Eastern North Dakota Research Articles

Resistance and partial resistance to Phytophthora sojae in early maturity group soybean plant introductions

Phytophthora sojae, an important yield limiting pathogen of soybean, causes seed, seedling, root, and stem rots. Losses caused by P. sojae can be controlled by both major gene and partial resistance. Early maturity group (MG) soybeans are an increasingly important crop in northwestern Minnesota and eastern North Dakota. Early MG plant introductions (PIs) from the USDA Soybean Germplasm Collection and early MG public and private cultivars were evaluated for resistance and partial resistance to P. sojae. Of the 113 PIs, PI438445, and PI438454 exhibited resistance to P. sojae races 4, 7, 17, and 28 indicating they may possess either Rps1c, Rps1k, previously unidentified or multiple resistance gene to Phytophthora sojae (Rps) genes. Because they exhibited partial resistance equal to or greater than the standard check cultivar Conrad, three early MG soybean cultivars (MN0902, MN0302, and 91B53) were selected as standard checks to evaluate early MG PIs for partial resistance. Sixty-nine PIs were evaluated for partial resistance to P. sojae races 7 and 25 using the inoculum layer method. Of this group of PIs, 22 had the same level of partial resistance as Conrad to P. sojae race 7 while 19 had the same degree of partial resistance to race 25. Twelve PIs had same level of partial resistance as Conrad to both P. sojae races 7 and 25. The PIs and cultivars identified in this study will be of great value in developing early MG soybean cultivars suitable for planting in Canada and the northern United States.

Syringa pekinensis ‘SunDak’ (Copper Curls®): A Widely Adapted Tree Lilac

Pekin lilac (Syringa pekinensis Rupr.), a tree lilac native to northern China, has many desirable horticultural traits but is underused as a landscape plant (Dirr, 1998). A combination of pest resistance and superior ornamental characteristics makes it desirable for reduced maintenance landscapes. Pekin lilac differs from the closely related Japanese tree lilac [S. reticulata (Bl.) Hara] primarily by its finer texture and variable colorful bark, which exfoliates horizontally in thin flakes or sheets. In North Dakota trials, both species usually flower at the same time, but the blooming date may vary slightly among seedlings, cultivars, and sites. Pekin lilac flowers in May in central North Carolina and in June in eastern North Dakota. The later flowering date for tree lilac species extends the season of bloom for lilacs. Within populations of S. pekinensis grown from seed, there is considerable genetic diversity in leaf size and winter hardiness of individuals. Several cultivar selections have been introduced to the nursery trade, including Beijing Gold ( Zhang Zhimjing ), China Snow ( Morton ), Pendula , and Summer Charm ( DTR 124 ) (Dirr, 1998). Although shrubby lilacs are often selected on the basis of color, quality, and fragrance of the flowers, SunDak is a new tree lilac cultivar selected primarily for its attractive exfoliating orange to coppery pigmented bark on the trunk and lateral branches, which provides landscape interest throughout the year. This environmentally durable cultivar fulfills consumer preferences for a low-maintenance small landscape tree with pest resistance (Tripp and Raulston, 1995).

Mallard Brood Movements, Wetland Use, and Duckling Survival During and Following a Prairie Drought

