Southwest Idaho Research Articles

Species delimitation tests of endemic Lepidium papilliferum and identification of other possible evolutionarily significant units in the Lepidium montanum complex (Brassicaceae) of western North America

Lepidium papilliferum of southwest Idaho was previously treated as an infraspecific variety of Lepidium montanum. Chloroplast (cpDNA) sequences, nuclear ribosomal internal transcribed spacer (ITS) sequences, and AFLPs were used to test species delimitations and other possible evolutionarily significant units (ESU) based on genetic differentiation, isolation by distance (IBD), and genetic admixture among 32 L. montanum and 21 L. papilliferum collections from the western US. The L. papilliferum AFLP genotypes formed a monophyletic clade. However, the AFLP genotypes of L. montanum samples from eight western sites were more similar to L. papilliferum, which together comprise a regionally significant West clade showing significant differentiation from eastern L. montanum collections (East clade). Bayesian analysis of AFLP genotypes detected possible admixture between L. papilliferum and related western L. montanum collections. Neither taxa nor regionally significant AFLP clades displayed reciprocally monophyletic cpDNA or ITS sequences, but the AFLP clades showed stronger cpDNA differentiation and unique ITS alleles. The East and West clades fit models of speciation with relatively strong IBD within groups and weak IBD between groups, based on correlations between the average number of AFLP differences and geographic distances among collection sites, but comparisons between taxa did not fit this model. Conversely, relatively strong partial correlations between AFLP and taxonomic differences, controlling for geography, support taxonomic delimitations. Results suggest that L. papilliferum is a distinct subgroup of L. montanum influenced by speciation. However, gene flow or common ancestry between L. papilliferum and western forms of L. montanum provide a basis for other possible ESUs.

Stratigraphic record of the Yellowstone hotspot track, Neogene Sixmile Creek Formation grabens, southwest Montana

The Sixmile Creek Formation fills deep grabens in southwest Montana and preserves a stratigraphic record of the evolution of the Yellowstone hotspot track from ~ 17 Ma to ~ 2 Ma. The Ruby, Beaverhead, Big Hole, Deer Lodge, Medicine Lodge-Grasshopper, Three Forks, Canyon Ferry, Jefferson, Melrose, Wise River, and Paradise grabens were active during outbreak of the hotspot. They appear to be parts of a radial system of extensional structures that may have formed on a broad dome that was centered on the hotspot outbreak area in southwest Idaho and southeast Oregon. Early in the evolution of the grabens, massive debris flows surged down Paleogene paleovalleys from uplifted and tilted horst blocks and accumulated in the grabens. The grabens captured runoff from the hotspot dome with thick deposits of river gravel that appear to have been derived, in part, from east-central Idaho. As the hotspot track propagated along the eastern Snake River Plain, silicic ash fell into the graben drainage basins and was reworked into thick fluvial beds along graben axes. The grabens were cross-cut by northwest-trending late Neogene grabens that propagated on the flanks of silicic volcanic centers along the hotspot track. The late Neogene grabens diverted the Middle Miocene drainage patterns in southwest Montana.

Spatio-temporal cluster analysis of county-based human West Nile virus incidence in the continental United States

BackgroundWest Nile virus (WNV) is a vector-borne illness that can severely affect human health. After introduction on the East Coast in 1999, the virus quickly spread and became established across the continental United States. However, there have been significant variations in levels of human WNV incidence spatially and temporally. In order to quantify these variations, we used Kulldorff's spatial scan statistic and Anselin's Local Moran's I statistic to uncover spatial clustering of human WNV incidence at the county level in the continental United States from 2002–2008. These two methods were applied with varying analysis thresholds in order to evaluate sensitivity of clusters identified.ResultsThe spatial scan and Local Moran's I statistics revealed several consistent, important clusters or hot-spots with significant year-to-year variation. In 2002, before the pathogen had spread throughout the country, there were significant regional clusters in the upper Midwest and in Louisiana and Mississippi. The largest and most consistent area of clustering throughout the study period was in the Northern Great Plains region including large portions of Nebraska, South Dakota, and North Dakota, and significant sections of Colorado, Wyoming, and Montana. In 2006, a very strong cluster centered in southwest Idaho was prominent. Both the spatial scan statistic and the Local Moran's I statistic were sensitive to the choice of input parameters.ConclusionSignificant spatial clustering of human WNV incidence has been demonstrated in the continental United States from 2002–2008. The two techniques were not always consistent in the location and size of clusters identified. Although there was significant inter-annual variation, consistent areas of clustering, with the most persistent and evident being in the Northern Great Plains, were demonstrated. Given the wide variety of mosquito species responsible and the environmental conditions they require, further spatio-temporal clustering analyses on a regional level is warranted.

