Eastern Washington State Research Articles

Assessment of Probable Causes of Reduced Aquatic Life in the Touchet River, Washington, USA

ABSTRACT The Touchet River in eastern Washington State is the site of the first causal assessment in the arid Northwest for salmonids using the U.S. Environmental Protection Agency's (USEPA's) Stressor Identification process. Seven candidate causes that affect salmonid density and macroinvertebrate abundance and diversity were considered: toxics, warm water temperature, sedimentation, low dissolved oxygen, alkaline pH, reduced detritus, and reduced habitat complexity. Candidate causes were evaluated using several types of evidence of preceding causation, co-occurrence, sufficiency, and alteration along with evaluation of the consistency of that evidence and consistency with other assessments. Evidence was scored, and the body of evidence was weighed based on credibility, strength, diversity, and coherence. Warm water temperature and sedimentation were highly probable causes of altered biological condition. Low dissolved oxygen and alkaline pH were also a problem for some areas but were less severe than temperature and sediment. Water removal and reduced habitat complexity and canopy cover were not directly causal but could affect sedimentation and temperature. This case study is noteworthy for using assemblage symptomology associated with temperature, sediment, and detritus as a type of evidence and for physiographically matching reference sites for comparisons and evaluation of natural and cumulative anthropogenic stressor gradients in the absence of state biological criteria.

Fusion of LiDAR and imagery for estimating forest canopy fuels

Due to increased fuel loading as a result of fire suppression, land managers in the American west are in need of precise information about the fuels they manage, including canopy fuels. Canopy fuel metrics such as canopy height (CH), canopy base height (CBH), canopy bulk density (CBD) and available canopy fuel (ACF) are specific inputs for wildfire behavior models such as FARSITE and emission models such as FOFEM. With finer spatial resolution data, accurate quantification of these metrics with detailed spatial heterogeneity can be accomplished. Light Detection and Ranging (LiDAR) and color near-infrared imagery are active and passive systems, respectively, that have been utilized for measuring a range of forest structure characteristics at high resolution. The objective of this research was to determine which remote sensing dataset can estimate canopy fuels more accurately and whether a fusion of these datasets produces more accurate estimates. Regression models were developed for ponderosa pine ( Pinus ponderosa) stand representative of eastern Washington State using field data collected in the Ahtanum State Forest and metrics derived from LiDAR and imagery. Strong relationships were found with LiDAR alone and LiDAR was found to increase canopy fuel accuracy compared to imagery. Fusing LiDAR with imagery and/or LiDAR intensity led to small increases in estimation accuracy over LiDAR alone. By improving the ability to estimate canopy fuels at higher spatial resolutions, spatially explicit fuel layers can be created and used in wildfire behavior and smoke emission models leading to more accurate estimations of crown fire risk and smoke related emissions.

When the prairie varies: the importance of site characteristics for strategising insect conservation

Abstract. 1. The bunchgrass prairies of the Palouse region in eastern Washington state and adjacent Idaho have been mostly converted to agriculture in the past century. Prairie habitat currently exists only on small remnants scattered across the landscape.2. The invertebrate fauna of these habitat remnants is poorly known, both in terms of species diversity and community composition.3. Baited pitfall traps were used to sample carrion‐attracted beetles during June and July of 2003 from high‐quality prairie remnants of varying size and soil characteristics.4. Twenty‐three beetle species in five families were found. Species richness and Shannon‐Wiener diversity were not significantly correlated with habitat area or perimeter–area ratio.5. Beetle abundance and community structure were strongly correlated with soil characteristics. Deeper, loessal soils had greater overall beetle abundance than shallower, rocky soils, although some species were more frequently captured in shallower, rocky soil sites.6. Conservation plans emphasising only remnant size and condition do not sufficiently capture variability in insect communities across Palouse prairie remnants.

