Factors influencing the spatial patterns of vertebrate roadkill in South Africa: The Greater Mapungubwe Transfrontier Conservation Area as a case study
- Collinson, Wendy J, Parker, Daniel M, Bernard, Ric T F, Reilly, Brian K, Davies-Mostert, Harriet T
- Authors: Collinson, Wendy J , Parker, Daniel M , Bernard, Ric T F , Reilly, Brian K , Davies-Mostert, Harriet T
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158320 , vital:40172 , https://0-doi.org.wam.seals.ac.za/10.1111/aje.12628
- Description: Few studies have investigated the factors that influence roadkill occurrence in developing countries. In 2013, we monitored a 100‐km section of the road (comprising the R572 and R521 regional highways and the D2662) that pass through the Greater Mapungubwe Transfrontier Conservation Area in South Africa, to assess the possible factors influencing roadkill. Over a period of 120 days, and across the three ecological seasons, we recorded 981 roadkills (rate = 0.08 roadkill/km/day) from four vertebrate taxonomic groups. We generated predictive models of roadkill from one combined data set that considered eight variables identified from the literature as potential correlates of roadkill. The model that included the distance of the fence from the road, habitat type adjacent to the road, and the presence of a hill in the road (i.e., elevation) or a bank on the side of the road best explained roadkill occurrence.
- Full Text:
- Date Issued: 2019
- Authors: Collinson, Wendy J , Parker, Daniel M , Bernard, Ric T F , Reilly, Brian K , Davies-Mostert, Harriet T
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158320 , vital:40172 , https://0-doi.org.wam.seals.ac.za/10.1111/aje.12628
- Description: Few studies have investigated the factors that influence roadkill occurrence in developing countries. In 2013, we monitored a 100‐km section of the road (comprising the R572 and R521 regional highways and the D2662) that pass through the Greater Mapungubwe Transfrontier Conservation Area in South Africa, to assess the possible factors influencing roadkill. Over a period of 120 days, and across the three ecological seasons, we recorded 981 roadkills (rate = 0.08 roadkill/km/day) from four vertebrate taxonomic groups. We generated predictive models of roadkill from one combined data set that considered eight variables identified from the literature as potential correlates of roadkill. The model that included the distance of the fence from the road, habitat type adjacent to the road, and the presence of a hill in the road (i.e., elevation) or a bank on the side of the road best explained roadkill occurrence.
- Full Text:
- Date Issued: 2019
Aardvark burrows: a potential resource for animals in arid and semi-arid environments
- Whittington-Jones, Gareth M, Bernard, Ric T F, Parker, Daniel M
- Authors: Whittington-Jones, Gareth M , Bernard, Ric T F , Parker, Daniel M
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443852 , vital:74166 , https://doi.org/10.1080/15627020.2011.11407509
- Description: Arid and semi-arid environments are characterized by extreme fluctuations in temperature and low rainfall, which present significant challenges to the animals inhabiting these areas. However, the presence of burrows may allow animals to avoid climatic extremes and predators and may act as valuable foraging sites. We assessed the microhabitat conditions (maximum and minimum temperature, relative humidity and seed abundance) of aardvark (Orycteropus afer) burrows in relation to paired non-burrow areas at three sites in South Africa. We also describe the extent to which they are used as resources by other vertebrates. Maximum temperatures were significantly lower and minimum temperatures and relative humidity values were significantly higher inside the burrows than outside. The concentration of seeds inside the burrows and at the paired non-burrow sites was similar. Twenty-seven vertebrate species (21 mammals, two birds, three reptiles and one amphibian) were recorded making use of the burrows and it is likely that these species accrue benefits (e.g. a buffered microclimate) from burrow use. However, our sampling was biased towards mammals and nocturnal species. Consequently, we recommend further work to establish the overall reliance of vertebrate taxa on aardvark burrows in arid and semi-arid environments.
