<p> Highly disturbed landscapes such as idle or abandoned farm land are known to experience losses in native plant diversity. Loss of diversity negatively impacts the ecological functions and services provided by an ecosystem. The restoration of native species to the landscape could therefore reverse this damage. This study examines the effects of prescribed burning, tilling, and mowing as site preparation prior to planting and biomass harvesting on the establishment of four native, edible, culturally significant forbs (<i> Apios americana, Helianthus annuus, Helianthus tuberosus,</i> and <i> Oenothera biennis</i>) over the first two years after they have been introduced to an idle farm field. Species&rsquo; responses to site preparation treatments varied, possibly driven by the type of propagule from which they were grown. Harvesting of biomass prevented <i>H. annuus</i> from returning in the second year and significantly reduced abundance for the other three species.</p>

<p> Seed exchange networks represent the patterns and processes of seed movement in society, a fundamental component of crop production with major biological and social implications. These networks can furthermore explain patterns in household willingness to experiment with and adopt new and unusual varieties. This body of research focused on common bean (<i>Phaseolus vulagris</i>) seed exchange networks among household producers in western Uganda, where household producers represented over 70% of the population. Among these household producers, nearly all produced beans for either subsistence or commercial purposes and exchanged seeds through social networks.</p><p> This study provided evidence that regional- and community-level seed exchange networks contributed to unique patterns of seed adoption and adoption-related outcomes. Households with different regional- and community-level seed exchange networks had distinct seed management practices and seed security constraints. Adoption, <i>in situ</i> genetic diversity and evidence of landrace replacement varied across households that participated in different seed exchange networks. Finally, the impact of public sector breeding activities on adoption and household market participation also varied across households that participated in different seed exchange networks.</p><p> The study found a unique example among one community-level seed exchange network (Kakindo Sustainable Cooperative) of seed management practices that achieved both diversification and conservation of bean varieties and stimulated participation in local seed markets. The analysis suggests that a households' ability to simultaneously increase diversity of household seed stocks and conserve landraces was accomplished through a combination of conservative management of the more historically predominant Andean varieties and willingness to adopt and experiment with rare Mesoamerican varieties.</p>

<p> Scientists widely accept that modern agriculture is unsustainable, but the best methods for addressing unsustainability are still contested (Constance, Konefal, and Hatanaka 2018). Grassroots sustainable agriculture communities have long participated in the exploration of solutions for agriculture unsustainability, and their momentum continues to grow in the technical age. Practitioners of grassroots sustainable agriculture use many information systems that were not originally built to support the design of agricultural systems. Based on ethnographic research with two grassroots sustainable agriculture communities, I show that participants&rsquo; personal and community values frequently clashed with those embedded in information systems, including ones used to look for and manage plant information. Furthermore, I demonstrate a range of information challenges that participants faced in the absence of tools designed to support their specific work. I argue that practitioners of grassroots sustainable agriculture need information systems tailored to their goals and values in order to productively address barriers to designing and building agroecosystems for their communities. </p><p> This dissertation provides an example of how to involve communities in the development of information technology artifacts and strengthen efforts to support sustainability via technological interventions. First, I engaged in two grassroots sustainable agriculture communities as a participant, experiencing their practices, values, and information challenges first hand. Then, I worked with the communities to create a plant database web application (SAGE Plant Database) that supports agroecosystem design in local contexts. Members of the communities participated in the design, development, and data population stages so that the SAGE Plant Database supports their design context and upholds their technological and holistic sustainability values. At the foundation of the database is a plant ontology grounded in the participants&rsquo; practice of designing agroecosystems. My comparative analysis of the design of the SAGE Plant Database to other databases demonstrates its relevance due to its emphasis on agroecological relationships among plants and between plants and the environment, the inclusion of ethnobotanical data, and the embedded community values. By engaging in this research, I seek to make progress towards transforming the technology-supported food system into one that furthers food security, food sovereignty, and holistic sustainability.</p><p>

