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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vegetation of arable field margins in Breckland

Critchley, C. N. R. January 1996 (has links)
In the Breckland Environmentally Sensitive Area (ESA), farmers are encouraged to manage arable field margins to conserve arable plant communities using uncropped, cultivated field boundary strips ("uncropped wildlife strips") (UWSs). This study aims to describe the vegetation ofUWSs and to carry out an ecological assessment against the ESA objectives. Data were collected from a sample ofUWS and normally cropped sites in three study areas between 1989 and 1992. Species richness and non-crop biomass were greater in UWS than cropped sites. Bromus sterilis became dominant in study area 1, and appeared to have a competitive effect on other species. In study area 2 cultivations were done less frequently and perennial Graminae spread and became abundant. In study area 3, Amsinckia micrantha showed greatest increase but no effect on other species was apparent. Weed ingress into adjacent crops was lower at UWS than normally cropped sites. ESA objectives were translated into ecological criteria which could be directly measured. Assessments by subjective expert opinion and using species autecological data were compared. Subjective data were collected by a postal questionnaire of experts. Indicator species for each criterion were identified by applying rule sets to a species-attribute matrix. Site values for each criterion were calculated, and overall site values (foci) assigned using a multiple criterion method. Subjective site assessments closely agreed with the site foci and also with three of the five criteria. Over four years, half the sites were above the threshold level which represented satisfying ofESA objectives. Multivariate analysis of variation in the vegetation, from the main dataset and from a second survey, showed sites with lower soil pH, K and total N were more successful. Those with many overhanging or broadleaved trees, or previously cropped with sugar beet were less successful. Some amendments to management prescriptions are recommended.
2

Street-level bureaucrats and agri-environmental schemes : the case of the FRCA project officer implementing ESA schemes in England and Wales

Cooper, Nicola Keppel January 1999 (has links)
No description available.
3

Land use and vegetation change in agricultural landscapes : case studies from north-west Ireland

Power, James January 1996 (has links)
No description available.
4

A multiple criteria decision-making approach to establishing environmental and economic trade-offs in Pennine Dales agriculture

Barron, Nicola-Jo January 1997 (has links)
No description available.
5

A GIS model for environmentally sensitive areas in Delaware County, Indiana / Geographic information system model for environmentally sensitive areas in Delaware County, Indiana

Sledz, Larysa January 2004 (has links)
This study has created a GIS model and comprehensive analysis of environmentally sensitive areas in Delaware County, Indiana. Values were assigned to environmentally sensitive areas for four categories, including woodlands, wetlands, floodplains, and threatened and endangered species. There was an inverse relationship between the size of an area and the environmental sensitivity of the area. These areas occupy twenty-three percent of the total county area. The distribution of these areas is almost equal throughout the county; however, a large portion is located along the banks of the White River and other water bodies. Forty two soil types were identified within environmentally sensitive areas. Poorly drained soils are slightly more represented in the environmentally sensitive areas, and somewhat poorly drained soils are under-represented compared with soils in other drainage classes. / Department of Natural Resources and Environmental Management

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