The thesis attempts a broad overall survey and classification according to the Zurich-Montpellier system ofplant sociology, of limestone grassland vegetation in the British Isles The classification is based on some 535 grassland Aufnahmen and 75 Aufnahmen of contact communities. In all, some 13 grassland Associations are recognised, whilst the zonal and successional communities are classified in 16 Associations. The Associations are classified in the system of classification advocated by Lohmeyer et al. (1962), and the phytogeographical relationships of the related Association-groups or Alliances are considered in detail. The limestone grassland communities of the British Isles have been found to be representative of four Classes: - (a) Festuco-Brometea - thermophilous dry grassland communities of the sub-mediterranean and sub - atlantic regions of Europe; (b) Elyno-Seslerietea - dry sub-montane, sub-alpine grass heaths of the low alpine region of central Europe and Scandinavia; ( c ) Molinio-Arrhenatheretea - mesophilous, grazed or mown hay meadows and pastures of the lowland zone of western Europe; (d) Violetea calaminariae - open grassland communities IV of heavy metal - rich strata and spoil banks. The thesis is divided into 5 parts : - Part 1 reviews the methods available for a vegetation survey and phytosociological technique in general; outlines the history and status of limestone grasslands; and summarises the methods used for previous description of British vegetation; Part 2 presents the results of the grassland survey and relates the change in overall floristic composition and grassland type to climatic factors using the climate diagrams of Walter & Lieth (1967); Part 3 considers the successional and zonal relationships of these grassland communities, whilst Part 4 discusses the validity of the methods used for the survey and suggests some of the logical extensions of t h is work with reference to the conservation and management of an area limestone grassland on the Magnesian Limestone of Co. Durham. Part 5 comprises 36 Association Tables and an Aufnahmen locality Appendix, and is to be found in the folio volume. References LOHMEYER, W. et a l . (1962). Contribution a 1 ' unification du systeme phytosociologique pour 1'Europe moyenne et nord-occidentale. Melhoramento, 15, 137-151. Walter, H. & Leith, H. (1967). Klimadiagramm Weltatlas. Jena.

Low input grassland systems depend on cheap fertiliser sources, such as clover or animal manures, to maintain sward productivity. Clover is a poor competitor for phosphate (P2O5) and potash (K2O), a mixed sward will therefore require adequate inputs of these nutrients. Nitrogen (N) leads to the suppression of clover. Recycling of cattle slurry would be followed by small N and P2O5 but large K2O effects. The K2O and P2O5 would be expected to have a beneficial effect on the clover while the N would be detrimental. Two investigations into the balance between these aspects of cattle slurry on clover in a mixed sward were performed. Slurry N led to clover suppression, this effect was strongest following spring applications. K2O had a beneficial effect on the clover, the P2O5 supplied had a small positive effect but was insufficient to fully meet the clover's requirements. There was a suggestion that these beneficial effects were strongest following summer applications. In addition to these fertiliser effects, non nutritional secondary effects often followed slurry with a deleterious action on the clover. These effects were most common following higher rates of slurry and summer applications. A further investigation was performed to establish the effect of varying clover variety and companion grass species on the clover's susceptibility to cattle slurry N and secondary effects and the nature of these effects following pig slurry applications. This revealed that clover's susceptibility to slurry N was inversely related to leaf size. No difference in secondary effects susceptibility arose with different clover varieties or companion grass species. Pig slurry was not accompanied by secondary effects. Slurry applications to mixed swards may therefore have positive and negative nutritional effects on the clover component but non nutritional secondary effects may also act with a deleterious effect on the clover.

No description available.

The diversity and zoogeography of Diptera (Brachycera) of disjunct xeric grasslands in the southern Yukon were studied. Over 20,000 flies were collected representing 32 families and 213 species. In terms of abundance, the predacious guild dominated (54% of total specimens) due mostly to the family Chamaemyiidae which represented 45% of all specimens. In terms of diversity, the phytophagous and parasitoid guilds were dominant (25.5% of total species each). The most diverse families were Agromyzidae (32 species), Chloropidae (31 species), Tachinidae (23 species) and Pipunculidae (20 species). Thirty-four undescribed species were collected and 58 species were recorded for the first time in the Yukon. Zoogeographic analysis indicates that the Diptera fauna of these grasslands is dominated by widespread Nearctic or Holarctic species, but the fauna also includes southern grassland species with disjunct distributions, and species endemic to Beringia. The presence of endemic and disjunct species suggests that these grasslands were present in Beringia during the Wisconsinan and acted as a refugium for grassland Diptera.

An inventory of the Agromyzidae (Diptera) of Canadian tallgrass prairies was conducted in southern Manitoba. Specimens were collected at primary study sites between 1996--2000, by sweeping, malaise traps and pan traps. In order to establish species distributions in eastern grasslands, Agromyzidae were also obtained from other surveys in southern Ontario grasslands. Over 850 specimens were identified from 49 species (15 genera) from the Manitoba sites. The most diverse genera were Liriomyza (10 species) and Cerodontha (8 species), and the latter genus was the most abundant, primarily because of two dominant species: C. superciliosa and C. inconspicua. The zoogeographic distribution of tallgrass prairie agromyzids is dominated by Nearctic and Holarctic species, suggesting that many of the species are generalists. Species shared with eastern grasslands are primarily widespread Nearctic species. Twenty-eight percent of the species show grassland affinities; further investigation is required to confirm the distribution and habitat preference of these species.

Thesis (Ph. D.)--University of Melbourne, 1985. / Typescript (photocopy). Includes bibliographical references (leaves 332-350).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [i]-iii).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 401-411). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S. in crop science)--Washington State University, August 2010. / Title from PDF title page (viewed on July 30, 2010). "Department of Crop and Soil Sciences." Includes bibliographical references.

No description available.