201 research outputs found

    Stomach contents of 19 species of small mammals from Swaziland

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    The stomach contents of 14 species of Rodentia and five species of Insectivora are reported from Swaziland. The importance of different food types in the diet of these species was estimated using two methods. The results of the frequency of occurrence method closely mirror those of the proportional contribution method. The rodents exhibited a wide range of diets, Otomys species were strictly herbivorous, while only three species (Mus minutoides, Tatera leucogaster and Dendromus mystacalis) were observed to have high proportions of all food types in their stomachs. All other rodents fed on green plant matter and seeds, in varying proportions. Shrews were predominantly insectivorous.S. Arr. J. Zool. 1997,32(1

    Population dynamics of Lemniscomys rosalia (Muridae: Rodentia) in a Swaziland grassland: effects of food and fire

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    The effects of food supplementation on a population of Lemniscomys rosalia were studied experimentally in a grassland habitat in Swaziland. Food was added bi-weekly to two I-ha grids, while a single I-ha grid served as the control. Rodent traps were set monthly over a 12 month period. Food supplementation may have affected the density of L. rosalia, but did not affect any other features of the population. Breeding commenced in September and ended in April (males) and May (females). Recruitment of juveniles occurred between January and March. Adult mean body mass increased from a low in winter (June/July) to a high in late summer (February). The drop in mean body mass in autumn was due to the disappearance of heavy adults and entry of the lighter subadults into the population. Mean survival of L. rosalia was low; 81% of all captured individuals disappeared within four months. An unscheduled fire burnt part of the study area and hence allowed an assessment of the effect of fire on L. rosalia. The fire did not cause undue mortality of L rosalia, however, burnt areas were avoided for three months until grass cover had sufficiently increased.S. Afr.l Zool. 1997,32(4

    Effects of supplemental food on the habitat selected by Mastomys natalensis (Muridae: Rodentia) in a subtropical grassland in Swaziland

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    Mastomys natalensis, the multimammate mouse, was live-trapped on six grids varying in vegetative cover and vegetation height between June 1996 and May 1997. There were three treatments, each with two replicates: reduced cover, reduced cover with supplementary food and control. The numbers of M. natalensis on the grids with reduced cover were lower than those on the control. Food supplementation, however, significantly increased numbers on one of the replicates. There were also significant differences in the number and proportion of resident and adult mice among the grids. The grids with reduced cover supported a population with a lower number and proportion of adult and resident mice than those on the control. In contrast, despite the reduced cover on the food supplemented grids, the population on one of the these grids exhibited a higher number and proportion of adult and resident mice than those on the control. Mastomys natalensis appears to select patches with greater vegetative cover but it will abandon cover in the presence of an abundant food source

    Species richness patterns and functional traits of the bat fauna of arid southern Africa

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    The bat fauna of arid regions is still poorly studied mostly due to a lack of interest in areas with low species richness and a low number of threatened species. In this study, we reviewed the status of bat diversity in the arid parts of southern Africa, with the aim of setting up a baseline for future work. In particular, we described species richness patterns across four arid zones within the region (Namib Desert, Kalahari, Nama Karoo and Succulent Karoo), exploring abiotic gradients and local landscape structure. Additionally, we examined bat functional groups in this region and compared them with those of three other arid regions of the world to identify potential similarities and differences. The southern African arid region hosted 17 bat species, representing eight families, of which three are endemic to the region (Rhinolophus denti, Laephotis namibensis and Cistugo seabrae) and one is vagrant (the fruit bat Eidolon helvum). Species richness varied spatially within this arid region, being highest in the drier but topographically heterogeneous Namib Desert, probably as a result of roost availability. With regards to functional groups, the southern African arid region had few bat species adapted to foraging in open spaces, particularly when compared with the neighbouring savannahs. Drawing from this study, we suggest that: a) despite species richness decreasing with increasing aridity at the sub-continental scale, at a more local scale landscape features (e.g. habitat structure) might be more relevant than aridity in determining bat species richness; and b) an unknown factor, possibly patterns of temperature limiting the availability of insects flying high above the ground, restricted the diversity of the open air foragers throughout the region. We highlight additional areas of research worth investigation