Innovation in Community Corrections and Probation Officers’ Fears of Being Sued

Probation departments are emphasizing a greater level of community interaction between officers and ordinary citizens as an integral part of effective offender supervision. This trend is due in part to the prisoner reentry correctional paradigm, which conceptualizes probation officers as relationship brokers between offenders and their employers, family members, and community stakeholders. Field probation officers are a critical part of implementing this community-oriented approach. Few scholars, however, have evaluated probation departments’ organizational capacities to implement this change in light of the legal vulnerabilities to torts faced by these officers. We use in-depth interview data from a sample of field probation officers in eastern Washington State to understand how probation officers’ concerns about being sued and their trust in the organization may affect its capacity to innovate. The theoretical and policy implications of our findings are discussed.

Microbial biomass and N cycling under native prairie, conservation reserve and no-tillage in Palouse soils

Tillage management practices that improve soil quality are needed to maintain agricultural productivity. Soil quality can be improved through increases in microbial biomass carbon (MBC) and the nitrogen (N) contents in different pools of soil organic matter (SOM). The objective of our experiment was to study the dynamics of MBC and N cycling in soils collected from the Palouse area of eastern Washington State. Soil managements were: no tillage for 4 (NT4) and 28 (NT28) years, conservation reserve program (CRP), native prairie (NP), and conventional tillage (CT). Microbial biomass carbon was 50% less in the CT soil than the NP soil and there was 74% less total soil N (TSN) in the surface CT soil compared to the NP soil. Conversion of CT to CRP, NT4, and NT28 increased MBC in the 0–5 cm depth by 40, 6 and 78%, respectively. Compared to CT, the TSN content was 20, 57, and 94% higher in CRP, NT4 and NT28, respectively. The net N mineralized (Nmin) over 180 days in the surface 5 cm was highest (69.5 µg N/cm 3) in NT28 soil and lowest (14.2 µg/cm 3) in CRP. Interestingly, the CT soil mineralized as much N as the NT systems but had less TSN than NT. Compared to NP, CT had a 70% reduction in particulate organic matter nitrogen (POM-N) to a depth of 20 cm. The conversion of CT soil to CRP, NT28, and NT4 enhanced the POM-N content by 65, 216, and 101% at 0–5 cm. The proportion of POM-N to TSN was lowest in CT soil whereas the NT and CRP soils were considerably higher. The lower Nmin/MBC ratios (qN) of the conservation systems imply a higher immobilization capacity and tighter soil N cycling. Mineralized N per unit of respiration (Nmin/CO 2-C) was highest in CT and NT28 management systems suggesting different factors were responsible in these systems for exhibiting almost similar values. The Nmin ratios along with MBC and POM-C relationships could be useful soil quality indicators in judging tillage-induced changes in soil management systems.

