Southwest Idaho Research Articles

Large‐scale manipulation of the acoustic environment can alter the abundance of breeding birds: Evidence from a phantom natural gas field

Abstract Altered animal distributions are a consequence of human expansion and development. Anthropogenic noise can be an important predictor of abundance declines near human infrastructure, yet more information is needed to understand noise impacts at the spatial and temporal scales necessary to alter populations. Energy development and associated anthropogenic noise are globally pervasive, and expanding. For example, 600,000 new natural gas wells have been drilled across central North America in less than 20 years. We experimentally broadcast energy sector noise (recordings of compressor engines) in Southwest Idaho (USA). We placed arrays of speakers creating a ‘phantom natural gas field' in a large‐scale experiment and tested the effects of noise alone on breeding songbird abundance. To examine variation in human‐caused noise, we broadcast two types of compressor noise, one with a slightly higher sound intensity and greater bandwidth than the other. Our phantom natural gas field encompassed approximately 100 km2. We broadcast noise over three continuous months, for each of two seasons, and quantified over 20,000 hr of background sound levels. Brewer's sparrows (Spizella breweri) were affected by our narrowband playback, declining 30%, 50 m from the speaker arrays. During our broadband playback, all species combined and Brewer's sparrows decreased 20% and 33%, respectively, at the scale of our sites (~0.5 km2; up to 400 m from speaker arrays). Synthesis and applications. Our results show the importance of incorporating the acoustic structure of noise when estimating the cost of noise exposure for populations. We suggest an urgent need for noise mitigation, such as quieting compressor stations, in energy extraction fields and other sources in natural areas broadly.

First Report of Ilyonectria robusta Associated with Black Foot Disease of Grapevine in the United States

In October 2017, a vineyard in southwest Idaho reported that up to 80% of self-rooted Cabernet sauvignon plants were dead or displaying poor growth and reduced vigor. Although this was initially attributed to extreme conditions from the previous winter, inspection of the roots of 10 affected plants showed signs of black foot disease. Symptoms included reduced root biomass, and black discoloration with sunken and necrotic root lesions. To isolate fungi associated with the necrotic root tissue, symptomatic pieces of root approximately 3 mm in length were surface sterilized with sodium hypochlorite solution (2%) and rinsed twice in sterile water prior to plating onto potato dextrose agar (PDA) amended with penicillin G (0.6%) and streptomycin sulfate (2%). Fungal colonies of interest were identified after 5 days and transferred to fresh PDA plates. After 2 weeks of growth on PDA at 20°C, colonies resembling Ilyonectria were frequently isolated. These colonies were light brown in color, had a cotton-like texture with abundant conidia, and were consistent with previous descriptions (Cabral et al. 2012; dos Santos et al. 2014; Martinez-Diz et al. 2018). Species identity was determined through sequencing part of the histone 3 (H3) gene. DNA was extracted using a Wizard DNA purification kit for food (Promega) in conjunction with a Kingfisher ML (ThermoFisher), and primers CYLH3F and CYLH3R were used as described previously (Crous et al. 2004). Polymerase chain reaction (PCR) products were purified using a QIAquick PCR clean up kit (Qiagen) and sent to Eurofins Genomics (Louisville, KY) for sequencing. The resulting sequence had 100% identity with another Ilyonectria robusta sequence in GenBank (JF735518). Therefore, from both sequence and morphological analysis, the isolate was identified as I. robusta. To confirm pathogenicity, cuttings of Cabernet sauvignon approximately 30 cm high were planted in individual pots containing approximately 1 kg of premium potting soil (Scotts, Marysville, OH) and grown for 3 months in the glasshouse at 25°C. Once sufficient root mass had developed, the roots were lightly wounded using a scalpel with four consistent strokes below the soil line in a systematic manner. The soil was then inoculated with 14 ml of a 10⁹ conidial suspension taken from 7-day-old plates of isolate G45. Control plants were inoculated with sterile water. Each treatment was replicated 10 times. After 24 days, the roots were inspected for disease. Black foot symptoms were present on all plants inoculated with isolate G45 with a mean root area affected of 59%. In the plants inoculated with sterile water, four had completely healthy roots, and light root browning was visible in six plants (mean root area affected was 4%). Plants inoculated with isolate G45 demonstrated significantly (t test, P < 0.001) more root discoloration than control plants. I. robusta was consistently reisolated from the affected tissue of inoculated roots, thereby confirming Koch’s postulates. To our knowledge, this is the first report of I. robusta on Vitis vinifera in the United States. I. robusta has previously been found associated with black foot disease in Portugal (Cabral et al. 2012), Brazil (dos Santos et al. 2014), Spain (Martinez-Diz et al. 2018), and British Columbia (Urbez-Torres et al. 2014). I. robusta is part of a species complex of Cylindrocarpon-like asexual morphs causing black foot disease, which causes economic losses to the grapevine industry worldwide. Growers in the United States should consider its presence when planting grapevines.

