Abundance and distribution of elephants in the Luangwa Valley, Zambia

Elephant density over 40 000 km² of the Luangwa Valley was estimated as 2–17 km^-2 to give a population size of around 86 000 in that area, a tally that would probably top 100 000 if unsurveyed areas within the drainage had been included. Seasonal movement is largely restricted to a migration on to the riverine strip during the wet season and reciprocal dispersal across the valley thereafter. The mean annual range of movement is about 25 km.     

Large herbivores in Upper Lupande Game Management Area, Luangwa Valley, Zambia

Upper Lupande Game Management area in Luangwa Valley, Zambia currently supports good populations of sixteen large and medium-sized herbivores. Impala was the most abundant constituting 34% of the total population estimates, followed by buffalo (19%), zebra (12%), wildebeest (10%), warthog (8%), elephant (6%) and hippopotamus (3%). Other species made up the remaining 8%. The survey zone contained a herbivore biomass of 10,796.18 times 10³ kg. Elephants contributed 50.2% and buffalo 25.1% of the total herbivore biomass of the area. The estimated maximum sustainable off-take potential in Upper Lupande was 1110.14 times 10³kg per annum. The distribution of most of the species studied suggested favourable recruitment status. There were species-specific distribution patterns and densities in the survey zone.     

The dating and interpretation of a Mode 1 site in the Luangwa Valley, Zambia

Flake based assemblages (Mode 1) comprise the earliest stone technologies known, with well-dated Oldowan sites occurring in eastern Africa between ∼ 2.6-1.7 Ma, and in less securely dated contexts in central, southern and northern Africa. Our understanding of the spread and local development of this technology outside East Africa remains hampered by the lack of reliable numerical dating techniques applicable to non-volcanic deposits. This study applied the still relatively new technique of cosmogenic nuclide burial dating (¹⁰Be/²⁶Al) to calculate burial ages for fluvial gravels containing Mode 1 artefacts in the Luangwa Valley, Zambia. The Manzi River, a tributary of the Luangwa River, has exposed a 4.7 m deep section of fluvial sands with discontinuous but stratified gravel layers bearing Mode 1, possibly Oldowan, artefacts in the basal layers. An unconformity divides the Manzi section, separating Mode 1 deposits from overlying gravels containing Mode 3 (Middle Stone Age) artefacts. No diagnostic Mode 2 (Acheulean) artefacts were found.Cosmogenic nuclide burial dating was attempted for the basal gravels as well as exposure ages for the upper Mode 3 gravels, but was unsuccessful. The complex depositional history of the site prevented the calculation of reliable age models. A relative chronology for the full Manzi sequence was constructed, however, from the magnetostratigraphy of the deposit (N>R>N sequence). Isothermal thermoluminescence (ITL) dating of the upper Mode 3 layers also provided consistent results (∼78 ka). A coarse but chronologically coherent sequence now exists for the Manzi section with the unconformity separating probable mid- or early Pleistocene deposits below from late Pleistocene deposits above. The results suggest Mode 1 technology in the Luangwa Valley may post-date the Oldowan in eastern and southern Africa. The dating programme has contributed to a clearer understanding of the geomorphological processes that have shaped the valley and structured its archaeological record.     

Observations of tree growth, woodland structure and elephant damage on Colophospermum mopane in Luangwa Valley, Zambia

Six samples of tagged Colophospermum mopane were monitored for five years in locations with varying soil characteristics but with similar elephant densities. Physiognomic variation among the samples was related to soil differences, which also correlated with different browsing habits by elephants. The impact of elephant browsing further influenced both the physiognomy and demography of C. mopane. Results from this study suggest that the influence of soils and elephants on C. mopane alter successional transitions from grassland to woodland. Soils that promote coppicing of C. mopane yield less stable woodlands when associated with elephants than soils promoting woodlands with large bolus, non-coppicing trees. The dynamics of the latter are determined more by tree recruitment as influenced by such agents as other browsers or frequency and seasonality of bush fires. Implications for forest/elephant management are discussed.     

Pollen and spore assemblages in the Luwumbu Coal Formation (Lower Karroo) of the North Luangwa Valley,Zambia, and their biostratigraphic significance

Pollen and spore assemblages from the Luwumbu Coal Formation (Lower Karroo) of the northern part of the Luangwa Valley, Zambia, are described. Two assemblages have been recognised, one from banded siltstones and mudstones in the lower part of the formation, and the other from the overlying carbonaceous sediments of the upper part of the formation. The older assemblage is dominated quantitatively by monosaccate forms (Cannanoropollis and Plicatipollenites), and is generally similar to assemblages recorded by other workers from the Lower Karroo glacial and peri-glacial rocks of Zaire.The younger assemblages comprises a variety of supra-generic groups; the most common forms are disaccate (striate and non-striate) and trilete, but monosaccate, polyplicate, colpate, monolete and alete forms all occur. Genera which are especially common include Protohaploxypinus, Vesicaspora and Acanthotriletes. Cannanoropollis is abundant in the lower part of the younger assemblage. In general, the assemblage is similar to that recorded from the upper part of the Lower Coal Measures of the Ketewaka/Mchuchuma coalfield of Tanzania.     

Barriers to insecticide-treated mosquito net possession 2 years after a mass free distribution campaign in Luangwa District, Zambia

Background and Methods

Roll Back Malaria set the goal of 100% of households in malaria endemic countries in Africa owning an insecticide-treated mosquito net (ITN) by 2010. Zambia has used mass free distribution campaigns and distribution through antenatal care (ANC) clinics to achieve high coverage.