We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988–1992) and during the first 2 years of the subsequent wet period (1993–1994) at 4 51-km2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked mallard broods initiated moves from the nest to water before noon, and all left the nest during daylight. On average, broods used fewer wetlands, but moved greater distances during the dry period than the wet period. Broods of all ages were more likely to make inter-wetland moves during the wet period and probabilities of inter-wetland moves decreased as duckling age increased, especially during the dry period. Brood use of seasonal wetlands nearly doubled from 22% to 43% and use of semi-permanent wetlands declined from 73% to 50% from the dry to the wet period. Eighty-one of 150 radiomarked ducklings died during 1,604 exposure days. We evaluated survival models containing variables related to water conditions, weather, duckling age, and hatch date. Model-averaged risk ratios indicated that, on any given date, radiomarked ducklings were 1.5 (95% CI = 0.8–2.8) times more likely to die when the percentage of seasonal basins containing water (WETSEAS) was ≤18% than when WETSEAS was >40%. An interaction between duckling age and occurrence of rain on the current or 2 previous days indicated that rain effects were pronounced when ducklings were 0–7 days old but negligible when they were 8–30 days old. The TMIN (mean daily minimum temperature on the current and 2 previous days) effects generally were consistent between duckling age classes, and the risk of duckling death increased 9.3% for each 1°C decrease in TMIN across both age classes. Overall, the 30-day survival rate of ducklings equipped with radiotransmitters was about 0.23 lower than the survival rate of those without radiotransmitters. Unmarked ducklings were 7.6 (95% CI = 2.7–21.3) times more likely to die on any given day when WETSEAS was ≤18% than when WETSEAS was >40%. Higher duckling survival and increased use of seasonal wetlands during the wet period suggest that mallard production will benefit from programs that conserve and restore seasonal wetland habitat. Given adverse effects of low temperatures on duckling survival, managers may want to include this stochastic variable in models used to predict annual production of mallards in the Prairie Pothole Region.

EFFECTS OF STATSGO AND SSURGO AS INPUTS ON SWAT MODEL'S SNOWMELT SIMULATION1

ABSTRACT: Soil data comprise a basic input of SWAT (Soil and Water Assessment Tool) for a watershed application. For watersheds where site specific soil data are unavailable, the two U.S. Department of Agriculture (USDA) soil databases, the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases, may be the best alternatives. Although it has been noted that SWAT models using the STATSGO and SSURGO data may give different simulation results for water, sediment, and agricultural chemical yields, information is scarce on the effects of using these two databases in predicting streamflows that are predominantly generated from melting snow in spring. The objective of this study was to assess the effects of using STATSGO versus SSURGO as an input for the SWAT model's simulation of the streamflows in the upper 45 percent of the Elm River watershed in eastern North Dakota. Designating the model as SWAT‐STATSGO when the STATSGO data were used and SWAT‐SSURGO when the SSURGO data were used, SWAT‐STATSGO and SWAT‐SSURGO were separately calibrated and validated using the observed daily streamflows. The results indicated that SWAT‐SSURGO provided an overall better prediction of the discharges than SWAT‐STATSGO, although both did a good and comparable job of predicting the high streamflows. However, SWAT‐STATSGO predicted the low streamflows more accurately and had a slightly better performance during the validation period. In addition, the discrepancies between the discharges predicted by these two SWAT models tended to be larger at upstream locations than at those farther downstream within the study area.

Snowpack control over the thermal offset of air and soil temperatures in eastern North Dakota

The close relationship between air and ground temperatures has been used to reconstruct paleoclimate conditions from ground temperatures. Unfortunately, the presence of snow decouples air and ground temperatures and obscures their relationship. The objective of this paper is to investigate the role that snowpack conditions play in affecting the relationship between air and soil temperatures. The annual thermal offset between mean annual soil and air temperatures is examined over a 12 year period (1990–2002) at Fargo, ND, using observed soil temperatures along with simulations from a physically based snowpack model. Early season snow cover does not necessarily lead to large thermal offsets. These snowpacks, while low in density, also tended to be shallow and therefore do not provide much thermal insulation. Winter snowpacks explain a greater portion of the annual thermal offset. While denser than fall snowpacks, the extra depth and longer persistence leads to superior insulation of the ground.

In situ mesocosms: Denitrification in the Elk Valley aquifer

AbstractLarge stainless steel chambers were designed, constructed, and installed to make in situ mesocosms (ISMs) of aquifer sediments. The advantages of the ISMs over in situ microcosms, their smaller counterparts, are that ISMs may be sampled for longer times with larger sampling volumes. The former advantage makes ISMs a good tool to study the natural attenuation of contaminants with slow degradation rates. The latter advantage allows samples to be large enough that they may be analyzed for contaminants and reaction products, plus major ions normally associated with “complete” water analyses. Having such a large suite of analytes provides insights into associated mineral saturation conditions and possible reaction pathways that may not be readily apparent. As an example of their utility, a tracer test was done in a pair of ISMs to test our hypothesis that S(−I) in pyrite was a major electron donor for denitrification in the Elk Valley aquifer in eastern North Dakota. During the 9‐month experiment, sediment data, ground water saturation indices, and trends in the geochemical evolution of the bromide tracer, calcium, inorganic carbon, magnesium, nitrate, and sulfate concentrations indicate that 58% of the denitrification was caused by S(−I) as the electron donor. These data also suggest that ferrous iron and organic carbon may have served as electron donors for the denitrification. The apparent zero‐order denitrification rate was 16 mM/d (r2= 0.93) with a δ15N isotopic enrichment factor of −20.4‰ (r2= 0.998).