- Full Text:
- Date Issued: 2011
- Authors: Whittington-Jones, Gareth M , Bernard, Ric T F , Parker, Daniel M
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443852 , vital:74166 , https://doi.org/10.1080/15627020.2011.11407509
- Description: Arid and semi-arid environments are characterized by extreme fluctuations in temperature and low rainfall, which present significant challenges to the animals inhabiting these areas. However, the presence of burrows may allow animals to avoid climatic extremes and predators and may act as valuable foraging sites. We assessed the microhabitat conditions (maximum and minimum temperature, relative humidity and seed abundance) of aardvark (Orycteropus afer) burrows in relation to paired non-burrow areas at three sites in South Africa. We also describe the extent to which they are used as resources by other vertebrates. Maximum temperatures were significantly lower and minimum temperatures and relative humidity values were significantly higher inside the burrows than outside. The concentration of seeds inside the burrows and at the paired non-burrow sites was similar. Twenty-seven vertebrate species (21 mammals, two birds, three reptiles and one amphibian) were recorded making use of the burrows and it is likely that these species accrue benefits (e.g. a buffered microclimate) from burrow use. However, our sampling was biased towards mammals and nocturnal species. Consequently, we recommend further work to establish the overall reliance of vertebrate taxa on aardvark burrows in arid and semi-arid environments.
- Full Text:
- Date Issued: 2011
Bushclumps as refugia for small mammals in two Eastern Cape conservation areas
- Whittington-Jones, Gareth M, Bernard, Ric T F, Parker, Daniel M
- Authors: Whittington-Jones, Gareth M , Bernard, Ric T F , Parker, Daniel M
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446975 , vital:74574 , https://hdl.handle.net/10520/EJC18077
- Description: Bushclumps are scattered islands of thicket-like vegetation within a matrix of more open vegetation. We investigated the role of bushclumps as refugia for small mammals, and examined the effect of a limited number of abiotic and biotic factors on their richness, diversity and abundance. Small mammals were surveyed using Sherman small mammal traps at two sites in the Eastern Cape Province, South Africa (Mountain Zebra National Park and Kwandwe Private Game Reserve). Soil hardness and seed abundance, inside and outside bushclumps, were determined. Trap success was significantly higher inside bushclumps than in areas outside, and species diversity and the abundance of small mammals were greater within bushclumps compared to outside. Bushclumps also had significantly softer soil and a higher concentration of seeds. We conclude that bushclumps provide a concentrated source of food and protection from predators for small mammals, and are thus used significantly more than adjacent open areas. The conservation of bushclumps is therefore important for the overall maintenance of ecosystem functioning.
- Full Text:
- Date Issued: 2008
- Authors: Whittington-Jones, Gareth M , Bernard, Ric T F , Parker, Daniel M
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446975 , vital:74574 , https://hdl.handle.net/10520/EJC18077
- Description: Bushclumps are scattered islands of thicket-like vegetation within a matrix of more open vegetation. We investigated the role of bushclumps as refugia for small mammals, and examined the effect of a limited number of abiotic and biotic factors on their richness, diversity and abundance. Small mammals were surveyed using Sherman small mammal traps at two sites in the Eastern Cape Province, South Africa (Mountain Zebra National Park and Kwandwe Private Game Reserve). Soil hardness and seed abundance, inside and outside bushclumps, were determined. Trap success was significantly higher inside bushclumps than in areas outside, and species diversity and the abundance of small mammals were greater within bushclumps compared to outside. Bushclumps also had significantly softer soil and a higher concentration of seeds. We conclude that bushclumps provide a concentrated source of food and protection from predators for small mammals, and are thus used significantly more than adjacent open areas. The conservation of bushclumps is therefore important for the overall maintenance of ecosystem functioning.
- Full Text:
- Date Issued: 2008
Lessons from aloes in the Thicket Biome: reconstructing past elephant browsing to understand the present
- Parker, Daniel M, Bernard, Ric T F
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6894 , http://hdl.handle.net/10962/d1011654
- Description: It is very difficult to quantify elephant-induced change to vegetation in the absence of adequate historical benchmarks. In this commentary, we explore the historical distribution of aloes in the Thicket Biome of South Africa. We contend that the large stands of aesthetically pleasing aloes in the Thicket Biome can be likened to the even-aged stands of tall trees in the riparian forests of Botswana, both being artefacts of the loss of large herbivores through disease and hunting in the past. Elephant browsing on aloes may therefore be the first step in the vegetation reverting to a situation similar to the one prior to excessive hunting in the region.
- Full Text:
- Date Issued: 2008
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6894 , http://hdl.handle.net/10962/d1011654
- Description: It is very difficult to quantify elephant-induced change to vegetation in the absence of adequate historical benchmarks. In this commentary, we explore the historical distribution of aloes in the Thicket Biome of South Africa. We contend that the large stands of aesthetically pleasing aloes in the Thicket Biome can be likened to the even-aged stands of tall trees in the riparian forests of Botswana, both being artefacts of the loss of large herbivores through disease and hunting in the past. Elephant browsing on aloes may therefore be the first step in the vegetation reverting to a situation similar to the one prior to excessive hunting in the region.