Methodology and Principal Findings

We conducted a probability survey of 801 households in 2008 to assess factors associated with households that lacked an ITN after mass distribution. Community perceptions of barriers to ITN access were also obtained from in-depth interviews with household heads that reported not owning an ITN. Nearly 74% of households in Luangwa district reported owning ≥1 ITN. Logistic regression showed households without a child <5 years old during the ITN distribution campaigns were twice as likely to not have an ITN as those with a child <5 during distribution (Adjusted odds ratio (AOR)  = 2.43; 95% confidence interval (CI): 1.67–3.55). Households without a woman who attended an ANC in the past 2 years were more likely to be without ITNs compared to households with a woman who attended an ANC in the past 2 years (AOR  = 1.52; 95% CI: 1.04–2.21). In-depth interviews with heads of households without an ITN revealed that old age was a perceived barrier to receiving an ITN during distribution, and that ITNs wore out before they could be replaced.

Conclusions and Significance

Delivery of a large number of ITNs does not translate directly into 100% household coverage. Due to their design, current ITN distribution strategies may miss households occupied by the elderly and those without children or ANC access. ITN distribution strategies targeting the elderly, those with limited access to distribution points, and others most likely to be missed are necessary if 100% ITN coverage of households is to be achieved.     

Mortality and female fecundity in an expanding black rhinoceros (Diceros bicornis minor) population

Identifying factors that affect demographic parameters and how those factors act is vital for understanding population dynamics, especially of endangered species. Moreover, specific ideas in the population dynamics of large herbivores underpin the management of the critically endangered black rhinoceros (Diceros bicornis). We studied an expanding black rhinoceros population since its establishment in 1986 in the Great Fish River Reserve, South Africa, through 2008 when managed removals interrupted natural dynamics. During the study, only 13 animals died, of which nine were subadults. In a linear modelling context, we used information-theoretic methods to evaluate the influence of independent variables expected to affect demographic parameters. For females, age at first reproduction (AFR) increased with abundance, but there was no effect of abundance on adult fecundity as measured by inter-birth intervals (IBIs). We evaluated these results in the theoretical context of population dynamics of large herbivores, in particular, Eberhardt’s proposal of a specific sequence in which demographic parameters first respond to increasing density. Our observations are consistent with Eberhardt’s prediction that immature individuals are impacted before adults, but the relative timing and magnitude of density effects on immature individuals was unclear. Rainfall did not influence AFR or IBIs. Maternal age influenced IBIs but much of the observed variation in IBIs was not accounted for by structural variation. Studies of populations more nearly approaching a stable age distribution and carrying capacity are needed to resolve remaining uncertainties and ambiguities in the life history of the black rhinoceros in particular and megaherbivores in general.     

Ranging behaviour and habitat usage in black rhinoceros, Diceros bicornis, in a Kenyan sanctuary

Home range area and habitat utilization by translocated black rhinoceros Diceros bicornis were studied at Sweetwaters Rhino Sanctuary in the Laikipia district of Kenya. Home ranges were estimated from sightings and tracking data; home range area was very variable between individuals (range 2.25–14.39km², minimum convex polygons), and was independent of age or sex. Groups of rhinoceros shared common home ranges, with little or no overlap between groups; each group consisted of one adult male, one or more adult females and their calves, and sometimes immature animals. Rhinoceros utilize a variety of habitats, but within these show positive selection for certain habitats. Home ranges generally included more Euclea bush, and less grassland and Acacia bush than expected. Rhinoceros make use of regular resting places, or bedding sites, generally situated in bushland in secluded areas, often in dense thickets. Rhinoceros defaecate at dung piles or middens. Middens are located throughout the range not just on the boundaries; the highest density of middens was found in riverine woodland, and the lowest density in grassland and Acacia bush.     

Trypanosome Diversity in Wildlife Species from the Serengeti and Luangwa Valley Ecosystems

Background

The importance of wildlife as reservoirs of African trypanosomes pathogenic to man and livestock is well recognised. While new species of trypanosomes and their variants have been identified in tsetse populations, our knowledge of trypanosome species that are circulating in wildlife populations and their genetic diversity is limited.

Methodology/Principal Findings

Molecular phylogenetic methods were used to examine the genetic diversity and species composition of trypanosomes circulating in wildlife from two ecosystems that exhibit high host species diversity: the Serengeti in Tanzania and the Luangwa Valley in Zambia. Phylogenetic relationships were assessed by alignment of partial 18S, 5.8S and 28S trypanosomal nuclear ribosomal DNA array sequences within the Trypanosomatidae and using ITS1, 5.8S and ITS2 for more detailed analysis of the T. vivax clade. In addition to Trypanosoma brucei, T. congolense, T. simiae, T. simiae (Tsavo), T. godfreyi and T. theileri, three variants of T. vivax were identified from three different wildlife species within one ecosystem, including sequences from trypanosomes from a giraffe and a waterbuck that differed from all published sequences and from each other, and did not amplify with conventional primers for T. vivax.

Conclusions/Significance

Wildlife carries a wide range of trypanosome species. The failure of the diverse T. vivax in this study to amplify with conventional primers suggests that T. vivax may have been under-diagnosed in Tanzania. Since conventional species-specific primers may not amplify all trypanosomes of interest, the use of ITS PCR primers followed by sequencing is a valuable approach to investigate diversity of trypanosome infections in wildlife; amplification of sequences outside the T. brucei clade raises concerns regarding ITS primer specificity for wildlife samples if sequence confirmation is not also undertaken.     

A note on eyelashes in an Arfican black rhinoceros, Diceros bicornis

The presence of eyelashes on the lower eyelid of an adult Diceros bicornis (L.) was observed and recorded by photography.