mirage

Amphibian diversity and breeding behaviour in the Okavango Delta / Marleen Le Roux

Boloka/Manakin Repository

Show simple item record

dc.contributor.author Le Roux, Marleen en_US
dc.date.accessioned 2011-08-25T06:07:29Z
dc.date.available 2011-08-25T06:07:29Z
dc.date.issued 2010 en_US
dc.identifier.uri http://hdl.handle.net/10394/4467
dc.description Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
dc.description.abstract Amphibians are of great ecological importance and a loss of species will have widespread and dire consequences. Recent population declines and extinctions have resulted in amphibians being labelled the most threatened vertebrate class on a global scale. The unique Okavango ecosystem is well known and documented, yet the amphibians of this region are poorly known. This project aimed at assessing diversity in the Okavango Delta by testing isolation as a possible driver for community composition; determining the effect of hydrology on breeding behaviour; and assessing the status and prevalence of the pathogen Batrachochytrium dendrobatidis (Bd) responsible for the widespread epidemic chytridiomycosis implicated in amphibian decline. Using various monitoring techniques, observations of species occurrence were made at three locations representing different degrees of isolation over a 20 month period. Breeding indicators were observed and frogs were screened for amphibian chytrid fungus. A total of 29 species were recorded, and results indicated that there were no significant differences in community composition between the sampled localities. Species presence, however, was significantly correlated with habitat type. Thus, the availability of suitable habitat appears to be driving amphibian diversity patterns, rather than geographic isolation; and increased habitat diversity near the Delta periphery explains increased amphibian diversity in these areas. Results from breeding indicators suggested that reproduction in continuous breeders was correlated with the annual flood as well as rainfall, whilst that of explosive breeders was correlated with rainfall alone. It is thus proposed that opportunistic breeding behaviour for some amphibian species is driven by the hydrology of the ecosystem; and this may be explained by increased biological production associated with the flood pulse. Outcomes highlight the unique nature of the Okavango Delta system, and emphasises the need for its preservation. A total of 249 swab samples were collected and screened for amphibian chytrid fungus. The geographical distribution of collection samples were evenly spread throughout the localities, and were obtained from at least 25 amphibian species. Analyses proved negative for Bd for the 79.92% swabs analysed thus far and it is concluded that Bd seems absent in the study region, a result which has massive conservation implications for the region. Despite the fact that the Okavango Delta has benefitted from conservation and tourism efforts in the past, the system and its biodiversity remains threatened and effective conservation management strategies must be devised and implemented to ensure its preservation. en_US
dc.publisher North-West University
dc.subject Amphibians en_US
dc.subject Diversity en_US
dc.subject Breeding en_US
dc.subject Chytrid en_US
dc.subject Okavango Delta en_US
dc.title Amphibian diversity and breeding behaviour in the Okavango Delta / Marleen Le Roux en_US
dc.type Thesis en_US
dc.description.thesistype Masters en_US


Files in this item

This item appears in the following Collection(s)

  • ETD@PUK [5486]
    This collection contains the original digitized versions of research conducted at the North-West University (Potchefstroom Campus)

Show simple item record

Search the NWU Repository


Advanced Search

Browse

My Account

Statistics