Buckwheat : a multi-purpose, short-season alternative (1994)

Most Americans know of buckwheat only from its use in buckwheat pancakes. Those more familiar with the crop know it to be a versatile, easy-to-grow, short-season grain crop adapted to many regions. It tolerates poor soils and is often used as a soil-improving crop, a role it served for such notables as Thomas Jefferson and George Washington on their Virginia farms

Systematic and reproductive studies of Mimulus (Scrophulariaceae) in the Pacific Northwest : implications for conservation biology

The Mimulus washingtonensis complex is a group of morphologically similar species centered in the Pacific Northwest. All are rare, and most are under consideration for listing as endangered. Morphometric and pollination data were used in developing a revised taxonomy for the group. Five species and two varieties are recognized. Mimulus pulsiferae Gray is the most widespread, occurring from southern Washington to northern California. Mimulus hymenophyllus Meinke and M. jungermannioides Suksd. are cliff species endemic to river drainages in northern Oregon. Mimulus washingtonensis Gand. occurs in east-central Oregon and western Idaho, represented by the var. washingtonensis and var. ampliatus (Grant) Meinke comb. et stat. nov., respectively. Mimulus patulus Pennell is resurrected from synonymy and differentiated from M. washingtonensis on the basis of morphology, distribution, and pollination biology. This autogamous species includes var. patulus, occurring in the Snake River drainage, and var. montanus Meinke var. nov., primarily from the northern Rocky Mountains. Mimulus evanescens Meinke sp. nov. is described from an extant population in Lassen County, California, and historic collections from widely scattered stations in Oregon and Idaho. The new species is morphologically intermediate between M. breviflorus Piper and M. latidens (Gray) Greene. Calyx and leaf morphology also suggest an affinity to M. grayi Grant, M. inconspicuus Gray, and M. acutidens Greene, of cismontane California. Mimulus evanescens should be considered critically endangered, because of its limited numbers and habitat degradation. Mimulus washingtonensis is pollinated by small native bees, primarily two species of Dialictus (Halictidae). These bees were specific to Mimulus flowers but did not distinguish between flowers of M. washingtonensis and M. guttatus DC., a related species that increases with habitat disturbance. Experiments showed that mixed pollen loads diminish seed set in M. washingtonensis, since the thigmotropic stigma of that species closes permanently after any amount of conspecific pollen is applied. Although M. washingtonensis has a low pollen/ovule ratio (29.9), it is considered facultatively xenogamous based on floral morphology, stigma sensitivity, and autogamous seed set levels. Populations occurred in small, edaphically restricted patches, and they exhibited seed set reductions related to outcrossing distance. Substrate disturbance may limit reproduction in M. washingtonensis by changing population structure, threatening pollinators, and increasing competition for pollination by promoting growth and flowering of M. guttatus

Biosystematic studies of the Mimulus moschatus complex in the Pacific Northwest

Populations of an unknown species of Mimulus, herein described as Mimulus hymenophyllus Meinke, were located and studied near Horse Creek, a tributary of the Snake River in eastern Wallowa County, Oregon. The new species is differentiated from its apparent closest relative, Mimulus jungermannioides Suksd., by an annual habit, long petioles, corollas that are three to four times the length of the calyx, rounded capsules, and seeds up to 0.85 mm long. Mimulus hymenophyllus and M. iungermannioides are members of the section Paradanthus, and are morphologically allied with Mimulus moschatus Dougl. in Lindl. and several related taxa. The Mimulus moschatus complex of species is distinguished within the genus by having firmly adherent placentae, glandular-sticky foliage and stems, prismatic calyces with equal to sub-equal teeth, elongate pedicels, and deciduous, funnelform corollas ranging in color from canary to lemon yellow. Mimulus hvmenophyllus is endemic to the steep canyons of Horse and Cow Creeks in Wallowa County, at altitudes ranging from 850 to 1300 m. The species is restricted to the damp crevices of vertical basalt cliffs, often growing in the shade under overhangs. The surrounding plant community is dominated by several coniferous species, primarily Pseudotsuga menziesii, pinus ponderosa, and Abies arandis. The habitat of M. hymenophyllus is isolated, and is presently not in danger from human disturbance. However, the species is currently maintained as a state and federal candidate for listing as threatened or endangered, based on limited abundance and narrow geographic range. Studies of the seed and seedling biology of Mimulus hymenophyllus and its Pacific Northwest relatives (i.e., M. moschatus, M. floribundus, M. jungermannioides, M. patulus, M. pulsiferae, M. washingtonensis, and M. breviflorus) were also conducted. Germination trials indicated that seeds of M. moschatus, M. jungermannioides, and M. floribundus are capable of germination immediately or soon after capsules dehisce, and do not become dormant upon later exposure to warm or cold temperatures. Seed lots of M. hymenophyllus and M. breviflorus germinate rapidly when first mature, but subsequently develop complete or partial dormancy after prolonged exposure to late summer temperatures. Dormant seeds of these species, as well as those of M. patulus, M. Dulsiferae, and M. washingtonensis which are dormant when capsules dehisce, will germinate readily after several weeks of cold-wet stratification. Four of the five species lacking innate seed dormancy develop inflated fruiting calyces that temporarily trap seeds as capsules dehisce. This prolongs the dispersal rate of seed crops, thereby minimizing the potential for catastrophic seedling mortality due to mass germination of cohorts during unfavorable environmental conditions. These species retain seed on the parent plant for significantly longer periods than species with unmodified calyces. Seed dispersal from parent plants is accomplished by wind and flowing water, except in M. hvmenophvllus, where negatively phototropic pedicels orient ripe capsules towards the darkened cliff substrate for dispersal directly into crevices. Two of the rarest species studied, M. hymenophyllus and M. patulus, were found to co-occur in nature with an indigenous and rather weedy, unrelated species of Mimulus, i.e., M. nasutus Greene. Experimental plantings showed that seedling lots of M. nasutus emerge sooner and over a shorter period than those of the two uncommon species, suggesting that M. nasutus may outcompete them and thereby contribute to their rarity. Seedlings of M. breviflorus and M. floribundus, which typically occur in habitats subject to sudden fluctuations in soil moisture, exhibit adaptations for accelerated sexual reproduction under experimental drought conditions. This trait, when coupled with inflated fruiting calyces, enables these species to exploit unpredictably arid environments despite the potential disadvantage of nondormant seeds. Mimulus jungermannioides and M. moschatus are not adapted for precocious sexual maturation, and offset their lack of seed dormancy by having a perennial life cycle and by occurring in more predictably mesic habitats. Significant differences between the annual and perennial species were observed in the timing and amount of seed production during droughtstress. The information provided in this thesis will be valuable to systematists and conservation biologists. Several of the species studied have been promoted for protection under endangered species laws. The formal naming of Mimulus hymenophyllus legitimizes efforts for the management of this unique species, while seed and seedling biology data will be important to germplasm studies, phylogenetic assessments, and possible reintroduction of species or populations should extirpation occur