Phylogenetic relationships among Lepidium papilliferum (L. Henderson) A. Nels. & J. F. Macbr., L. montanum Nutt., and L. davisii Rollins (Brassicaceae)1

Previous phylogenetic analyses of Lepidium included only a few accessions of L. montanum, L. flavum, and L. fremontii to represent western North American species. Two additional species endemic to southwest Idaho have posed both taxonomic and conservation questions regarding their species status. Lepidium papilliferum was originally described as a variety of L. montanum, is morphologically similar to L. montanum, and is found in small scattered populations in southwest Idaho. The plant is restricted to specific edaphic conditions known as slick spots where high clay content creates conditions amenable to L. papilliferum, but to few other species. Resolving whether the populations of L. papilliferum merit species status distinct from L. montanum is a vexing question and phylogenetic analyses can assist in resolving this issue. Like L. papilliferum, L. davisii has specific edaphic requirements and is found in playas, areas similar to slick spots, but larger and with deeper soils. Unlike L. papilliferum, L. davisii is morphologically distinct from L. montanum and has posed less of a taxonomic quandary. Previous phylogenetic studies have shown that American species of Lepidium are derived from an ancestral allopolyploid species. In this study we have expanded previous analyses to include L. papilliferum, L. davisii, and several accessions of L. montanum along with published sequences of ITS, cpDNA, and PISTILLATA first intron. The western North American species form a monophyletic group with L. davisii sister to the remainder of the clade. Within this clade, L. papilliferum and L. fremontii are each monophyletic and sister to each other, but are imbedded within a paraphyletic L. montanum.

Simulated soil water storage effects on streamflow generation in a mountainous snowmelt environment, Idaho, USA

AbstractAlthough soil processes affect the timing and amount of streamflow generated from snowmelt, they are often overlooked in estimations of snowmelt‐generated streamflow in the western USA. The use of a soil water balance modelling approach to incorporate the effects of soil processes, in particular soil water storage, on the timing and amount of snowmelt generated streamflow, was investigated. The study was conducted in the Reynolds Mountain East (RME) watershed, a 38 ha, snowmelt‐dominated watershed in southwest Idaho. Snowmelt or rainfall inputs to the soil were determined using a well established snow accumulation and melt model (Isnobal). The soil water balance model was first evaluated at a point scale, using periodic soil water content measurements made over two years at 14 sites. In general, the simulated soil water profiles were in agreement with measurements (P < 0·05) as further indicated by high R2 values (mostly > 0·85), y‐intercept values near 0, slopes near 1 and low average differences between measured and modelled values. In addition, observed soil water dynamics were generally consistent with critical model assumptions. Spatially distributed simulations over the watershed for the same two years indicate that streamflow initiation and cessation are closely linked to the overall watershed soil water storage capacity, which acts as a threshold. When soil water storage was below the threshold, streamflow was insensitive to snowmelt inputs, but once the threshold was crossed, the streamflow response was very rapid. At these times there was a relatively high degree of spatial continuity of satiated soils within the watershed. Incorporation of soil water storage effects may improve estimation of the timing and amount of streamflow generated from mountainous watersheds dominated by snowmelt. Copyright © 2008 John Wiley & Sons, Ltd.

ISOLATION AND CHARACTERIZATION OF HUMIC ACIDS IN IDAHO SLICKSPOT SOILS

Naturally occurring humic substances in soils hold promise as a factor related to restoring native plants. We have characterized the humic acids (HA) from inside and outside slickspots of two sites in the Juniper Butte Range soils on the Snake River Plain in Southwest Idaho. These HA may promote the establishment of native slickspot peppergrass (Lepidium papilliferum) seedlings. The HA were extracted from the silt, vesicular, and clay layers using a modified International Humic Substances Society method, and isolated by membrane filtration, precipitation, dialysis, and freeze-drying. Elemental analyses showed minor differences between HA; the inside surface silt samples had higher C and N values than the outside or the deeper samples. Differences were also noted between sample sites and between the samples for carbohydrates, amino acids, and acidity functionalities. Fourier transform infrared and fluorescence, and especially cross-polarization magic angle spinning 13C-nuclear magnetic resonance spectroscopies, provided compositional information and highlighted differences between the samples.

