Northeastern Botswana Research Articles

Helminth parasites of impalas, Aepyceros melampus, in eastern southern Africa, collected during 1973 to 2007.

This paper summarises published and unpublished data on helminths collected systematically from 424 impalas at 11 localities in eastern southern Africa, from St. Lucia in KwaZulu-Natal (KZN) to the Tuli Block in north-eastern Botswana. It includes data on collections in the Kruger National Park (KNP) in the drought of 1982, and in 1992/93 following the 1991/92 drought. Thirty-three species of nematodes, plus six taxa identified only to the generic level, three taxa of trematodes, and three species of cestodes were collected. Helminth species richness was highest in the southern KNP and lowest in the Tuli Block. The prevalence and intensity of infection of several helminths also declined from KZN and the southern KNP to the drier areas in the north and west. With the exception of St. Lucia and Nylsvley, > 80% of the helminths collected at each locality were collected in the southern KNP. St. Lucia was the most dissimilar locality; of the 20 helminths collected, five were unique. Ten of 33 species of nematodes, the paramphistomines (Trematoda) and the cestode Stilesia hepatica were collected at seven or more localities. Six of the most common nematodes, Cooperia hungi, Cooperioides hamiltoni, Impalaia tuberculata, Longistrongylus sabie, Strongyloides papillosus and Trichostrongylus deflexus are primarily parasites of impalas in the southern KNP, whereas many of the helminths collected at only one or two localities are parasites of other hosts. Nematode burdens were increased in the drought affected impalas in 1982, but helminth burdens decreased in 1992/93 following a dry cycle.

Aerial photography and machine learning for estimating extremely high flamingo numbers on the Makgadikgadi Pans, Botswana

Monitoring biodiversity over time and space is essential for effective conservation of habitats, processes, and dependent organisms. Estimating large abundances of individuals can be challenging (e.g. birds and mammals), demanding efficient and effective methods. The Makgadikgadi Pans in north-eastern Botswana have high concentrations of breeding and feeding flamingos (Phoenicopterus roseus and Phoeniconaias minor), among the world’s most important breeding sites. No published estimates of flamingos exist since 2009, with historical estimates providing limited details on methods. We developed a semi-supervised machine learning method for counting a large feeding concentration of flamingos (2 June 2019) in aerial photographs from northern Sua Pan of the Makgadikgadi Pans. We also analysed rainfall and flooding frequency and extent, using satellite imagery, estimating likely frequency of these flamingo concentrations. Lastly, we reviewed the site’s global importance as flamingo breeding habitat. Our analysis successfully provided an estimate of 372,172 to 689,473 flamingos, with methods producing over 97 % test accuracy. Uncertainty related primarily to data coverage and collection rather than methodology. This estimate underlined the Makgadikgadi Pans’ significance for flamingos, supported by a high frequency of flooding (>5:10 years). Sua Pan ranked in the top ten breeding sites for the lesser and greater flamingos in the world. These methods can be applied to other large concentrations of flamingos and other animals. Our techniques provide considerable promise for tracking flamingo populations to ensure their protection. We provide code, for use in Google Earth Engine.

K’ui tii ‘Don’t speak!’ – Morphology and syntax of commands in Ts’ixa (Kalahari Khoe) and beyond

The Khoe-Kwadi language family makes up part of the typological unit “Southern African Khoisan” and is currently distributed across Botswana, Namibia, Angola, Zimbabwe and South Africa. Despite a recent surge of new data from a broad range of languages, no descriptive or comparative study on the expression of commands has been undertaken. In this article, I show that the Kalahari Khoe language Ts’ixa spoken in northeastern Botswana possesses a dedicated imperative clause type characterized by lack of tam marking. Ts’ixa imperatives make use of a special kind of morphology encompassing a prohibitive marker, conjunction and subordination morpheme which appear with canonical (2nd person) and extended (1st and 3rd person) imperatives. In the domain of politeness, Ts’ixa imperatives may combine with interrogative and vocative morphology. When considered within a cross-Khoe-Kwadi framework taking into account languages from all major subgroups, it further becomes evident that many aspects of Ts’ixa imperatives can be generalized for the family as a whole. In addition, the comparative viewpoint not only reveals a historical link between interrogative and imperative morphology, but also opens up new perspectives for both genealogical and areal approaches to imperatives in Khoe-Kwadi.

