Establishment of Wildflower Islands to Enhance Roadside Health and Aesthetics

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline is to establish more habitat corridors on public rights-of-way, such as roadsides. Planting pollinator-friendly native wildflowers on roadsides provides nutrient-rich forage and nesting resources for bees and is aesthetically pleasing. With 97,256 miles of public roadways in Nebraska (~4 million miles of roadways in the United States), roadsides play ever increasing roles in sustaining biodiversity within our state and beyond. Federal guidelines state that wildflowers are to be used in roadside seeding mixtures, and NDOT includes a diversity of wildflower species in its seeding mixtures. However, these complex seeding mixtures are often expensive because of the diversity of species and high seed price of many of these native species, particularly the wildflowers which compose roughly 10% of the total seeds but represent 30% of the total cost of seed mixtures. Further, wildflowers on roadsides are typically seeded with competitive grasses and are costly to establish and manage long term. This research explored ways to improve wildflower establishment by separating wildflower seeds from the conventional seed mixture with includes both wildflower and grass seeds. Additionally, wildflower plots were seeded at different patch or island sizes to assess cost-effective ways of reducing competition by nonnative weeds and enhancing the longevity of roadside habitat. Optimal patch sizes and treatment groups included 100% wildflower mix seeded to the entire 3 m x 18.3 m plot (treatment 100), only 50% of the plot seeded in one continuous patch (treatment 50) or in two small patches (treatment 25x2) compared to current practices of seeding wildflower-grass mixtures (treatment conventional). Ecological benefits of roadside habitat, wild bee abundance, diversity, and nesting activity was assessed and compared across seeding practices and patch size treatments. Floral diversity and abundance were also analyzed to compare plant-pollinator interactions across treatments. Conventional roadside seeding methods yielded plots with lower abundance and richness of forbs and bees compared to plots seeded with wildflowers only (treatments 100, 50, 25x2) but only in the first year of establishment. Bee richness was highest in the late season, while forb abundance and richness were highest in the mid-season. No differences were observed across differently sized wildflower-only patches likely because of the recent establishment of plots. In fact, only ~50% of seeded forbs had established and roughly 14 plants out of the 40 species in the seed mixture did not establish in either survey years and may therefore be replaced in future seed mixtures. Our results indicate that wildflower segregation in strips or islands may be a cost-effective method of improving wildflower establishment and persistence in diverse roadside mixtures. As plots mature and become vulnerable to weed encroachment, the effect of patch size may become more distinguished across treatment groups, therefore, further monitoring and research may be necessary to further address issues with low establishment and high competitive pressure from volunteer species. This data contributes to NDOT’s ongoing pursuit to more effectively establish wildflowers on roadsides and to better understand the role floral enhancements have on supporting and sustaining vulnerable wildlife, such as our pollinator communities

Plant Community Patterns on Upland Prairie in the Eastern Nebraska Sandhills

Topography is an important factor in determining vegetation patterns in grasslands. We collected frequency of occurrence data from transects on dune tops, south-facing slopes, north-facing slopes, and interdunal valleys in the eastern Sandhills of Nebraska to determine the effect of topographical position on plant species composition. We used canonical discriminant analysis to separate the four topographical positions based on frequency of occurrence of the 18 principal planttaxa. Topographic position played an important role in plant distribution on upland prairie with interdunal transects strongly separated from transects on other topographical positions. Bluegrasses (Poa L. spp.), switchgrass (Panicum virgatum L.), and white sage (Artemisia ludoviciana Nutt.) were highly associated with interdunal valleys. Little bluestem [Schizachyrium scoparium (Michx.)] and cool-season grasses, such as needlegrasses (Stipa L. spp.) and Junegrass [Koeleria pyramidata (Lam.) Beauv.], tended to be associated with north-facing slopes and warm-season grasses, such as prairie sandreed [Calamovilfa longifolia (Hook) Scrihn.] and sand bluestem (Andropogon hallii Hack.), tended to be associated with south-facing slopes. Sedges (Carex L. spp.), western ragweed (Ambrosia psilostachya DC.), and Scribner dichanthelium [Dichanthelium oligosanthes (Schult.) Gould var. scribnerianum (Nash)] were the most common taxa occurring over all topographic positions. Aspect proved to be an important factor in influencing vegetation distribution in the eastern Sandhills of Nebraska

