An overview of some interesting student projects!
Nest Temperature and the African Penguin
By Jenny Griffin UCT
African penguinsSpheniscus demersus come ashore to breed from mid-January/February where they lay a clutch of 1-2 eggs. This is frequently followed by a mass abandonment of eggs during periods of extreme heat experienced in February/March. On Robben Island a variety of nest types and habitats are used as nest sites, including scrapes, burrows and artificial nest boxes in open grassland, rooikrans thickets and woody forested areas. During this study, mini-biologgers recording temperature at 15 minute intervals were placed in a sample of active nests of various nest and habitat types. The nests were monitored weekly, where nest contents and presence of an adult bird were recorded until nest failure occurred, when the logger was removed the data was downloaded to a PC. Only nests that were clearly abandoned (i.e. unattended, but still had eggs present) were used in the analysis. The aim of this study is to ascertain to what extent temperature extremes may vary between different nest and habitat types, and whether all nest desertions are a direct result of heat stress experienced by the incubating bird, or whether perhaps some are an indirect result, as the birds may not be suffering from heat stress themselves, but merely‘following the crowd’ due to their colonial nesting instincts.
Long-term Changes in the Benthic Macrofauna
of Saldanha Bay
By Natasha Kruger UCT
Over the last 30 years Saldanha Bay has developed into an international port. Major developments include the construction of a causeway and ore jetty, the establishment of a mussel farm and the expansion of two fish factories within the Bay. These factors together have been shown to alter the physical processes in the within the Bay, specifically in terms of water movement. This study is a quantitative investigation of the effects of development on the benthic macrofaunal community structure of Saldanha Bay. To determine community structure, grab and dredge samples were collected between 1960 and 1964, before construction commenced, and sites were resampled in 2001. Multivariate analyses of species abundance showed that the community structures pre- and post development were significantly different (ANSOIM, p<0.01), separating out into two major groups in an MDS ordination. This indicates that development alters the community structure of benthic macrofauna. Sediment texture and organic content, degree of wave exposure and depth are the physical factors considered in explaining the changes in community structure.
Cape clawless otter: Diet & Potential use as a bio-indicator along the Cape Peninsula
By Leigh Potter UCT
The diet of Cape Clawless otters, Aonyx capensis, along the Cape Peninsula was assessed using faecal analysis. Data concerning otter diat at Betty’s Bay were used for comparison with Cape Peninsula sites. Six sites were sampled (4 West Coast and 2 East Coast) from April to October 2002. At Betty’s Bay the main prey species had switched from fish to West Coast Rock Lobster, Jasus lalandii as a result of an increase in abundance of rock lobster in that area. Otters are known for their prey switching ability in response to changes in availability and abundance. Knowledge of otter diet could, therefore, be useful for monitoring fluctuations in J. lalandii abundance. Otter diet along the Cape Peninsula comprised mainly fish, with J. lalandii varying in importance among the sites. Results indicate that A. capensiscould be used as an indicator of rock lobster abundance. However, further research could better define the relationship between the presence of J. lalandii in otter diet with J. lalandiiabundance in the benthos.
Range size and distribution patterns of thirteen groups of South African Marine invertebrate species
By Robyn ScottUCT
The nature of a coastline, with its unique current flows, shape and other oceanographic conditions, has a significant effect on the distribution patterns and as a result on the range of marine species. Data compiled on species distribution and endemicity for 11 groups of South African marine (Awad et al., 2002) invertebrates with two new groups added was examined. The data recorded presence or absence of 2505 species in successive 100 km unit of the South African coastline; range size and distribution patterns for each group were determined. The mean range size for endemic invertebrate groups fell between 300 km for anemones and 1300 km for prosobranchs. For non-endemic the range sizes varied from 500 km for octochorals to 2000 km for chitons. The mean range size of the endemic invertebrates was 900 km and for non-endemics was 1300 km, with an overall mean of 1100 km. Fifty percent of all the species examined had ranges smaller than 1200 km of which with 53 % were smaller than 300 km. Range sizes of the groups differed significantly. A graphic simulation program “Range Finder” was used to look at the distribution of ranges between shared boundaries and to determine the possible influence of the mid domain effect on the species richness peaks.