Northeastern Plains Village Complex Timelines and Relations

Research in eastern North Dakota over the past three decades has brought to light considerable new information on what has come to be known as the Northeastern Plains Village complex. It is suggested that the Northeastern Plains Village complex is an extension of the Cambria complex of southwestern Minnesota, and that its culmination lies in the Scattered Village complex of the Knife River region on the Missouri River in western North Dakota. A new archaeological taxonomic unit, the Northeastern Plains Village tradition, is proposed to facilitate further study and verification of these hypothesized relationships. The Northeastern Plains Village tradition, as a whole, is tentatively linked to the larger Hidatsa nation.

Argillic Horizons in Stratified Drift

Although pedogenesis and landscape evolution have occurred on the eastern North Dakota till plain since the inception of the Holocene, soils with argillic horizon are recognized on a very limited basis. Argillic soils are not mapped in well‐drained positions on the youngest drift prairie landscapes. Roughly half of 47 pedons examined at a precision farming research site in Barnes County, North Dakota show evidence of genetic argillic horizons based on soil structure, hand texturing, and cutan presence. This study applies physical and micromorphological evidence to verify that diagnostic argillic horizons have formed in well‐drained settings on this eastern North Dakota landscape. Total clay distributions and fine/total clay ratios show marked increases in genetic argillic horizons compared with surface horizons and parent materials. The argillic horizons average about 28 cm in thickness; only two pedons were thinner than 7.5 cm. Consequently, the increase in total clay and fine clay distributions, and the thickness criteria required to meet diagnostic horizon status as established by Soil Taxonomy are satisfied. The upper argillic horizon boundary of seven profiles was 50 cm or more below the surface, possibly indicating relict argillic horizons. Micromorphologic evidence shows the presence of illuvial clay in the three soils sampled for microscopy. Porosity variations caused by the argillic horizons likely affect subsurface flow and may be responsible for variable N levels measured for these soils. These soils formed in well‐drained landscape settings, where stratified drift may predispose the soils to illuviation.

Predators on Red-winged Blackbird nests in eastern North Dakota

Predation has consistently been identified as the most common cause of nest failure for Red- winged Blackbirds (Agelaius phoeniceus). During May and June, 2000 and 2001, we used infrared-triggered camera systems to identify potential nest predators on artificially relocated Red-winged Blackbird nests in eastern North Dakota. For some of the species observed, these observations represent the first documentation of predation on Red-winged Blackbird nests in the northern Great Plains. SINOPSIS. Depredadores de los nidos de Agelaius phoeniceus en Dakota del Norte La depredacion ha sido identificada consistentemente como la causa mas comun de la perdida de nidos en la especie Agelaius phoeniceus. Durante mayo y junio de 2000 y 2001, utilizamos una camara que se disparaba con rayos infrarojos para identificar los posibles depredadores en nidos del ave en discusion. El estudio se llevoa cabo en Dakota del Norte. Se documentaron un considerable numero de visitantes a los nidos vigilados y depredacion por parte de organismos previamente no descritos para las Grandes Planicies.