    Domestic cats and dogs create a landscape of fear for pest rodents around rural homesteads

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    Using domestic predators such as cats to control rodent pest problems around farms and homesteads is common across the world. However, practical scientific evidence on the impact of such biological control in agricultural settings is often lacking. We tested whether the presence of domestic cats and/or dogs in rural homesteads would affect the foraging behaviour of pest rodents. We estimated giving up densities (GUDs) from established feeding patches and estimated relative rodent activity using tracking tiles at 40 homesteads across four agricultural communities. We found that the presence of cats and dogs at the same homestead significantly reduced activity and increased GUDs (i.e. increased perception of foraging cost) of pest rodent species. However, if only cats or dogs alone were present at the homestead there was no observed difference in rodent foraging activity in comparison to homesteads with no cats or dogs. Our results suggest that pest rodent activity can be discouraged through the presence of domestic predators. When different types of predator are present together they likely create a heightened landscape of fear for foraging rodents

    Patterns of survival and roost switching in an African insectivorous bat

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    Variation in survival over time and amongst age and sex classes drives population dynamics for a large majority of long-lived species and is critical to understanding species demography. For highly mobile species that actively move among potential breeding locations, coupling survival information with estimates of locational fidelity provides the basis for our understanding of species population dynamics. We studied the effect of time, age and sex class, and climatic variables on survival and roost transition probabilities on a population of Egyptian slit-faced bats in Swaziland from 1450 marked individuals from 16 roosts over a 10 year period. We then used variance components analysis to estimate average annual survival and associated temporal process variance. Annual apparent survival varied with sex and age, being highest in adult males and lowest in juvenile females. We did not find evidence of survival being influenced by climatological factors as commonly observed in temperate bats. Roost switching occurred frequently, with more transitions to roosts harboring larger number of bats. Furthermore, the probability of transitioning to another roost was related to its distance from the original roost. The dispersal patterns revealed in this study were consistent with the fission-fusion dynamics common for colonial bats.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-79982016-05-31hb2015Zoology and EntomologyMammal Research Institut

    New records of bats (Mammalia: Chiroptera) and karyotypes from Guinean Mount Nimba (West Africa)

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    Abstract New bats were recorded from various habitats on the Guinean side of Mount Nimba during two surveys in 2008 and coupled with a cytotaxonomic survey. A total of 152 specimens comprising 15 species in 12 genera from five families were collected, of which 13 individuals were karyotyped. The most numerous species was Rhinolophus guineensis followed by four fruit bats (Epomops buettikoferi, Lissonycteris angolensis, Roussettus aegyptiacus, Nanonycteris veldkampii). We confirm the presence of Hipposideros lamottei in the mine adits at 1500 m as well as the exceptional diversity of this habitat. First standard karyotypes are provided for Epomops buettikoferi and Nanonycteris intermedia. We also document for the first time karyotypes for West African populations of Mops thersites, Lissonycteris angolensis and Roussettus aegyptiacus, and cytogenetical comparisons with the existing literature are provided. We add five new species to the list of Guinean Nimba and two to the whole Nimba list (including Liberian side), which now stands at 42 species. This confirms the importance of Mount Nimba as a hotspot of diversity and the necessity to protect it

    Factors affecting diet, habitat selection and breeding success of the African Crowned Eagle Stephanoaetus coronatus in a fragmented landscape

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    This study aimed to identify variables that affect habitat selection and nesting success of the African Crowned Eagle Stephanoaetus coronatus, the largest forest raptor, in north-eastern South Africa. A preference for nesting in the Northern Mistbelt Forest vegetation type was established and 82% of all nests were located in indigenous trees. Nest abandonment was less common when distances to the nearest neighbour were greater. The diet of this species was investigated by examination of prey remains beneath nests and verified by comparison with museum specimens. In total, 156 remains were found, representing a minimum of 75 prey individuals. The diet of African Crowned Eagles constituted almost entirely mammals (99%), which were predominantly antelopes (61%) and monkeys (25%). It was also found that the proportion of primates in the diet correlates with latitude: populations in equatorial latitudes have a higher proportion of primates in their diets, whereas further south antelopes are a much more common diet component
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