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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The influence of pan characteristics on their seasonal usage by mammals within the Makuleke Ramsar Wetland System

Antrobus, Romy 30 January 2015 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. / Central to the study of animal ecology is the usage an animal makes of its environment. In arid and semi-arid environments worldwide, the availability of surface water largely determines the behaviour, distribution and abundance of animals. As a consequence, the distribution and quality of water are factors that influence carrying capacities of protected areas in environments such as the Kruger National Park, South Africa. Just as wildlife may select water sources according to water quality, they may also select drinking locations according to perceived predation risk. Predation risk can therefore strongly influence the patch use and resource selection of animals. Similarly, human traffic and activity in natural areas can also have an effect on the behaviour and resource use of resident wildlife. This research investigates mammal usage patterns at selected water sources within the Makuleke Wetland System in Kruger National Park to contribute towards management planning for this important Ramsar Wetland Site. The research examines daily and seasonal trends in usage as well as possible links to water quality, land cover and human disturbance. Camera traps were set up seasonally at perennial pans and rivers within the Makuleke Wetland system to determine mammal species’ usage patterns. Environmental characteristics associated with each water source, such as water quality, vegetation cover and extent of human activity were also determined. A cluster analysis and Canonical Correspondence Analysis (CCA) were run in order to determine how environmental variables may influence mammal species’ seasonal drinking site selection. Overall, mammals appear to be selecting for drinking sites with increased distances to ground cover where they are more likely to see predators in advance. Mammal species appear to be avoiding the Zimbabwean border as a result of human activity in the Zimbabwean side of the Great Limpopo Transfrontier Park. The perennial pans and rivers appear to be a significant water source during the dry months to large herbivore and large carnivore species, which display the greatest seasonal fluctuations. Elephants show the greatest demand for water during the dry season and access the perennial water sources throughout the day and night. The Makuleke wetland system, and in particular the perennial water sources, provide an important dry season refuge for the northern Kruger National Park’s and the Greater Limpopo Transfrontier Park’s elephant population. The Luvuvhu River and its associated pan (Nwambe), within its floodplain, are sources of water for the greatest diversity and richness of species when compared to the water sources associated with the Limpopo floodplain, within the Makuleke Wetland System. Information from this study may aid South African National Parks management with their “adaptive management” strategy for Kruger National Park, to manage the park in an ever changing environment. It is widely accepted that emphasis be placed on the major role river systems play in biodiversity, and hence their high priority in conservation.
2

Human disturbance affects the ecology and population dynamics of the tammar wallaby, Macropus eugenii, on Garden Island, Western Australia

Chambers, Brian Kevan January 2009 (has links)
[Truncated abstract] Understanding the effect that the disturbance of habitat by humans has on the population dynamics and ecology of wild animals is critical for the management of these populations. By understanding the demographic effects of disturbance the ways in which a population can be managed to increase or decrease its rate of change in size also become apparent. This thesis describes the effect that human disturbance, through the establishment of a large naval base, has had on the population dynamics and ecology of tammar wallabies (Macropus eugenii) on Garden Island, Western Australia. The disturbance of the environment on the HMAS Stirling Naval Base included the establishment of large areas of irrigated and fertilised couch grass (Cynodon dactylon) that increased and made virtually constant the amount of food available to the tammars in that area. In addition, traffic associated with the naval base resulted in large numbers of tammar wallabies being killed by vehicles. The effects of these disturbances were determined by comparing population dynamics, through vital rates of survival and fecundity and population growth rates, and spatial ecology, through the size of the animals' home ranges, in three areas of Garden Island. The three areas were the naval base (highly disturbed), southern bushland (adjacent to the naval base) and the northern bushland (undisturbed). The tammars on the naval base were in better body condition than those living in the two bushland areas of the island. ... When the impact of road-kills was removed, increased to 1.150.101 per year on the naval base and 0.960.076 per year in the southern bushland. Fecundity transitions, defined as the product of the rates of birth and pouch-young survival, and adult survival rates were lower in the bushland areas compared with the naval base in two of the three years, which were the main reasons for the lower estimates. There were no significant differences in the size of the tammars' home ranges between areas with modified or unmodified habitats or between the sexes (P>0.05). In summer the mean size of the home ranges was 3.90.66 ha, which was larger than winter when home ranges were 3.20.54 ha, but this difference failed to reach significance (P=0.058). These results indicate that the modification of the tammars' habitat has probably not caused significant changes in the size of the animals' home ranges. The size of the home ranges of tammar wallabies is likely to be determined by a complex interaction of many factors, and habitat modification alone has not been sufficient to cause substantial changes. The results presented in this thesis demonstrate that the disturbance caused by the establishment of the naval base on Garden Island has altered the population dynamics of the tammars wallabies, through increasing in the amount of food available to the tammars and through high numbers of road-kills. These results also demonstrate how gaining detailed knowledge of population dynamics can have direct application to managing the impact of disturbance on populations of wild animals.

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