558 research outputs found
Stomach contents of 19 species of small mammals from Swaziland
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
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
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
Post-Lie algebra structures for perfect Lie algebras
We study the existence of post-Lie algebra structures on pairs of Lie
algebras , where one of the algebras is perfect
non-semisimple, and the other one is abelian, nilpotent non-abelian, solvable
non-nilpotent, simple, semisimple non-simple, reductive non-semisimple or
complete non-perfect. We prove several non-existence results, but also provide
examples in some cases for the existence of a post-Lie algebra structure. Among
other results we show that there is no post-Lie algebra structure on
, where is perfect non-semisimple,
and is . We also show that there is
no post-Lie algebra structure on , where
is perfect and is reductive with a
-dimensional center
An experimental investigation of the effects of supplementary food and ground cover on small mammal population dynamics and community structure in a Swaziland grassland.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1997.The primary aim of this study was to investigate the role of food supply and ground cover on the
community structure, population dynamics and demography of terrestrial small mammals in a
subtropical grassland. This aim was achieved through a series of food supplementation and cover
manipulation experiments conducted at eKundizeni Farm near Matsapha, Swaziland, over a 28
month period.
The effects of five different diets on the rodent Mastomys natalensis were investigated in the
laboratory, and the results showed that rolled oats and rabbit pellets were suitable for growth and
reproduction in this species.
The effects of supplementary food were investigated on two supplemented grids and one
control over a twelve month period. Small mammal biomass increased significantly on the
supplemented grids in relation to the control. This increase in biomass was the result of a twofold
increase in the numbers of M natalensis. Food supplementation further affected M. natalensis by:
extending the breeding season of females; increasing body weight; increasing survival; and
decreasing home range area. Food supplementation had a weak positive effect on the density of
another rodent Lemniscomys rosalia, but did not affect any other demographic feature of this
species. Food supplementation did not have a demographic effect on any other species of small
mammal captured.
The effects of vegetative cover were investigated, over a twelve month period, on two control
grids and four manipulated grids on which the vegetative cover was mechanically reduced.
Supplementary food was added to two of the latter four manipulated grids. The biomass of small mammals, including M. natalensis, was lower on grids with reduced vegetative cover than on the
controls. However, food supplementation resulted in a significant increase in the biomass of M.
natalensis on one of the manipulated grids. Hence, M. natalensis was induced to shift to a habitat
with reduced cover by the provision of supplementary food.
Additional information on the population dynamics, age structure, reproduction and diet of M
natalensis, L. rosalia, Mus minutoides and Steatomys pratensis is also presented
Species richness patterns and functional traits of the bat fauna of arid southern Africa
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
Revised Distribution for Otomops martiensseni (Chiroptera: Molossidae) in Southern Africa
We provide new data on the distributional range and abundance of the giant mastiff bat,Otomops martiensseni for which information on distribution and ecology are sorely needed. Because this species can forage at high altitudes, it is difficult to capture and most observations have been from caves and buildings. With the advent of new sonar gathering devices and analysis software, recording of echolocation calls can give unprecedented information on evasive bat species. Previous records from South Africa were restricted to the Durban area where several colonies in buildings were documented. No published records were available for Botswana. Our data expand the range of O. martiensseni in South Africa about 870km northward. However, this species’ relative occurrence continues to be rare, composing \u3c0.74% of all our recorded call sequences across the region. We provide the first evidence of O. martiensseni in Kruger National Park (KNP) and Mapungubwe National Park (MNP) in South Africa and from Molema Bush Camp in the Tuli Block of Botswana. Of the 13,449 call sequences analyzed in our study, 91 were determined to be from O. martiensseni and of these, 84 occurred in KNP. Our data show that O. martiensseni is more widely distributed in eastern South Africa than previously thought; however, this species is rare throughout the region and thus faces an uncertain future
Species richness patterns and functional traits of the bat fauna of arid southern Africa
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.Peer reviewe
Survival and population dynamics of the Marabou Stork in an isolated population, Swaziland
Investigating the ecology of long lived birds is particularly challenging owing to the time scales involved. Here an analysis is presented of a long term study of the survival and population dynamics of the marabou stork (Leptoptilos crumeniferus), a wide ranging scavenging bird from Sub-Saharan Africa. Using resightings data of tagged nestlings and free flying birds we show that the stork population can be divided into three general life stages with unique survival probabilities and fecundities. Fecundity of the storks is inversely related to rainfall during their breeding season. Corroborative evidence for a metapopulation structure is discussed highlighting the impact of the Swaziland birds on the ecology of the species in the broader region. The importance of tag loss or illegibility over time is highlighted. Clearly, any attempt at conserving a species will require a detailed understanding of its population structure, of the sort examined here
Domestic cats and dogs create a landscape of fear for pest rodents around rural homesteads
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
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