An investigation of the effect of Meloidogyne hapla, M. arenaria, M. arenaria thamesi, M. incognita acrita, and M. incognita on Ligustrum ovalifolium, L. japonicum, and Abelia floribunda was conducted. With the exception of M. hapla on L. ovalifolium and M. arenaria thamesi on A. floribunda, all 5 species of nematodes were pathogenic on the 3 host species. Striking differences in growth of the L. ovalifolium plants inoculated with the 4 root-knot species that caused significant reduction could easily be seen. Reduction in weight of the plants inoculated with the 4 root-knot species varied from 39.8% to 63.6% of the controls, and the reduction in total length of stems of these plants varied from 37.2% to 58.5% of the controls at the termination of the experiment. Reduction in weight of the L. japonicum plants inoculated with root-knot species varied from 29.2% to 51.7% of the controls. All plants inoculated with root-knot were significantly reduced in weight compared to controls. There were no visual differences in growth among the A. floribunda treatments; however, omitting the M. arenaria thamesi treatment which was not significantly different from control, the reduction in weight of the inoculated plants varied from 26.81 to 41.71 of the controls. / M.S.

The conversion of grasslands to woodlands is an ecosystem transformation that threatens grassland biodiversity, the provision of important ecosystem services, and the sustainability of rural livelihoods. A global phenomenon, woody plant encroachment (WPE) has been particularly problematic in the Southern Great Plains of the United States where the actions of private landowners are integral to sustaining grasslands. Increased diversity in landowners’ motivations for owning land have shifted the social landscape of rural areas necessitating a better understanding of landowners’ perspectives about WPE and their subsequent management actions. Towards this purpose, I employed a mail survey to private landowners in the Edwards Plateau of Texas, Central Great Plains of Oklahoma, and Flint Hills of Kansas to investigate landowner perceptions and management responses to WPE. First, I assessed landowners’ acceptance of WPE as a function of how they relate to their land (i.e., sense of place), their beliefs about the positive and negative consequences of woody plants, and their perceived threat of grassland conversion. Then, I examined the drivers of landowners’ goal intentions to manage woody plants and their current use of five adaptive management practices that prevent WPE. My results demonstrate that landowners vary in their sensitivity to WPE based on how they feel connected to their land. This was true even though most landowners had low acceptance thresholds for WPE, believed it led to numerous negative outcomes, and perceived it as increasingly threatening at greater levels of encroachment. Most landowners wanted to control or remove woody plants and were actively engaged in management practices to do so. These findings address uncertainties about landowners’ acceptance of WPE and grassland conservation actions and provide broad implications for how people perceive and respond to ecosystem transformation. / Master of Science / Around the world, grasslands are converting to tree and shrub woodlands at an unprecedented rate. This transformation profoundly reduces habitat available for grassland plants and animals and diminishes many ecosystem services that people and rural communities rely on. This loss of grasslands has been especially far-reaching throughout the Southern Great Plains of the United States. Because most of this region is privately owned, the management actions of landowners play a crucial role in preventing or allowing this conversion to continue. Recent shifts in land ownership motivations expanding beyond traditional agricultural production have created increased uncertainty about how private landowners view and react to this change. To investigate how landowners perceive and respond to this woody plant encroachment (WPE) phenomenon, I conducted a mail survey of landowners in the Edwards Plateau of Texas, the Central Great Plains of Oklahoma, and the Flint Hills of Kansas. Using sense of place, landowners’ beliefs about the potential positive and negative consequences of woody plants, and their perceptions of how threatening grassland conversion is, I assessed the thresholds at which landowners’ do or do not accept WPE. Then, I examined how acceptance of WPE relates to landowners’ management goals and current use of management practices to control or reduce woody plants. I found that most landowners believed that woody plants had many negative consequences and perceived increasing levels of threat at greater levels of encroachment. This related to low levels of acceptance for woody plants in grasslands. However, landowners’ threat perceptions and acceptance of WPE varied based on their sense of place. Finally, most landowners wanted to control or remove woody plants and were actively engaged in management practices to do so. My results provide critical information regarding how current landowners’ view and respond to grassland conversion and offer broad implications for how people perceive and respond to large-scale environmental change.