- Full Text:
- Date Issued: 2008
The use of archaeological and ethnographical information to supplement the historical record of the distribution of large mammalian herbivores in South Africa
- Bernard, Ric T F, Parker, Daniel M
- Authors: Bernard, Ric T F , Parker, Daniel M
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6914 , http://hdl.handle.net/10962/d1011877
- Description: Introduction: The introduction of animal taxa to areas where they do not naturally occur has the potential to damage severely the native fauna and flora. Introductions, both accidental and intentional, to Australia, New Zealand, Marion Island and other oceanic islands provide spectacular examples of this.1,2 Non-native mammalian herbivores often become invasive in the absence of their natural predators2 and their impact on vegetation, which may include alterations to plant species composition, structure and diversity, is exaggerated, especially if the vegetation has evolved in the absence of similar herbivores.3,4 This influence is not limited to the direct consequence for the vegetation and there may be a cascade effect on ecosystem functioning through, for example, a decline in the amount of available forage for indigenous herbivores,3 a reduction in the breeding efficiency of birds that rely on the vegetation,5,6 and a negative effect on carbon storage by transforming stands of dense vegetative cover to open savannah like systems.7 Nor are these outcomes restricted to non-native herbivores; the re-introduction of a species, such as the elephant (Loxodonta africana), to areas from which it has been absent for many years may have similar consequences.8–11 Additional problems associated with the uncontrolled movement of large mammals include the transmission of disease, such as brucellosis in the United States,3 and a threat to the genetic integrity of a species through hybridization.12 It is thus clear that deliberate introductions of herbivores to areas where they do not naturally occur may not be sound conservation practice.
- Full Text:
- Date Issued: 2006
- Authors: Bernard, Ric T F , Parker, Daniel M
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6914 , http://hdl.handle.net/10962/d1011877
- Description: Introduction: The introduction of animal taxa to areas where they do not naturally occur has the potential to damage severely the native fauna and flora. Introductions, both accidental and intentional, to Australia, New Zealand, Marion Island and other oceanic islands provide spectacular examples of this.1,2 Non-native mammalian herbivores often become invasive in the absence of their natural predators2 and their impact on vegetation, which may include alterations to plant species composition, structure and diversity, is exaggerated, especially if the vegetation has evolved in the absence of similar herbivores.3,4 This influence is not limited to the direct consequence for the vegetation and there may be a cascade effect on ecosystem functioning through, for example, a decline in the amount of available forage for indigenous herbivores,3 a reduction in the breeding efficiency of birds that rely on the vegetation,5,6 and a negative effect on carbon storage by transforming stands of dense vegetative cover to open savannah like systems.7 Nor are these outcomes restricted to non-native herbivores; the re-introduction of a species, such as the elephant (Loxodonta africana), to areas from which it has been absent for many years may have similar consequences.8–11 Additional problems associated with the uncontrolled movement of large mammals include the transmission of disease, such as brucellosis in the United States,3 and a threat to the genetic integrity of a species through hybridization.12 It is thus clear that deliberate introductions of herbivores to areas where they do not naturally occur may not be sound conservation practice.
- Full Text:
- Date Issued: 2006
Variation in the timing of reproduction of the four-striped field mouse, Rhabdomys pumilio, in the Eastern Cape Province, South Africa
- Jackson, Claire, Bernard, Ric T F
- Authors: Jackson, Claire , Bernard, Ric T F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447101 , vital:74584 , https://doi.org/10.1080/15627020.2006.11407367
- Description: We used the four-striped field mouse, Rhabdomys pumilio (Sparrmann, 1784), to test the hypothesis that reproduction in a small, short-lived mammal will be opportunistic, characterized by temporal and spatial variation in the timing of events, and only be inhibited under harsh and predictable winter conditions. Field mice were trapped for three years in two regions of the Eastern Cape Province of South Africa, one that experienced a predictable and harsh winter (Mountain Zebra National Park; MZNP) and the other which experienced a milder winter (Thomas Baines Nature Reserve; TBNR). There was no winter inhibition of reproduction at TBNR, while at MZNP female reproductive activity was inhibited but males continued to produce spermatozoa in winter. We interpret this flexibility in the timing of reproduction as supporting an opportunistic reproductive strategy which may be an adaptation to the seasonal and often unpredictable climate of the region.
