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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

Conservation of the invertebrate fauna on the Cape Peninsula

Pryke, James Stephen 12 1900 (has links)
Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The Cape Peninsula is an area of outstanding biological importance, having 158 endemic angiosperm species in only 470 km2. The peninsula invertebrates are known to be highly endemic, yet very little else is known about them. This study has four components: (1) ascertaining whether the influence of environmental variables on epigaeic, foliage and aerial invertebrate assemblages of Table Mountain, (2) determinination of the influence of Table Mountain’s fires and land transformation, on the local invertebrate assemblage, (3), identification of areas of conservation priority and influential environmental variables across the entire Cape Peninsula, and (4) determinination whether invertebrate food availability is a restricting factor for the localised and threatened Knysna warbler (Bradypterus sylvaticus), which inhabits the forests on the east side of Table Mountain. Epigaeic, foliage and aerial invertebrates were intensively sampled using a suite of techniques. Sites were chosen to allow for comparisons between vegetation structure and type, elevation and aspect. Vegetation structure and elevation were the most important environmental variables in determining species composition. Fynbos had a higher beta diversity of epigaeic and aerial invertebrates than forests, so the conservation of as much fynbos as possible is needed. The forests had many unique and endemic species, highlighting their conservation importance. As elevation had a strong influence, yet only the higher elevations receive extensive conservation, it is critical to conserve as much of the disturbed and fragmented lower elevations as soon as possible. There was little correlation between the diversity of aerial and epigaeic‐foliage invertebrate assemblages. Thus, the aerial and epigaeic‐foliage invertebrate assemblages need to be assessed separately.
2

Variations in the Invertebrate Communities of Wild Cape Cod Cranberry Bogs

Wagner, Barbara 23 March 2016 (has links)
As a species domesticated only in the last century, agricultural cranberry plants (Vaccinium macrocarpon) remain little removed from their wild relatives. Thus, it is a potential model species for studies of the earliest stages of domestication; however, there is little available quantitative information on its wild population biology and ecology. As such information is vital to studies of the ecological changes occurring during domestication, the purpose of this study was to consolidate the relevant knowledge available and conduct a preliminary search for patterns in the invertebrate communities of wild bogs. The alpha diversity was found to be greater than the overall (gamma diversity), which is likely a result of the metric used and the fact that there was minimal overlap in rare species between bogs. In addition, alpha diversity was found to be significantly negatively correlated with bog age. Two pairs of species were found to be correlated with each other, Blunt-nosed (Limotettix vaccinia (Van Duzee)) and Sharp-nosed leafhopper (Scaphytopius sp.), along with fleabeetle (Sysena frontalis (F.)) and firebeetle (Cryptocephalus incertus (Oliv.). In addition, it was found that spiders are significantly more common in western bogs, while firebeetle is significantly more common in eastern bogs. However, this may be indicative of a correlation with bog age rather than a true correlation with geographic location. More work is needed to determine the true dynamics driving these findings, so that the information could eventually be used to improve the efficacy and decrease the environmental impact of pest management on agricultural bogs.

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