A Tribute to Donald Meinig

Donald Meinig's probing mind, clear prose, and sweeping geographical perspective have enlivened American historical and cultural geography for more than fifty years. His contributions to the discipline span many scales: His ideas on the evolution and meaning of landscape have enriched our regional appreciation for localities across North America; his geopolitical assessments of colonization, imperialism, and globalization still resonate today; and his continental-scale analysis of more than 500 years of North American historical geography marks a piece of scholarship and illustrates a point of view that has in fundamental ways influenced ideas both within and beyond the bounds of academic geography. As two of Don's former doctoral students, we are delighted to offer this special issue of the Geographical Review in recognition of Don's impact on the field. The contributors, including other former students, friends, and kindred geographical spirits, reflect both Don's depth and breadth, his insatiable curiosity about the world, and his fascination with the links between geography, history, culture, and landscape. LIFE OF LEARNING--THE MAKING OF A GEOGRAPHER Don was born in 1924 and raised in the Palouse country of eastern Washington State. Indeed, a splendid autobiographical account of his life, entitled A Life of Learning, was published in 1992 as part of the Charles Homer Haskins Lecture Series at the University of Chicago. In that account Don recalls his early fascination with maps, railroads, and the unfolding global events of the 1930s. Those years revealed his geographical bent and prefigured a post-World War II decision to enroll in Georgetown University's School of Foreign Service. Nourished by some fine professors--including Carroll Quigley and Ernst Feilchenfeld--but chastened by Washington, D.C.'s stifling political environment, Don decided to return west after Georgetown and enter graduate school in geography at the University of Washington. The Australian geographer Graham Lawton proved pivotal in guiding Don's graduate work in geography. With Lawton's encouragement, Don turned toward a reconnaissance of his own backyard. The product was a dissertation on the historical geography of the interior Pacific Northwest that resulted in the publication of The Great Columbia Plain (1968). Don's long academic career began in 1950 with a position in a small geography department at the University of Utah. While along the Wasatch Front, Don and his wife, Lee, raised a family, and Don settled into a busy new career of teaching and research that even included a pioneering foray into television as the host of a locally broadcast lecture series in geography. In 1958 a Fulbright award took Don to the University of Adelaide, where he completed research on the historical geography of the South Australian wheat frontier. On the Margins of the Good Earth was published four years later. New opportunities at Syracuse University prompted Don and his family to make the permanent move east in 1959. Settling into upstate New York, Don's work in historical geography continued to reflect western American interests, including pathbreaking regional studies on the Mormon culture region (1965), Texas (1969), and the Southwest (1971b), as well as three chapters on New York State's historical geography in a volume edited by John Thompson (Meinig 1966a, 1966b, 1966c). Don took the helm as chair of the Geography Department between 1968 and 1973 and assumed an active role in shaping the university's Maxwell School of Citizenship and Public Affairs (becoming a Maxwell Professor of Geography in 1973). He also served as chair for more than twenty doctoral students during the Syracuse years, while teaching an array of popular graduate and undergraduate courses. Don's pen was particularly productive between 1976 and 2004. He authored more than two dozen research articles and book chapters, served as editor for the enduring The Interpretation of Ordinary Landscapes (1979), a rich collection of essays that became a classic in the field, and completed his sweeping four-volume interpretation of historical geography entitled The Shaping of America: A Geographical Perspective on 500 Years of History (1986, 1993, 1998, 2004). …

Chemical Composition of Residue from Cereal Crops and Cultivars in Dryland Ecosystems

Cropping systems in the dryland farming region of eastern Washington State are dominated by winter and spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.). Excessive levels of residue may be an obstacle in the adoption of conservation farming systems. Decomposition of cereal crop residues is associated with fiber and nutrient content, and growers have observed differences in decomposition among cultivars; however, little information exists on their residue characteristics. Cultivars of spring barley (SB), spring wheat (SW), and winter wheat (WW) grown at four locations over two crop years were analyzed for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), C, and N contents, and winter wheat decomposition was tested in a laboratory incubation study. Acid detergent lignin was highest in spring barley (9.9%), and least in winter wheat (9.2%) and hard white spring wheat (9.5%). Fiber components and nutrient content varied by location, precipitation zone, and cultivar. Residue in the drier year of the study had lower NDF, ADF, ADL, C, and C/N ratio. Foot rot (Fusarium spp.)–resistant winter wheat cultivars had higher NDF, ADF, and ADL than susceptible cultivars. Laboratory incubation studies showed decomposition of winter wheat straw in soil was correlated with ADF (R2 > 0.66, P = 0.002) and total N (R2 > 0.67, P = 0.04). Fiber and nutrient characteristics of residue from wheat and barley cultivars currently produced in the Pacific Northwest can be used to predict residue decomposition in cropping systems that conserve soil and water, and enhance build‐up of organic matter.

The Holocene history of bighorn sheep (Ovis canadensis) in eastern Washington state, northwestern USA

Historical data are incomplete regarding the presence/absence and distribution of bighorn sheep ( Ovis canadensis) in eastern Washington State. Palaeozoological (archaeological and palaeontological) data indicate bighorn were present in many areas there during most of the last 10 000 years. Bighorn occupied the xeric shrub-steppe habitats of the Channeled Scablands, likely because the Scablands provided the steep escape terrain bighorn prefer. The relative abundance of bighorn is greatest during climatically dry intervals and low during a moist period. Bighorn remains tend to increase in relative abundance over the last 6000 years. Bighorn were present in eastern Washington in the nineteenth century, but were largely locally extirpated by the twentieth century. A collection of prehistoric bighorn astragali that likely includes specimens spanning the terminal Pleistocene and the entire Holocene consists of specimens that are, with one exception, the same size as a collection of modern bighorn astragali from Wyoming. The single exceptionally large specimen falls in the middle of the size range of specimens from the late Pleistocene of northern Wyoming, suggesting that Washington's prehistoric bighorn, like those from other areas, were larger than modern bighorn.