Intermountain Presettlement Juniper: Distribution, Abundance, and Influence on Postsettlement Expansion

Successful implementation of watershed restoration projects involving control of piñon and juniper requires understanding the spatial extent and role presettlement trees (> 140 yr) play in the ecology of Intermountain West landscapes. This study evaluated the extent, abundance, and spatial pattern of presettlement western juniper (Juniperus occidentalis Hook.) in four woodlands located in southeast Oregon and southwest Idaho. The potential for modeling presence/absence of presettlement juniper using site characteristics was tested with logistic regression and the influence presettlement trees had on postsettlement woodland (trees < 140 yr) expansion was evaluated with a Welch’s t-test. Pre- and postsettlement tree densities, tree ages, site characteristics, and understory vegetation were measured along four 14–27 km transects. Presettlement juniper occurred in 16%–67% of stands in the four woodlands and accounted for 1%–10% of the population of trees > 1 m tall. Presettlement trees were generally widely scattered and more common in lower elevation stands with greater surface rock cover and higher insolate exposure. Presettlement trees sparsely occupied productive sites on deeper soils in southwest Idaho, suggesting the area had sustained a different disturbance regime than southeast Oregon. Southwest Idaho might have experienced a high frequency of lower severity fire that afforded survival to widely distributed legacy trees. This supposition is in contrast to most reports of a disturbance regime including either stand replacement or frequent fire of sufficient intensity to preclude survival of trees to maturity. Stands sustaining presettlement trees initiated woodland expansion 24 yr earlier than stands lacking presettlement trees. Presettlement trees may serve as a seed source potentially reducing the longevity of juniper control treatments. For areas with greater abundances and spatial distribution of presettlement trees such as southwest Idaho, management maintaining low intensity fire or cutting treatments at frequencies of less than 50 yr should sustain relatively open stands. La implementación exitosa de proyectos de restauración de cuencas hidrológicas que involucran el control de “Piñon” y “Juniper” requiere de entender la cantidad espacial y el papel que los árboles (> 140 años) existentes desde antes de la colonización (precolonización) juegan en la ecología de los paisajes de los valles del oeste. Este estudio evaluó la cantidad, abundancia y patrón espacial del “Western juniper” (Juniperus occidentalis Hook.) de la precolonización en cuatro bosques localizados en el sudeste de Oregon y sudoeste de Idaho. El potencial para modelar la presencia/ausencia del “Juniper” de la precolonización usando características del sitio se probó con regresión logística; la influencia que los árboles de la precolonización tuvieron en la expansión de del bosque en la postcolonización (árboles < 140 años) fue evaluada con la prueba de t de Welch. Las densidades de árboles pre- y postcolonización, las edades de los árboles, las características del sitio y la vegetación del estrato herbáceo fueron medidas a lo largo de 14 transectos de 27 km. El “Juniper” precolonización ocurrió en 16%–67% de las poblaciones de los cuatro bosques y aportó de 1%–10% de la población de árboles mayores a 1 m de altura. Los árboles precolonización, generalmente estuvieron muy dispersos y fueron más comunes en las poblaciones de baja elevación con una mayor cobertura de rocas en la superficie y mayor exposición a la insolación. Los árboles precolonización ocuparon escasamente los sitios productivos de suelos profundos del sudoeste de Idaho, sugiriendo que el área había sostenido un régimen de disturbio diferente al sudeste de Oregon. El sudoeste de Idaho pudo haber experimentado una mayor frecuencia de fuegos de baja severidad que permitió la supervivencia de un legado de árboles ampliamente distribuido. Esta suposición esta en contraste a la mayoría de los reportes de un régimen de disturbio que incluye tanto el reemplazo de poblaciones o de fuegos frecuentes de intensidad suficiente para imposibilitar la supervivencia de los árboles en la madurez. Las poblaciones con árboles de precolonización iniciaron la expansión del bosque 24 años antes que las poblaciones carentes de ellos. Los árboles precolonización pueden servir como fuente de semilla, reduciendo potencialmente la longevidad de los tratamientos de control de “Juniper.” Para áreas con altas abundancias y mayor distribución espacial de árboles precolonización, tales como las del sudoeste de Idaho, el manejo para mantener fuegos de baja intensidad o tratamientos de corte a frecuencias menores de 50 años deben mantener poblaciones relativamente abiertas.