Examining Interactions Between and Among Predictors of Net Ecosystem Exchange: A Machine Learning Approach in a Semi-arid Landscape

Net ecosystem exchange (NEE) is an essential climate indicator of the direction and magnitude of carbon dioxide (CO2) transfer between land surfaces and the atmosphere. Improved estimates of NEE can serve to better constrain spatiotemporal characteristics of terrestrial carbon fluxes, improve verification of land models, and advance monitoring of Earth’s terrestrial ecosystems. Spatiotemporal NEE information developed by combining ground-based flux tower observations and spatiotemporal remote sensing datasets are of potential value in benchmarking land models. We apply a machine learning approach (Random Forest (RF)) to develop spatiotemporally varying NEE estimates using observations from a flux tower and several variables that can potentially be retrieved from satellite data and are related to ecosystem dynamics. Specific variables in model development include a mixture of remotely sensed (fraction of photosynthetically active radiation (fPAR), Leaf Area Index (LAI)) and ground-based data (soil moisture, downward solar radiation, precipitation and mean air temperature) in a complex landscape of the Reynolds Creek Experimental Watershed (RCEW) in southwest Idaho, USA. Predicted results show good agreement with the observed data for the NEE (r2 = 0.87). We then validate the temporal pattern of the NEE generated by the RF model for two independent years at the two sites not used in the development of the model. The model development process revealed that the most important predictors include LAI, downward solar radiation, and soil moisture. This work provides a demonstration of the potential power of machine learning methods for combining a variety of observational datasets to create spatiotemporally extensive datasets for land model verification and benchmarking.

Including Variability across Climate Change Projections in Assessing Impacts on Water Resources in an Intensively Managed Landscape

：In intensively managed watersheds, water scarcity is a product of interactions between complex biophysical processes and human activities. Understanding how intensively managed watersheds respond to climate change requires modeling these coupled processes. One challenge in assessing the response of these watersheds to climate change lies in adequately capturing the trends and variability of future climates. Here we combine a stochastic weather generator together with future projections of climate change to efficiently create a large ensemble of daily weather for three climate scenarios, reflecting recent past and two future climate scenarios. With a previously developed model that captures rainfall-runoff processes and the redistribution of water according to declared water rights, we use these large ensembles to evaluate how future climate change may impact satisfied and unsatisfied irrigation throughout the study area, the Treasure Valley in Southwest Idaho, USA. The numerical experiments quantify the changing rate of allocated and unsatisfied irrigation amount and reveal that the projected temperature increase more significantly influences allocated and unsatisfied irrigation amounts than precipitation changes. The scenarios identify spatially distinct regions in the study area that are at greater risk of the occurrence of unsatisfied irrigation. This study demonstrates how combining stochastic weather generators and future climate projections can support efforts to assess future risks of negative water resource outcomes. It also allows identification of regions in the study area that may be less suitable for irrigated agriculture in future decades, potentially benefiting planners and managers.

