ABSTRACT The flightless dung beetle Circellum bacchus (Fabricius, 1781) is a unique, ectothermic ... more ABSTRACT The flightless dung beetle Circellum bacchus (Fabricius, 1781) is a unique, ectothermic dung beetle that is of conservation concern due to a massive decline in its distribution. Very little is known about its conservation ecology and the upgrade of roads in one of its last strongholds, South Africa's Addo Elephant National Park, led to concerns that road kill was threatening the population because drivers could not see the beetles due to their similar colour as the upgraded roads. We tested whether the upgraded, black, tar roads led to more road kills than the original sandy-red, gravel roads using counts of live and dead beetles along transects through similar habitats of the park. There was no significant difference between the number of live and dead dung beetles on the tar or gravel roads illustrating that the infrastructure improvements themselves are not threatening the persistence of the species. The high levels of vehicle-derived mortality along roads, however, suggest that road kills may be a threatening process with potentially 100,000 C. bacchus killed on roads annually (although 45,000 is a more conservative estimate). Further research is needed to ascertain whether this off-take is sustainable and to formulate mitigation measures.
Fencing conservation areas is ubiquitous in South Africa, however, the impact of these on predato... more Fencing conservation areas is ubiquitous in South Africa, however, the impact of these on predator ecology has not been tested. We used relationships between prey abundance and predator space use to create equations to predict the home range size of lions Panthera leo and leopards Panthera pardus. We then successfully tested these predictions using published data (Phinda, Makalali) and home range estimates from radio collared individuals reintroduced to Addo Elephant National Park. Spotted hyaena Crocuta crocuta ranges also seem food dependent. Lion home ranges in Addo (114 ± 5 km 2 ) required 180 fixes to be accurately estimated, spotted hyaena ranges (91 ± 10 km 2 ) required 200 fixes, and the solitary leopard had 295 fixes for a range of 38 km 2 . There were no sexual differences in home range sizes of lions or hyaenas. The daily food intake rate of lions, measured during continuous follows, was 9.8 kg per female equivalent unit. Dominant male lions (14.3 km for 8.3 kg) traveled furthest but obtained the least amount of food per day compared to subordinate males (8.9 km for 16.0 kg) and females (5.8 km for 17.9 kg). Subordinate males traveled the fastest and during the day, to avoid competition and harassment from the dominant males. From an evolutionary viewpoint, the use of fences for conservation has not affected the natural behaviour of the predators as they still conform to predictions derived from unfenced reserves; that is, prey abundance is the key factor in determining space use of large predators.
... Matt W. Hayward1,2,3) & Gina J. Hayward1) (1 Mammal Research Institute, Polish Academy of... more ... Matt W. Hayward1,2,3) & Gina J. Hayward1) (1 Mammal Research Institute, Polish Academy of Science, 17-230 Białowie˙za, Poland; 2 Centre for ... However, intruding females in oestrus may be attracted to approach terri-tory owners (Gosling & Roberts, 2001a; Rich & ...
Africa's large predator guild competes for a limited food resource base. To minimize the degree o... more Africa's large predator guild competes for a limited food resource base. To minimize the degree of competition, we hypothesized that the two largest members of this guild and its fiercest competitors, the lion and the spotted hyaena, would partition their activity patterns to avoid interacting. We used 96-h continuous follows of focal animal(s) to determine when the six radio-collared lions and eight radio-collared spotted hyaenas, reintroduced into Addo Elephant National Park in 2003/2004, were active using a binomial measure of activity which was defined as movements >100 m during each hourly period. Contrary to our predictions, lions and hyaenas did not partition their activity times, probably because of their current low population densities. Both species exhibited a crepuscular activity pattern although hyaenas were far less active during daylight. A sub-adult lioness minimized competitive interactions by becoming diurnal. This is likely to be a common strategy for lions that have been expelled from their natal pride to become nomadic, as it allows them to minimize kleptoparasitic and agonistic interactions from competitively dominant conspecifics and competitors. The increase in testosterone that occurs in males upon reaching sexual maturity, darkens their pelage and causes them to be more directly impacted by the heat, and thereby affords females an opportunity to escape from males during hot temperatures. Similarly, the longer pelage of young hyaenas restricts their activity to the cooler night-time.
Research on coursing predators has revealed that actions throughout the predatory behavioral sequ... more Research on coursing predators has revealed that actions throughout the predatory behavioral sequence (using encounter rate, hunting rate, and kill rate as proxy measures of decisions) drive observed prey preferences. We tested whether similar actions drive the observed prey preferences of a stalking predator, the African lion Panthera leo. We conducted two 96 hour, continuous follows of lions in Addo Elephant National Park seasonally from December 2003 until November 2005 (16 follows), and compared prey encounter rate with prey abundance, hunt rate with prey encounter rate, and kill rate with prey hunt rate for the major prey species in Addo using Jacobs' electivity index. We found that lions encountered preferred prey species far more frequently than expected based on their abundance, and they hunted these species more frequently than expected based on this higher encounter rate. Lions responded variably to non-preferred and avoided prey species throughout the predatory sequence, although they hunted avoided prey far less frequently than expected based on the number of encounters of them. We conclude that actions of lions throughout the predatory behavioural sequence, but particularly early on, drive the prey preferences that have been documented for this species. Once a hunt is initiated, evolutionary adaptations to the predator-prey interactions drive hunting success.
