Detecting changes in elephant body condition in relation to resource quality
- Authors: De Klerk, Christelle
- Date: 2009
- Subjects: Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10704 , http://hdl.handle.net/10948/939 , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: Elephants, as megaherbivores, are known to have extensive impacts on vegetation, especially in enclosed areas. This raises the issue that elephants in enclosed areas may become limited by resource availability. Resource limitation is generally expressed via density dependence, but elephants, due to their slow demography, may not be affected by initial changes in resource availability. This highlights the need for a more sensitive measure of resource limitation to allow for the detection of energy stress within a population before changes in vital rates occur. This study investigated visual changes in elephant body condition in relation to resource availability in a number of Eastern Cape reserves to assess whether body condition could be used to detect life stages, as well as seasons and sites which may be resource limited. Elephant life stages were divided into energy stressed (newly weaned calves, lactating females, and old females) and non-energy stressed classes (sub-adults and non-lactating females) to determine whether energy stressed life stages were more vulnerable to resource limitation. In the AENP it was found that lactating and old females exhibited significantly poorer body condition than non-energy stressed individuals, but that weaned calves had body conditions similar to non-energy stressed individuals. Comparisons between seasons revealed that all life stages exhibited better condition in winter than summer or spring, with lactating females showing little recovery of condition over time. Seasonal body conditions were correlated with rainfall recorded in the Addo Elephant National Park. Comparisons of elephant body condition between sites (n = 6) revealed that body condition varied across sites, with poorer body condition associated with areas of higher elephant density and low rainfall during the study period. Comparisons with faecal dietary quality data both between sites and seasons indicated that body condition also responded to changes in the availability of protein and neutral detergent fibre (NDF) of plant resources, with higher protein and lower values associated with better condition. Based on condition estimates of elephants occurring in the Addo Main Camp, it was established that this population is experiencing nutritional stress, with energy stressed individuals exhibiting the lowest body conditions. This was supported by dietary quality measures. Our findings suggest that elephant body condition is a good measure for detecting resource limitation, both within populations and between seasons, and that elephant body condition respond to relatively small changes in resource conditions, thus making it an effective measure for the detection of nutritional stress. Additionally, our findings show that energy stressed individuals, particularly lactating and old females are more vulnerable to resource limitation. This demonstrates the importance of monitoring these life stages for the detection of density dependence within populations. Finally, our data suggest that threshold values of faecal dietary quality may exist at which body condition within a population begins to deteriorate, making it possible to determine the condition of a population through values obtained in faecal samples.
- Full Text:
- Date Issued: 2009
- Authors: De Klerk, Christelle
- Date: 2009
- Subjects: Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10704 , http://hdl.handle.net/10948/939 , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: Elephants, as megaherbivores, are known to have extensive impacts on vegetation, especially in enclosed areas. This raises the issue that elephants in enclosed areas may become limited by resource availability. Resource limitation is generally expressed via density dependence, but elephants, due to their slow demography, may not be affected by initial changes in resource availability. This highlights the need for a more sensitive measure of resource limitation to allow for the detection of energy stress within a population before changes in vital rates occur. This study investigated visual changes in elephant body condition in relation to resource availability in a number of Eastern Cape reserves to assess whether body condition could be used to detect life stages, as well as seasons and sites which may be resource limited. Elephant life stages were divided into energy stressed (newly weaned calves, lactating females, and old females) and non-energy stressed classes (sub-adults and non-lactating females) to determine whether energy stressed life stages were more vulnerable to resource limitation. In the AENP it was found that lactating and old females exhibited significantly poorer body condition than non-energy stressed individuals, but that weaned calves had body conditions similar to non-energy stressed individuals. Comparisons between seasons revealed that all life stages exhibited better condition in winter than summer or spring, with lactating females showing little recovery of condition over time. Seasonal body conditions were correlated with rainfall recorded in the Addo Elephant National Park. Comparisons of elephant body condition between sites (n = 6) revealed that body condition varied across sites, with poorer body condition associated with areas of higher elephant density and low rainfall during the study period. Comparisons with faecal dietary quality data both between sites and seasons indicated that body condition also responded to changes in the availability of protein and neutral detergent fibre (NDF) of plant resources, with higher protein and lower values associated with better condition. Based on condition estimates of elephants occurring in the Addo Main Camp, it was established that this population is experiencing nutritional stress, with energy stressed individuals exhibiting the lowest body conditions. This was supported by dietary quality measures. Our findings suggest that elephant body condition is a good measure for detecting resource limitation, both within populations and between seasons, and that elephant body condition respond to relatively small changes in resource conditions, thus making it an effective measure for the detection of nutritional stress. Additionally, our findings show that energy stressed individuals, particularly lactating and old females are more vulnerable to resource limitation. This demonstrates the importance of monitoring these life stages for the detection of density dependence within populations. Finally, our data suggest that threshold values of faecal dietary quality may exist at which body condition within a population begins to deteriorate, making it possible to determine the condition of a population through values obtained in faecal samples.