- Full Text:
- Date Issued: 2006
- Authors: Jackson, Claire , Bernard, Ric T F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447101 , vital:74584 , https://doi.org/10.1080/15627020.2006.11407367
- Description: We used the four-striped field mouse, Rhabdomys pumilio (Sparrmann, 1784), to test the hypothesis that reproduction in a small, short-lived mammal will be opportunistic, characterized by temporal and spatial variation in the timing of events, and only be inhibited under harsh and predictable winter conditions. Field mice were trapped for three years in two regions of the Eastern Cape Province of South Africa, one that experienced a predictable and harsh winter (Mountain Zebra National Park; MZNP) and the other which experienced a milder winter (Thomas Baines Nature Reserve; TBNR). There was no winter inhibition of reproduction at TBNR, while at MZNP female reproductive activity was inhibited but males continued to produce spermatozoa in winter. We interpret this flexibility in the timing of reproduction as supporting an opportunistic reproductive strategy which may be an adaptation to the seasonal and often unpredictable climate of the region.
- Full Text:
- Date Issued: 2006
Life history of the springhare (Pedetes capensis) from a strongly seasonal environment in the Eastern Cape Province of South Africa
- Peinke, Dean, Bernard, Ric T F
- Authors: Peinke, Dean , Bernard, Ric T F
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447089 , vital:74583 , doi.org/10.1080/15627020.2005.11407327
- Description: The life history of the springhare (Pedetes capensis, Forster, 1778) at 33°S, in the Eastern Cape Province of South Africa, was characterized by continuous, aseasonal and asynchronous reproduction. Females were monotocous and consecutive pregnancies were separated by a non pregnant period (30–50 days) similar in length to the period of lactation. Young were relatively large at birth (8% of adult body weight) but were altricial and only emerged from the burrow at weaning. Towards the end of lactation, many females mated again (20% of all females were both lactating and in early pregnancy) and annual fecundity was probably two but never more than three. For a rodent, albeit a large one, this is a very slow rate of reproduction and we propose that the ricochetal locomotion (jumping on the hind legs) and semi-fossorial life style of the springhare will have resulted in decreased juvenile and adult mortality, and increased longevity, and that these factors have shaped the evolution of the life history of the springhare.
- Full Text:
- Date Issued: 2005
- Authors: Peinke, Dean , Bernard, Ric T F
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447089 , vital:74583 , doi.org/10.1080/15627020.2005.11407327
- Description: The life history of the springhare (Pedetes capensis, Forster, 1778) at 33°S, in the Eastern Cape Province of South Africa, was characterized by continuous, aseasonal and asynchronous reproduction. Females were monotocous and consecutive pregnancies were separated by a non pregnant period (30–50 days) similar in length to the period of lactation. Young were relatively large at birth (8% of adult body weight) but were altricial and only emerged from the burrow at weaning. Towards the end of lactation, many females mated again (20% of all females were both lactating and in early pregnancy) and annual fecundity was probably two but never more than three. For a rodent, albeit a large one, this is a very slow rate of reproduction and we propose that the ricochetal locomotion (jumping on the hind legs) and semi-fossorial life style of the springhare will have resulted in decreased juvenile and adult mortality, and increased longevity, and that these factors have shaped the evolution of the life history of the springhare.
- Full Text:
- Date Issued: 2005
The diet and ecological role of giraffe (Giraffa camelopardalis) introduced to the Eastern Cape, South Africa
- Parker, Daniel M, Bernard, Ric T F
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2005
- Subjects: Giraffe Giraffa camelopardalis Herbivore
- Language: English
- Type: Article
- Identifier: vital:6942 , http://hdl.handle.net/10962/d1011967
- Description: With an increase in the popularity of wildlife ranching in southern Africa has come the introduction of non-native (extralimital) mammalian herbivores. Financial gain has arguably been at the forefront of these introductions, with little or no assessment of the ecological consequences. The diet of three populations of introduced giraffe Giraffa camelopardalis was assessed by direct observation in the Eastern Cape Province, South Africa between January 2002 and October 2003, as the first step towards understanding the ecological role played by giraffe in the region. Similar to the diet of giraffe within their native range, a deciduous species from the genus Acacia (Acacia karroo) was the most important species in the diet. Giraffe in the Eastern Cape Province, however, consumed more evergreen species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a probable explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident with members of the genus Rhus being more important in the winter months. This was attributed to the deciduous nature of A. karroo. The potential for giraffe to have a detrimental effect on the indigenous vegetation is discussed. We conclude that the study provides a much-needed list of plant species threatened by giraffe browsing in a region where the vegetation is thought to have evolved in the absence of such a browser.