Prediction of leaf:stem ratio in grasses using near infrared reflectance spectroscopy

Leaf:stem ratio of grass stands is an important factor affecting diet selection, quality, and forage intake. Estimates of leaf:stem ratios commonly are based on a labor intensive process of hand separating leaf and stem fractions. Near infrared reflectance spectroscopy (NIRS) has been used successfully to predict forage quality and botanical composition of vegetation samples. The objective of this study was to evaluate the use of NIRS to predict leaf:stem ratios in big bluestem (Andropogon gerardii Vitman), switchgrass (Punicum virgatum L.), and smooth bromegrass (Bromus inermis Leyss.). A total of 72 hand-clipped samples of each species was taken from seeded monocultures in eastern Nebraska throughout the 1992,1993, and 1994 growing seasons. Leaf:stem ratio was determined first for each sample and then the entire sample was ground. Samples were scanned by a Perstorp model 6500 near infrared scanning monochromator. Three calibration equations were developed based on using 18, 36, and 54 (l/4, l/2, and 3/4 of total samples, respectively) samples. These 3 calibration equations were used to determine the number of samples necessary to achieve an r2 of 0.70 or higher for each data set. Big bluestem and switchgrass had coefficients of determination (r2) of ≤ 0.69 for all calibration equations except for the equation using only 18 samples of big bluestem r2 = 0.60). Smooth bromegrass had a r2 ranging from only 0.06 to 0.14 for the calibration equations regardless of the number of samples used. Near infrared reflectance spectroscopy was a rapid means of estimating leaf:stem ratios in monocultures of big bluestem and switchgrass but it was not suitable for smooth bromegrass

Socioecological Determinants of Drought Impacts and Coping Strategies for Ranching Operations in the Great Plains

In Great Plains rangelands, drought is a recurring disturbance. Ranchers in this region expect to encounter drought but may not be adequately prepared for it. Efforts to encourage drought preparednesswould benefit froma better understanding of the conditions under which managers make decisions to minimize the impacts of drought.We tested the direct andmoderating roles of the drought hazard and the social-ecological context on drought impacts and response. This study was conducted with ranchers in western and central South Dakota and Nebraska following the drought that began in 2012. We surveyed ranchers regarding the effects of the drought and their responses and used multimodel analysis to explore the relationships among measures of drought preparedness, drought response, and drought impacts. Drought severity was the primary predictor of all impacts, but specific types of impacts were varied depending on the operation’s enterprisemix, resources, and management. The socioecological characteristics of the ranch system predicted drought response actions taken, by either providing the necessary resources and capacity to take action or creating sensitivity in the system that required action to be taken. We conclude with recommendations for learning from current drought experiences in order to better adapt to future drought events

INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission

We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations of early 2006. We analyse the modulation of the IBIS/ISGRI detector counts induced by the passage of the Earth through the field of view of the instrument. Unlike previous studies, we do not fix the spectral shape of the various contributions, but model instead their spatial distribution and derive for each of them the expected modulation of the detector counts. The spectra of the diffuse emission components are obtained by fitting the normalizations of the model lightcurves to the observed modulation in different energy bins. The obtained CXB spectrum is consistent with the historic HEAO-1 results and falls slightly below the spectrum derived with Swift/BAT. A 10% higher normalization of the CXB cannot be completely excluded, but it would imply an unrealistically high albedo of the Earth. The derived spectrum of the GRXE confirms the presence of a minimum around 80 keV with improved statistics and yields an estimate of ~0.6 M_Sun for the average mass of white dwarfs in the Galaxy. The analysis also provides updated normalizations for the spectra of the Earth's albedo and the cosmic-ray induced atmospheric emission.Comment: 13 pages, 13 figures, minor changes to text, A&A in pres