Ecological Monitoring of Vascular Plant Resources at the Governor Tom McCall Preserve at Rowena Plateau: Initiation of Long-term Studies for Management.

The bluffs and plateaus of the eastern Columbia River are floristically rich and ecologically intricate. A previous descriptive study of the unique scabland vegetation on the Gov. Tom McCall Preserve at Rowena Plateau in Oregon included delineation of several distinct or intergrading native and non-native vegetation units. In this study we: 1) established permanent transects in the swale-mound mosaic for monitoring compositional changes over time, in order to determine trends in community dynamics; 2) implemented a permanent plot system to monitor population demography of Astragalus hoodianus; and 3) resampled the vernal pool communities. Monitoring of the vegetation existing in the swale-mound mosaic grasslands is expected to provide information regarding whether the exotic annuals are continuing to increase at the expense of the indigenous flora, or if an equilibrium has been reached due to the cessation of grazing. Astragalus hoodianus is a rare and potentially threatened endemic, thus it is important to monitor this population's stability in terms of recruitment, mortality, and the apparent effects of competing vegetation on recruitment and on mortality

An Evaluation of Putative Sympatric Speciation within Limnanthes (Limnanthaceae)

Limnanthes floccosa ssp. floccosa and L. floccosa ssp. grandiflora are two of five subspecies within Limnanthes floccosa endemic to vernal pools in southern Oregon and northern California. Three seasons of monitoring natural populations have quantified that L. floccosa ssp. grandiflora is always found growing sympatrically with L. floccosa ssp. floccosa and that their flowering times overlap considerably. Despite their subspecific rank within the same species crossing experiments have confirmed that their F1 hybrids are sterile. An analysis of twelve microsatellite markers, with unique alleles in each taxon, also shows exceedingly low levels of gene flow between populations of the two subspecies. Due to the lack of previous phylogenetic resolution among L. floccosa subspecies, we used Illumina next generation sequencing to identify single nucleotide polymorphisms from genomic DNA libraries of L. floccosa ssp. floccosa and L. floccosa ssp. grandiflora. These data were used to identify single nucleotide polymorphisms in the chloroplast, mitochondrial, and nuclear genomes. From these variable loci, a total of 2772 bp was obtained using Sanger sequencing of ten individuals representing all subspecies of L. floccosa and an outgroup. The resulting phylogenetic reconstruction was fully resolved. Our results indicate that although L. floccosa ssp. floccosa and L. floccosa ssp. grandiflora are closely related, they are not sister taxa and therefore likely did not diverge as a result of a sympatric speciation event

Flight Behavior of Methyl-Parathion-Resistant and –Susceptible Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations from Nebraska