Biological soil crust diversity and composition in southwest Idaho, U.S.A.

Biological soil crusts (BSCs) were sampled by habitat types within and adjacent to the Orchard Combat Training Center (OCTC) in southwest Idaho, U.S.A. Plots consisting of a 34.7 m radius circle, approximately equal to one acre or 0.38 hectares were sampled. We focused on five native vascular plant-dominated current habitat types within the OCTC, including: 1) Wyoming sagebrush, 2) saltbush, 3) rabbitbrush, 4) winterfat, and 5) Sandberg bluegrass. We describe how BSC cover and species richness varied with habitat types in the study area. We recorded the relative abundance of BSCs and vascular plant species and collected voucher specimens for each BSC. The biodiversity of each BSC in these arid habitat types was much greater than many ecologists have assumed. We found a total of 68 species of BSC across all 17 plots. BSC cover differed significantly across the different habitat types. BSC cover was significantly higher in sagebrush and saltbush as compared with Poa, rabbitbrush and winterfat habitat types. Overall, there was substantially more BSC richness (17–47 species) than vascular plant richness (4– 13 species), and BSC richness was positively related to vascular plant richness (R2=0.18, p=0.041). On average, each additional plant species was associated with 1.36 additional BSC species. BSC communities also varied across the habitat types with Buellia punctata as a significant indicator species for sagebrush, Toninia sedifolia for saltbush, and Cladonia pocillum for winterfat. Several BSC species were associated with 2 or 3 habitat types; for example, Cladonia fimbriata, Diploschistes muscorum, Leptogium lichenoides, Massalongia carnosa, Riccia sorocarpa and Trapeliopsis steppica were most common in the sagebrush, Poa, and rabbitbrush habitats. In contrast, Caloplaca tominii, Endocarpon loscosii, Placidium squamulosum and Psora tuckermanii were most common in winterfat and saltbush habitats.

First U-Pb zircon ages for late Miocene Ashfall Konservat-Lagerstätte and Grove Lake ashes from eastern Great Plains, USA.

This paper documents the first U-Pb zircon ages for Ashfall Fossil Beds (Nebraska, USA), a terrestrial Konservat-Lagerstätte mass-death assemblage that is arguably the most diverse of its type and age. The Ashfall tephra was correlated with ignimbrites from the Bruneau-Jarbidge volcanic field (12.7–10.5 Ma) in southwest Idaho based on geochemical analysis. The methods and geochemical data supporting the original age assessment of the ash bed, however, were never published, and there has been a persistent misconception that dateable heavy minerals (e.g., zircon) are absent. Notwithstanding, we recovered abundant zircons from Ashfall Fossil Beds, and from an ash bed ~6 km to the southeast at Grove Lake, Nebraska, and analyzed them through LA-ICP-MS. Our new zircon U-Pb age of 11.86 ± 0.13 Ma substantiates correlation of the Ashfall Fossil Beds deposit to tuffs originating from the Bruneau-Jarbidge caldera (~12.7–10.5 Ma). Our U-Pb zircon age of 6.42 ± 0.06 Ma for the Grove Lake ash bed coincides with supervolcanic activity in the Heise volcanic field (6.6–4.3 Ma) in eastern Idaho. These new dates improve age constraints of strata comprising the Ogallala Group and the important paleontological site. Moreover, we find that detrital and airfall zircons are unevenly distributed in the stratified ash beds we describe herein and presumably in similar deposits worldwide. Therefore, a higher-resolution sampling scheme is necessary in such cases.

