Doctoral Degrees (Conservation Ecology and Entomology)

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Browsing Doctoral Degrees (Conservation Ecology and Entomology) by Subject "African penguin -- Health -- South Africa"

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    Parasites of African penguins: diversity, ecology and effect on hosts
    (Stellenbosch : Stellenbosch University, 2019-04) Espinaze Pardo, Marcela Paz Alejandra; Matthee, Sonja; Hui, Cang; Waller, Lauren; tellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
    ENGLISH ABSTRACT: The African penguin (Spheniscus demersus) is a critically endangered seabird species endemic to southern Africa. Recent reports of soft ticks on penguins raised concerns that parasites may pose a risk to the species’ conservation. To date, it is uncertain if parasite populations are similar across colonies and what factors drive parasite infestations. It is further uncertain if current parasite burdens affect penguin health. The aims of the study were to: (1) record the parasite diversity associated with African penguins and their nests across penguin colonies, and determine the factors that shape parasite infestations; (2) document clinical parameters for wild African penguins and establish the relationship between parasite infestations and penguin health across colonies; (3) at a local scale, record the relationship between nest characteristics and nest ectoparasites and determine the potential impact on the health of African penguins at the Stony Point colony; and (4) ascertain the efficiency of a modified Berlese funnel system, with naphthalene as repellent, as a quantitative method for the extraction of nest ectoparasites. Adult penguins (210), chicks (583) and nests (628) were sampled across five colonies along the south-western coast of South Africa in the autumn/winter season in 2016 and 2017, and also in spring 2016 at the Stony Point colony. Ectoparasites were recorded on all penguins and in nests. Helminths were recorded from chick faecal material. Blood samples were screened for haemoparasites and health parameters recorded. Penguin age and morphometric measurements (chicks) were recorded. Across colony data included nest density and weather conditions, while nest characteristic and microclimatic conditions in nests were recorded at Stony point. Ectoparasites (Parapsyllus humboldti, Echidnophaga gallinacea and Ornithodoros capensis s. s.), haemoparasites (Piroplasmorida/Haemospororida and Spirochaetales) and helminth parasites (Cardiocephaloides spp., Renicola spp., Contracaecum spp. and Cyathostoma spp.) were recorded from penguins, while ticks and fleas were recorded from their nests. At a regional scale, parasite infestations were higher in chicks than adult penguins; mainland colonies recorded more on-host and in-nest ectoparasites, Piroplasmorida/Haemospororida and Cardiocephaloides spp. than islands. Nest ticks, Piroplasmorida/Haemospororida and Cardiocephaloides spp. infecting penguins were positively associated with total nest density, while total nest ectoparasites increased with active nest density. Clinical health parameters of wild African penguins varied among colonies and several parameters were adversely affected by ecto- and haemoparasite species richness, but positively related to helminth species richness. At Stony Point, tick abundance in addition to ecto- and haemoparasite richness adversely affected haematocrit values. Chick body condition was significantly lower in spring compared to autumn/winter. At a local scale, tick and flea infestations were higher in artificial nests, nests close to the coastline, warmer and drier nests. Flea burdens were higher in nests occupied by a penguin. Conditions associated with artificial nests were not significantly related to penguin health parameters. Climatic conditions associated with spring were negatively related to on-host and in-nest parasite infections and clinical health parameters. The modified Berlese funnel consistently underestimated the abundance and prevalence of all ectoparasites in nest samples and particularly more so for the abundance of flea larvae. To conclude, although parasites are widely associated with African penguins it seems that at present penguins are able to withstand current infestation levels at most colonies. Regional differences in parasite infestation patterns may be driven by the eastward migration of prey fish, which in the case of Stony Point is intensified by the ability of ticks and fleas to take advantage of conditions associated with artificial nests.