Mandibular hypodontia and osteoarthritis in prehistoric bighorn sheep (Ovis canadensis) in eastern Washington State, USA

Mandibular hypodontia of the p2 was found to occur in 3 out of 21 individual prehistoric Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from Moses Coulee Cave in eastern Washington State, similar to its frequency of occurrence in modern bighorn. There is no evidence of lumpy jaw (mandibular osteomyelitis) in the Moses Coulee Cave collection. Evidence from Moses Coulee Cave aligns with the hypothesis that low frequencies of hypodontia and lumpy jaw occur in healthy, evolutionarily old (maintenance) populations in order to maintain the occlusal area and thus maximise efficiency of food procurement and processing. Osteoarthritis was found to occur in 1 out of 70 individual Rocky Mountain bighorn sheep (Ovis canadensis canadensis) astragali in the Moses Coulee Cave collection. This prevalence is unsurprising given a population dominated by prime-age individuals. Osteoarthritis was likely selected against given that individuals must be agile to effectively use rugged terrain to escape predation and as a general measure suggests a healthy population. Copyright © 2009 John Wiley & Sons, Ltd.

Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system

Subsurface simulation is used to build, test, and couple conceptual process models to better understand the persistence of uranium concentrations above federal drinking water standards in a 0.4 km by 1.0 km groundwater plume beneath the 300 Area of the U.S. Department of Energy's Hanford Site in eastern Washington State. At this location, the unconfined aquifer and the variably saturated lower vadose zone sediments are subject to significant variations in water levels driven by diurnal, weekly, and seasonal fluctuations in the Columbia River stage. In the near‐river aquifer, uranium‐contaminated sediments in the highly transmissive Hanford formation are subject to high groundwater velocities, daily flow reversals, and exposure to river water. One‐ and two‐dimensional simulations of variably saturated flow and reactive transport based on laboratory‐derived models of uranium sorption are used to assess the representation of uranium transport processes in the vadose zone‐aquifer‐river system. The simulations show that the various frequencies of river stage fluctuation are capable of driving significant inland transport above the average water table, which is in contrast to the net groundwater flow to the river. Inclusion of a rate‐limited uranium mass transfer process model is notably more important to the timescales of the river stage‐driven groundwater flow than for vadose zone flow driven by natural recharge. Spatially and temporally variable solution chemistry from the dynamic exchange of river water and groundwater in the unconfined aquifer is shown to significantly alter uranium mobility as represented by a multicomponent uranium surface complexation model.

Distribution, Abundance, and Habitat Associations of the Night Snake (Hypsiglena torquata) in Washington State

The Night Snake (Hypsiglena torquata) is a secretive snake that is rarely encountered. Subsequently, little is known about the ecology of this species. Since it was first collected in 1943 in Washington State, few (<40) specimens have been found. From May to October 2004 and 2005, I collected 121 specimens from 8 counties in eastern Washington State by road-cruising appropriate habitat. Snakes were collected crossing roads bisecting a variety of habitats including areas of talus (such as rocky canyons), oak savannah-woodlands, sagebrush-rabbitbrush flats, pine-fir forests, grasslands, and areas of agricultural development (cropland). Snakes were most often observed in areas with an abundance of talus, followed by oak savannah-woodlands, sagebrush-rabbitbrush flats, and to a much lesser extent pine-fir forests, grasslands, and croplands. Based upon my research, H. torquata is much more common in Washington than previous work has shown.