The objective of this work was to determine if summer dormancy of boxwood could be removed either through nutritional or hormonal means. Buxus sempervirens L. "Suffruticosa", B. sempervirens "Vardar Valley", and B sinica var. insularis (Nakai) "Justin Brouwers" were used for these studies. In the nutrition study, experiments were conducted to examine the effects of various levels of Osmocote 15-9-12 and liquid 10-4-6 on growth of boxwood. Optimal shoot dry weight was achieved at applications of 12 to 16 g Osmocote and 100 – 150 ppm N liquid fertilizer. Leachate EC corresponding to optimal shoot dry weight ranged from 0.5 to 0.7 dS/m for Osmocote and from 0.7 to 1.5 dS/m for liquid fertilizer. While the fertilizer requirements for boxwood optimal dry weight accumulation were determined, additional flushes of growth subsequent to the initial spring flush did not occur for "Vardar Valley" and English boxwood. In the phytohormone study, experiments were conducted that examined the effects of pruning, Promalin (GA4+7 and BA), and defoliation on the growth of three boxwood species. While Promalin applied alone or in conjunction with pruning shows promise of increasing new shoot growth, its response was not consistent from experiment to experiment. In fact, when it was applied in conjunction with defoliation, it dramatically decreased number of new shoots and actually resulted in some shoot mortality. Pruning was also erratic in its promotion of new shoots. Defoliation increased new shoot number dramatically and shows the most promise in overcoming summer dormancy. / Master of Science

The effects of high medium temperatures on the growth and mineral nutrition of selected woody plants and on the composition of the medium solution were studied. Medium temperature profiles were established for 3.8-liter black polyethylene containers exposed to solar radiation under Virginia nursery conditions. On clear days in mid-summer, maximum recorded medium temperatures on the southwest side of containers were as high as 45°C and could exceed 40°C for 4 to 5 hours. The high medium temperatures in exposed containers reduced the shoot relative growth rate and the specific rate of nitrogen uptake for Ilex crenata ‘Convexa’ in comparison to that of plants grown in containers insulated from solar radiation. Shoot dry weights of J. crenata ‘Helleri’ , Juniperus chinensis, Buxus microphylla, and Nandina domestica were at least 20% lower in exposed containers than in insulated containers. In a pine bark medium, growth response of J. crenata, J. horizontalis, or N. domestica to increased N application rate was similar when root-zones were at 40°C for 6 hrs/day or more optimal growth temperature. In unlimed pine bark, root-zone temperature of 40°C for 6 hrs/day resulted in higher medium solution pH and NH₄- N:NO₃-N ratio than at lower temperature. Limestone addition to the medium negated these effects and alleviated growth reductions due to high root-zone temperature for N. domestica and J. horizontalis. The higher medium solution pH associated with heated root-zones resulted in lower medium solution and shoot tissue Mn concentrations for I. crenata. A limed pine bark medium periodically fertilized with ammonium N was heated to temperatures of 28°, 34°, 40°, 46°, or 52°C for daily exposure duration of 1, 2, 4, 6, or 24 hours for 20 days. Treatment temperature of at least 40°C with a daily exposure duration of 24 hours resulted in an increase in medium solution NH₄-N concentration. Similar increase in NH₄-N was found for 2 hr/day exposure to 46°C, with further increases in NH₄-N at longer exposure times. The maximum level of NH₄- N occurred after 1 hr/day exposure to 52°C or 24 hr/day exposure to 46°C. Decreases in medium solution NO₃-N concentration generally coincided with the increases in NH₄- N. Results indicate that high container temperature may increase the ratio of NH₄- N:NO₃-N in the medium solution of plants fertilized with predominately ammoniacal N. / Ph. D.