- Full Text:
- Date Issued: 2009
Urban community development: an understanding of social change and identity in a social housing estate in post-apartheid South Africa
- Authors: Packery, Rajendra
- Date: 2009
- Subjects: Communities , Social change , Community development -- South Africa
- Language: English
- Type: Thesis , Masters , M Soc Sc
- Identifier: vital:11967 , http://hdl.handle.net/10353/241 , http://hdl.handle.net/10353/d1001312 , Communities , Social change , Community development -- South Africa
- Description: This study focuses on the lives of people living in a social housing estate which was a joint venture between the Housing Association of South Africa (HASA), a Netherlands based foundation and the Buffalo City Municipality. This type of social housing estate is a relatively new concept in post-apartheid South Africa and a first for the City of East London. Apartheid spawned the separation of different groups of people into racial enclaves. It also created barriers between races, advantaged certain races over others and created fear, hatred and general distrust among different racial groups in South Africa. The dislocation of apartheid was accompanied by rapid urbanization and ‘reconstruction’ of infrastructure and inter-racial relationships. The opening up of the country’s borders in compliance with Globalisation made South Africa a melting pot to people of different cultures. South African cities became fragmented and fear and strangeness was everywhere. Housing or the lack of it has been a constant problem that the new post apartheid government has grappled with. The solution of building RDP housing estates has not solved this burgeoning problem. But even more importantly it has failed to reorganize urban life in South Africa. In approaching this study I look at how these new social housing estates have reorganized urban life. I explore the concepts of community, home, generation, gender, material culture and ‘new’ urbanization to provide a framework for my study. This study is a qualitative study based in the city of East London in the Eastern Cape. It is a community study which attempts to go inside the home to unlock some of the intricacies of urban life. Ethnography is the research key used to unlock these intricacies.In conclusion, this study attempts to examine a non-western narrative of community life. Are these housing estates a solution to South Africa’s housing problem? Do they conform only to western narratives of urban life? What kind of citizens do these housing estates produce? These are some of the questions that this study hopes to answer.
- Full Text:
- Date Issued: 2009
- Authors: Packery, Rajendra
- Date: 2009
- Subjects: Communities , Social change , Community development -- South Africa
- Language: English
- Type: Thesis , Masters , M Soc Sc
- Identifier: vital:11967 , http://hdl.handle.net/10353/241 , http://hdl.handle.net/10353/d1001312 , Communities , Social change , Community development -- South Africa
- Description: This study focuses on the lives of people living in a social housing estate which was a joint venture between the Housing Association of South Africa (HASA), a Netherlands based foundation and the Buffalo City Municipality. This type of social housing estate is a relatively new concept in post-apartheid South Africa and a first for the City of East London. Apartheid spawned the separation of different groups of people into racial enclaves. It also created barriers between races, advantaged certain races over others and created fear, hatred and general distrust among different racial groups in South Africa. The dislocation of apartheid was accompanied by rapid urbanization and ‘reconstruction’ of infrastructure and inter-racial relationships. The opening up of the country’s borders in compliance with Globalisation made South Africa a melting pot to people of different cultures. South African cities became fragmented and fear and strangeness was everywhere. Housing or the lack of it has been a constant problem that the new post apartheid government has grappled with. The solution of building RDP housing estates has not solved this burgeoning problem. But even more importantly it has failed to reorganize urban life in South Africa. In approaching this study I look at how these new social housing estates have reorganized urban life. I explore the concepts of community, home, generation, gender, material culture and ‘new’ urbanization to provide a framework for my study. This study is a qualitative study based in the city of East London in the Eastern Cape. It is a community study which attempts to go inside the home to unlock some of the intricacies of urban life. Ethnography is the research key used to unlock these intricacies.In conclusion, this study attempts to examine a non-western narrative of community life. Are these housing estates a solution to South Africa’s housing problem? Do they conform only to western narratives of urban life? What kind of citizens do these housing estates produce? These are some of the questions that this study hopes to answer.
- Full Text:
- Date Issued: 2009
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