Children's inhalation exposure to methamidophos from sprayed potato fields in Washington State: Exploring the use of probabilistic modeling of meteorological data in exposure assessment

We examined the significance of meteorology and postspray volatilization of methamidophos (an organophosphorus insecticide) in assessing potential inhalation risk to children in an agricultural community. We combined fluxes from sources and dispersion modeling with a range of possible local meteorology to create output to study the variability in potential community exposure as a result of changing temperature, wind speeds and wind directions. This work is based on an aerial spray drift study where air sampling measurements of methamidophos were made before, during and after a spray event were used to examine acute inhalation risk for children living in an Eastern Washington State community in close proximity (between 15 and 200 m) to sprayed potato fields. We compared the measured average air concentrations of methamidophos in the community to a "no observed adverse effect level" for subchronic inhalation to characterize acute and subchronic inhalation risks. The baseline estimates of inhalation exposure were below Environment Protection Agency's (EPA) level of concern based on a target margin of exposure of 300. As meteorological conditions during and after spraying influence the amount of material moving into areas where children reside we used historical meteorological data to drive model simulations that predicted likely air residue concentrations under different wind and temperature conditions. We also added variability to the decay constant and initial emission fluxes to create a 2-D simulation of estimated air concentrations in the community near the fields. This work provides a methodological framework for the assessment of air concentrations of pesticides from agricultural sprays in the absence of extended measurements, although including variability from meteorological conditions. The deterministic as well as the probabilistic risk analyses in this study indicated that postspray volatilization in the specific spray situation analyzed (methamidophos applied on potato fields in Eastern Washington) did not pose acute or subchronic risks as defined by the EPA. However, this study did not consider any pathway of exposure other than inhalation (e.g. diet, dermal, etc.) and the risk assessment should be evaluated in that context.

Climatic implications of latest Pleistocene and earliest Holocene mammalian sympatries in eastern Washington state, USA

For more than fifty years it has been known that mammalian faunas of late-Pleistocene age are taxonomically unique and lack modern analogs. It has long been thought that nonanalog mammalian faunas are limited in North America to areas east of the Rocky Mountains and that late-Pleistocene mammalian faunas in the west were modern in taxonomic composition. A late-Pleistocene fauna from Marmes Rockshelter in southeastern Washington State has no modern analog and defines an area of maximum sympatry that indicates significantly cooler summers than are found in the area today. An earliest Holocene fauna from Marmes Rockshelter defines an area of maximum sympatry, including the site area, but contains a single tentatively identified taxon that may indicate slightly cooler than modern summers.

Prevalence of Heartworm (Dirofilaria immitis) in Coyotes (Canis latrans) in Washington State

A total of 556 hearts from free-ranging coyotes (Canis latrans) in eastern and central Washington State were examined for heart-worms (Dirofilaria immitis) during 2005–2007. Sampling occurred in fall and winter and only heart tissues were examined. No immature or adult heartworms were detected, indicating that heartworm infection is either not currently present in eastern and central Washington, or the prevalence is very low. These data do not support the concept of heartworm transmission in eastern or central Washington State at this time.

First Report of the Occurrence of Grapevine fanleaf virus in Washington State Vineyards.

Grapevine fanleaf virus (GFLV; genus Nepovirus, family Comoviridae), responsible for fanleaf degeneration disease, is one of the most important viruses of grapevines worldwide (1). During our reconnaissance studies during 2007, dormant wood cuttings from individual grapevines of wine grape cv. Chardonnay were collected randomly from two geographically separate vineyards in eastern Washington State. Extracts made from cambial scrapings of these cuttings were tested separately for different viruses by single-tube reverse transcription (RT)-PCR using virus-specific primers. Two of the thirty-one grapevines in one vineyard tested positive for GLFV as mixed infection with Grapevine leafroll-associated virus (GLRaV)-3. In another vineyard, six of the twenty-six grapevines tested positive for GFLV as mixed infection with GLRaV-1, GLRaV-3, and Grapevine virus A (GVA) A forward primer (5'-ACCGGATTGACGTGGGTGAT, corresponding to nucleotides [nt] 2231-2250) and reverse primer (5'-CCAAAGTTGGTTTCCCAAGA, complementary to nt 2533-2552) specific to RNA-2 of GFLV-F13 isolate (GenBank Accession No. X16907) were used in RT-PCR assays for the detection of GFLV (4). Primers used for RT-PCR detection of GLRaV-1, GLRaV-2, and GVA were described in Martin et al (2) and Minafra et al (3). The RT-PCR results indicated mixed infection of GFLV with GLRaV-1, GLRaV-3, and GVA. To confirm the presence of GFLV, the 322-bp sequence representing a portion of the coat protein encoded by RNA-2 genomic segment was cloned into pCR2.1 (Invitrogen Corp., Carlsbad, CA). Amplicons obtained from six individual grapevines in the two vineyards were used for cloning. Three independent clones per amplicon were sequenced from both orientations. Pairwise comparison of these sequences showed 99 to 100% nucleotide sequence identity among themselves, indicating that GFLV isolates from the two vineyards may be identical. A comparison of the consensus sequence (GenBank Accession No. EU573307) with corresponding sequences of other GFLVs deposited in GenBank showed 89 to 91% identity at the nucleotide level and 95 to 99% identity at the amino acid level. However, mixed infection of GFLV with different viruses in the two vineyards suggests separate introduction of the planting material. ELISA with GFLV-specific antibodies further confirmed the presence of the virus in samples that were positive in RT-PCR. To our knowledge, this is the first report of GFLV in grapevines grown in the Pacific Northwest states of the United States. Further investigations are being carried out on the distribution, symptoms, molecular variability, and nematode vector transmission of GFLV.