ABSTRACT The flightless dung beetle Circellum bacchus (Fabricius, 1781) is a unique, ectothermic ... more ABSTRACT The flightless dung beetle Circellum bacchus (Fabricius, 1781) is a unique, ectothermic dung beetle that is of conservation concern due to a massive decline in its distribution. Very little is known about its conservation ecology and the upgrade of roads in one of its last strongholds, South Africa's Addo Elephant National Park, led to concerns that road kill was threatening the population because drivers could not see the beetles due to their similar colour as the upgraded roads. We tested whether the upgraded, black, tar roads led to more road kills than the original sandy-red, gravel roads using counts of live and dead beetles along transects through similar habitats of the park. There was no significant difference between the number of live and dead dung beetles on the tar or gravel roads illustrating that the infrastructure improvements themselves are not threatening the persistence of the species. The high levels of vehicle-derived mortality along roads, however, suggest that road kills may be a threatening process with potentially 100,000 C. bacchus killed on roads annually (although 45,000 is a more conservative estimate). Further research is needed to ascertain whether this off-take is sustainable and to formulate mitigation measures.
Fencing conservation areas is ubiquitous in South Africa, however, the impact of these on predato... more Fencing conservation areas is ubiquitous in South Africa, however, the impact of these on predator ecology has not been tested. We used relationships between prey abundance and predator space use to create equations to predict the home range size of lions Panthera leo and leopards Panthera pardus. We then successfully tested these predictions using published data (Phinda, Makalali) and home range estimates from radio collared individuals reintroduced to Addo Elephant National Park. Spotted hyaena Crocuta crocuta ranges also seem food dependent. Lion home ranges in Addo (114 ± 5 km 2 ) required 180 fixes to be accurately estimated, spotted hyaena ranges (91 ± 10 km 2 ) required 200 fixes, and the solitary leopard had 295 fixes for a range of 38 km 2 . There were no sexual differences in home range sizes of lions or hyaenas. The daily food intake rate of lions, measured during continuous follows, was 9.8 kg per female equivalent unit. Dominant male lions (14.3 km for 8.3 kg) traveled furthest but obtained the least amount of food per day compared to subordinate males (8.9 km for 16.0 kg) and females (5.8 km for 17.9 kg). Subordinate males traveled the fastest and during the day, to avoid competition and harassment from the dominant males. From an evolutionary viewpoint, the use of fences for conservation has not affected the natural behaviour of the predators as they still conform to predictions derived from unfenced reserves; that is, prey abundance is the key factor in determining space use of large predators.
... Matt W. Hayward1,2,3) & Gina J. Hayward1) (1 Mammal Research Institute, Polish Academy of... more ... Matt W. Hayward1,2,3) & Gina J. Hayward1) (1 Mammal Research Institute, Polish Academy of Science, 17-230 Białowie˙za, Poland; 2 Centre for ... However, intruding females in oestrus may be attracted to approach terri-tory owners (Gosling & Roberts, 2001a; Rich & ...
Africa's large predator guild competes for a limited food resource base. To minimize the degree o... more Africa's large predator guild competes for a limited food resource base. To minimize the degree of competition, we hypothesized that the two largest members of this guild and its fiercest competitors, the lion and the spotted hyaena, would partition their activity patterns to avoid interacting. We used 96-h continuous follows of focal animal(s) to determine when the six radio-collared lions and eight radio-collared spotted hyaenas, reintroduced into Addo Elephant National Park in 2003/2004, were active using a binomial measure of activity which was defined as movements >100 m during each hourly period. Contrary to our predictions, lions and hyaenas did not partition their activity times, probably because of their current low population densities. Both species exhibited a crepuscular activity pattern although hyaenas were far less active during daylight. A sub-adult lioness minimized competitive interactions by becoming diurnal. This is likely to be a common strategy for lions that have been expelled from their natal pride to become nomadic, as it allows them to minimize kleptoparasitic and agonistic interactions from competitively dominant conspecifics and competitors. The increase in testosterone that occurs in males upon reaching sexual maturity, darkens their pelage and causes them to be more directly impacted by the heat, and thereby affords females an opportunity to escape from males during hot temperatures. Similarly, the longer pelage of young hyaenas restricts their activity to the cooler night-time.
Research on coursing predators has revealed that actions throughout the predatory behavioral sequ... more Research on coursing predators has revealed that actions throughout the predatory behavioral sequence (using encounter rate, hunting rate, and kill rate as proxy measures of decisions) drive observed prey preferences. We tested whether similar actions drive the observed prey preferences of a stalking predator, the African lion Panthera leo. We conducted two 96 hour, continuous follows of lions in Addo Elephant National Park seasonally from December 2003 until November 2005 (16 follows), and compared prey encounter rate with prey abundance, hunt rate with prey encounter rate, and kill rate with prey hunt rate for the major prey species in Addo using Jacobs' electivity index. We found that lions encountered preferred prey species far more frequently than expected based on their abundance, and they hunted these species more frequently than expected based on this higher encounter rate. Lions responded variably to non-preferred and avoided prey species throughout the predatory sequence, although they hunted avoided prey far less frequently than expected based on the number of encounters of them. We conclude that actions of lions throughout the predatory behavioural sequence, but particularly early on, drive the prey preferences that have been documented for this species. Once a hunt is initiated, evolutionary adaptations to the predator-prey interactions drive hunting success.
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