Ric T.F. Bernard

Bats of Southern and Central Africa: A Biogeographic and Taxonomic Synthesis

This is a magnificent book that deserves a place on the bookshelves of everyone with an interest, professional or amateur, in the biology of the fauna of Africa. While the focus of the authors might have been on biogeography and taxonomy, and this is emphasized in the title, the species descriptions include information on echolocation and feeding ecology, roosting sites and reproduction. This is far from a dry and difficult to read synthesis of the taxonomy of bats but rather an easy to read consolidation of much of what we know about the bats of southern and Central Africa. In many ways it is an atlas of adaptation and diversity within a single mammalian order. While diversity within the ungulates and carnivores of the region is widely appreciated (because of the size and activity patterns of members of these groups) the same cannot be said for the bats. Their nocturnal activity, small size and habit of roosting in hard to reach places means that they are easily overlooked and even when seen are little more than a blur in the night sky. Bats of Southern and Central Africa: A Biogeographic and Taxonomic Synthesis will go a long way towards rectifying this by providing an easily accessible synthesis of bat diversity.

Endocrine Regulation of Reproduction in Bats: The Role of Circulating Gonadal Hormones

Publisher Summary This chapter explores the endocrine system of bats. In many bats, there are no obvious changes in vaginal cytology during the breeding season or pregnancy; often the state of the ovary cannot be judged from visual examination; radioimmunoassays of estrogen and progesterone give anomalous results; there is no distinct period of behavioral estrus to pinpoint time of ovulation; and females may copulate frequently and repeatedly over long periods and well into pregnancy. Such variation from the mammalian norm is perhaps at its most extreme in the hibernating bats where there may be temporal separation of spermatogenesis, libido and accessory gland function in males, and temporal separation of behavioral oestrus and ovulation in females. In addition, delays in implantation and development of the embryo occur in some bats. Not surprisingly, where data are available, patterns of circulating hormones are often peculiar. Gonadal endocrine activity can be inferred from the structure, ultrastructure and enzyme histochemistry of endocrine tissues. Further evidence of changes in gonadal endocrine activity may be gained from examination of target organs such as the reproductive accessory glands, and sebaceous glands in males, and the uterus and vagina in females. However, changes, or often their absence, in the morphology of target organs of bats must be interpreted with caution.

Wildlife road traffic accidents: a standardized protocol for counting flattened fauna

Previous assessments of wildlife road mortality have not used directly comparable methods and, at present, there is no standardized protocol for the collection of such data. Consequently, there are no internationally comparative statistics documenting roadkill rates. In this study, we used a combination of experimental trials and road transects to design a standardized protocol to assess roadkill rates on both paved and unpaved roads. Simulated roadkill were positioned over a 1 km distance, and trials were conducted at eight different speeds (20–100 km·h−1). The recommended protocol was then tested on a 100-km transect, driven daily over a 40-day period. This recorded 413 vertebrate roadkill, comprising 106 species. We recommend the protocol be adopted for future road ecology studies to enable robust statistical comparisons between studies.

Habitat selection by transient African wild dogs (Lycaon pictus) in northern KwaZulu-Natal, South Africa : implications for range expansion

Reintroductions of African wild dogs (Lycaon pictus) in the KwaZulu-Natal Province, through the managed metapopulation approach, promoted a population expansion from one pack in Hluhluwe-iMfolozi Park in 1997 to nine packs in three reserves by 2009. Consequently, the likelihood of dispersing wild dogs leaving their natal ranges from within fenced reserves also increased. Land outside these reserves could potentially be utilized to expand wild dog distribution and provide connectivity between the geographically isolated subpopulations. We used Maximum Entropy Modelling (Maxent) to characterize habitat niche selection of transient wild dogs outside of resident reserves, and to identify potential dispersal linkages between subpopulations. A habitat suitability model indicated four variables (elevation, land cover, road density and human density) best predicted probability of presence for transient wild dogs. Elevation (AUC > 0.80) and land cover (AUC > 0.75) were the two most influential variables when considered independently. Transient wild dogs preferred lower lying locations (130–330 m a.s.l.) covered by woodland or bushland; habitat indicative of the preferred prey of wild dogs. Considerable habitat exists for subpopulation linkages; however, the majority of wild dog movements between subpopulations required mitigation of potential or real game or livestock losses. Development of formal linkages and wild dog management between subpopulations will require a sustained approach to improving tolerance towards wild dogs, clarity on financial obligations and management responses to pack and prey population dynamics.

