A dissertation submitted to the faculty of science, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of science, Johannesburg, 2018 / Defining the spatial distributions of species with regards to habitat selection and landscape structure is an important part of biogeography, ecology and conservation research. I investigated reptile occurrence and community structure in two patches of dry forest in north western Madagascar using detection/non-detection data collected on repeated transect surveys for four years. A Bayesian hierarchical occupancy model and multispectral satellite imagery were used to assess the effects of vegetation structure, proximity to human development and edge proximity on the site presence of 37 squamate species in the context of taxonomic family and Threat Status. Mean species richness was highest at sites within a forest patch (23 (4, 30)). Sites with dense green vegetation promoted the highest levels of reptile occupancy among the Chamaeleonidae and Gekkoniidae families (with regression coefficient estimates up to 0.75 (0.12, 1.53)) and all species were more likely to occur at sites closer to the forest patch periphery. The Boidae had the widest 95% CRI for the regression coefficient estimates representing the effects of habitat variables on occupancy, indicating that they are highly variable in their habitat use. The regression coefficient estimates of mean reptile occupancy had 95% credible intervals (CRIs) including zero due to high variability between species. The proximity to roads did not have a statistically significant effect on any of the species, and Uroplatus guentheri was the only species which showed a significant preference for being further from a settlement (0.81 (0.05, 1.77)). The findings demonstrated the importance of using caution when assessing Threat Status at a regional level and suggest that the Red List’s measure of Population Trend may be significantly influenced by imperfect detection / MT 2019

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 3 May 2018. / The movement ecology of a species can dictate their survival and success. Animals are motivated to move depending on resource priorities and in turn their movements are influenced by the surrounding environment. Natural habitats are being increasingly disturbed by anthropogenic changes which often creates several implications for the existing wildlife. One of these changes include extensive road networks that may fragment landscapes and increase mortality risks for local fauna. This current and global issue is often researched with the aid of road kill statistics which can create a biased view. My study highlights a more realistic method for understanding how organisms interpret and react to road infrastructure by using the movement patterns of 109 telemetered Puff Adders (Bitis arietans). To assess the effect of roads on these snakes within Dinokeng Game Reserve (Gauteng, South Africa) over eight years, Puff Adder lie-up locations (to the nearest road) and movement paths were analysed. Sex, season, years, and the types of roads within the reserve were included to evaluate the motivation for movement and if roads were inhibiting or aiding movement patterns. Compared to random, Puff Adders were closer too, and crossed roads more often. Males crossed roads more frequently than females and during non-mating season, both sexes were closer to roads. Narrow roads with low levels of traffic were also crossed more often. Overall, the roads in Dinokeng Game Reserve do not inhibit movement and patterns suggest that roads may be advantageous for Puff Adders. Roads appear to be foraging hotspots because of micro habitats created along the verges. However, these positive attributes could result in a potential risk when road usage is intensified by traffic. Understanding how species interact with changes to their environment is essential for appropriate management and mitigation and this study illustrates the necessity for unbiased research to properly evaluate these changes and reactions. / EM2018