- Full Text:
- Date Issued: 2005
- Authors: Parker, Daniel M , Bernard, Ric T F
- Date: 2005
- Subjects: Giraffe Giraffa camelopardalis Herbivore
- Language: English
- Type: Article
- Identifier: vital:6942 , http://hdl.handle.net/10962/d1011967
- Description: With an increase in the popularity of wildlife ranching in southern Africa has come the introduction of non-native (extralimital) mammalian herbivores. Financial gain has arguably been at the forefront of these introductions, with little or no assessment of the ecological consequences. The diet of three populations of introduced giraffe Giraffa camelopardalis was assessed by direct observation in the Eastern Cape Province, South Africa between January 2002 and October 2003, as the first step towards understanding the ecological role played by giraffe in the region. Similar to the diet of giraffe within their native range, a deciduous species from the genus Acacia (Acacia karroo) was the most important species in the diet. Giraffe in the Eastern Cape Province, however, consumed more evergreen species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a probable explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident with members of the genus Rhus being more important in the winter months. This was attributed to the deciduous nature of A. karroo. The potential for giraffe to have a detrimental effect on the indigenous vegetation is discussed. We conclude that the study provides a much-needed list of plant species threatened by giraffe browsing in a region where the vegetation is thought to have evolved in the absence of such a browser.
- Full Text:
- Date Issued: 2005
The diet of Cape clawless otters at two sites along the Bloukrans River, Eastern Cape Province, South Africa
- Parker, Daniel M, Burchell, R K, Bernard, Ric T F
- Authors: Parker, Daniel M , Burchell, R K , Bernard, Ric T F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6959 , http://hdl.handle.net/10962/d1012004
- Description: The diet of Cape clawless otters was assessed at two sites along the Bloukrans River using faecal analysis. Spraints (n = 78) were collected during 2000 and 2001 and analysed using the relative frequency of occurrence and the reconstituted wet weight methods. Both methods found crab (Potamonautes perlatus) to be the most important component (>50%) of the diet. Frog, Xenopus and Rana spp., (11–42%) was the second most important component while fish (Micropteris salmoides) was relatively unimportant (<14%). Although the diet of Cape clawless otters in the Eastern Cape Province was similar to that reported elsewhere, the fact that they were preying on an alien invasive fish and not the indigenous endemic Sandelia bainsii is significant. The validity of faecal analysis methods is also discussed.
- Full Text:
- Date Issued: 2005
- Authors: Parker, Daniel M , Burchell, R K , Bernard, Ric T F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6959 , http://hdl.handle.net/10962/d1012004
- Description: The diet of Cape clawless otters was assessed at two sites along the Bloukrans River using faecal analysis. Spraints (n = 78) were collected during 2000 and 2001 and analysed using the relative frequency of occurrence and the reconstituted wet weight methods. Both methods found crab (Potamonautes perlatus) to be the most important component (>50%) of the diet. Frog, Xenopus and Rana spp., (11–42%) was the second most important component while fish (Micropteris salmoides) was relatively unimportant (<14%). Although the diet of Cape clawless otters in the Eastern Cape Province was similar to that reported elsewhere, the fact that they were preying on an alien invasive fish and not the indigenous endemic Sandelia bainsii is significant. The validity of faecal analysis methods is also discussed.
- Full Text:
- Date Issued: 2005
The effect of prolonged cold storage of eland (Taurotragus oryx) cauda epididymides on the spermatozoa: possible implications for the conservation of biodiversity
- Bissett, Charlene, Bernard, Ric T F
- Authors: Bissett, Charlene , Bernard, Ric T F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6947 , http://hdl.handle.net/10962/d1011976
- Description: The objectives of this study were to investigate the effects of prolonged storage of cauda epididymides at 4 °C on spermatozoa, and to determine the practicality of utilising epididymal sperm, harvested from testes collected during routine culling of game animals, in assisted reproductive technologies. Testes from eland (Taurotragus oryx) were collected and epididymides removed and maintained at 4 °C. Sperm motility, viability, morphology and membrane integrity were examined at 12 h intervals for 108 h. Sperm motility and viability were significantly lower at the end of the experiment than at the start (P < 0.05) and there was individual variation in the rate at which motility and viability declined. The total number of normal sperm decreased significantly with prolonged storage at 4 °C. Midpiece defects were the most common and head and tail abnormalities were rare. A significant decrease in acrosomal and nuclear membrane integrity was observed with prolonged cold storage but there was no significant change in cell membrane integrity. However, about 30% of epididymal sperm survived for 3 days at 4 °C and more than 10% survived for 4 days, and it should be possible to use sperm from culled animals in some assisted reproductive technologies.