Relative flight behavior of methyl-parathion-resistant and -susceptible western corn rootworm, Diabrotica virgifera virgifera LeConte populations, was studied as part of a larger effort to characterize the potential impact of insecticide resistance on adult life history traits and to understand the evolution and spread of resistance. A computer interfaced autograph was used to compare flight of resistant and susceptible individuals, and flight of resistant individuals with and without prior exposure to methyl-parathion. In each case, mean trivial and sustained flight durations were compared among treatments. In general, there were few differences in trivial or sustained flight characteristics as affected by beetle population, insecticide exposure, sex, or age and there were few significant interactions among variables. Tethered flight activity was highly variable and distributions of flight duration were skewed toward flights of short duration. Tethered flight activity was similar among resistant and susceptible beetles with the exception that susceptible beetles initiated more flights per beetle than resistant beetles. After sublethal exposure to methyl-parathion, total flight time, total trivial flight time, and mean number of flights per resistant beetle declined significantly. Because long-range flight was uncommon, short- to medium-duration flights may play an important role in determining gene flow and population spread of resistant D. v. virgifera. These results suggest that organophosphate- resistant beetles can readily move and colonize new areas, but localized selection pressure (e.g., management practices) and exposure to methyl-parathion may contribute to the small-scale differences in resistance intensity often seen in the field

Larval Susceptibility of an Insecticide-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae) Population to Soil Insecticides: Laboratory Bioassays, Assays of Detoxification Enzymes, and Field Performance

Soil insecticides were evaluated in laboratory and field studies against larvae of an insecticide resistant population (Phelps County, NE) of western corn rootworm, Diabrotica virgifera virgifera LeConte. Insecticide toxicity was evaluated by topical application of technical insecticides to 3rd instars from Saunders County, NE (susceptible) and Phelps County populations. Resistance ratios (LD50 Phelps County/LD50 Saunders County) for the insecticides methyl parathion, tefluthrin, carbofuran, terbufos, and chlorpyrifos were 28.0, 9.3, 8.7, 2.6 and 1.3, respectively. Biochemical investigation of suspected enzymatic resistance mechanisms in 3rd instars identified significant elevation of esterase activity (alpha and beta naphthyl acetate hydrolysis [3.8- and 3.9-fold]). Examination of 3rd instar esterases by native PAGE identified increased intensity of several isoenzymes in the resistant population. Assays of cytochrome P450 activity (4-CNMA demethylation and aldrin epoxidation) did not identify elevated activity in resistant 3rd instars. Granular soil insecticides were applied at planting to corn, Zea mays L., in replicated field trials in 1997 and 1998 at the same Phelps County site as the source of resistant rootworms for the laboratory studies. In 1997, planting time applications of Counter 20CR, Counter 15 G (terbufos), and Lorsban 15 G (chlorpyrifos) resulted in the lowest root injury ratings (1Ð6 Iowa scale); 2.50, 2.55, 2.65, respectively (untreated check root rating of 4.55). In 1998, all insecticides performed similarly against a lower rootworm density (untreated check root rating of 3.72). These studies suggest that resistance previously documented in adults also is present in 3rd instars, esterases are possibly involved as resistance mechanisms, and resistance to methyl parathion in adults is also evident in larvae, but does not confer cross-resistance in larvae to all organophosphate insecticides

Seed viability studies for recovery of Plagiobothrys hirtus (Boraginaceae), the rough popcornflower

Plagiobothrys hirtus is Oregon’s top priority for endangered plant species recovery, and the wetlands of Douglas County provide the only habitat for this plant in the world. The goal is to downlist this species from endangered to threatened, and in order to do that, existing populations must be protected, and new populations must be created. Genetic diversity plays a major role in the long-term viability of most endangered species, as their populations are small, however, little is known about the genetic diversity in populations of P. hirtus. Seed viability studies are one way to quantify genetic diversity, as germination is one of the many traits that can be observed indicating variation between individuals. Observing a wide range in traits among maternal lines indicates that there is a wide range in genetic variation within the population. We conducted these studies in the OSU greenhouses to examine variation in germination of maternal lines in four populations. Unexpected findings indicate that P. hirtus expresses dormancy, and that this dormancy is most effectively broken with cold stratification. Total germination was highest (and had the highest range) from maternal lines with the largest populations, and the highest assumed genetic diversity. These observations are consistent with our predictions. Seed management protocol was developed using these findings, providing information needed to create stable populations moving toward downlisting this species from endangered to threatened

Rainfall variability at decadal and longer time scales: signal or noise?

Rainfall variability occurs over a wide range of temporal scales. Knowledge and understanding of such variability can lead to improved risk management practices in agricultural and other industries. Analyses of temporal patterns in 100 yr of observed monthly global sea surface temperature and sea level pressure data show that the single most important cause of explainable, terrestrial rainfall variability resides within the El Nino-Southern Oscillation (ENSO) frequency domain (2.5-8.0 yr), followed by a slightly weaker but highly significant decadal signal (9-13 yr), with some evidence of lesser but significant rainfall variability at interclecadal time scales (15-18 yr). Most of the rainfall variability significantly linked to frequencies tower than ENSO occurs in the Australasian region, with smaller effects in North and South America, central and southern Africa, and western Europe. While low-frequency (LF) signals at a decadal frequency are dominant, the variability evident was ENSO-like in all the frequency domains considered. The extent to which such LF variability is (i) predictable and (ii) either part of the overall ENSO variability or caused by independent processes remains an as yet unanswered question. Further progress can only be made through mechanistic studies using a variety of models