Characterizing Times Between Storms in Mountainous Areas

Storm simulation models are sometimes used to provide input to watershed models where there are no precipitation data. However, a basic understanding of the seasonal and spatial characteristics of parameters that comprise the inputs to the models is needed, and then methods for estimating the parameters must be developed. This study is an investigation of the behavior and estimation of two parameters for storm-occurrence modeling, average time between storms (ATBS) and minimum time between storms (MDPD), and how they vary with average annual precipitation (Pann), average monthly precipitation (Pmo), and elevation (E) in mountainous terrain where snow is a major component of precipitation. Data used came from the dual-rain-gauge network in the USDA-ARS Reynolds Creek Experimental Watershed (RCEW) in southwest Idaho. Median ATBS and MDPD data show consistent trends over the RCEW with narrow variability. The exponential distribution adequately models times between storms in snowfall-predominant mountainous areas except for very long dry periods. The power equation form generally fitted the data best for regressions where there was a statistically significant regression compared with a linear equation. For four of the regressions found in this article (Pmo vs. E, ATBS vs. Pmo, ATBS vs. E, and MDPD vs. ATBS), parameters were correlated, suggesting parameter mapping may be useful in their estimation. ATBS can be estimated by using the power equation for ATBS vs. Pmo and ATBS vs. E (both inversely correlated). MDPD vs. ATBS correlations were positive, showing that as the average time between storms increases, so does the minimum time between storms. Guidance is given for estimating ATBS and MDPD for a specific location. Magnitudes of often-used fixed values of MDPD (e.g., 6 h) are too small to be representative of times between storms, and are not representative of the seasonal variability of times between storms. The results in this article for characterizing ATBS and MDPD in the mountainous 239-km2 RCEW area follow closely those found for the 225,000-km2 Colorado plains area in another study. Thus, equation forms identified in this article can suggest those that might be expected in general and may be used as guidance for estimating ATBS and MDPD in ungauged areas, including areas with snowfall as a major component of precipitation.

First Report of Iris yellow spot virus on Onion and Leek in Western Oregon.

Onion (Allium cepa) and leek (Allium porrum) are grown on approximately 600 ha in western Oregon annually for bulb and seed production. During July and August of 2006, surveys of onion bulb crops and onion and leek seed crops in western Oregon found plants with symptoms of elongated to diamond-shaped, straw-colored lesions characteristic of those caused by Iris yellow spot virus (IYSV) (1-4). Symptomatic plants were collected from fields of an onion bulb crop, an onion seed crop, and two leek seed crops located in Marion County. The onion bulb crop had been planted in the spring of 2006, and the onion and leek seed crops had been planted in the fall of 2005, all direct seeded. Cultivar names were not provided for proprietary purposes. Symptomatic plants in the onion bulb crop and leek seed crop generally were found near the borders of the field. Disease incidence was less than 5% and yield losses in these crops appeared to be negligible. In the onion seed crop, symptomatic plants were found throughout the field and disease incidence was approximately 20%. Approximately 1% of the onion plants in this field had large necrotic lesions that caused the seed stalks (scapes) to lodge. The presence of IYSV was confirmed from symptomatic leaves and scapes by ELISA (Agdia Inc., Elkhart, IN) using antiserum specific to IYSV. RNA was extracted from symptomatic areas of onion leaves and scapes, and a portion of the nucleocapsid gene was amplified by reverse transcription-PCR. The amplicons were sequenced and found to share more than 99% nucleotide and amino acid sequence identity with an onion isolate of IYSV from the Imperial Valley of California (GenBank Accession No. DQ233475). In the Pacific Northwest region of the United States, IYSV has been confirmed in the semi-arid regions of central Oregon (1), central Washington (2), and the Treasure Valley of eastern Oregon and southwest Idaho (3). To our knowledge, this is the first report of the disease on a host crop in the mild, maritime region west of the Cascade Mountain Range and the first report of IYSV on leek seed crops in the United States, which complements a simultaneous report of IYSV on commercial leek in Colorado. The presence of IYSV may have implications for the iris and other ornamental bulb industries in western Oregon and western Washington. This report underscores the need for further research to determine the impact of the disease on allium crops and other hosts and the development of effective management programs for IYSV and the vector, Thrips tabaci.

Multiple phases of Tertiary extension and synextensional deposition of the Miocene-Pliocene Salt Lake Formation in an evolving supradetachment basin, Malad Range, southeast Idaho, U.S.A.