- Full Text:
- Date Issued: 2005
- Authors: Bissett, Charlene , Bernard, Ric T F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6947 , http://hdl.handle.net/10962/d1011976
- Description: The objectives of this study were to investigate the effects of prolonged storage of cauda epididymides at 4 °C on spermatozoa, and to determine the practicality of utilising epididymal sperm, harvested from testes collected during routine culling of game animals, in assisted reproductive technologies. Testes from eland (Taurotragus oryx) were collected and epididymides removed and maintained at 4 °C. Sperm motility, viability, morphology and membrane integrity were examined at 12 h intervals for 108 h. Sperm motility and viability were significantly lower at the end of the experiment than at the start (P < 0.05) and there was individual variation in the rate at which motility and viability declined. The total number of normal sperm decreased significantly with prolonged storage at 4 °C. Midpiece defects were the most common and head and tail abnormalities were rare. A significant decrease in acrosomal and nuclear membrane integrity was observed with prolonged cold storage but there was no significant change in cell membrane integrity. However, about 30% of epididymal sperm survived for 3 days at 4 °C and more than 10% survived for 4 days, and it should be possible to use sperm from culled animals in some assisted reproductive technologies.
- Full Text:
- Date Issued: 2005
The diet of a small group of extralimital giraffe
- Parker, Daniel M, Bernard, Ric T F, Colvin, S A
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
Changes in the abundance of cells in the anterior pituitary gland and the possible roles of luteinizing hormone, prolactin and progesterone in the control of delayed implantation in the straw-coloured fruit bat (Eidolon helvum)
- Simbauni, J A, Bernard, Ric T F
- Authors: Simbauni, J A , Bernard, Ric T F
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447131 , vital:74586 , https://doi.org/10.1080/15627020.2001.11657115
- Description: Eidolon helvum (Megachiroptera) is a large frugivorous bat found in equatorial and tropical Africa. The reproductive cycle is characterized by a three-month period of delayed implantation and the total length of pregnancy may be as much as 10 months. A histochemical study of the gonadotrophs and mammotrophs of the anterior pituitary, in conjunction with assays of LH-like, progesterone-like and prolactin-like immunoreactivity in the plasma suggest that during delayed implantation the gonadotrophs were inactive while the mammotrophs were active and plasma PRL-like immunoreactivity high. We interpret this as indicating that, in the straw-coloured fruit bat, implantation was inhibited by high levels of prolactin and, as such, the endocrine control of delayed implantation may be quite different from that described for other mammals.
- Full Text:
- Date Issued: 2001
- Authors: Simbauni, J A , Bernard, Ric T F
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447131 , vital:74586 , https://doi.org/10.1080/15627020.2001.11657115
- Description: Eidolon helvum (Megachiroptera) is a large frugivorous bat found in equatorial and tropical Africa. The reproductive cycle is characterized by a three-month period of delayed implantation and the total length of pregnancy may be as much as 10 months. A histochemical study of the gonadotrophs and mammotrophs of the anterior pituitary, in conjunction with assays of LH-like, progesterone-like and prolactin-like immunoreactivity in the plasma suggest that during delayed implantation the gonadotrophs were inactive while the mammotrophs were active and plasma PRL-like immunoreactivity high. We interpret this as indicating that, in the straw-coloured fruit bat, implantation was inhibited by high levels of prolactin and, as such, the endocrine control of delayed implantation may be quite different from that described for other mammals.