A 900-Year Isotopic Proxy Rainfall Record from Northeastern Botswana

A high-resolution climate archive was reconstructed based on carbon isotope analysis and radiocarbon dating of the Chapman baobab in northeastern Botswana. The Chapman baobab, which exhibited an open ring-shaped structure composed of six stems, collapsed in January 2016 during an intense El Niño event. Two samples belonging to the oldest stems were investigated in order to obtain a proxy rainfall record, which provides insight into the precipitation regime over the last millennium, evincing centennial and decadal scale variability. The results indicate that the Medieval Warm Period was marked by relatively stable precipitation, whereas rainfall variability and drought frequency increased during the Little Ice Age. The investigated area has experienced both wetter and drier conditions in the past. The wettest conditions of the last millennium were registered before 1450 while the driest period occurred in 1835. For southern Africa, inter-annual rainfall variability is mainly associated with sea surface temperatures in the Agulhas Current core region, which determine the east–west displacement of tropical temperate troughs. Previous studies suggested that positive sea surface temperature anomalies in the Mozambique Channel led to an eastward movement of the troughs but the Chapman record demonstrates a westward displacement in the past, causing drought in northeastern South Africa and wetter conditions in the central part of southern Africa. The positive rainfall correlation with SST anomalies reversed after 1900, causing a gradual decrease in precipitation and confirming the current aridity trend for Botswana. The results contribute to a better understanding of the past climate of southern Africa for which paleoclimate reconstructions remain scarce.

Impact of Climate Variability on Rainfall Characteristics in the Semi-Arid Shashe Catchment (Botswana) from 1981–2050

Futuristic rainfall projections are used in scale and various climate impact assessments. However, the influence of climate variability on spatial distribution patterns and characteristics of rainfall at the local level, especially in semi-arid catchments that are highly variable and are not well explored. In this study, we explore the influence of climate variability on the spatial distribution and rainfall characteristics at a local scale in the semi-arid Shashe catchment, Northeastern Botswana. The LARS-WG, Long Ashton Research Station Weather Generator downscaling method, three representative scenarios (RCP 2.6, RCP 4.5, and RCP 4.5), three trend detection methods (Mann-Kendall, Sen’s slope, and innovative trend analysis) and L-moment method were used to assess climate change impacts on rainfall. Two data sets were used; one with 40 years of observed data from 1981–2020 and the other with 70 years from 1981–2050 (40 years of observed and 30 years of projected data from 2021–2050). Generally, the study found trend inconsistencies for all the trend detection methods. In most cases, Sen’s Slope has a high estimate of observed and RCP 2.6, while ITA overestimates rainfall totals under RCP 4.5 and RCP 8.5. The trend is increasing for annual total rainfall in most gauging stations while decreasing for annual maximum rainfall. The catchment is homogeneous, and Generalized Logistic distribution is the dataset’s best-fit distribution. Spatial coverage of a 100-year rainfall between 151–180 mm will be 81% based on observed data and 87% based on projected data under RCP 2.6 scenario when it happens. A 200-year rainfall between 196–240 mm under RCP 4.5 and 8.5 has high spatial areal coverage, at least 90% of the total catchment. The outcomes of this study will provide insightful information for water resource management and flood risk assessment under climate change. There is a need, however, to assess the transferability of this approach to other catchments in the country and assess the performance of other advanced modelling systems, such as machine learning, in this region.

Nature and conditions of gold mineralization at the Tau deposit, Mupane mine, Tati Greenstone Belt, Botswana: Evidence from fluid inclusion and arsenopyrite geothermometer

AbstractThe gold mineralization at the Tau deposit in northeastern Botswana can be distinguished into two stages. The first stage of mineralization consists of invisible gold associated with early, sulfur‐rich arsenopyrite (Apy1). The second stage is characterized by native gold associated with late, sulfur‐poor arsenopyrite (Apy2). This study aims to constrain the nature of the ore‐forming fluid at the Tau deposit on the basis of fluid inclusion microthermometry and arsenopyrite geothermometry. Quartz crystals closely associated with gold‐bearing sulfides (Apy1) from the host rock host three types of fluid inclusions occurring in the same assemblages: Type I, two‐phase aqueous fluid inclusions, Type II three‐phase aqueous‐carbonic fluid inclusions and Type III one‐ or two‐phase CO2‐rich fluid inclusions. Microthermometric and Raman spectroscopic studies revealed the dominance of coexisting H2O+NaCl (Type I) and CO2N2CH4 (Type III) fluid inclusions. The coexisting Type I and Type III fluid inclusions could represent products of the immiscibility of a homogenous H2OCO2NaClN2CH4 primary ore fluid. The salinity of Type I (calculated from melting temperature of ice) and Type II (calculated from dissolution temperature of clathrate) fluid inclusions vary from 3.4 to 9.2 wt% NaCl equiv. and 5.8 to 9.8 wt% NaCl equiv., respectively. The overall fluid inclusion salinity range (<10 wt% NaCl equiv.) and gas compositions of fluids suggest that the primary ore‐forming fluid at the Tau deposit was of low salinity and H2OCO2N2CH4NaCl composition. Integration of fluid inclusion microthermometry and arsenopyrite geothermometer results suggest that the first stage and second stages of gold mineralization and the associated alteration at the Tau deposit occurred at pressure and temperature conditions of 75–145 MPa and 290–370°C and 85–160 MPa and 330–370°C, respectively. These results suggest that there was an increase in temperature from the first stage to the second stage of mineralization, resulting in the recrystallization of invisible gold‐bearing arsenopyrite in the first stage to form native gold‐bearing arsenopyrite in the second stage. Fluid composition and the estimated physico‐chemical conditions at the Tau deposit confirm that gold was transported as reduced bisulfide complexes and initial gold deposition was likely caused by a reduction in sulfur contents as a result of sulfidation reactions and pressure‐induced phase separation (fluid immiscibility).