The aim of the thesis "Legal regulation of the protection of woodspecies" is to summarize the main instruments of the Czech law to ensuring the protection of woody plants. The thesis focuses mainly on the current legislation in the Czech Republic. The thesis is divided into seven chapters. The first part of the thesis defines the woody plant in the meaning of law, its functions and questions of its protection. The other parts of the thesis describe legal regulation of woody plants in a lot of different czech statutes. In the conclusion were made some suggestions, how to improve the current legal regulation of woody plants in the Czech Republic.

Woody plant encroachment is one of the major problems worldwide because it affects negatively the herbaceous layer, which provide forage for livestock production. However, the role of ruminants particularly browsers in the dispersal of woody plant seeds still remains a concern for farmers interested in grass production. Seedpods of various woody plant species constitute a crucial part of the diet of herbivores during the dry season because of their high nutritional quality compared to herbaceous material. The interaction of associated diet quality, seed characteristics and animal species among other factors play a pivotal part in the success of livestock faecal seeds dispersion. Furthermore, dispersed seeds that successfully grow into mature woody plants become an important source of protein for herbivores. The use of woody plants as a source forage is known to be limited by plant secondary metabolites (PSMs) such as condensed tannins. The objectives of this study were to determine 1) the effects of condensed tannins and crude protein of Vachellia tortilis and Dichrostachys cinerea pods in seed recovery and germination fed to goats, and 2) the effects of diet mixing on the feed intake of plant species by goats. In the first experiment, a total of 12 female indigenous goats and 12 female Pedi sheep were utilised in this study, with the average body weights of 29.50 kg ± 1.60 (S.E) and 28.70 kg ± 1.60, respectively. Twelve goats were grouped into two groups of six goats per group, one group was fed D. cinerea pods and the other group was fed V. tortilis pods. The group of 12 sheep were divided similarly, the one group was fed D. cinerea pods and the other group was fed V. tortilis pods. Each animal was given V. tortilis and D. cinerea pods at 2.50% of their body weight. All animals were allowed to consume D. cinerea or V. tortilis pods within 24 h, after which the remaining pods were collected and weighed. Faecal collection commenced immediately after the 24 h pods feeding and was carried on until no seeds were discovered in faeces. All faeces extracted from sheep and goats were collected daily in the morning from the faecal bags. In the second experiment, a total of 24 indigenous goats with average body weight of 26.6 kg ± 0.51 were utilised. Goats were arbitrarily selected and grouped into four groups of six goats per group (goats were placed individually in 2 m2 pens). Each group was fed one of the following diets: diet one - Searsia lancea, diet two - S. pyroides, diet three - Euclea crispa and diet four - was a combination of the three plant species (Searsia lancea, S. pyroides and Euclea crispa). Searsia lancea, S. pyroides and E. crispa branches were collected every morning prior to feeding, and were weighed before offering the animals. Refusals were gathered and weighed, and intake was calculated as distinction between weight in and refusals. Plant species foliage were analysed for crude protein, condensed tannin, acid detergent lignin, acid detergent fibre and neutral detergent fibre. During the first experiment, the cumulative percentage seed recovery of V. tortilis from goats (46.00 % ± 1.90) and sheep (52.00 % ± 2.93) was significantly higher than D. cinerea from goats (13 % ± 1.47) and sheep (24.00 % ± 1.16). Germination percentage of D. cinerea seeds that passed through the gastro-intestinal tract of goats (33.12 % ± 2.94) and sheep (36.00 % ± 2.68) was significantly higher than V. tortilis seeds that passed through the gastro-intestinal tract of goats (28.98 % ± 2.68) and sheep (23.04 % ± 2.81). Average D. cinerea (34.56 % ± 1.99) and V. tortilis (26.02 %± 2.10) seeds that went through the gastro-intestinal of goats and sheep had a significantly higher germination rate than the control (i.e. no passage through the gut; D. cinerea = 2.31 % ± 1.55, V. tortilis = 5.07 % ± 2.68). The high mean cumulative percentage seed recovery of V. tortilis (18.80 %) may be attributed to the relatively higher crude protein than D. cinerea (12.20 %). This may encourage animal seed dispersal and germination of woody plant species with relatively high crude protein content. In the second experiment, Searsia lancea contained 8.50 % CP, 21.46 % acid detergent fibre (ADF), 12.50 % ADL and 39.37 % NDF. Searsia pyroides had 9.03 % CP, 27.07 % ADF, 10.89 % ADL and 40.30 % NDF. Euclea crispa had 6.19 % CP, 26.20 % ADF, 16.63 % ADL and 30.02 % NDF. Mixed diet (combination of the three plant species) had 8.96 % CP, 23.72 % ADF, 11.13 % ADL and 38.28 % NDF. Searsia lancea had 2.70 % of CTs while S. pyroides had 5.20 % CT, E. crispa had 6.44 % CT and mixed diet had 7.20 % CT. The mean dry matter intake varied significantly among dietary groups (P < 0.001). Similarly, goats offered a mixed diet consumed more CTs (P < 0.01) than those offered individual forage species. The high mean cumulative percentage seed recovery of V. tortilis may be attributed to the higher crude protein of V. tortilis (18.80 %) than D. cinerea (12.20 %). Higher passage rate may encourage animal seed dispersal and germination of plant species. The results from experiment two support the postulation that animals foraging in mixed diet systems consume more PSMs and achieve higher dry matter intake than animals confined to monocultures or single species feeding systems. Given that woody plant encroachment is already reducing farm-grazing capacities in African savannas and this problem is predicted to double by 2050, strategies that improve herbivore ability to consume woody plants will increase forage availability and inform bush control programmes and policies. Moreover, the concomitant increase in CTs by goats exposed to diets with diverse species also has positive implications for animal / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Esta dissertação trata dos mecanismos de geração do humor no conto “No Kaddish for Weinstein” (ALLEN, 1975). É possível identificar nessa narrativa a forte e frequente presença do humor étnico, mais especificamente do humor judaico-americano. Porém acredita-se que este não seja o único tipo de humor de que o autor faz uso, considerando-se também que o humor possui diversos mecanismos e pode emergir de diversas situações. Por essa razão, há a necessidade de não só identificar o humor característico de Woody Allen, mas também analisar o tipo de narrativa que esse escritor constrói em seus contos. Além disso, é necessário verificar a relevância do conhecimento cultural na construção do humor e nas relações identitárias que constituem as personagens e narradores. Partindo do pressuposto de que o humor de WA é singular, surgem as questões desta pesquisa: (a) Quais são os domínios, estratos e parâmetros que tipificam a narrativa de Allen?, (b) Quais os mecanismos de humor que o autor usa em seus contos?, (c) Que elementos linguísticos, culturais, identitários e cognitivos são peças-chave na construção do humor alleniano? A partir dessas questões, surgem questionamentos derivados: por que o humor e o judaísmo estão conectados? Qual a relação entre eles? O objetivo geral da pesquisa é examinar o humor nos contos de Woody Allen e sua relação com elementos sociocognitivos e identitários da cultura judaica e judaico-americana. Os objetivos específicos são (a) analisar a estrutura narrativa dos contos de WA, (b) identificar as características dos tipos de humor no conto alleniano “No Kaddish for Weinstein”, (c) analisar os elementos linguísticos que fazem emergir o humor no conto em questão, (d) relacionar elementos linguísticos e fatores socioculturais no conto do escritor e (e) relacionar os elementos que constituem o humor alleniano. Entre os vários contos pré-analisados de diferentes coletâneas da produção de Allen, escolheu-se o conto “No Kaddish for Weinstein", por ser uma narrativa que reúne características que estão presentes, em maior ou menor grau, em seus contos como um todo. Embora variem as temáticas narrativas, o conto “No Kaddish for Weinstein" pode ser considerado prototípico. Por prototípico, entende-se a propriedade de reunir, de forma bastante condensada, atributos gerais do estilo narrativo do autor. Os resultados demonstram que o autor utiliza uma ampla variedade de mecanismos geradores de humor, tais como: quebra