The extensional history of the Malad and Bannock ranges in southeast Idaho and northern Utah involves multiple phases of Tertiary normal faulting and synextensional deposition. Detailed geologic mapping, structural and stratigraphic analyses, and geochronologic data from this study elucidate previously defined deformational events in the region, and define two new extensional episodes. The largest-magnitude extension took place along low-angle normal faults of the ∼10–4-Ma Bannock detachment system, with concurrent sedimentation of the Miocene–Pliocene Salt Lake Formation in a regionally continuous supradetachment basin. This basin developed by ∼10.2 Ma, and was preceded by two phases of smaller-magnitude, aerially restricted normal faulting and sedimentation. In the Henderson Creek quadrangle of the southern Malad Range, the earliest event involved ∼8% north–south extension during deposition of the Paleocene–Eocene Wasatch (?) Formation. This conglomerate unit was deposited in an asymmetric, south-tilted half-graben bounded on the south by the syntectonic Willow Spring normal fault. The next pre-detachment extensional event produced a north-striking, east-tilted half-graben in which the Middle to Late Miocene Skyline Member of the Salt Lake Formation (∼11.9–10.2 Ma) was deposited as an ash-rich alluvial fan. This half-graben is bounded on the east and south by the syntectonic Red Knoll and Spring Trail normal faults. Detrital zircon age data from a tuffaceous sandstone bed in the Skyline Member suggest incorporation of reworked zircons from the ∼12.5–15-Ma Owhyee-Humboldt volcanic field in southwest Idaho with 10.3-Ma glass. The inception of the regional Bannock detachment system is recorded by the breakup and ∼16% west-southwest extension of its hanging wall by a set of north- to north–northwest-striking Late Miocene normal faults. These faults were associated with syntectonic deposition of the Cache Valley Member of the Salt Lake Formation (∼10.2− <9.2 Ma) in a regional-scale lake system. During deposition, the northeast-dipping Steel Canyon normal fault accommodated uplift of an intrabasinal horst that shed a wedge of Third Creek Member conglomerate eastward into the lake system between ∼10.0 and <9.2 Ma. The Third Creek Member interfingers with a Cache Valley Member lake-margin tufa-bearing facies, which changes eastward into a deeper-water, micritic limestone-bearing facies. The most recent extensional event in the Henderson Creek quadrangle involved ∼9% east–west extension on the north-striking Pliocene–Quaternary Wasatch fault. A segment boundary of the Wasatch fault, consisting of a 2.5–3.5-km-wide relay ramp that formed between two right-stepping en echelon segments, lies just north of the Idaho-Utah border. In addition, a broad, north- to north–northwest-trending antiformal zone of extensional folds is present in the south half of the study area and is interpreted as a double-rollover anticline that formed progressively in Late Miocene and Pliocene–Quaternary time above two oppositely dipping listric normal faults.

Effects of Radiomarking on Prairie Falcons: Attachment Failures Provide Insights About Survival

From 1999–2002, we attached satellite-received platform transmitter terminals (PTTs) to 40 adult female prairie falcons (Falco mexicanus) on their nesting grounds in the Snake River Birds of Prey National Conservation Area (NCA) in southwest Idaho. We used 3 variations of a backpack harness design that had been used previously on raptors. Each radiomarked falcon also received a color leg band with a unique alphanumeric code. We monitored survival of birds using radiotelemetry and searched for marked birds on their nesting grounds during breeding seasons after marking. Because 6 falcons removed their harnesses during the first year, we were able to compare survival rates of birds that shed PTTs with those that retained them. We describe a harness design that failed prematurely as well as designs that proved successful for long-term PTT attachment. We resighted 21 marked individuals on nesting areas 1–5 years after they were radiomarked and documented 13 mortalities of satellite-tracked falcons. We used a Cormack-Jolly-Seber model to estimate apparent survival probability based on band resighting and telemetry data. Platform transmitter terminals had no short-term effects on falcons or their nesting success during the nesting season they were marked, but birds that shed their transmitters increased their probability of survival. Estimated annual survival for birds that shed their transmitters was 87% compared to 49% for birds wearing transmitters. We discuss possible reasons for differences in apparent survival rates and offer recommendations for future marking of falcons.