Partitioning of space, habitat, and timing of activity by large felids in an enclosed South African system

Reintroductions of large carnivores into enclosed reserves that confine movements may fail due to intensive intra-guild interspecific conflict. To assess conflict potential, in winter 2006 we used direct observations aided by radio-tracking to focally monitor continuously one female cheetah with cub (Acinonyx jubatus), a female leopard (Panthera pardus), and a lion pride (Panthera leo) at Shamwari Private Game Reserve, South Africa. Home ranges of all individuals/social groups overlapped, whereas core areas had little overlap. The cheetah core area had no overlap with the lion core area, with lion avoidance also recorded for a radio-tracked single female cheetah and a male leopard. The female cheetah with cub selected thicket habitat which was avoided by lions, the latter preferring naturally revegetated areas that were also selected by the female leopard. Lions also selected low elevations, which were avoided by the smaller felids. Habitat preference differences occurred at study area and home range levels, suggesting a broad-scale feline avoidance strategy to minimize intra-guild conflict. In addition, the focally monitored cheetah and leopard were often stationary when the lions were active, especially during nocturnal lion hunts. These intra-guild mechanisms of reintroduced carnivore coexistence should be tested with longer-term studies across enclosed systems of different sizes, and hosting varying carnivore guilds.

The response of lions (Panthera leo) to changes in prey abundance on an enclosed reserve in South Africa

Large mammalian carnivores place significant pressure on their prey populations and this is exacerbated within the fenced reserves of Africa. However, foraging theory predicts that diet switching by predators may mitigate this pressure. In this study, we use data collected between 2003 and 2007 from an enclosed system in the Eastern Cape Province of South Africa to examine the response of lions Panthera leo to changes in the abundance of two important prey species — kudu Tragelaphus strepsiceros and warthog Phacochoerus africanus. As the relative abundance of warthogs increased, the number of kudu kills decreased significantly, whereas warthog kills became significantly more frequent. A similar pattern was observed for lion prey preference and the switch from kudu to warthog was also reflected in a significant decrease in the mean prey mass. Our results suggest that a diet shift occurs in lions and that the change in diet is primarily in response to an increase in warthog numbers. Prey switching may promote the persistence of predator–prey systems, which is particularly important for fenced systems where natural immigration of prey is not possible. However, continued collection and analysis of long-term observational data from the multipredator, multiprey systems of Africa is required to facilitate a full understanding of predator–prey dynamics.

Variation in the timing of reproduction of the four-striped field mouse, Rhabdomys pumilio, in the Eastern Cape Province, South Africa

ABSTRACT 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.

Management-Induced Niche Shift? The Activity of Cheetahs in the Presence of Lions

Habitat loss, persecution and population declines have resulted in the restriction of many large carnivores, including cheetahs (Acinonyx jubatus), to fenced reserves. These reserves are often small and the likelihood of interference competition between dominant and subordinate predators is increased, while the possibility of spatial avoidance is reduced. Given artificial space limitations, subordinate predators may reduce competitive interactions along niche axes other than habitat type such as time, coined a ‘management-induced niche shift’. We collected data on the activity patterns of male and female cheetahs using continuous follows and satellite GPS collars on two small, fenced reserves in the Eastern Cape Province of South Africa, one with lions (Panthera leo) and one without lions. There was a significant difference in the activity patterns of male and female cheetahs between the two reserves. In the presence of lions, nocturnal activity of cheetahs was greatly reduced, particularly for females. There was a corresponding increase in crepuscular activity for male cheetahs and diurnal activity for female cheetahs. In the context of other studies, our results suggest that space limitation affects cheetah response to lions and provides the first quazi-experimental evidence of a management-induced niche shift.

An Inventory of Vertebrate Roadkill in the Greater Mapungubwe Transfrontier Conservation Area, South Africa

Using a standard protocol, we conducted vertebrate roadkill surveys in the Greater Mapungubwe Transfrontier Conservation Area (GMTFCA), South Africa, which is a World Heritage Site. A total of 991 roadkill were recorded on the paved roads and 36 roadkill on the unpaved roads. Identifiable roadkill comprised 162 species from 24 orders and 65 families. Ninety-three roadkill could not be identified to species level. Roadkill counts were strongly influenced by road type and season. More roadkill was recorded on the paved than the unpaved roads. Irrespective of road type, the proportion of roadkill was greatest in the hot/wet season (4.3 paved roadkill/km/day paved and 1.3 roadkill/km/day unpaved) and lowest in the cold/dry season (2.0 roadkill/km/day paved and 0.1 roadkill/km/day unpaved). The high numbers of vertebrates identified as roadkill suggests that road traffic has the potential to directly and negatively affect biodiversity conservation in this part of South Africa. We recommend continued roadkill data collection across South Africa to assist with creating an inventory of species most likely to be at risk from roads. This will, in turn, better inform the implementation of potential mitigation measures.