<p> Natural nesting habitat for Common Nighthawks (<i>Chordeiles minor </i>) in the Northern Prairie region of North America is in decline due to row-crop conversion. Other nesting habitats used by nighthawks in this region includes flat, gravel rooftops, but such rooftop habitat is scheduled to be replaced by other materials within the next 20 years. These changes present substantial challenges to population persistence for nighthawks in this region. </p><p> This study used point counts and land cover analysis at 396 points in two study areas in southeastern South Dakota, northeastern Nebraska and northwestern Iowa to document that nighthawk presence is positively associated with flat, gravel rooftops and heterogeneous land cover and negatively associated with row crops in agriculturally dominated landscapes. </p><p> In addition to land cover change challenges, continuing trends toward increasing summer temperatures, decreasing cloud cover and increasing humidity might make rooftops unsuitable for nest habitat. Mean daily minimum, average and maximum operative temperatures (T_e) recorded at rooftop nest sites in 2016-2017 were 26.3, 31.7, and 36.3 &deg;C, respectively, with a 71.1 &deg;C overall maximum T_e. I monitored 50 rooftop nests during 2015-2017 in southeastern South Dakota. Like many nightjars, 7- to 14-day old nighthawk chicks are extremely heat tolerant. Evaporative water loss rates rapidly increased at temperatures above 44.1 &deg;C in humid conditions (i.e. up to 16 &deg;C dew point), and chicks had similar evaporative water loss rates at 51&deg;C (2.44 g H₂0 h^-1) to adult nightjars. However, baseline corticosterone levels increased in chicks acutely exposed to high ambient temperatures, suggesting that these temperatures were stressful. In addition, low hatching (0.252) and fledging (0.262) success rates, similar to those for other declining nighthawk populations, and a negative association between ambient temperature and hatching success, suggest that future microclimate trends may make rooftops an unsuitable nesting habitat. </p><p> This study recommends conservation of grasslands and heterogeneous landscapes of row crops and grazed pastures to promote nighthawk occurrence in the region where row crops dominate. In addition, provision of urban ecoroofs, with gravel patches, as alternative nesting habitats in agriculturally dominated landscapes will also be important for maintaining populations of this declining aerial insectivore species.</p><p>

<p> In Arctic Alaska, Dolly Varden <i>Salvelinus malma </i> is highly valued as a subsistence fish; however, little is known about oceanic dispersal or ecology. This study addresses this knowledge gap, by using a fisheries independent method, pop-up satellite archival tags (PSATs). In spring of 2012 and 2013, we attached 52 PSATs to Dolly Varden in a river in northwestern Alaska, which flows into the Arctic Ocean, to examine the marine dispersal, behavior and habitat occupancy of this species. Tagged Dolly Varden demonstrated two types of dispersal, including offshore and nearshore dispersal. The offshore type was the first documented northwesterly dispersal and occupancy of Outer Continental Shelf (OCS) areas of the Russian Chukchi Sea. While occupying this area, tagged Dolly Varden demonstrated affinity for the first 5 m of the water column, diel patterns in depth occupancy, and dive depths of up to 50 m, while experiencing a thermal environment of generally 3&ndash;7&deg;C. During the nearshore dispersal type, Dolly Varden transited in coastal areas of northwest Alaska, likely returning to their natal rivers to spawn. While in nearshore areas, tagged Dolly Varden always occupied shallow waters (&lt; 6 m), and experienced a rapidly changing thermal environment (&plusmn; 15&deg;C), including some waters temperatures cooler than -1&deg;C. This study demonstrates that PSATs offer an alternative and effective platform with which to study several aspects of large adult Dolly Varden dispersal and ecology in areas where it is not practical or feasible to capture these fish, such as in coastal and offshore regions of Arctic Alaska. Additionally, the results of this study have increased our knowledge of the summer marine distribution, behavior and thermal environment of Dolly Varden in Arctic regions of Alaska, and this knowledge is important to several stake holders for the conservation of this important subsistence species.</p>

<p> Arctic Grayling (<i>Thymallus arcticus</i>) are widely distributed on the Arctic Coastal Plain (ACP) of Alaska, and are one of the few upper level consumers in streams, but the trophic pathways and food resources supporting these fish are unknown. Grayling migrate each summer into small beaded streams, which are common across the landscape on the ACP, and appear to be crucial foraging grounds for these and other fishes. I investigated prey resources supporting different size classes of grayling in a beaded stream, Crea Creek, where petroleum development is being planned. The specific objectives were to measure terrestrial prey subsidies entering the stream, quantify prey ingested by Arctic Grayling and Ninespine Stickleback (<i>Pungitius pungitius </i>), determine if riparian plant species affect the quantity of terrestrial invertebrates ingested by grayling, and determine if prey size and type ingested were a function of predator size. Results indicated that small grayling (&lt; 15 cm fork length (FL)) consumed mostly aquatic invertebrates (caddisflies, midges, and blackflies) early in the summer, and increasing quantities of terrestrial invertebrates (wasps, beetles, and spiders) later in summer, while larger fish (> 15 cm FL) foraged most heavily on stickleback. Riparian plant species influenced the quantity of terrestrial invertebrates entering the stream, however these differences were not reflected in fish diets. This study showed that grayling can be both highly insectivorous and piscivorous, depending upon fish size class, and that both aquatic and terrestrial invertebrates, and especially stickleback, are the main prey of grayling. These results highlight the importance of beaded streams as summer foraging habitats for grayling. Understanding prey flow dynamics in these poorly studied aquatic habitats, prior to further petroleum development and simultaneous climate change, establishes essential baseline information to interpret if and how these freshwater ecosystems may respond to a changing Arctic environment. </p>