MECHANICAL PROPERTY ASSESSMENT FOR ESTABLISHING DESIGN VALUES OF WESTERN JUNIPER

Western juniper (Juniperus occidentalis) is a conifer that is native to Oregon, California, Washington, Nevada, and Idaho. Juniper is highly decay resistant and, therefore, is a popular choice for fence posts and landscape timbers. Forest management practices over the past 100 yr have resulted in an immense population increase in western juniper stands, transforming the grasslands/sagebrush biome into juniper forests. Landowners have been encouraged to cut back western juniper to restore grassland habitat, but there is no major market associated with juniper lumber. This study assessed the mechanical properties of western juniper to develop its design values for inclusion in the National Design Specification. Small clear samples were prepared from juniper harvested from three locations in eastern Oregon, one location in northeast California, and one location in southwest Idaho according to ASTM D143 for compression, bending, and shear. Average strength values were calculated and compared with similar wood species. Most properties were similar to those of other species, but modulus of elasticity was significantly lower. Compressive properties of western juniper also differed, with compression parallel-to-grain being lower and compression perpendicular-to-grain being relatively higher. Differences between species might be attributed to cell wall structure and distribution of lignin in the cells. Design values for western juniper were calculated using the strength values to establish allowable properties for visually graded lumber. © 2018 by the Society of Wood Science and Technology.

Group Characteristics Influence Distribution Patterns of Off-Road Vehicle Recreation within a Complex Trail System in Southwest Idaho

ABSTRACTRecreation on public lands is growing and is increasingly recognized as an ecosystem service providing improved health, connection to nature, and social time while also disturbing and degrading ecosystems. Human impacts must be managed, but often managers have little information about the factors that affect recreation patterns. We combined data from global positioning system receivers to record off-road vehicle (ORV) travel with a pretrip survey to determine how group characteristics, site experience, site knowledge, and motivation are associated with ORV trip patterns on public lands in southwest Idaho. Spatial and temporal extent and distribution could summarize most variation in ORV trips. Both trip distribution and extent were associated with group characteristics and site knowledge. Spatial and temporal extent was additionally associated with motivations and distribution was associated with riding experience. These findings can help land managers to identify use patterns, direct informational programs, and effect indirect management strategies.

Form and function relationships revealed by long‐term research in a semiarid mountain catchment

Fifteen years of cumulative research in the Dry Creek Experimental Watershed in southwest Idaho, USA, has revealed relationships between catchment form and function that would not have been possible through independent short‐term projects alone. The impacts of aspect and elevation on incident energy and water, coupled with climate seasonality, have produced tightly connected landform properties and hydrologic processes. North‐facing hillslopes have steeper slope angles, thicker soil mantles, finer soil texture, and higher water holding capacities than their south‐facing counterparts. This trend is modulated by elevation and vegetation; higher elevation sites, where aspect differences in vegetation are less evident, exhibit less distinct hydrologic properties. The storage of water first as snow, then as soil moisture determines how upland ecosystems survive the seasonal and persistent water stress that happens each year, and sustains streamflow throughout the year. The cumulative body of local knowledge has improved general understanding of catchment science, serves as a resource for conceptual and numerical evaluation of process‐based models, and for data‐driven hydrologic education. WIREs Water 2018, 5:e1267. doi: 10.1002/wat2.1267This article is categorized under: Science of Water &gt; Hydrological Processes Science of Water &gt; Water and Environmental Change

Estimating vegetation biomass and cover across large plots in shrub and grass dominated drylands using terrestrial lidar and machine learning

