Conservation biogeography of South African dragonflies (Odonata)

Simple item page
dc.contributor.advisorSamways, Michael J.en_ZA
dc.contributor.authorSimaika, John P.en_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
dc.date.accessioned2008-11-12T09:19:46Zen_ZA
dc.date.accessioned2010-06-01T08:31:15Z
dc.date.available2008-11-12T09:19:46Zen_ZA
dc.date.available2010-06-01T08:31:15Z
dc.date.issued2008-12
dc.descriptionThesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
dc.description.abstractThe great pressures on freshwaters require their conservationists and managers to develop methods to rapidly and accurately assess their condition. Dragonflies are excellent indicators of habitat integrity and are effective organisms for this purpose. However, assessment must be done at the correct spatial scale. My aim here is to optimize the spatial resolution at which species are mapped, using three different concepts and methods in freshwater invertebrate distribution mapping, with special emphasis on IUCN Red Listing. The first is the extent of occurrence (EOO) concept, using the minimum convex polygon, and the second, the area of occupancy (AOO) concept, using IUCN and quaternary catchments. The third approach uses a river layer to compare the suitability of grids as opposed to catchments in mapping. In this study I found that area estimation based on minimum convex polygons should not be encouraged for aquatic organisms. This study also suggests that the IUCN concept of area of occupancy (AOO) should be redefined simply as occurrence, referring to known point-locality presences only and, if future data allow, to known absences. The IUCN extent of occurrence (EOO), for aquatic species, should be defined as ‘the sum of the smallest hydrological units identified of presently known, inferred or projected occurrences of a taxon, excluding cases of vagrancy, that are used to estimate the threat to a taxon’. A single hydrological unit is also the conservation or management unit. Currently, that unit is the quaternary catchment. Dragonflies have excellent potential as indicators of habitat integrity. For this purpose, my aim was to develop the Dragonfly Biotic Index (DBI) for South Africa and compare the DBI to another index, the Average Taxonomic Distinctness Index (AvTD), which was believed to have potential in assessments. The DBI and AvTD are correlated, which suggests that they could be used on a complementary basis to prioritize sites. The DBI is a low-cost, easy-to-use method and is already used for measuring habitat recovery. It has great potential for environmental assessment and monitoring freshwater biodiversity, especially as a complement to freshwater quality assessments that use macroinvertebrate scores. I thus recommend its integration into freshwater management and conservation schemes.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/1710
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectDragonfliesen_ZA
dc.subjectFreshwater managementen_ZA
dc.subjectFreshwater conservationen_ZA
dc.subjectHabitat quality indicatorsen_ZA
dc.subjectFreshwater invertebrate distribution mappingen_ZA
dc.subjectRed Listingen_ZA
dc.subjectBiodiversity indicesen_ZA
dc.subjectTheses -- Conservation ecology and entomologyen_ZA
dc.subjectDissertations -- Conservation ecology and entomologyen_ZA
dc.subject.lcshDragonflies -- South Africaen_ZA
dc.subject.lcshDragonflies -- South Africa -- Geographic distributionen_ZA
dc.subject.lcshWater quality biological assessmentn -- South Africaen_ZA
dc.subject.lcshHabitat (Ecology) -- South Africaen_ZA
dc.subject.lcshIndicators (Biology) -- South Africaen_ZA
dc.subject.otherConservation Ecology and Entomologyen_ZA
dc.titleConservation biogeography of South African dragonflies (Odonata)en_ZA
dc.typeThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
simaika_conservation_2008.pdf
Size:
1.77 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters Degrees (Conservation Ecology and Entomology)