de expectativa do leitor, punch lines e scripts opostos. Quanto as questões identitárias da cultura judaico-americana, são mais salientes as referências à autodepreciação e a costumes próprios desta cultura. Fica evidente a construção de uma narrativa que demanda a evocação de conhecimentos enciclopédicos (frames) por parte do leitor, sem os quais não é possível reconhecer o humor potencial do conto. Todos esses resultados se encontram relacionados com o tipo de estrutura narratológica do conto, segundo o framework do Sistema Cognitivo da Narrativa de Talmy (2000), principalmente em relação ao perfilamento de um leitor que compartilhe de conhecimentos da cultura judaico-americanca e de referências as mais diversas à história e cultura nova-iorquina. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-03-30T16:36:07Z No. of bitstreams: 1 Dissertacao Cíntia Brunetta Moreira.pdf: 1436905 bytes, checksum: 5f270e4ff2f3d61937e25705566549f3 (MD5) / Made available in DSpace on 2015-03-30T16:36:07Z (GMT). No. of bitstreams: 1 Dissertacao Cíntia Brunetta Moreira.pdf: 1436905 bytes, checksum: 5f270e4ff2f3d61937e25705566549f3 (MD5) / This dissertation is about humor mechanisms generation present in the short story “No Kaddish for Weinstein” (ALLEN, 1975). It is possible to identify in the narrative the frequent presence of ethnic humor, more specifically the Jewish-American humor. However, it is believed that this is not the only type of humor the author uses, considering also that humor can emerge from many different mechanisms and situations. For this reason, there is the necessity of not only identifying the characteristic humor of Woody Allen, but also the necessity of analyzing the narrative type built by the author in his short stories. Besides all that, it is necessary to verify the relevance of cultural background in humor generation, as well as in identity relations within characters and narrators. The research questions derive from the presupposition that the humor created by Allen is singular, they are: (a) what are the domains, strata and parameters that typify Allen’s narrative?, (b) what are the humor mechanisms that the author uses in his short stories?, (c) what linguistic, cultural, identity and cognitive elements are essential in the Allenian humor? Other questions rise from these interrogations: why humor and Judaism are connected? What is the relation between them? The general objective of this research is to examine the humor present in Allen’s short stories and its relation with sociocognitive and identity elements of Jewish culture. The specific objectives are (a) to analyze the narrative structure in Allen’s short stories, (b) to identify the characteristics of the type of humor in Allen’s “No Kaddish for Weinstein”, (c) analyze what linguistic elements make humor rise in Allen’s referred short story, (d) make relations between linguistic and sociocultural elements in Allen’s short story and (e) make relations between the elements that constitute allenian humor. Among the many short stories pre-analyzed from different collection books produced by Woody Allen, “No Kaddish for Weinstein” was chosen for being a narrative that encompasses the characteristics that are present, in higher or lower degree, in all his short stories as a whole. Although the narrative themes vary, the short story “No Kaddish for Weinstein" can be considered prototypical. By prototypical it is understood the property of encompassing, in a condensed manner, the general requisites of the narrative style of the author. The results demonstrate that the author makes use of a great variety of humor mechanisms, among them: rupture of the reader’s expectation, punch lines e opposite scripts. In relation to the identity issues of Jewish-American culture, the references to selfhatred and habits are more relevant. It is evident, the construction of a narrative that demands from the reader the evocation of encyclopedic knowledge (frames). Without the recognition of these frames it is not possible to recognize the potential humor of the short story. All the results are related with the narratologic structure type of the short story, according to the framework of the Cognitive Approach to the Analysis of Narrative by Talmy (2000). This is mainly because it permits designing a reader’s profile that shares the knowledges concerning the Jewish-american and New Yorker culture, moreover references about history.