Terrestrial laser scanning (TLS) has been shown to enable an efficient, precise, and non-destructive inventory of vegetation structure at ranges up to hundreds of meters. We developed a method that leverages TLS collections with machine learning techniques to model and map canopy cover and biomass of several classes of short-stature vegetation across large plots. We collected high-definition TLS scans of 26 1-ha plots in desert grasslands and big sagebrush shrublands in southwest Idaho, USA. We used the Random Forests machine learning algorithm to develop decision tree models predicting the biomass and canopy cover of several vegetation classes from statistical descriptors of the aboveground heights of TLS points. Manual measurements of vegetation characteristics collected within each plot served as training and validation data. Models based on five or fewer TLS descriptors of vegetation heights were developed to predict the canopy cover fraction of shrubs (R2=0.77, RMSE=7%), annual grasses (R2=0.70, RMSE=21%), perennial grasses (R2=0.36, RMSE=12%), forbs (R2=0.52, RMSE=6%), bare earth or litter (R2=0.49, RMSE=19%), and the biomass of shrubs (R2=0.71, RMSE=175g) and herbaceous vegetation (R2=0.61, RMSE=99g) (all values reported are out-of-bag). Our models explained much of the variability between predictions and manual measurements, and yet we expect that future applications could produce even better results by reducing some of the methodological sources of error that we encountered. Our work demonstrates how TLS can be used efficiently to extend manual measurement of vegetation characteristics from small to large plots in grasslands and shrublands, with potential application to other similarly structured ecosystems. Our method shows that vegetation structural characteristics can be modeled without classifying and delineating individual plants, a challenging and time-consuming step common in previous methods applying TLS to vegetation inventory. Improving application of TLS to studies of shrub-steppe ecosystems will serve immediate management needs by enhancing vegetation inventories, environmental modeling studies, and the ability to train broader datasets collected from air and space.

Assessing a Multi-Platform Data Fusion Technique in Capturing Spatiotemporal Dynamics of Heterogeneous Dryland Ecosystems in Topographically Complex Terrain

Water-limited ecosystems encompass approximately 40% of terrestrial land mass and play a critical role in modulating Earth’s climate and provisioning ecosystem services to humanity. Spaceborne remote sensing is a critical tool for characterizing ecohydrologic patterns and advancing the understanding of the interactions between atmospheric forcings and ecohydrologic responses. Fine to medium scale spatial and temporal resolutions are needed to capture the spatial heterogeneity and the temporally intermittent response of these ecosystems to environmental forcings. Techniques combining complementary remote sensing datasets have been developed, but the heterogeneous nature of these regions present significant challenges. Here we investigate the capacity of one such approach, the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) algorithm, to map Normalized Difference Vegetation Index (NDVI) at 30 m spatial resolution and at a daily temporal resolution in an experimental watershed in southwest Idaho, USA. The Dry Creek Experimental Watershed captures an ecotone from a sagebrush steppe ecosystem to evergreen needle-leaf forests along an approximately 1000 m elevation gradient. We used STARFM to fuse NDVI retrievals from the MODerate-resolution Imaging Spectroradiometer (MODIS) and Landsat during the course of a growing season (April to September). Specifically we input to STARFM a pair of Landsat NDVI retrievals bracketing a sequence of daily MODIS NDVI retrievals to yield daily estimates of NDVI at resolutions of 30 m. In a suite of data denial experiments we compared these STARFM predictions against corresponding Landsat NDVI retrievals and characterized errors in predicted NDVI. We investigated how errors vary as a function of vegetation functional type and topographic aspect. We find that errors in predicting NDVI were highest during green-up and senescence and lowest during the middle of the growing season. Absolute errors were generally greatest in tree-covered portions of the watershed and lowest in locations characterized by grasses/bare ground. On average, relative errors in predicted average NDVI were greatest in grass/bare ground regions, on south-facing aspects, and at the height of the growing season. We present several ramifications revealed in this study for the use of multi-sensor remote sensing data for the study of spatiotemporal ecohydrologic patterns in dryland ecosystems.