- Full Text:
- Date Issued: 2001
Influences of food quality and quantity on the male reproductive organs of a seasonally breeding rodent, the pouched mouse (Saccostomus campestris), from a seasonal but unpredictable environment
- Tinney, Gregory M, Bernard, Ric T F, White, Rehema M
- Authors: Tinney, Gregory M , Bernard, Ric T F , White, Rehema M
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447258 , vital:74600 , https://doi.org/10.1080/15627020.2001.11657110
- Description: Reproduction in the pouched mouse (Saccostomus campestris) is inhibited in winter in the field and this seasonality is not controlled by photoperiod alone. The present study examines the hypothesis that reproduction in the pouched mouse is opportunistic (sensu Bronson 1989) and that the winter inhibition of reproduction is controlled by a reduction in either food quantity or quality. Food restriction (70 % of normal daily food intake) for six weeks, under short day conditions, was associated with a significant decrease in body fat index and mass of the accessory glands, testes and epididymides, while a high-fibre diet resulted in a significant reduction in fat index and masses of both the accessory glands and epididymides. A low-fibre/low-protein diet had no significant effect on either fat index or masses of the reproductive organs. Although the three experimental diets resulted in assimilation of significantly less energy than the controls, they did not inhibit spermatogenesis. We conclude that reproduction in the pouched mouse in the Eastern Cape Province is probably opportunistic and that the winter inhibition of reproduction may be controlled by a reduction in available energy which results from a combination of the lower ambient temperatures of winter and reduced food quantity and/or quality.
- Full Text:
- Date Issued: 2001
- Authors: Tinney, Gregory M , Bernard, Ric T F , White, Rehema M
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447258 , vital:74600 , https://doi.org/10.1080/15627020.2001.11657110
- Description: Reproduction in the pouched mouse (Saccostomus campestris) is inhibited in winter in the field and this seasonality is not controlled by photoperiod alone. The present study examines the hypothesis that reproduction in the pouched mouse is opportunistic (sensu Bronson 1989) and that the winter inhibition of reproduction is controlled by a reduction in either food quantity or quality. Food restriction (70 % of normal daily food intake) for six weeks, under short day conditions, was associated with a significant decrease in body fat index and mass of the accessory glands, testes and epididymides, while a high-fibre diet resulted in a significant reduction in fat index and masses of both the accessory glands and epididymides. A low-fibre/low-protein diet had no significant effect on either fat index or masses of the reproductive organs. Although the three experimental diets resulted in assimilation of significantly less energy than the controls, they did not inhibit spermatogenesis. We conclude that reproduction in the pouched mouse in the Eastern Cape Province is probably opportunistic and that the winter inhibition of reproduction may be controlled by a reduction in available energy which results from a combination of the lower ambient temperatures of winter and reduced food quantity and/or quality.
- Full Text:
- Date Issued: 2001
Lack of a response of the sub-tropical rodent (Saccostomus campestris) to a secondary plant compound, 6-methoxybenzoxazolinone—consequences for reproductive strategy
- White, Rehema M, Bernard, Ric T F
- Authors: White, Rehema M , Bernard, Ric T F
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447273 , vital:74601 , https://www.ajol.info/index.php/az/article/view/154795
- Description: A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxybenzoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent Saccostomus campestris utilised this compound to enhance reproductive activity. 6MBOA or control vehicle were injected into adult females and into peri-pubertal females under long day (LD) and short day (SD) photoperiods (adults n= 6 to 8: peri-pubertals n= 5 to 10/treatment). There was no significant effect of 6MBOA or photoperiod on uterine or ovarian masses nor on ovarian development in sacrificed animals, nor on age at vaginal opening of peri-pubertals It was concluded that 6MBOA is not a major stimulant of reproduction in this species. Rather, we propose that seasonal breeding occurs in response to multiple environmental cues. This reproductive strategy and omnivory permit.
- Full Text:
- Date Issued: 1999
- Authors: White, Rehema M , Bernard, Ric T F
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447273 , vital:74601 , https://www.ajol.info/index.php/az/article/view/154795
- Description: A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxybenzoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent Saccostomus campestris utilised this compound to enhance reproductive activity. 6MBOA or control vehicle were injected into adult females and into peri-pubertal females under long day (LD) and short day (SD) photoperiods (adults n= 6 to 8: peri-pubertals n= 5 to 10/treatment). There was no significant effect of 6MBOA or photoperiod on uterine or ovarian masses nor on ovarian development in sacrificed animals, nor on age at vaginal opening of peri-pubertals It was concluded that 6MBOA is not a major stimulant of reproduction in this species. Rather, we propose that seasonal breeding occurs in response to multiple environmental cues. This reproductive strategy and omnivory permit.
- Full Text:
- Date Issued: 1999
Does calcium constrain reproductive activity in insectivorous bats? Some empirical evidence for Schreibers’ long-fingered bat (Miniopterus schreibersii)
- Bernard, Ric T F, Davison, A
- Authors: Bernard, Ric T F , Davison, A
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447231 , vital:74598 , https://www.ajol.info/index.php/az/article/view/154435
- Description: Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in female and male long-fingered bats (Miniopterus schreibersii) through a full reproductive cycle. The results indicate that winter was not a period of calcium stress and, therefore, that seasonal changes in insect abundance and dietary calcium availability are not a satisfactory explanation for the occurrence of delayed implantation in the long-fingered bat. Bone calcium concentrations of females did not differ significantly throughout pregnancy, indicating that the insects available in winter and early summer were sufficient to meet the calcium demands of pregnancy. Lactating females had the lowest bone calcium concentrations of all specimens, supporting the suggestion that lactation is indeed a period of severe calcium stress in aerial insectivores. We conclude that parturition is probably timed so that lactation coincides with the period of maximal insect abundance and corresponding dietary calcium availability.
- Full Text:
- Date Issued: 1996
- Authors: Bernard, Ric T F , Davison, A
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447231 , vital:74598 , https://www.ajol.info/index.php/az/article/view/154435
- Description: Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in female and male long-fingered bats (Miniopterus schreibersii) through a full reproductive cycle. The results indicate that winter was not a period of calcium stress and, therefore, that seasonal changes in insect abundance and dietary calcium availability are not a satisfactory explanation for the occurrence of delayed implantation in the long-fingered bat. Bone calcium concentrations of females did not differ significantly throughout pregnancy, indicating that the insects available in winter and early summer were sufficient to meet the calcium demands of pregnancy. Lactating females had the lowest bone calcium concentrations of all specimens, supporting the suggestion that lactation is indeed a period of severe calcium stress in aerial insectivores. We conclude that parturition is probably timed so that lactation coincides with the period of maximal insect abundance and corresponding dietary calcium availability.
- Full Text:
- Date Issued: 1996
Seasonally monoestrous reproduction in the molossid bat, Tadarida aegyptiaca from low temperate latitudes (33 S) in South Africa
- Bernard, Ric T F, Tsita, Johannes N
- Authors: Bernard, Ric T F , Tsita, Johannes N
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447333 , vital:74611 , https://doi.org/10.1080/02541858.1995.11448366
- Description: A histological study of reproduction in Egyptian free-tailed bats (Tadarida aegyptiaca) Irom the Eastern Cape Province of South Alrica (c. 33°S) showed that females were seasonally monoestrous. Copulation, ovulation and lerlilizalion occurred in August, at the encf of winter, and births in December, after a four-month pregnancy. These results are compared with those of other molossid bats from tower latitudes in Africa. We conclude that the monoestrous habit of the Egyptian Iree-tailed bat at 33°S may be due to its relatively long pregnancy, and to the short summer period during which minimum temperatures are high enough to ensure an abundance of nocturnal flying insects.
- Full Text:
- Date Issued: 1995
- Authors: Bernard, Ric T F , Tsita, Johannes N
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447333 , vital:74611 , https://doi.org/10.1080/02541858.1995.11448366
- Description: A histological study of reproduction in Egyptian free-tailed bats (Tadarida aegyptiaca) Irom the Eastern Cape Province of South Alrica (c. 33°S) showed that females were seasonally monoestrous. Copulation, ovulation and lerlilizalion occurred in August, at the encf of winter, and births in December, after a four-month pregnancy. These results are compared with those of other molossid bats from tower latitudes in Africa. We conclude that the monoestrous habit of the Egyptian Iree-tailed bat at 33°S may be due to its relatively long pregnancy, and to the short summer period during which minimum temperatures are high enough to ensure an abundance of nocturnal flying insects.
- Full Text:
- Date Issued: 1995
Ecological correlates of relative brain size in some South African rodents
- Bernard, Ric T F, Nurton, Jane P
- Authors: Bernard, Ric T F , Nurton, Jane P
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447245 , vital:74599 , https://www.ajol.info/index.php/az/article/view/154234
- Description: Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder.
- Full Text:
- Date Issued: 1993
- Authors: Bernard, Ric T F , Nurton, Jane P
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447245 , vital:74599 , https://www.ajol.info/index.php/az/article/view/154234
- Description: Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder.
- Full Text:
- Date Issued: 1993
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