Esta dissertação trata dos mecanismos de geração do humor no conto “No Kaddish for Weinstein” (ALLEN, 1975). É possível identificar nessa narrativa a forte e frequente presença do humor étnico, mais especificamente do humor judaico-americano. Porém acredita-se que este não seja o único tipo de humor de que o autor faz uso, considerando-se também que o humor possui diversos mecanismos e pode emergir de diversas situações. Por essa razão, há a necessidade de não só identificar o humor característico de Woody Allen, mas também analisar o tipo de narrativa que esse escritor constrói em seus contos. Além disso, é necessário verificar a relevância do conhecimento cultural na construção do humor e nas relações identitárias que constituem as personagens e narradores. Partindo do pressuposto de que o humor de WA é singular, surgem as questões desta pesquisa: (a) Quais são os domínios, estratos e parâmetros que tipificam a narrativa de Allen?, (b) Quais os mecanismos de humor que o autor usa em seus contos?, (c) Que elementos linguísticos, culturais, identitários e cognitivos são peças-chave na construção do humor alleniano? A partir dessas questões, surgem questionamentos derivados: por que o humor e o judaísmo estão conectados? Qual a relação entre eles? O objetivo geral da pesquisa é examinar o humor nos contos de Woody Allen e sua relação com elementos sociocognitivos e identitários da cultura judaica e judaico-americana. Os objetivos específicos são (a) analisar a estrutura narrativa dos contos de WA, (b) identificar as características dos tipos de humor no conto alleniano “No Kaddish for Weinstein”, (c) analisar os elementos linguísticos que fazem emergir o humor no conto em questão, (d) relacionar elementos linguísticos e fatores socioculturais no conto do escritor e (e) relacionar os elementos que constituem o humor alleniano. Entre os vários contos pré-analisados de diferentes coletâneas da produção de Allen, escolheu-se o conto “No Kaddish for Weinstein", por ser uma narrativa que reúne características que estão presentes, em maior ou menor grau, em seus contos como um todo. Embora variem as temáticas narrativas, o conto “No Kaddish for Weinstein" pode ser considerado prototípico. Por prototípico, entende-se a propriedade de reunir, de forma bastante condensada, atributos gerais do estilo narrativo do autor. Os resultados demonstram que o autor utiliza uma ampla variedade de mecanismos geradores de humor, tais como: quebra de expectativa do leitor, punch lines e scripts opostos. Quanto as questões identitárias da cultura judaico-americana, são mais salientes as referências à autodepreciação e a costumes próprios desta cultura. Fica evidente a construção de uma narrativa que demanda a evocação de conhecimentos enciclopédicos (frames) por parte do leitor, sem os quais não é possível reconhecer o humor potencial do conto. Todos esses resultados se encontram relacionados com o tipo de estrutura narratológica do conto, segundo o framework do Sistema Cognitivo da Narrativa de Talmy (2000), principalmente em relação ao perfilamento de um leitor que compartilhe de conhecimentos da cultura judaico-americanca e de referências as mais diversas à história e cultura nova-iorquina. / This dissertation is about humor mechanisms generation present in the short story “No Kaddish for Weinstein” (ALLEN, 1975). It is possible to identify in the narrative the frequent presence of ethnic humor, more specifically the Jewish-American humor. However, it is believed that this is not the only type of humor the author uses, considering also that humor can emerge from many different mechanisms and situations. For this reason, there is the necessity of not only identifying the characteristic humor of Woody Allen, but also the necessity of analyzing the narrative type built by the author in his short stories. Besides all that, it is necessary to verify the relevance of cultural background in humor generation, as well as in identity relations within characters and narrators. The research questions derive from the presupposition that the humor created by Allen is singular, they are: (a) what are the domains, strata and parameters that typify Allen’s narrative?, (b) what are the humor mechanisms that the author uses in his short stories?, (c) what linguistic, cultural, identity and cognitive elements are essential in the Allenian humor? Other questions rise from these interrogations: why humor and Judaism are connected? What is the relation between them? The general objective of this research is to examine the humor present in Allen’s short stories and its relation with sociocognitive and identity elements of Jewish culture. The specific objectives are (a) to analyze the narrative structure in Allen’s short stories, (b) to identify the characteristics of the