Master of Arts / Department of Geography / John A. Harrington Jr / In late summer and fall, many migratory birds journey south from the North American Great Plains to spend the winter in locations with greater food availability. As spring returns, a combination of genetics and environmental cues trigger these birds to return north to their breeding grounds. Several bird migration phenology studies from Europe, Australia, and the eastern/northern United States have discovered that some bird species are returning earlier in the spring, a change that has often been correlated with a warming climate. This study aimed to be the first to analyze possible changes in both spring bird migration phenology and regional spring climate change in Kansas. First arrival dates (FADs) were collected for thirty bird species, resulting in a database with over 6,000 FAD entries. For northeast Kansas, 1997-2007 median arrival dates were calculated and compared to dates published by Dr. Richard Johnston in 1965. In southcentral Kansas, 1997-2007 and 1947-1967 median arrival dates were calculated and compared. Temperature data from spring (February through May) were also obtained from the National Climate Data Center's United States Historical Climatology Network for all stations within northeast and south central Kansas and temporal trends were analyzed with linear regression analysis. A comparison between median arrival dates in northeast Kansas found that eleven species had altered their arrival date by a potentially significant number of days. Nine of these had advanced their arrival and two showed a delay. In south central Kansas, nine species were shown to have statistically significant differences in median arrival dates between time periods. Six of these showed an advance and three showed a delay. Five species showed the same trend between both regions, with four arriving earlier by an average 9.4 days and one delaying by an average of 4.5 days. Temperature trends for both subregions in Kansas showed significant warming of 1.8-2.6°F (1.0-1.4°C) over the last century, with the largest warming observed in February and associated strongly with increasing minimum temperatures. The results from this study provide the first evidence that some bird species have recently altered the timing of their arrival in Kansas, with a greater shift toward earlier arrival dates. While the majority of these shifts were correlated with spring warming in Kansas, additional research is necessary to determine the precise cause(s) of these phenological shifts. Still, given existing literature and Intergovernmental Panel on Climate Change predictions for continued warming in the next century, continued alterations to bird migration phenology seem likely.

Master of Science / Department of Biology / Craig Paukert / I investigated the influence of anthropogenic threats and hydrologic alteration on fish assemblages within the Lower Colorado River Basin (LCRB). Life history traits of fish assemblages for individual stream segments were summarized by species presence/absence data of current (1980-2006) records. To assess anthropogenic threats, I developed a series of ecological risk indices at various scales (e.g., catchment, watershed, aquatic ecological system and upstream of aquatic ecological system) and related each index to fish life-history traits to determine the method and scale that best related to biotic metrics. Hydrologic alteration was quantified using the Indicators of Hydrologic Alteration software to calculate hydrologic alteration values using the range of variability approach. Ecological risk indices within all scales were strongly correlated (r[superscript]2>0.54, p<0.0001) to one another. Relationships between fish life history traits and ecological risk indices occurred only at the catchment and watershed scales. Strongest relationships were at the watershed scale where increased levels of anthropogenic risk were related to reduced occurrences of native, fluvial dependent species (r[superscript]2=0.12, p<0.0001) and increased occurrences of nonnative generalist species (r[superscript]2=0.22, p<0.0001). The percent agriculture was positively related to indices of alteration of low flows (r=0.401, p=0.006) while forested land cover was negatively related to alteration of low flow events (r=-0.384, p=0.008). Relationships between indices of hydrologic alteration and fish traits indicate the occurrence of piscivorous, nonnative fishes increased with alteration of low flow events whereas occurrence of fluvial dependent fishes that preferred rubble substrate decreased with alteration of low flow events (r=0.64, p=0.001). Our analysis suggests that ecological risk indices and hydrologic alteration in the LCRB are related to composition of biotic communities. Incorporating cost-effective risk indices into conservation planning will likely increase the effectiveness of conservation efforts while understanding biotic responses to modified flow regimes are a necessity in sustainable development of water resources as human populations grow and water resources decrease in the LCRB.