Long-Range Movements and Breeding Dispersal of Prairie Falcons From Southwest Idaho

Abstract From 1999–2003, we tracked movements of adult female Prairie Falcons (Falco mexicanus) using satellite telemetry to characterize long-range movement patterns and breeding dispersal. We radio marked 40 falcons from April–May on their nesting grounds in the Snake River Birds of Prey National Conservation Area in southwest Idaho. All falcons with functioning transmitters left the Snake River Canyon from late June through mid-July. Most headed northeast across the Continental Divide to summering areas in Montana, Alberta, Saskatchewan, and the Dakotas. Prairie Falcons stayed at their northern summer areas for 1–4 months before heading to the southern Great Plains or to southwest Idaho. The Great Plains was a key migration pathway. Important wintering areas included the Texas Panhandle and southwest Idaho. Most falcons completed their seasonal migrations within 2 weeks. Use of widely separated nesting, summering, and wintering areas appears to be a strategy to exploit seasonally abundant prey resources. Most falcons had three or fewer use areas during the nonbreeding season, and falcons showed a high degree of fidelity to their use areas during each season. At least 21 falcons returned to nest within 2.5 km of where they nested in the previous year, but one falcon moved to a new nesting area 124 km south of her previous breeding area. Prairie Falcon movements suggest large-scale connectivity of grassland and shrubsteppe landscapes throughout western North America. Conservation of Prairie Falcons must be an international effort that considers habitats used during both nesting and non-nesting seasons. Movimientos de Largo Alcance y Dispersión Reproductiva de Falco mexicanus del Sudoeste de Idaho Resumen. Entre los años 1999 y 2003, seguimos los movimientos de hembras adultas de Falco mexicanus utilizando telemetría satelital para caracterizar los patrones de movimiento de largo alcance y la dispersión reproductiva. Marcamos con radios a 40 halcones desde abril hasta mayo en sus sitios de nidificación en el Área de Conservación Nacional de Aves de Presa Snake River en el sudoeste de Idaho. Todos los halcones con transmisores funcionando dejaron el cañón de Snake River desde fines de junio hasta mediados de julio. La mayoría se dirigió hacia el noreste a lo largo de la línea de división continental rumbo a las áreas de veraneo en Montana, Alberta, Saskatchewan y Dakotas. F. mexicanus permaneció en sus áreas de veraneo del norte durante 1 a 4 meses antes de dirigirse hacia las Great Plains del sur o hacia el sudoeste de Idaho. Las Great Plains representaron una ruta migratoria clave. Las áreas de invernada importantes incluyeron al Texas Panhandle y el sudoeste de Idaho. La mayoría de los halcones completaron su migración estacional en menos de dos semanas. El uso de áreas de nidificación, de veraneo e de invernada ampliamente separadas entre sí parece ser una estrategia para explotar presas estacionalmente abundantes. La mayoría de los halcones tuvo tres o menos áreas de uso durante la estación no reproductiva y los halcones mostraron un alto nivel de fidelidad a sus áreas de uso durante cada estación. Al menos 21 halcones regresaron a nidificar a menos de 2.5 km de donde nidificaron el año previo, pero un halcón se desplazó a una nueva área de nidificación ubicada a 124 km al sur de su área previa de cría. Los movimientos de F. mexicanus sugieren la existencia de una conectividad a gran escala de los paisajes de pastizal y la estepa arbustiva a través del oeste de América del Norte. La conservación de F. mexicanus debe ser un esfuerzo internacional que considere los ambientes usados durante las estaciones reproductivas y no reproductivas.

Fish and stream habitat risks from uncharacteristic wildfire: Observations from 17 years of fire-related disturbances on the Boise National Forest, Idaho

Several large, uncharacteristic wildfires occurred on the Boise National Forest in Southwest Idaho, from 1986 to 2003. From 1987 to 1994, severe wildfires burned almost 50% of the ponderosa pine forest types (about 200,000 ha). The intensity of the fires varied across the landscape, with a mix of low to moderate severity, and lesser amounts of high burn severity. After the fires, localized debris flows favored smaller order streams in watersheds less than 4000 ha in size, where there had been mostly high severity burning. Locally, areas experiencing high heat and post-fire debris flows had reduced fish numbers and altered fish habitats. Uncharacteristic wildfires on the managed portions of the Boise National Forest appeared to have more pronounced, short-term effects on fish habitats as compared with characteristic wildfires in the Central Idaho Wilderness. Even in the most severely impacted streams, habitat conditions and trout populations improved dramatically within 5–10 years. Post-fire floods apparently rejuvenated stream habitats by exporting fine sediments and by importing large amounts of gravel, cobble, woody debris, and nutrients, resulting in higher fish productivities than before the fire. These observations suggest that important elements of biodiversity and fish productivity may be influenced, or even created by fire-related disturbances. In some cases, habitats that were completely devoid of salmonid fishes just after the debris floods, were later re-colonized with migrants returning from downstream or nearby tributary rearing habitats. Re-population was likely enhanced by higher fecundity, homing instinct, and greater mobility of the larger migratory fish. Ecosystem restoration activities that reduce both short- and long-term threats of uncharacteristic wildfire on imperiled fishes could be emphasized in areas where local populations may be weak and/or isolated, but potentially recoverable. But forest ecosystem restoration alone may not reduce risks to fish if existing habitat conditions and isolation are limiting the population.