Lupine Induced “Crooked Calf Disease” in Washington and Oregon: Identification of the Alkaloid Profiles in Lupinus sulfureus, Lupinus leucophyllus, and Lupinus sericeus

Several lupines (Lupinus spp.) present on western U.S. rangelands contain alkaloids that are teratogenic to livestock and cause congenital birth defects in calves (crooked calf disease). Periodically, large losses of calves due to lupine-induced "crooked calf disease" occur in northern Oregon and eastern Washington state. Five lupine populations from this area representing three species (L. leucophyllus, L. sulfureus, and L. sericeus) were evaluated taxonomically and by gas chromatography/mass spectrometry, and the major alkaloids in each lupine species were identified. The teratogenic alkaloid anagyrine was present in both of the lupine species responsible for the high outbreaks in east-central Washington and northeastern Oregon. However, the alkaloid profiles of the two lupines identified as L. leucophyllus were dissimilar, as were the alkaloid profiles of the two lupines identified as L. sulfureus. Botanical classification is not sufficient to determine potential teratogenicity, and it must be followed by chemical characterization to determine risk to livestock.

A brief review of the fossil history of the family Rosaceae with a focus on the Eocene Okanogan Highlands of eastern Washington State, USA, and British Columbia, Canada

Many of the oldest definitive members of the Rosaceae are present in the Eocene upland floras of the Okanogan Highlands of northeastern Washington State and British Columbia, Canada. Over a dozen rosaceous taxa representing extant and extinct genera of all four traditionally recognized subfamilies are known from flowers, fruits, wood, pollen, and especially leaves. The complexity seen in Eocene Rosaceae suggests that hybridization and polyploidy may have played a pivotal role in the early evolution of the family. Increased species diversity and the first appearance of additional modern taxa occur during the Late Paleogene in North America and Europe. The Rosaceae become increasingly important components of fossil floras during the Neogene, with taxa adapted to many habitats.

New Diversity among the Trochodendraceae from the Early/Middle Eocene Okanogan Highlands of British Columbia, Canada, and Northeastern Washington State, United States

Newly recognized fossil infructescences and leaves of the Trochodendraceae are described from the Early/Middle Eocene McAbee and One Mile Creek sites of British Columbia, Canada, and Republic, eastern Washington State, United States. Trochodendron drachukii Pigg, Dillhoff, DeVore, & Wehr sp. nov., from McAbee, is an infructescence similar to that of extant Trochodendron aralioides Sieb. & Zucc. but strongly paniculate rather than racemose. This new species is larger and more robust than those of the Eocene flora of Republic, Washington, and has attached fruits quite similar to both extant Trochodendron Sieb. & Zucc. and Miocene fossils from Asia and western North America. Associated leaves are similar to those of extant Trochodendron except for sometimes bearing short basal auriculate extensions of the lamina. They differ from Trochodendron nastae Pigg, Wehr, & Ickert‐Bond leaves from Republic that have palmate rather than pinnate venation. Tetracentron hopkinsii Pigg, Dillhoff, DeVore, & Wehr sp. nov. from One Mile Creek and Tetracentron sp. from Republic have leaves remarkably like those of extant Tetracentron Oliver, firmly establishing the presence of this genus in the Eocene. This study demonstrates that within the Trochodendraceae, a poorly understood group within the eudicot grade, both extinct forms as well as plants with quite modern‐appearing fruits and leaves were present by the Eocene in northwestern North America.