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters of Science, Johannesburg 2018 / The morphology and functionality of surface microornamentation in southern African snakes is well-established in terms of resulting optical effects. Velvet-blackness, a type of optical effect is produced when light incident on a scale is scattered by microornamentation. I tested microornamentation from Bitis arietans dorsal exuvia for these optical effects. Scales were excised from shed skins of B. arietans and sputter coated with 15 nm Gold-Palladium to control the effect of pigment. Spectral intensity (SI) of three scale regions of known micro topography was recorded using spectrophotometry over the visible spectrum only as a measure of reflectivity of the scales. Given that surface roughness (the deviation of a membrane’s surface topography from an ideal surface) is a product of the size of surface asperities and its degree of randomness, the three scale regions in order of decreasing surface roughness were dark (dorsal) scales, pale (dorsal) scales, and ventral scales. Measures of SI on dorsal and ventral scale regions revealed lowest SI on dark dorsal scales and highest on ventral scales. In general, the level of micro-structuring was inversely proportional to SI. To test if optical effects are angle-dependent, I measured differences in SI between normal (90) and oblique (45) angles of incidence. Differences in SI between 90 and 45 were significant for all scale regions which revealed that while microornamentation produces optical effects at both normal and oblique incidence, the effect is greater at 45. Given that SI varies with surface roughness such that dark scales have a lower SI than pale scales, I conclude that scale colour in B. arietans is a product of optical effects created by microornamentation. The optical effect may improve the visual camouflage of B. arietans during ambush. While microornamentation is best known for its optical effects, it may have other functions. I examined the microornamentation in Bitis schneideri (Namaqua Dwarf Adder) using electron microscopy and found small, tooth-like protuberances distributed uniformly across the scales and across all body regions. I measured the distance between adjacent denticles which I 5 compared to the mean dimensions of sand grains from two study sites: Noup, within the distribution of B. schneideri, and Tswalu, outside of it but with significantly smaller grains. The space between denticles is smaller than sand grains from both sites. Due to its physical characteristics, microornamentation in B. schneideri has the potential to restrict sand grains from direct contact with the scale surface. These results suggest that microornamentation can function to shield the integument from sand abrasion in B. schneideri. This study demonstrates specific functions of microornamentation in the ecology of two species of Bitis. / XL2019

M.A. (Environmental Management) / Reptiles are internationally one of the least studied taxa compared to all other vertebrates, and even less is known about the large arachnids. This proves problematic as the environmental management of reptile and large arachnid species is generally neglected or only partially considered in environmental impact studies and conservation. Consequently, there is a considerable lack of knowledge on the ecological requirements (dietary and habitat requirements) of reptiles and invertebrates. Furthermore, the environmental management of reptiles and large arachnids in the Leeuspruit Private Nature Reserve is restricted as no data exists on the assemblage of these taxa in the study area. A model based approach was used to examine the ecology of species of reptiles and large arachnids (scorpions and baboon spiders) that were found in the Leeuspruit Private Nature Reserve during this study. The study proposes a baseline analysis between the species found in the study area and the suitability and availability of the ecological requirements necessary to their survival. The ecological requirements of each species were noted and utilised as the variable input categories in a scoring model developed for this study. Each species identified in the study area was allocated points from the scoring model based on favourable ecological requirements for that particular species. Field work was conducted in the Leeuspruit Private Nature Reserve in the northern Free State Province (March 2012 – March 2013) to do a survey on reptile and large arachnid diversity and to record the habitats in which they occur. A list of the reptiles and large arachnids found in the Leeuspruit Private Nature Reserve was compiled. One of the significant results which came to light during this study is that the diversity and abundance of reptiles and large arachnids are dependent on the availability and diversity of habitats with the necessary ecological requirements for those species. For example, the distribution of snake species was largely dependent on the abundance of amphibians and birds for food which coincided with a seasonal wetland in the study area; while rocks and detritus proved imperative to the seasonal functionality of the reptiles.

Many herpetofaunal species are imperiled, and the causes of this are often a synergy of multiple factors. In wetlands specifically, two of the possible determinants of species occurrence and faunal community assemblage are fish presence and wetland permanence, which are not always correlated. Twenty wetlands were sampled in Jonathan Dickinson State Park, Florida, USA to observe how wetland herpetofaunal communities vary with fish, wetland permanence and other environmental factors. Herpetofaunal communities with and without fish were significantly different from one another and differences between herpetofaunal communities were primarily due to the contribution of four species of frogs, two generalist ranids and two specialist hylids. Wetland permanence had no observable effect on community structure. Fishless wetlands were significantly more species-rich and possessed higher numbers of individuals even for species that occurred in both fishless and fish wetlands, regardless of their permanence. These findings have implications for wetlands restoration and herpetofaunal conservation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection