria and producing DEMs for each discretization and using three interpolation methods: Universal Kriging, TIN, and Simple Interpolation. Each DEM is then compared to the 1-meter DEM in order to define the spatial distribution of vertical and volumetric error.
Author(s):Hank Hetrick, John Bradford, and Hans-Peter Marshall
Title:Determining the significance of lateral flow of water in the snowpack with a resistivity grid
Abstract:
Knowledge relating to the process of lateral distribution of water in the snowpack can improve the development of predictive models for soil moisture, groundwater recharge, and streamflow generation. Although most modeling approaches assume water travels vertically through the snowpack, errors may be present due to neglecting a significant amount of lateral flow. The goal of this project is to understand the occurrence and hydrologic relevance of lateral flow in snow. One of the primary methods that will be used is the use of a resistivity grid. Several stainless steel plates have been buried in the ground, which span a large area of a hillside located in the Dry Creek Watershed northeast of Boise, Idaho. An electric potential will be generated across each plate, which will induce currents through the ground. The current measurements will directly be converted into resistivity measurements. Since the presence of water can significantly vary the resistivity of soil, the resistivity measurements can be converted to approximate a soil moisture profile along the hillside. If the overlying snowpack diverts the vertical flow path of the water to a lateral flow path, then the expected result is that more water will infiltrate into the soil at lower potions of the hillside, which will be observed in the soil moisture profiles along the hillside. With the use of empirical equations and estimations of variables in the soil, more quantitative estimations of lateral flow can possibly be evaluated to further determine the significance of this process.
Author(s):Kyle Makovsky
Title:Miocene-recent tectono-magmatic framework for the basin and range of southeast Oregon
Abstract:
The role of faults and stratigraphy in geothermal systems of the northwest basin and range is important yet poorly constrained. Faulting in this province provides an excellent opportunity to study young extensional terrane. The field area for this project is near Paisley, OR which resides in the northwestern most section of the basin and range province. Geologic mapping has revealed that the rocks in this area are early Cenozoic ash-flow tuffs and rhyolite lava flows. These rocks are also host to geothermal fluids. Geothermometry using the Giggenbach method has estimated that these fluids have a theoretical maximum temperature of 330° F. The maximum recorded temperature of these fluids is 206.6° F, still allowing for the possibility of electrical power production. Stable isotope analysis of this water reveals it came from a meteoric source, given by mean δ18O values of -14.31‰ and mean δD values of -120.07‰. The stratigraphic and structural framework must be identified to properly assess geothermal potential within these rocks. To do this, a gravity survey was conducted to help determine the orientation of the major fault system. The data reduction process has started and promises to shed light into the structural framework of the Paisley area.
Author(s):Thomas Othiem
Title:CO2 sequestration in basalts: laboratory measurements
Abstract:
Geologic sequestration of CO2 is proposed as being the only promising large-scale method to help reduce CO2 gas emission by its capture at large point sources and subsequent long-term storage in deep geologic formations. Reliable and cost-effective monitoring will be an important aspect of ensuring geological sequestration is a safe, effective, and an acceptable method for CO2 emission mitigation. Once CO2 injection begins, seismic methods can be used to monitor the migration of the carbon dioxide plume. To calibrate changes in rock properties from field observations, we propose to first analyze changes in elastic properties on basalt cores.
Carbon dioxide sequestration in basalt rocks results in fluid substitution, mixing of CO2 with water, and rock mineralization. Carbon dioxide sequestration in mafic rock creates reactions such as Mg2SiO4 + CaMgSi2O6 + 4CO2 = Mg3Ca(CO3)4 + 3SiO2 whereby primarysilicate minerals within the basalt react with carbonic acid laden water to creating secondary carbonate minerals and silicates.
Using time-lapse laboratory scale experiments, such as laser generated ultrasonic wave propagation; it is possible to observe small changes in the physical properties of a rock. We will show velocity and modulus measurements on three basalt core samples for different saturations. The ultimate goal of the project is to track seismic changes in rock properties due to fluid substitution and mineralization. The porosity of our basalts ranges from 8% to 14%, and the P-wave velocity increases by 20% to 40% from dry to water saturated conditions. Petrographic analysis (CT-scans, thin sections, XRF, XRf) will aid in the characterization of the mineral structure in these basalts and its correlation to seismic properties changes resulting from fluid substitution and mineralization.
Keynote Speaker: Dr. Alistair Pooreof the School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
TITLE: From tiny grazers to global patterns in marine herbivory
Herbivory is one of the fundamental processes that regulate the biomass and composition of primary producers, and thus ecosystem functioning. Herbivory is particularly intense in marine systems, strongly determining the abundance of macroalgae and seagrasses and leading to the evolution of a wide range of chemical defenses. I will give an overview of my research into the ecology and evolution of the small marine herbivores whose interactions with algae are likened to insect-plant interactions, and outline current efforts to understand global patterns in the impact of marine grazers.
Molecular Biology
Author(s):Cheri L. Lamb & Kristen A. Mitchell
Title:Ah receptor interacts with activated Stat1 to promote cell proliferation
Abstract:
The aryl hydrocarbon receptor (AhR) is a soluble, ligand-activated transcription factor that mediates the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related chemicals. AhR activity has been shown to regulate cell cycle progression both in vitro and in vivo, although the mechanisms are unclear. Additionally, recent evidence shows that AhR interacts with Stat1 to regulate cell differentiation and inflammatory responses. Stats are cytoplasmic signaling proteins that function as transcription factors to regulate many aspects of cell growth, survival and differentiation. Stat1 activation frequently leads to pro-apoptotic effects thus suppressing proliferation. The goal of this study was to determine if alterations in STAT1 signaling contribute to the suppression of proliferation observed in TCDD-treated cells. 5L rat hepatoma and LX2 human stallate cells were serum starved and released +/- TCDD (6nM) or vehicle. Cell lysates, 24 hr after treatment, were analyzed by co-immunoprecipitation and western blotting. Levels of STAT1 increased in vehicle-treated cells compared to TCDD treated cells. Furthermore, phosphorylated STAT1 (pSTAT1) coimmunoprecipitated with AhR in vehicle-treated cells. In contrast, phosphorylated STAT1 was not detected in the AhR complex in TCDD-treated cells. Based on these results, it is conceivable that the AhR-pSTAT1 interaction inhibits STAT1 signaling, and that TCDD treatment abolishes this interaction, thereby enabling STAT1 signaling leading to pathways suppressing cell proliferation.