Performance of Six Wine Grapes Under Southwest Idaho Environmental Conditions

Abstract Adaptability, yield, quality attributes, and cumulative growing degree day (GDD) requirements of ‘Barbera 02’, ‘Cabernet Sauvignon 02’, ‘Cabernet Sauvignon 04’, ‘Chardonnay 29’, ‘Merlot 01’, and ‘Sangiovese 04’ wine grapes cultivar clones (Vitis spp.) under climatic conditions of southwest Idaho (Intermountain West region, USA) were evaluated during 2000 and 2001 seasons. ‘Sangiovese 04’ had significantly higher yield than ‘Cabernet Sauvignon 02’, ‘Cabernet Sauvignon 04’, ‘Chardonnay 29’, and ‘Merlot 01’ in both 2000 and 2001. ‘Barbera 02’ also had relatively higher yield than many other cultivar clones. ‘Cabernet Sauvignon 02’ had the lowest yield, although differences were not always significant. Other than cluster weight in 2000, no significant differences existed for yield, fruit quality attributes, or GDD requirements between the two ‘Cabernet Sauvignon’ clones (’Cabernet Sauvig non 02’ and ‘Cabernet Sauvignon 04). ‘Barbera 02’ and ‘Sangiovese 04’ had the largest, while ‘Cabernet Sauvignon 0...

LONG-RANGE MOVEMENTS AND BREEDING DISPERSAL OF PRAIRIE FALCONS FROM SOUTHWEST IDAHO

Abstract From 1999–2003, we tracked movements of adult female Prairie Falcons (Falco mexicanus) using satellite telemetry to characterize long-range movement patterns and breeding dispersal. We radio marked 40 falcons from April–May on their nesting grounds in the Snake River Birds of Prey National Conservation Area in southwest Idaho. All falcons with functioning transmitters left the Snake River Canyon from late June through mid-July. Most headed northeast across the Continental Divide to summering areas in Montana, Alberta, Saskatchewan, and the Dakotas. Prairie Falcons stayed at their northern summer areas for 1–4 months before heading to the southern Great Plains or to southwest Idaho. The Great Plains was a key migration pathway. Important wintering areas included the Texas Panhandle and southwest Idaho. Most falcons completed their seasonal migrations within 2 weeks. Use of widely separated nesting, summering, and wintering areas appears to be a strategy to exploit seasonally abundant prey resource...

SEDIMENT POND EFFECTIVENESS FOR REMOVING PHOSPHORUS FROM PAM-TREATED IRRIGATION FURROWS

Polyacrylamide (PAM) greatly reduces erosion on furrow-irrigated fields and sediment ponds can be constructedto remove suspended sediment from irrigation runoff. Both practices are approved for reducing phosphorus (P) loading inthe Lower Boise River Pollution Trading Project in southwest Idaho, but information is not available about using bothpractices on the same field. The objective of this study was to measure the combined effects of PAM application and sedimentponds on sediment and P losses from a furrow-irrigated field. Small sediment ponds (5.8 m2) with a 60-min design retentiontime were installed on two fields to receive runoff from PAM-treated or control furrows. Pond inflow and outflow weremonitored during a total of 11 irrigations on the two fields. Three crop years of data showed that applying PAM to furrowsreduced sediment and total P mass transport to the ponds 50% to 80%, which reduced the mass of sediment and total P retainedin the ponds. However, PAM application did not change the percentage of sediment (86%) and total P (66%) retained. ThePAM-sediment pond combination reduced average total P loss by 86% to 98%, based on the difference between untreatedinflow and PAM-treated outflow. PAM and sediment ponds had little or no effect on dissolved reactive P (DRP)concentrations. The mass of DRP retained in sediment ponds was directly related to the amount of water that infiltrated withinthe ponds. Applying PAM to irrigation furrows and installing sediment ponds at the end of the field can be an effectivecombination for reducing sediment and total phosphorus losses from furrow-irrigated fields, but these practices only reducedsoluble P losses by decreasing the volume of water that ran off the fields.