Focus, Vol. 1 No. 1

A literary magazine of student writing published by the Department of English of Stephen F. Austin State College.https://scholarworks.sfasu.edu/focus/1000/thumbnail.jp

The Freshman, vol. 5, no. 3 [issue misnumbered]

The Freshman was a weekly, student newsletter issued on Mondays throughout the academic year. The newsletter included calendar notices, coverage of campus social events, lectures, and athletic teams. The intent of the publication was to create unity, a sense of community, and class spirit among first year students. Included in this edition is an editorial authored on behalf of The Co-eds of \u2738 commenting on the divisive nature of Freshman Rules imposed by upper classmen and requesting first-year students be treated with respect

Kinematic Control of the Inertiality of ICRS Catalogs

We perform a kinematic analysis of the Hipparcos and TRC proper motions of stars by using a linear Ogorodnikov-Milne model. All of the distant (r more than 0.2 kpc) stars of the Hipparcos catalog have been found to rotate around the Galactic y axis with an angular velocity of -0.36 +/- 0.09 mas/year. One of the causes of this rotation may be an uncertainty in the lunisolar precession constant adopted when constructing the ICRS. In this case? the correction to the IAU (1976) lunisolar precession constant in longitude is shown to be -3.26 +/- 0.10 mas/yr. Based on the TRC catalog, we have determined the main Oort constants: A = 14.9 +/- 1.0 and B = -10.8 +/- 0.3 km/s/kpc. The component of the model that describes the rotation of all TRC stars around the Galactic y axis is nonzero for all magnitudes, My= -0.86 +/- 0.11 mas/yr.Comment: 10 pages, 4 figures, 2 table

Microporous polyolefin strands as controlled-release devices for mosquito repellents

The main vectors of malaria in Africa, i.e. An. arabiensis, An. gambiae s.s. and An. funestus, are attracted by human foot odour and they tend to bite victims in the ankle area. Hence, affordable mosquito-repellent polymer-foot bracelets with long lasting protection could reduce infective lower limb bites and therefore help to reduce the overall malaria transmission rate. This study investigated the possibility of increasing the duration of repellence activity by incorporating repellents into inexpensive thermoplastic polymers, namely poly(ethylene-co-vinyl acetate) (EVA) and linear low-density polyethylene (LLDPE). Volatile repellents need to be released into the surrounding air to be effective, i.e. they are continuously lost to the atmosphere. This means that the bracelet should also act as a reservoir for relatively large quantities of the active compound. Towards this goal, polymer strands containing mosquito repellent were prepared by twin-screw extrusion compounding. A co-continuous phase structure was achieved by rapid quenching in an ice bath of the homogeneous polymer-repellent melt mixture exiting the extruder. Phase separation occurred through spinodal decomposition that trapped the liquid repellent in the microporous polymer matrix. A skin-like membrane that covered the extruded polymer strands controlled the release rate. Strands that contained up to 30 wt-% of either DEET or Icaridin provided effective protection against mosquito bites even after 12 weeks of ageing at 50 °C.The Deutsche Forschungsgemeinschaft (DFG), Germany, under Grant AN 212/22-1.http://http://www.elsevier.com/locate/cej2020-03-15hj2019Chemical EngineeringMedical VirologyStatistic

Who will make the 'best' use of Africa's land? Lessons from Zimbabwe

Conflict over African land – between small holders and large industrial farmers and between domestic farmers and global agribusinesses – raises key questions about who will make the best use of African land and which farmers do most to decrease poverty and produce more food, industrial inputs, and exports. Zimbabwe has already gone through two major changes in land occupation, and thus provides an important test of what is the 'best' use of the land. Three measures of 'best' use have been cited in Zimbabwe: reward for military victory, poverty reduction, and agricultural production. Initial evidence indicates that commercial small holder production is a better use of the land than larger, more mechanised farming