The Bruneau Woodpile: A Miocene Phosphatized Fossil Wood Locality in Southwestern Idaho, USA

The Bruneau Woodpile site has long been popular among fossil collectors; however, the deposit has received scant attention from scientists. Our research reveals that the fossilized wood was deposited ca. 6.85 Ma, within the Chalk Hills Formation, and was mineralized with carbonate-fluorapatite. The diverse assemblage of conifers and hardwoods is representative of the warm temperate forests that flourished in southwest Idaho, USA during the late Miocene. Limb and trunk fragments preserved in a single thin sandstone bed appear to represent woody debris that was transported by streams. One possible explanation is that wood, pumice, and sandy volcaniclastic sediment arrived separately as a result of ordinary stream action, and later were combined into a single assemblage during a subsequent high-energy sedimentation event. We favor an alternate hypothesis: a catastrophic event (e.g., a windstorm) damaged trees on slopes bordering the ancient lake. Branches and small trunk fragments were carried by wind and rain into local streams and ponds where they became waterlogged. After a delay that allowed pumice and wood to become saturated, storm water transported these materials, along with finer volcaniclastic sediment, into a lake. The resulting density current produced a fining-upward sedimentary cycle where wood was preserved in the lowest, coarsest stratum.

A machine learning approach to estimation of downward solar radiation from satellite-derived data products: An application over a semi-arid ecosystem in the U.S.

Shortwave solar radiation is an important component of the surface energy balance and provides the principal source of energy for terrestrial ecosystems. This paper presents a machine learning approach in the form of a random forest (RF) model for estimating daily downward solar radiation flux at the land surface over complex terrain using MODIS (MODerate Resolution Imaging Spectroradiometer) remote sensing data. The model-building technique makes use of a unique network of 16 solar flux measurements in the semi-arid Reynolds Creek Experimental Watershed and Critical Zone Observatory, in southwest Idaho, USA. Based on a composite RF model built on daily observations from all 16 sites in the watershed, the model simulation of downward solar radiation matches well with the observation data (r2 = 0.96). To evaluate model performance, RF models were built from 12 of 16 sites selected at random and validated against the observations at the remaining four sites. Overall root mean square errors (RMSE), bias, and mean absolute error (MAE) are small (range: 37.17 W/m2-81.27 W/m2, -48.31 W/m2-15.67 W/m2, and 26.56 W/m2-63.77 W/m2, respectively). When extrapolated to the entire watershed, spatiotemporal patterns of solar flux are largely consistent with expected trends in this watershed. We also explored significant predictors of downward solar flux in order to reveal important properties and processes controlling downward solar radiation. Based on the composite RF model built on all 16 sites, the three most important predictors to estimate downward solar radiation include the black sky albedo (BSA) near infrared band (0.858 μm), BSA visible band (0.3–0.7 μm), and clear day coverage. This study has important implications for improving the ability to derive downward solar radiation through a fusion of multiple remote sensing datasets and can potentially capture spatiotemporally varying trends in solar radiation that is useful for land surface hydrologic and terrestrial ecosystem modeling.

An evaluation of the ecohydrological separation hypothesis in a semiarid catchment

The ecohydrological separation hypothesis states that transpiration through plants and drainage to streams and groundwater are sourced from separate soil water pools, which possess distinct isotopic signatures. Evidence for ecohydrological separation has relied on the globally ubiquitous observation that plant water and draining water are isotopically distinct. We evaluated the ecohydrological separation hypothesis in the Dry Creek Experimental Watershed in the semiarid, snow-dominated landscape of southwest Idaho, USA. We found that plant water is indeed isotopically distinct from streams and groundwater. However, we were unable to track those waters to subsurface soil waters, nor were we able to relate soil water mobility to isotopic composition. Soil waters of different mobility can be isotopically similar, and isotopic distinction in soil water can occur for reasons not related to mobility. We suggest that isotopic distinction between root-absorbed and draining waters may not be an appropriate indicator of ecohydrological separation of soil waters, and that hydrologic explanations for such isotopic distinction may not be sufficient.