MULE DEER SURVIVAL AMONG ADJACENT POPULATIONS IN SOUTHWEST IDAHO

Abstract We investigated survival and cause-specific mortality of mule deer (Odocoileus hemionus) on 3 distinct winter ranges in southwest Idaho from 1992 to 1997 to identify demographic variation and potential limiting factors based on a sample of 447 radiocollared deer. During winters 1995–1996 and 1996–1997, we modeled overwinter fawn mortality based on early winter mass, sex, activity, and habitat use variables. Annual survival rates of adult mule deer varied among the 3 adjacent study areas (χ22 = 10.93, P = 0.004). Overwinter deer survival also varied among study areas (χ22 = 8.00, P = 0.018), and the study area × year, study area × sex, and study area × age interactions were all significant (P ≤ 0.018). Overwinter survival differences among the study areas were not consistent over time or among sexes and ages of deer. Winter malnutrition was the main cause of mortality for both adults and fawns during the severe winter of 1992–1993, when overall survival was low. Excluding harvest, predation was th...

Large-volume, low-δ18O rhyolites of the central Snake River Plain, Idaho, USA

The Miocene Bruneau-Jarbidge and adjacent volcanic fields of the central Snake River Plain, southwest Idaho, are dominated by high-temperature rhyolitic tuffs and lavas having an aggregate volume estimated as 7000 km3. Samples from units representing at least 50% of this volume are strongly depleted in 18O, with magmatic feldspar δ18OVSMOW (Vienna standard mean ocean water) values between −1.4‰ and 3.8‰. The magnitude of the 18O depletion and the complete lack of any rhyolites with normal values (7‰–10‰) combine to suggest that assimilation or melting of a caldera block altered by near- contemporaneous hydrothermal activity is unlikely. Instead, we envisage generation of the high-temperature rhyolites by shallow melting of Idaho Batholith rocks, under the influence of the Yellowstone hotspot, affected by Eocene meteoric-hydrothermal events. The seeming worldwide scarcity of strongly 18O-depleted rhyolites may simply reflect a similar scarcity of suitable crustal protoliths.

Observations on the movement of coarse gravel using implanted motion‐sensing radio transmitters

AbstractMotion‐sensing radio transmitters were implanted in cobbles (72–92 mm diameter) and placed in a stream in south‐west Idaho for 43 days during a snowmelt period. The radios transmit different pulse rates depending on whether the rocks are at rest or in motion. Every 30 s, a datalogger samples the receiver and records the pulse rate of the transmitters. Such information can be used to assess numerous properties of particle transport that are beyond the capabilities of conventional tracking methods. Conclusions include: (i) rocks are more likely to move on rising hydrograph limbs than on falling hydrograph limbs; (ii) the average Shields' parameter is 0·046; (iii) rocks move only a fraction of the time between initial and final motion during an event; (iv) the distributions of motion and rest periods are best modeled by gamma functions rather than exponential, but the distributions approach exponential as the tails are trimmed. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Vehicle-based road dust emission measurement—Part II: Effect of precipitation, wintertime road sanding, and street sweepers on inferred PM10 emission potentials from paved and unpaved roads

Abstract Testing Re-Entrained Kinetic Emissions from Roads (TRAKER) is a new technique to infer paved and unpaved road dust PM 10 emission potentials based on particulate matter (PM) measurements made onboard a moving vehicle. Light scattering instruments mounted in front and behind the vehicle's tires measure the differential particle concentration of dust suspended by the vehicle's tire in contact with the road surface. Through empirical regressions relating the differential concentration (i.e. TRAKER signal) with the vehicle speed and the downwind flux of PM 10 particles from the road, an equation is derived to infer the speed independent road dust emission potential from the measured TRAKER signal. Measurements from TRAKER offer a new perspective on the processes that affect road dust emissions. The system was used to investigate temporal changes in emission potentials from paved roads in both the winter and summer in the Treasure Valley in Southwest Idaho. During the 3-week wintertime sampling period, the residential road dust PM 10 emission potential decreased by ∼50%. Summertime PM 10 emission potentials were similar to those observed at the end of the winter sampling and showed no upward or downward trends. Wintertime unpaved road emissions increased consistently with the number of days since the last rainfall. Measurement of road dust emission potentials after road sanding on dry roads indicated a 75% increase in PM 10 emissions after 2.5 h. This effect was short lived and emission potentials returned to their pre-sanding levels within 8 h of the sand application. Street sweeping with mechanical and vacuum sweepers was found to offer no measurable reduction in PM 10 emission potentials. On several roads, the PM 10 emission potentials actually increased immediately after vacuum sweeping. Long term effects of street sweeping on road dust emissions were not evaluated as part of this study and may offer some overall reduction in PM emissions from paved roads.