Le compostage est un procédé anthropique basé sur le processus naturel de décomposition de la biomasse qui exploite l'activité enzymatique des microorganismes sous le contrôle de plusieurs facteurs environnementaux. Les résidus lignocellulosiques de par leur composition et leur faible pourcentage d'humidité sont particulièrement adaptés au compostage dans lequel ils jouent le rôle d’élément structurant. Bien que majoritairement d’origine végétale, la matière organique dirigée vers les sites de compostages est très diversifiée, tout comme les types de contaminants qu’elle peut incidemment contenir et dont l’impact sur les processus de biodégradation, et de surcroit leur rémanence dans l’environnement, reste largement à investiguer. L’objectif de cette thèse vise ainsi à faire état de l’effet de la composition de la biomasse lignocellulosique et de la présence d’un contaminant fréquent tel que le glyphosate sur le compostage. Pour ce faire, le suivi de la transformation de la matière organique végétale et de la dégradation du glyphosate, l’évolution des paramètres physicochimiques et la dynamique de recrutement des populations bactériennes ont été effectués tout au long du processus. Deux expériences menées sur le terrain visaient dans un premier temps à mesurer l’effet de l’âge d’une plante ligneuse, dans ce cas-ci le saule arbustif (Salix), et d’une période d’entreposage hivernal sur la transformation de la biomasse, et dans un deuxième temps à étudier les dynamiques de succession bactériennes impliquées dans le cycle du carbone et de l’azote lors du compostage de résidus végétaux. Les résultats obtenus ont révélé une différence dans la composition de la biomasse des tiges âgées de 2 ans et de 3 ans. Alors que les premiers contenaient plus de composés extractibles, les seconds étaient plus riches en sucres structuraux. Ces différences expliquent une hausse des températures plus forte et plus rapide dans le tas de copeaux de tiges plus jeunes. La diminution des composés extractibles, la conservation des sucres structuraux et l’augmentation de la proportion de lignine démontrent l’importance de la source de carbone soluble pour l’initiation de la décomposition du bois et la récalcitrance des éléments lignocellulosiques durant l’entreposage hivernal. La seconde expérience a mis en évidence une très grande diversité de bactéries responsables de la décomposition de la cellulose, des hémicelluloses et de la lignine durant la phase thermophile du compostage. Cette phase qui était le théâtre d’une activité intense comptait moins d’espèces, mais ces dernières étaient très abondantes, une tendance qui s’est inversée avec la maturation de la matière organique. La dynamique observée traduit une redondance fonctionnelle des communautés qui semblent évoluer selon la température, le taux d’oxygène et la nature du substrat disponible. Une troisième expérience menée en milieu contrôlé a ensuite démontré l’impact négligeable du glyphosate sur l’activité microbienne et l’évolution des paramètres physicochimiques lors du compostage. Le glyphosate était presque ou entièrement dégradé à l’issue du compostage et la présence du principal produit de dégradation, l’acide aminométhylphosphonique (AMPA) n’a d’ailleurs même pas pu être quantifiée durant l’expérience. L’impact du glyphosate sur les communautés bactériennes était également négligeable. Seules quelques bactéries étaient différentiellement abondantes entre les deux traitements, la grande majorité étant moins abondante dans le traitement contenant du glyphosate. La richesse en espèces aux différents temps d’échantillonnage était la même entre le traitement témoin et le traitement contenant du glyphosate « pur » et l’analyse de la bêta-diversité n’a relevé aucune différence significative entre les communautés présentes dans le traitement témoin et le traitement glyphosate. Cette thèse a ainsi fait valoir l’importance de la nature initiale de la matière organique sur l’activité microbienne, le recrutement et la dynamique des communautés durant le compostage, tandis que la présence du contaminant glyphosate s’est présenté comme un facteur beaucoup moins déterminant sur les processus de décomposition et l’abondance des espèces bactériennes. Ces informations devraient non seulement permettre d’optimiser le traitement de la matière organique par compostage, mais aussi de mieux évaluer les risques potentiels associés au compostage de biomasse contaminé. / Composting is an anthropic process based on the natural decay of biomass that exploits the enzymatic activity of microorganisms under the control of several environmental factors. Due to their composition and low moisture content, lignocellulosic residues are particularly suitable for composting and serve as a structuring element, which confers them an important role in the process. Although mostly of plant origin, the organic matter (OM) directed towards composting sites is highly diversified, as are the types of contaminants it can contain. The impact of these contaminants, such as glyphosate, on the biodegradation process and their persistence in the environment remain to be investigated. The objective of this thesis is thus to report on the effect of the composition of the lignocellulosic biomass and the presence of glyphosate on the evolution of the physicochemical parameters and the recruitment of bacteria during composting, while ensuring the follow-up of the transformation of the vegetable organic matter and the degradation of glyphosate during the process. Two field studies were conducted to measure the effect of stem age and winter storage on the transformation of wood chips, and to study the dynamics of bacterial succession involved in the carbon and nitrogen cycle during the composting of plant residues. The results obtained revealed a difference in the composition of 2-year-old and 3-year-old stems from shrub willow (Salix sp.), with the younger ones containing more extractable compounds and the more mature ones richer in structural sugars. These differences were reflected in a higher and faster temperature rise in the younger chip pile. A decrease in extractives, retention of structural sugars, and an increase in the proportion of lignin demonstrate the importance of the soluble carbon source for the initiation of wood decomposition and recalcitrance of lignocellulosic elements. The second experiment revealed a very high diversity of bacteria responsible for the decomposition of cellulose, hemicelluloses and lignin during the thermophilic phase of composting. This phase, during which intense activity took place, had fewer species, but they were very abundant, a trend that reversed as the organic matter matured. The observed dynamics reflect a functional redundancy of the communities, which seems to evolve according to the temperature, oxygen level and nature of the available substrate. A third experiment conducted in a controlled environment demonstrated the negligible impact of glyphosate on microbial activity and the evolution of physicochemical parameters during composting. Glyphosate was almost or completely degraded after composting, while the main product of degradation, aminoethylphosphonic acid (AMPA), was not detected. The impact of glyphosate on bacterial communities was also negligible, while species richness at different sampling times was the same when comparing the control treatment and the treatment containing "pure" glyphosate. The beta-diversity analysis found no significant difference between the communities present in the control and glyphosate treatments, while a few bacteria were differentially abundant between the two treatments, the vast majority being less abundant in the glyphosate treatment. This thesis has thus highlighted the importance of the initial nature of the organic matter on microbial activity as well as on the recruitment and dynamics of bacterial communities during composting, while the presence of glyphosate was shown to be a weak determinant of decomposition processes and species abundance. This information should help to optimize the treatment of organic matter by composting and to better assess the potential risks associated with composting contaminated biomass.

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