The Performance and Quality of Three Alternative Fruits in the Intermountain West Region of the United States

Adaptability and feasibility of table grape (Vitis vinifera or Vitis labrusca), asian pear (Pyrus pyrifolia), and quince (Cydonia oblonga) production under the high desert conditions of southwest Idaho in the Intermountain West region of the United States were studied. ‘Alborz’ table grape was harvested between 1 and 15 Sept. and with proper thinning, this cultivar had outstanding clusters and berries and could be a successful table grape for planting at commercial scales in warmer spots under conditions of this study. ‘Kashishi’ and ‘Autumn Royal’ were late-season cultivars and had large berries with excellent quality. ‘Ralli’, also called ‘Anahita’ in the Intermountain West, had attractive clusters and berry color, but was sensitive to frost and had poor production. ‘Princess’ grape was harvested between 5 and 30 Sept. and had poor fruit set, but berries had outstanding flavor. ‘Niitaka’ asian pear had the largest and firmest fruit with the lowest soluble solids concentration (SSC) among all tested asian pears. ‘Semi Dwarf Shinko’ asian pear had larger fruit than ‘Kikusui’ and ‘20th Century’ but smaller than ‘Niitaka’. However, ‘Kikusui’ and ‘20th Century’ had excellent fruit flavor and quality. Thus, ‘Kikusui’, ‘20th Century’, and ‘Niitaka’ asian pears can be chosen for planting under condition of this study. ‘Aromantnaya’ and ‘Rich’ quinces matured earlier and had lower fruit firmness than other cultivars. These cultivars can be planted for early market. Based on this study, ‘Van Deman’ can be chosen for fresh consumption if sweet cultivars are in demand by the market. However, ‘Rich’ and ‘Smyrna’ quinces can be chosen if fruit with large size and bright yellow color is preferred.

Assessment of the Timing of Daily Peak Streamflow during the Melt Season in a Snow-Dominated Watershed

AbstractPrevious studies have shown that gauge-observed daily streamflow peak times (DPTs) during spring snowmelt can exhibit distinct temporal shifts through the season. These shifts have been attributed to three processes: 1) melt flux translation through the snowpack or percolation, 2) surface and subsurface flow of melt from the base of snowpacks to streams, and 3) translation of water flux in the streams to stream gauging stations. The goal of this study is to evaluate and quantify how these processes affect observed DPTs variations at the Reynolds Mountain East (RME) research catchment in southwest Idaho, United States. To accomplish this goal, DPTs were simulated for the RME catchment over a period of 25 water years using a modified snowmelt model, iSnobal, and a hydrology model, the Penn State Integrated Hydrologic Model (PIHM). The influence of each controlling process was then evaluated by simulating the DPT with and without the process under consideration. Both intra- and interseasonal variability in DPTs were evaluated. Results indicate that the magnitude of DPTs is dominantly influenced by subsurface flow, whereas the temporal shifts within a season are primarily controlled by percolation through snow. In addition to the three processes previously identified in the literature, processes governing the snowpack ripening time are identified as additionally influencing DPT variability. Results also indicate that the relative dominance of each control varies through the melt season and between wet and dry years. The results could be used for supporting DPTs prediction efforts and for prioritization of observables for DPT determination.

Best Practices for Outreach and Engagement to Latino Audiences Using Community-Based Programs

The Latino community continues to grow at an increasing rate. Latinos have become the “majority-minority,” and by 2043, minorities will be the majority in the United States with Latinos as the largest ethnic minority group. The lack of targeted programming to ethnically diverse audiences is a growing concern for many organizations. This article describes research-based strategies and best practices for providing culturally appropriate Extension programs to the Latino community through community-based programs. This is illustrated through examples incorporated into three community-based programs offered in Southwest Idaho, Southeast Oregon, and Southwest Washington. The objective is to discuss the value of each key component when providing services to the Latino community; describe what the research indicates; and offer practical applications for educators, staff, and other professionals to expand outreach and engagement efforts to the Latino population. Implications for professionals working with the Latino community are discussed.