72 An examination of the periphytic algae in the sheyenne river, north dakota, usa, and the factors influence the community structure

The Sheyenne River is a third order stream in central and eastern North Dakota. The algae in this river had not been previously studied. For this study, periphytic algal samples were collected Fall 1997, April–November 1998, and May–October 1999. Two hundred sixteen periphytic algal taxa were identified. These taxa included 137 Bacillariophyceae, 33 Cyanophyta, 40 Chlorophyta, 8 Xanthophyceae, and 3 Euglenophyta. Several species of algae found in the river appear to be previously undescribed taxa. Two of these organisms were described as new species, Nitzschia sheyennensis and Nitzschia dakotensis (Bacillariophyceae). The distribution of the periphytic algae was correlated to changes in the selected environmental variables using canonical correspondence analysis (CCA) and mult‐dimensional scaling (MDS). The statistically significant environmental variables were nitrite‐nitrate, pH, arsenic, potassium, magnesium, manganese, and total dissolved solids. A reservoir, Lake Ashtabula on the river was formed by a dam in 1954. In the initial statistical analysis, the effects of this reservoir on the periphytic algae downstream were so great that an upstream/downstream covariable had to be used. Further statistical analysis was used to determined that this effect could be correlated to changes in the nutrient levels rather than hydrologic changes.

Distribution and ecology of meningeal worm, Parelaphostrongylus tenuis (Nematoda), in northcentral North America.

Meningeal worm (Parelaphostrongylus tenuis), a common nematode parasite in white-tailed deer (Odocoileus virginianus) and pathogenic for several species of ungulates in eastern North America, is not known to occur in the west. Heads of 1,902 white-tailed deer were examined for adult meningeal worm to determine geographic distribution of the parasite in Saskatchewan and Manitoba (Canada) and North Dakota (USA). Finding the parasite in a deer in eastern Saskatchewan near the Manitoba border established the current northern and western limits in Canada. Prevalence of infection was < 1, 18.6, and 8.2% in Saskatchewan, Manitoba, and North Dakota, respectively. Infected deer occurred throughout southern Manitoba and eastern North Dakota. Distribution appears to have changed little since the last published survey for P. tenuis in the region in 1972. We examined precipitation, temperature, deer density, and forest cover as likely correlates to prevalence and distribution of P. tenuis. Deer management units used for hunting purposes were the scale of analysis in the three jurisdictions. Presence of P. tenuis was positively correlated with precipitation during frost-free periods and deer density, and it was negatively correlated with winter and spring temperatures. Landscapes with > 25 and < 75% forest cover were most likely to have infected deer. Low rainfall and low density of white-tailed deer likely influence the westernmost limit of P. tenuis.

Dwarf sunflower response to row spacing, stand reduction, and defoliation at different growth stages

Growth compensation of dwarf sunflower (Helianthus annuus L.) hybrids to low initial stands, later stand losses, or plant defoliation has not been reported regarding replanting decisions and crop insurance yield loss assessment. Three experiments were conducted to study the affect of stand reduction, defoliation, and row spacing on dwarf sunflower yield and quality when grown in eastern North Dakota. Experiment 1 evaluated stand reduction (0, 25, 50 and 75%) applied at growth stages (V4, R1 and R6) in 15, 45 and 76 cm spaced rows. Row spacing interactions with stand reduction and growth stage were not significant for yield indicating growth stage and stand reduction effects on yield response were independent of row spacing. In exp. 2, significant growth stage (V4, V8, R1, R2, R3, R5 and R6) by stand reduction (0, 12, 25, 37, 50, 62 and 75%) interaction showed stand reduction at vegetative growth stages not influencing yield, but as maturity progressed yield reductions became greater with increased stand reduction. Achene weight increased with increasing stand reduction at vegetative and early reproductive stages. A reciprocal relationship was noted between achene weight and achene oil content where oil content decreased as achene weight increased. Interaction of growth stage (R1 and R6) and defoliation (0, 25, 50, 75 and 100%) in exp. 3 indicated greater reduction in yield, test weight, 1000-achene weight, and achene oil conte nt as defoliatin increased at growth stage R6. Yield compensating ability of dwarf sunflower is dependent on type and level of damage and growth stage of occurrence, with total yield reduction considering all effects. Key words: Sunflower, Helianthus annuus L., row spacing, stand reduction, defoliation

