| dc.description.abstract | The Nematology Unit, Biosystematics, Agricultural Research Council—Plant Health and Protection (ARC—PHP) founded the South African Plant-Parasitic Nematode Survey (SAPPNS) in 1987. The aim of the SAPPNS was to make a comprehensive assessment of the nematode biodiversity resources of South Africa with the following main objectives, namely to: i) make an inventory, ii) study the biogeography, iii) establish an electronic database of and iv) compile distribution maps of the different species of all the plant—parasitic nematodes of South Africa. To contribute to the assessment of nematode biodiversity in South Africa and the knowledge of nematode diversity in grassland and in protected areas, the present survey of the Telperion Nature Reserve was conducted, the results of which will be incorporated in the SAPPNS database. This reserve is situated in Mpumalanga, stretches over 7 350 ha and forms part of the Rand Highveld Grassland of the important Grassland Biome. The Grassland Biome is one of the largest and most important vegetation types in South Africa and the Rand Highveld Grassland is considered endangered with only 1 % protected. The aim of the study was to conduct an extensive nematode survey of the Telperion Nature Reserve, including all trophic levels, to determine the nematode diversity in a pristine, natural habitat in the Grassland Biome.The nematode survey of the Telperion Nature Reserve was conducted over four consecutive seasons during 2015 to 2016 (autumn, winter, spring and summer, in this order). Samples were collected from 30 different sites which were divided into the following: 1) 26 terrestrial sites which were subdivided into open grassland, covered rocky grassland and water related habitats; 2) four freshwater sites where samples were collected from the Wilge River, a wetland and two other freshwater sources in the reserve. Soil and root samples were collected from the terrestrial sites, water sediment samples from the freshwater sites and finally grass seed samples from the terrestrial sites during the summer season. Nematodes were extracted from these various substrates and fixed and mounted using standard methods. Nematode genera and species were identified using traditional morphological methods and the present thesis therefore includes descriptions of species based on morphological and morphometric methods only.As expected from a pristine habitat within the Grassland Biome, the diversity of nematodes found at the Telperion Nature Reserve was remarkable. A total of 109 nematode genera were recorded from all the habitats sampled, with 59 species identified. Of the plant—parasitic nematodes 47 species belonging to 30 genera were identified. Pratylenchus pseudopratensis is reported for the first time in South Africa. Undescribed species of the genera Helicotylenchus, Hemicycliophora, Lindseyus, Subanguina, Trichodorus, Tylenchorhynchus, Xiphinema and Xiphinemella were also found and will be described in future publications. Seventy nematode genera were found in soil samples from the terrestrial habitats of which four genera are reported for the first time in South Africa. These included Discomyctus, Drilocephalobus, Heterocephalobellus, and Seinura. From the grass seed samples six nematode species from three genera were identified which included four new species reports for South Africa i.e. Aphelenchoides lichenicola, A. rutgersi, A. spicomucronatus and Panagrolaimus leperisini. The samples from the freshwater habitats yielded 48 genera of which 17 species were identified. Here three new species were found Aphanolaimus strilliae n. sp., Ironus telperionensis n. sp. and Makatinus africanus n. sp. as well as two new species reports for South Africa viz. Chronogaster aspinata and Paraphanolaimus behningi. Several specimens of Chronogaster africana, Eutobrilus annetteae and Neotobrilus ampiei (previously found in South Africa) were collected from the freshwater sites and are described herein for the first time using Scanning Electron Microscopy. As three species of the genus Pratylenchus were found during this study the need for a compendium as well as a key to the South African species of the family Pratylenchidae was identified and is therefore included in this thesis. Also, several members of Pratylenchidae are well—known in South Africa due to their economic importance in agriculture and the correct identification of the members of this family is crucial. The nematode survey in the Telperion Nature Reserve resulted in new and novel information and broadens our knowledge of nematode diversity not only in South Africa, but also on a global scale. The potential for future work, to use as reference data in other fields of Nematology such as Ecology, was also identified especially in protected areas of South Africa. The importance of traditional morphological identification was also highlighted and supports the use of these methods in future work. | en_US |