Stratified Random vs Traditional Line-transect Sampling on Beaches
Sonette du Preez and David S. Schoeman UPE
Intertidal ecology is becoming increasingly quantitative and this trend is currently being driven largely by rocky shore studies. By comparison, ecological studies on sandy beaches are often seen as unsophisticated and, in some respects, weak. There are several reasons for this perception, but perhaps the most significant relates to the line-transect-sampling methodologies used on beaches; these have remained practically unchanged for the past 30 years. Although this approach has ensured some degree of comparability among studies, it simply does not provide data that fit comfortably into conventional linear statistical analyses. From an analytical perspective, a far more acceptable approach would involve both stratification and randomisation. This would facilitate analyses using conventional nested ANOVAs and might also hold other advantages. In order to test this idea, we sampled three sites along a beach running westward from the mouth of the Umngazi River, in the northern Eastern Cape. Using both conventional line-transects as well as a modified stratified random design, we collected data relating to macroinfaunal abundance and diversity. These were used to evaluate the costs and benefits associated with each method and also to investigate“optimal” sampling designs. Initial results show that the line transect method seems to be adequate, except when species richness is high or the fauna are patchily distributed. The benefits associated with the Stratified Random sampling method is that it lends itself both to calculating variability associated with estimates of the mean abundance and to the more explicit study of zonation (not yet done in this study). The costs however can be measured in increased time and effort. Further analyses of the results will contribute to an ongoing review of sandy beach research methodology and will help to drag this discipline into a more general ecological acceptance.
SANCOR Student Symposium
Western Cape Component
25 August 2003
Tamaryn Morris
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The Western Cape SANCOR Student Symposium was recently held at the Zoology Department at UCT, encompassing a multi-institutional component to improve communication and networking between students from different institutes. Representatives from the University of Cape Town, University of the Western Cape, University of Stellenbosch, University of Pretoria and the Cape Technikon were present. The workshop was also aimed at helping students with their thesis’s, including data collection and processing, analysis and interpretation. Students were divided into groups relating to their thesis topics and sat in different lectures theaters to flesh out the major problems and try to find some solutions. Some problems were experienced in every group, such as supervisor and student relations, resources, equipment and funding as well as never-ending saga of statistics and relating them back to the data effectively. This ensued some scary moments for some students, especially those just starting out on their thesis, while others looked relieved that the majority of their hard work was sorted out with only small problems left to deal with, but a good learning curve to be had by all.
Dr Gary Bronner of the Zoology Department at UCT managed to clear up some uncertainties concerning the relationship between students and their supervisors, and even suggested a legal document set-up at the onset of a thesis clearly indicating the roles each person plays in the thesis and ensuring that the objectives of the thesis is met so as to avoid conflict and stress. The key to a good relationship between supervisor and student is CHARM; Communication, Honesty, Allegiance, Respect and Mutualism. Prof George Branch, also from the Zoology Department (UCT), showed us the value in publishing and ensuring that good science which usually remains trapped in a completed thesis makes it out into a journal for the entire world to see. “Never fear rejection” was an important point which many students worry about as they prepare to submit papers to journals where respected, well-established scientists make their mark. Other valuable knowledge was obtained about how often, where, when and how to publish. Fundiswa Sayo explained some aspects and benefits about funding your research, but referred mainly to the University of Cape Town’s system.
It was a good opportunity from a Cape Technikon point of view as we are trained as Oceanographic Technicians and only once we embark on a B-Tech diploma do you realize the problems associated with research and producing a thesis. It is a lot of hard work and should never be taken lightly. However the joys and benefits gleaned out of research is substantial and anybody who is willing to try should go ahead and do it.