Impact of Smoking on Cancer Stage at Diagnosis

Studies evaluating the relationship between smoking and cancer spread are limited. We studied the relationship between cancer stage at diagnosis (local, regional, or metastatic) and smoking history (current, previous, or nonsmoker). For lung cancer, patterns of spread were also studied. In a tumor registry for eastern North Dakota, northwestern Minnesota, and northern South Dakota, 11,716 cases were identified from 1986 to 2001. Current smokers (relative risk [RR], 2.11; 95% confidence interval, 1.93 to 2.32; P <.001) and previous smokers (RR, 1.56; 95% confidence interval, 1.42 to 1.72; P <.001) had an increased risk of metastatic disease at diagnosis. Current smokers (RR, 1.39; 95% confidence interval, 1.29 to 1.51; P <.001), but not previous smokers, also had an increased risk of regional disease. An increase in metastatic disease was most evident for prostate cancer (RR, 1.53; P =.003). An increase in regional disease was most evident for head and neck (RR, 3.53; P <.001), prostate (RR, 1.83; P =.030), and breast cancer (RR, 1.22; P =.005). Compared with previous smokers, current smokers with metastatic lung cancer were more likely to have involvement of the brain (33.6% v 23.0%; P =.004), bone marrow, adrenal gland, and pericardium (24.7% v 15.9%; P =.004). Previous or current smoking is a risk factor for increased cancer stage in a wide range of malignancies. Further study is required to determine whether this association is causal.

Factors Affecting Gadwall Brood and Duckling Survival in Prairie Pothole Landscapes

Waterfowl biologists need reliable predictors of brood and duckling survival to accurately estimate recruitment rates. We examined 30-day survival rates of gadwall (Anas strepera) broods (1992-1994) and ducklings (1990-1994) in eastern North Dakota, USA, during years when water conditions ranged from extremely dry to extremely wet. We evaluated effects of several variables on brood survival: (1) percent of seasonal wetland basins containing water, (2) occurrence of rain on the current or 2 previous exposure days, (3) minimum ambient temperature averaged over the current and 2 previous exposure days, (4) hatch date, (5) duckling age, and (6) brood size. Only 9 of 58 radiomarked females lost their entire broods; Kaplan-Meier 30-day survival rate for broods was 0.84. Brood size (adjusted for hatch date) was a better brood-survival predictor than were any of the environmental variables. Risk of tool brood loss decreased by 24% for each additional duckling in the brood. We monitored fates of 212 radiomarked ducklings from 94 broods. Daily risk of death for ducklings was twice as high when seasonal ponds were scarce as when ponds were abundant. Duckling survival rate was lower during the first 7 days of life whether it rained or not; survival rate was greater for 8- to 30-day-old ducklings, but was reduced by rain. Thirty-day duckling survival was greatest when minimum daily temperatures exceeded 10°C and no rain occurred. We attributed 86% of 87 deaths of radiomarked ducklings to predation; American mink (Mustela vison) accounted for ≥68% of the 40 deaths for which predator type could be ascertained. Despite apparent resilience of gadwall populations during drought, our study documented a positive effect of seasonal wetland availability on gadwall duckling survival. Management efforts to improve recruitment will be more effective in years when most seasonal basins contain water.

First Report of Charcoal Rot (Macrophomina phaseolina) on Sunflower in North and South Dakota.

In September 1998, symptoms suggestive of charcoal rot were observed on oilseed sunflower (Helianthus annuus L.) plants in western North and South Dakota. Symptoms first observed on plants approaching physiological maturity consisted of silver-gray lesions girdling the stem at the soil line, premature plant death, and reduced head diameter. The pith in the lower stem was completely absent or compressed into horizontal layers. Black, spherical microsclerotia were observed in the pith of the lower stem, underneath the epidermis, and on the exterior of the taproot. Confirmation of Macrophomina phaseolina (Tossi) Goid. as the causal agent was based on the size of the microsclerotia, which ranged from 80 to 90 μm in diameter, from both infected sunflowers and pure cultures (1). The only other sunflower pathogen known to form microsclerotia is Verticillium dahliae Kleb., whose microsclerotia are irregular in shape and are 15 to 50 μm in diameter. Some prematurely dead sunflower plants lacked typical charcoal rot stem lesions, but contained Macrophomina microsclerotia. Plants with atypical symptoms were colonized by the sunflower stem weevil (Cylindrocopturus adspersus (LeConte)) and the black sunflower stem weevil (Apion occidentale Fall). This agrees with observations in Texas, where Macrophomina-infected sunflower plants parasitized by stem-feeding insects often displayed atypical charcoal rot symptoms (3). Charcoal rot incidence in 1998 in western North Dakota was 25%, compared with 0% in eastern North Dakota. Charcoal rot was not observed in 1999, the fourth wettest growing season on record, but was observed again in 2000 and 2001. The recent increase in sunflower production in western North and South Dakota, areas typically hotter and drier than the eastern portions of both states, and the potential involvement of stem weevils as vectors of Macrophomina (2) may lead to an increased incidence of charcoal rot in sunflower.

Birdseed: A Potential Disease Problem for the Plantscape, Yard, and Garden?

Bird feeding and bird watching are on the rise in the United States, and as a consequence many homeowners are planting naturalized areas in their yards to create an environment to attract birds and wildlife. The natural source of food and shelter provided by these areas is often supplemented with bird feeders to provide a year-round haven for a variety of birds. Black oil sunflower seed, Helianthus annuus L., is promoted as the top choice of seed for most wild birds and provides a high-quality protein and a high concentration oil source to their diet (Wild Birds Forever, 1999). A recent observation into the contents of some commercial sunflower seed bags sold as feed for wild birds indicated the presence of the overwintering or resistant structures (sclerotia) of Sclerotinia sclerotiorum (Lib.) de Bary (Fig. 1). This pathogenic fungus produces a head rot (cottony rot) in commercial sunflowers that has a dramatic effect on the yield and oil components in the crop. Field surveys in eastern North Dakota in 1986 detected Sclerotinia head rot symptoms in 98% of the fields with 10.2% of the crop being affected (Gulya et al., 1989). Sclerotinia sclerotiorum has a very wide host range and can cause disease in a variety of native plants, herbaceous perennials, annual bedding plants, vegetables, and woody ornamentals (Farr et al., 1989). An infected sunflower can produce hundreds of sclerotia that can get into the harvested seed and eventually make their way to bird feeders. Birds will not eat the sclerotia but will discard them to the ground around the feeders. The sclerotia can lay dormant for months or years. Under the proper conditions, sclerotia will produce fruiting bodies that will produce plant-infecting spores or they can produce fungal hyphae that infect the host directly (Abawi and Grogan, 1979). The incidence of cottony rot in backyard flower, perennial, and vegetable gardens is on the increase (The C. Wayne Ellett Plant and Pest Diagnostic Clinic, 1997–2000). Therefore, a survey was initiated in an effort to determine the number of sclerotia found in a typical bag of commercial sunflower seed. A representative one pound (453.6 g) sample of sunflower seed was scooped from 10 different bags of commercial sunflower seed purchased throughout the greater Columbus, Ohio, area. The contents of the scoop were spread out over a hard surface with a light background and the sclerotia were separated by hand and counted. Sclerotia collected from the sample were also weighed. To check the viability of the sclerotia in the infested seed, a random sample of sclerotia taken from each bag was surface sterilized and placed in the center of a petri dish containing potato dextrose agar and incubated at room temperature. After 1 week of incubation the plates were examined for the characteristic fungal growth. The results of the survey are recorded in Table 1. Of the 10 bags analyzed, five contained sclerotia of S. sclerotiorum. One bag contained 7.47 g of sclerotia in a 463.6-g sample or 1.7%. Of the sclerotia tested, 100% were viable. There was a great amount of variation among brands and types of sunflower seed in quantity of sclerotia present. This study indicates a potential plant disease problem associated with feeding sunflower seed in areas planted with bedding plants, herbaceous perennials, or vegetables. Management of Sclerotinia head rot is difficult since no resistant sunflower hybrid has been developed and no fungicides are registered in North Dakota for ascospore infection of sunflower (North Dakota State Univ. Extension, 2001). Proper rotation of crops, planting the least susceptible hybrids, and a rigid monitoring schedule are crucial to reducing disease in the field. After harvest, a double screen cleaning followed by cleaning on a gravity table can reduce the sclerotia of S. sclerotiorum to below 1%. Considering the viability of sclerotia and the close to 400 species attacked by Sclerotinia sclerotiorum (North Dakota State Univ. Extension, 2001), the occurrence of any sclerotia in birdseed needs to be an issue that is seriously addressed by the sunflower industry.

An Examination of the Effects of a Reservoir, Lake Ashtabula, on the Periphytic Algae in the Sheyenne River, North Dakota

AbstractThe Sheyenne River is a third order stream that drains a significant portion of central and eastern North Dakota. In 1950, the Baldhill Dam was built and as a result, the reservoir, Lake Ashtabula, was formed. The periphytic algae in this river were extensively studied from 1997 to 1999. During this research, the effects of differences in environmental variables on the algal communities were assessed with Canonical Correspondence Analysis (CCA). In this analysis, the periphytic algal communities in the downstream sites appeared to be quite different from those communities found upriver of Lake Ashtabula. Other research on different rivers has shown profound changes in the algal community after a dam was built along the river. Redundancy Analysis (RDA) was used to determine if the sites downstream are more statistically similar with Lake Ashtabula than with the upstream sites. Finally, CCA was used to examine which environmental variables explain the most variance in Lake Ashtabula and the downstream sites.

Assessing the Biodiversity of Monoraphidium Using 18S rDNA Sequences

AbstractThe taxonomy of the genus Monoraphidium is unclear due in part to the absence of morphological features to clearly distinguish one species from another. Phytoplankton samples collected from lakes in the Arrowwood National Refuge in eastern North Dakota were found to contain several morphological species of Monoraphidium. Eighteen Monoraphidium isolates were examined with light microscopy and six morphological species were identified. PCR–RFLP of the 18S rDNA was used to type the isolates. Following digestion by Hae III and Taq I, the 18S rDNA PCR–RFLP patterns indicated 10 different types. Presently, the 18S rDNA product is being sequenced for each of the 10 types. By examining morphological characters and 18S rDNA sequences, congruence between morphology and sequence data may be compared. Also, because there is a lack of morphological characters defining Monoraphidium species, diversity within the 18S rDNA sequences may aid in the taxonomy of the genus and its place within the Chlorococcales. Supported by National Science Foundation Grants MCB‐0084188 and DBI‐0070387.

Applying survey research methods to account for denied access to research sites on private property

Needs for environmental information have led to more emphasis on surveys that assess changing environmental conditions. In order to obtain biological, physical, and chemical measures of environmental change, it is critical to obtain repeated access to research sites. Use of established survey methodology can improve access rates to private property in order to visit randomly selected research sites. Surveys initiated by the U.S. Environmental Protection Agency’s Environmental Monitoring and Assessment Program (EMAP) were conducted in 1995 and 1996 in Eastern North Dakota to monitor environmental conditions in prairie wetlands. These surveys required written permission from landowners to access private property. A summary of survey research methods designed to improve access rates to sites on private property is presented. Approximately 20% of the landowners who granted access did so in response to telephone calls after attempts by mail failed. The data show that a disproportionate number of accessible sites were located on non-agricultural lands, particularly in 1996. Owners of sites where agricultural land abutted wetlands tended to deny access. This may introduce bias in the monitoring data. A weighting class adjustment procedure was applied to account for any nonresponse bias resulting from denied access. This procedure deals with the imbalance from denied access and at least partially returns a balance to the collected data.

THREE POSSIBLE NEW SPECIES OF NITZSCHIA HASSALL (BACILLARIOPHYTA) FROM THE SHEYENNE RIVER, ND

Jaskowiak, M. A., Phillips, K. A. and Fawley, M. W.Department of Botany, North Dakota State University, Fargo, ND, 58105‐5517The Sheyenne River is a third order river that flows through central to eastern North Dakota. The first study of this river's periphyton was completed in the summers of 1998‐1999. One hundred sixty diatom species were identified. Navicula and Nitzschia were the most abundant genera. Among this group were three Nitzschia that appear to be new species. These three species were studied extensively using light microscopy. During this examination, one hundred specimens were measured. Preliminary results indicate that Nitzschia sp.1 belongs to the sect. Obtusae and Nitzschia sp. 4 and sp. 5 belong in the sect. Lanceolatae. These specimens will be examined using scanning electron microscopy in a future study.