Re-examining fire severity relations in pre-management era mixed conifer forests: inferences from landscape patterns of forest structure

For some time, ecologists have known that spatial patterns of forest structure reflected disturbance and recovery history, disturbance severity and underlying influences of environmental gradients. In spite of this awareness, historical forest structure has been little used to expand knowledge of historical fire severity. Here, we used forest structure to predict pre-management era fire severity across three biogeoclimatic zones in eastern Washington State, USA, that contained extensive mixed conifer forests. We randomly selected 10% of the subwatersheds in each zone, delineated patch boundaries, and photo-interpreted the vegetation attributes of every patch in each subwatershed using the oldest available stereo-aerial photography. We statistically reconstructed the vegetation of any patch showing evidence of early selective harvesting, and then classified them as to their most recent fire severity. Classification used published percent canopy mortality definitions and a dichotomized procedure that considered the overstory and understory canopy cover and size class attributes of a patch, and the fire tolerance of its cover type. Mixed severity fires were most prevalent, regardless of forest type. The structure of mixed conifer patches, in particular, was formed by a mix of disturbance severities. In moist mixed conifer, stand replacement effects were more widespread in patches than surface fire effects, while in dry mixed conifer, surface fire effects were more widespread by nearly 2:1. However, evidence for low severity fires as the primary influence, or of abundant old park-like patches, was lacking in both the dry and moist mixed conifer forests. The relatively low abundance of old, park-like or similar forest patches, high abundance of young and intermediate-aged patches, and widespread evidence of partial stand and stand-replacing fire suggested that variable fire severity and non-equilibrium patch dynamics were primarily at work.

FRAGMENTION BY AGRICULTURE INFLUENCES REPRODUCTIVE SUCCESS OF BIRDS IN A SHRUBSTEPPE LANDSCAPE

Shrubsteppe communities are among the most imperiled ecosystems in North America as a result of conversion to agriculture and other anthropogenic changes. In the Intermountain West of the United States, these communities support a unique avifauna, including several species that are declining and numerous others that are of conservation concern. Extensive research in the eastern and central United States and in Scandinavia suggests that fragmentation of formerly continuous forests and grasslands adversely affects reproductive success of birds, yet little is known of the potential effects on avian communities in Western shrublands. I used multi-model inference to evaluate the potential effects of local and landscape variables on nest predation and brood parasitism, and behavioral observations of color-banded birds to evaluate the potential effects of habitat fragmentation on seasonal reproductive success of passerines in the shrubsteppe of eastern Washington State, USA. Reproductive success of shrubsteppe-obligate passerines was lower in landscapes fragmented by agriculture than in continuous shrubsteppe landscapes. Daily survival rates for nests of Brewer's Sparrows (Spizella breweri; n=496) and Sage Thrashers (Oreoscoptes montanus; n=128) were lower in fragmented landscapes, and seasonal reproductive success (percentage of pairs fledging young) of Sage Sparrows (Amphispiza belli; n=146) and Brewer's Sparrows (n=59) was lower in fragmented landscapes. Rates of parasitism by Brown-headed Cowbirds (Molothrus ater) overall were low (4%) but were significantly greater in fragmented landscapes for Brewer's Sparrows, and parasitism resulted in fewer young fledged from successful nests. Simple models of population growth using landscape-specific fecundity and estimates of adult survival derived from return rates of banded male Sage Sparrows and Brewer's Sparrows suggest that fragmented shrubsteppe in Washington may be acting as a population sink for some species. Immediate conservation needs include halting further fragmentation of shrubsteppe, restoring low-productivity agricultural lands and annual grasslands to shrubsteppe where possible, and convincing the public of the intrinsic value of these imperiled ecosystems.