Water stress, nano silica, and digoxin effects on minerals, chlorophyll index, and growth in ryegrass

Water shortages worldwide mandate minimum use of irrigation water with maximum efficiency and productivity in all agricultural crops, landscape plants and turf. The objective of this experiment was to study the effect of two levels of evapotranspiration-based (ETc) drought in combination with two levels of nano silicon dioxide (SiO2; NanSi1 = 1 mM and NanSi2 = 2 mM), two levels of digoxin (Dig1 = 0.25 mg.l -1 and Dig2 = 0.5 mg.l -1 ) and Dig1 plus NanSi1 on mineral nutrient concentration, chlorophyll index and visual performance of perennial ryegrass (Lolium perenne) under climatic conditions of southwest Idaho in the Intermountain West Region of the United States. Clippings with 50% ETc had higher percentage dry weight but lower chlorophyll index and visual rating than those with 75%. Clippings of 75%ETc treatment had significantly higher concentrations of nitrogen (N), potassium (K), zinc (Zn) and copper (Cu) but lower sodium (Na), than those receiving the 50%ETc treatment. Considering all mineral nutrient values, chlorophyll indices and visual performance ratings, we conclude that application of 75%ETc is sufficient for maintaining a healthy lawn with satisfactory appearance while we can saving 25% water as compared to application of water at 100%. Root growth was un affected by any of these treatments. Based on the results of this study, applications of NanSi1 or Dig1, either individually or simultaneously, can slow the process of quality decline in perennial ryegrass turf under extremely severe drought conditions.

Bedrock infiltration estimates from a catchment water storage-based modeling approach in the rain snow transition zone

Summary Estimates of bedrock infiltration from mountain catchments in the western U.S. are essential to water resource managers because they provide an estimate of mountain block recharge to regional aquifers. On smaller scales, bedrock infiltration is an important term in water mass balance studies, which attempt to estimate hydrologic states and fluxes in watersheds with fractured or transmissive bedrock. We estimate the a daily time series of bedrock infiltration in a small catchment in the rain snow transition zone in southwest Idaho, using the difference between measured stream discharge and modeled soil drainage. The accuracy of spatial patterns in soil water storage are optimized, rather than the more common approach of minimizing error in integrated quantities such as streamflow. Bedrock infiltration is estimated to be 289 mm ± 50 mm for the 2011 water year, which is 34% ± 12% of the precipitation (95% confidence). Soils on the southwest facing slope drain more often throughout the snow season, but the northeast facing slope contributes more total soil drainage for the water year. Peaks in catchment soil drainage and bedrock infiltration coincide with rain on snow events.

Flood flow attenuation diminishes cottonwood colonization sites: an experimental test along the Boise River, USA

AbstractThe Boise River in southwest Idaho, USA, flows from forested mountain headwaters to the sagebrush steppe where the river was first regulated in 1909 for irrigated agriculture. Large upstream dams constructed in 1915, 1950, and 1955 are now operated to manage water for both irrigation and the attenuation of flood flows. This, in combination with bank armoring and channelization, has produced a narrowed river channel with simplified morphology. After damming, the native black cottonwood forest, Populus trichocarpa, expanded onto positions previously within the active channel. Since then, sexual reproduction of these cottonwoods appears to have become limited, apparently because of the lack of colonization sites devoid of competing vegetation. We investigated this hypothesis by constructing a channel that simulated recruitment sites previously formed by flood flow events. We observed extensive black cottonwood seedling recruitment along this channel in contrast to nearby reference sites where there were no seedlings, only saplings that originated as clonal root suckers. We conclude that the attenuation of flood flows has removed the geomorphic disturbance that previously created sites for colonization. As a consequence, the forest currently propagates primarily by clonal suckering that fails to introduce genetic diversity essential for adapting to change in the environment. To compensate for this loss, we recommend selective clearing and regrading of the floodplain according to an engineered design as one method to create cottonwood colonization sites. Copyright © 2015 John Wiley &amp; Sons, Ltd.