type of humor in Allen’s “No Kaddish for Weinstein”, (c) analyze what linguistic elements make humor rise in Allen’s referred short story, (d) make relations between linguistic and sociocultural elements in Allen’s short story and (e) make relations between the elements that constitute allenian humor. Among the many short stories pre-analyzed from different collection books produced by Woody Allen, “No Kaddish for Weinstein” was chosen for being a narrative that encompasses the characteristics that are present, in higher or lower degree, in all his short stories as a whole. Although the narrative themes vary, the short story “No Kaddish for Weinstein" can be considered prototypical. By prototypical it is understood the property of encompassing, in a condensed manner, the general requisites of the narrative style of the author. The results demonstrate that the author makes use of a great variety of humor mechanisms, among them: rupture of the reader’s expectation, punch lines e opposite scripts. In relation to the identity issues of Jewish-American culture, the references to selfhatred and habits are more relevant. It is evident, the construction of a narrative that demands from the reader the evocation of encyclopedic knowledge (frames). Without the recognition of these frames it is not possible to recognize the potential humor of the short story. All the results are related with the narratologic structure type of the short story, according to the framework of the Cognitive Approach to the Analysis of Narrative by Talmy (2000). This is mainly because it permits designing a reader’s profile that shares the knowledges concerning the Jewish-american and New Yorker culture, moreover references about history.

Master of Science / Department of Biology / Walter K. Dodds / Human-induced stressors such as increased nitrogen (N) loadings, altered watershed land-use, and biodiversity losses are a few of the numerous threats to aquatic systems. Prairie streams experience natural disturbances, such as flooding and desiccation, which may alter responses to anthropogenic stressors. Denitrification, the dissimilatory reduction of NO3- to N gas (N2O or N2), is the only permanent form of N removal from terrestrial or aquatic ecosystems, and is important in mitigating N pollution to streams and downstream waters. Little is known about the relationships between denitrification and riparian prairie vegetation or large consumers. In the first chapter, I used outdoor mesocosms to determine the impact of a grazing minnow, Campostoma anomalum, on structural and functional responses of prairie streams to a simulated flood, focusing on denitrification. In terrestrial ecosystems, grazing can stimulate denitrification, but this has not been studied in streams. Ammonium (NH4+) enrichments, used to simulate fish excretion, alleviated N limitations on denitrification. Both fish and NH4+ affected algal biomass accrual, but only fish affected algal filament lengths and particulate organic matter. In a second experiment, I examined the impact of woody vegetation expansion, a primary threat to tallgrass prairie, on riparian and benthic denitrification. Expansion of woody vegetation in these grasslands is due primarily to altered fire regimes, which historically inhibited woody vegetation growth. To determine the effect of woody vegetation expansion on benthic and riparian denitrification, woody vegetation was removed from the riparian zone of a grazed and an ungrazed watershed. Both soil and benthic denitrification rates from this removal buffer were compared to rates in grassy or woody riparian zones. Riparian soil denitrification was highly seasonal, with greatest rates occurring during early spring, and rates being low throughout the remainder of the year. Benthic denitrification was also temporally variable but did not exhibit seasonal trends, suggesting benthic denitrification is driven by factors other than water temperature. Removal of woody vegetation stimulated soil and benthic denitrification rates over rates found in naturally vegetated riparian zones. Elevated N loadings will continue to affect aquatic ecosystems, and these effects may be exacerbated by biodiversity losses or changing riparian vegetation.

The utilization of radial growth responses of trees to diagnose air pollution injury, and problems of growth defects interfering with the establishment of growth chronologies, is discussed. Cores from trees in an air pollution-stressed forest are examined for their potential to crossdate. Less than half, and usually less than a third of the trees on all plots can be crossdated, and number appears to be associated with changing conditions along a transect of elevational and pollution levels. Chronologies developed along this transect are presented.