The ecology of large-spotted genets within an urban landscape.
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Date
2015
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Abstract
Urbanization is one of the most damaging and rapidly expanding forms of anthropogenic landscape modification and is having profound consequences on biodiversity worldwide. The global increase in urbanization has resulted in exclusion of many carnivore species from human-altered landscapes due to a variety of anthropogenic impacts. However, despite the negative impacts of urbanization on carnivores, certain species such as large-spotted genets (Genetta tigrina) exhibit an ability to persist within urban areas. Despite their extensive distribution range, large-spotted genets are poorly studied in comparison to other African carnivores, with a handful of studies conducted on genetics, activity patterns and diet. Furthermore, no studies have focused on their ecology in an urban environment.
There have been increasing reports of large-spotted genets within urban areas throughout KwaZulu-Natal, South Africa. The mosaic of patches of native vegetation within this urban landscape provides habitats for a variety of wildlife species. The main aim of the study was to investigate the ecology of large-spotted genets within an urban landscape and to determine what factors facilitate their ability to persist in an urban environment.
Residential interviews were conducted to ascertain information pertaining to behavioural observations, land use as well as wildlife conflict and public perceptions of genets. Chi-square (x2) goodness-of-fit tests were used to determine significant differences in the frequency of responses. Domestic pet food was the main food item genets were observed eating. The most cited cause of genet fatalities were attacks by domestic animals and collisions with vehicles. Genets were reported using roof spaces for resting during daylight hours and as locales for breeding. The majority of respondents expressed positive attitudes towards genets in urban areas; negative views stemmed from concerns of disease transfer and impacts on wild bird populations.
We investigated the relationship between occurrence of large-spotted genets with various environmental variables believed to influence their site occupancy and detection in an urban environment. Presence/absence data was collected from 28 camera trap stations between June 2012 and October 2013 in Kloof, KwaZulu-Natal, South Africa. Average estimated occupancy of urban genets was 0.62 ± 0.14 with a detection probability 0.19 ± 0.03. Model selection indicated that bush cover and placement of camera traps on wide paths negatively influenced large-spotted genet occupancy. Both winter and fringe habitats influenced the site occupancy of large-spotted genets positively. Furthermore, bush cover was negatively associated with detection probability of urban genets.
The dietary composition and the influence of predictable feeding stations on urban large-spotted genets were investigated through scat analysis. Scats were collected on a monthly basis over a year from eleven midden sites. Invertebrates were the dominant prey items consumed with small mammals also forming an important component of the diet. Significant seasonal variation was recorded with the presence of birds and pollution in the scats with highest recorded frequencies during spring and winter respectively. During winter, when invertebrate abundance declined, urban genets increased their intake of anthropogenic refuse resulting in plastic, elastic bands and various other waste products present in the scats.
We investigated the effect of anthropogenic structures on the roost temperatures of large-spotted genets. Roost temperatures were recorded using i-Button® temperature loggers at known genet roosts in anthropogenic structures as well as in natural roost sites (tree hollows and rocky overhangs). Over the seasons temperatures varied significantly between months and among different roosts. However, anthropogenic roost temperatures were significantly higher than ambient temperatures throughout the study period. Furthermore, anthropogenic roosts had higher
temperatures (with lower variability) than natural roost sites. This study indicated the importance of anthropogenic structures as daytime roosts and for breeding for large-spotted genets within an urban matrix.
Given their adaptability and apparent success within the urban environment, we investigated the movement ecology of large-spotted genets within the urban landscape. Large-spotted genets were captured and fitted with global positioning system mobile transmitters. Although seven individuals were trapped, detailed data were only obtained for two individuals. Minimum convex polygons (MCPs), 95% and 50% kernel density estimates (KDEs) were calculated for a male and female large-spotted genet. The 95% kernel density home range sizes showed relatively small home range sized for both individuals, with an area of 48.2 ha (female) and 17.5 ha (male). Habitat selection within home ranges indicated that the male large-spotted genet preferred urban residential habitat while the female genet avoided nearby croplands. Both individuals used most of the habitats within their study area. Variable habitat used by both individuals in this study confirmed the species’ ability to adapt to the urban mosaic of habitats.
This thesis showed the importance of a variety of factors on the distribution of large-spotted genets in landscapes where natural habitats are threatened by changing land use and increasing human populations. Furthermore, this thesis illustrated the ability of genets to live in an urban mosaic landscape by using a variety of anthropogenic resources.
Description
Doctor of Philosophy in Ecology. University of KwaZulu-Natal, Pietermaritzburg 2015.
Keywords
Genetta tigrina -- South Africa., Rural-urban migration -- South Africa., Urban ecology (Sociology) -- South Africa., Theses -- Ecology., Large-spotted genets.