<p>Oak (<i>Quercus</i>) forests in the Arkansas Ozarks have been important culturally, ecologically and environmentally for centuries. Historically these forests were fire dependent and dominated by oak species. In the past century, fire suppression and land management have caused these forests to densify. As a result, oaks are increasingly less abundant following disturbance in natural hardwood stands. Many applied ecological studies have explored methods and practices to maintain oak species in newly developing stands. This study attempted to link the mechanistic physiology of oak and non-oak reproduction to the applied ecological work. Varying stand conditions were generated in an undisturbed mature hardwood forest. Photosynthesis physiology was evaluated through direct and in-direct measures for six upland hardwood species in the Springfield Plateau of the Arkansas Ozarks. Environmental conditions, including sunlight canopy penetration, were significantly different based on treatment/slope position combinations. Corresponding differences in photosynthesis, development and abundance of hardwood reproduction were also significant across treatments, topographic position, and species. In conclusion, this study demonstrates that <i>in situ</i> measurements of photosynthetic performance are a valuable tool in predicting stand performance in oaks growing in their natural environment. </p>

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3273. Adviser: Edward J. Heske. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

<p> The Riverlands Migratory Bird Sanctuary (1500 ha) was established in 1988 on US Army Corps of Engineers (USACE) land along the Mississippi river in West Alton, Missouri (38.87&deg; N, -90.17&deg; W). It is now cooperatively operated by USACE and the National Audubon Society. About 485 ha consist of actively managed restored bottomland prairie and marshland. The Great Flood of 1993 caused prolonged inundation and destroyed vegetation beds and moist soil plants in the Sanctuary&mdash;an impact still visible today. The goal of this study was to improve plant species diversity and cover, as well as generate more natural vegetation. We employed differing degrees of soil disturbance (tilling and disking) as a means stimulate seed germination from the seed bank. We predicted that the more extreme soil disturbance, tilling, would achieve our goals best. Six replicate marshes within the Sanctuary were chosen for this study. Each marsh was divided into three similarly sized areas and which were randomly assigned one of three treatments: disking, tilling, and control. Vegetative cover and species presence were recorded in 0.25 m² sampling plots at random intervals along each transect in each treatment area. A pre-treatment sample was obtained for comparison. ANOVA of a randomized complete block design revealed strong interactions between marsh (block) and treatment for nearly every community measure. However, marsh effects for cover, species richness, and Shannon diversity were significant beyond this effect. Treatment effects were not significant. Community ordinations by NMDS revealed a strong tendency for plots to aggregate by marsh, not treatment. Preliminary management recommendations can be given based on this study. Restoration activities should focus on site specific characteristics such as the species pool and local hydrology and lean away from immediate additional disturbances. </p>

<p>Invasive fishes frequently change natural aquatic habitats due to predation and competition. The Alaska blackfish (Dallia pectoralis) is indigenous to some regions of Alaska but was illegally introduced to the Cook Inlet Basin in the 1950s. By the 1970s, fisheries managers expressed concern over possible ecosystem-altering effects of the blackfish introduction, especially in waterbodies containing popular sport fish. Descriptive food habit studies may assist fisheries managers in making decisions regarding management of non-native populations of Alaska blackfish. This project characterizes diet of three Cook Inlet Basin Alaska blackfish populations through stomach contents analysis. Shifts in diet across season, sex, and size of individuals from a lake, wetland pond, and stream are discussed using the Index of Relative Importance. Cook Inlet Basin Alaska blackfish consume similar invertebrate prey as native juvenile salmonids and stickleback, with major prey consisting of epiphytic/benthic dipteran larvae, gastropods, and ostracods. Piscivory, including cannibalism, is infrequent in these populations. Due to the high degree of dietary overlap with native fishes and stocked sport fish, and evidence that many Cook Inlet Basin waterbodies contain established populations of Alaska blackfish, fisheries managers should take actions to restrict the spread of blackfish through public awareness education, law enforcement, and funding for additional research. An Alaska blackfish husbandry manual outlines closed-system rearing and artificial fertilization protocols useful to researchers and educators for keeping live Alaska blackfish in the laboratory and classroom, in order to add to our body of knowledge about this species.