Fault controlled geometries by inherited tectonic texture at the southern end of the East African Rift System in the Makgadikgadi Basin, northeastern Botswana

One of the three narrow rift belts that mark the southern end of the East African Rift System (EARS) intersects the Makgadikgadi Basin of northeastern Botswana. Although tectonic activity in the region is known to have influenced the evolution of these pans, the interrelationship between shoreline geometry, fault strikes, and the intersection of the underlying tectonic terranes has yet to be fully realized. We analyzed faults and subsurface structures in the region of the pans using a field investigation in combination with satellite imagery and geophysical data, to constrain the influence that the regional tectonic regime has had on the formation of the present-day pan geometry. We find that pan shorelines are controlled by the intersection of three preferred fault orientations which can be understood in the context of the “older” terranes they overlie, namely the Magondi Belt and the Limpopo Belt. We propose that the pronounced curvature of the southern Magondi Belt has influenced the eastward curvature of the rift-related faults and was likely produced by the impingement of the developing fold belt on the Zimbabwe Craton. Furthermore, limited focal mechanism solutions data from earthquakes north and south of the pans suggests a change in regional extension direction from NW-SE to NE-SW. Determining the relationship between these fault orientations and the underlying tectonic terrains is an important step in understanding the formation of the Makgadikgadi Basin, and more broadly the current tectonic regime of Botswana. The evidence of fault-controlled shorelines within an evaporitic environment may also have implications for regional groundwater activity.

Fault Controlled Geometries by Inherited Tectonic Texture at the Southern End of the East African Rift System in the Makgadikgadi Pans, Northeastern Botswana

Fault Controlled Geometries by Inherited Tectonic Texture at the Southern End of the East African Rift System in the Makgadikgadi Pans, Northeastern Botswana

Zooplankton composition of temporary pools within the lower Nata River channel, Botswana, during dry season

The Nata River is a seasonal system situated in the semi-arid north-eastern Botswana, where rainfall is unpredictable and drought is common. The annual flow of approximately 279 million cubic meters is regionally significant and it forms an important resource for people and biota in the region. Information on the biological diversity of the Nata River is scarce and, to our knowledge, no data is available on its invertebrate fauna. The aim of the study was to provide the first record of the aquatic microinvertebrates of the lower Nata River and examine likely influences of water quality parameters on its species diversity. Physical water quality parameters were measured and zooplankton sampled along the lowermost reaches of the Nata River in August 2012. Salinity, TDS and electrical conductivity ranged widely between sites. Remarkable differences were evident in the zooplankton species composition between the four study sites, evidently related to prevailing levels of salinity.

Land Restitution and the Communities of North-Eastern Botswana, 1889–2012

ABSTRACT This paper argues that land alienation that occurred in the Tati District (North East District) of Botswana can best be returned to its original inhabitants through land restitution. This is because the Tati is unique from other districts in that other districts did not suffer from severe or intense colonial land alienation, whilst the Tati, in many ways, resembled the overcrowded and impoverished African reserves of the settler dominated territories of Zimbabwe, Kenya and South Africa, which had large prosperous farms for white farmers. It holds that a historical wrong was committed in the Tati and that this justifies land restitution. The paper concurs with the contention that the Market Based Land Reform (MBLR) programme which adopts the ‘Willing Buyer–Willing Seller’ (WBWS) approach adopted by the Botswana government since independence to ease the land shortage in the Tati District has not succeeded. The land restitution process in South Africa is used as a case for adoption in Tati. The paper acknowledges the complexities of the process there, and proposes that the situation in Botswana is somewhat different. It is argued that in Botswana, the economic empowerment measures that are currently in place, particularly the agricultural schemes would to a large extent overcome some of the major challenges of land restitution in the Tati.

Crustal and Upper Mantle Shear Wave Velocity Structure of Botswana: The 3 April 2017 Central Botswana Earthquake Linked to the East African Rift System

AbstractRayleigh wave group and phase velocity measurements obtained from ambient noise and earthquake data at 51 broadband stations were used to construct the first 3‐D crustal and upper mantle shear wave velocity model of Botswana. The model shows low crustal velocities associated with the Passarge and Nosop sedimentary basins, whereas the Kaapvaal, Zimbabwe, Maltahohe, and Congo Cratons are recognized by high mantle velocities. The lowest upper mantle shear wave velocity, beneath northeastern Botswana, is associated with the southwestern branch of the East African Rift System. This low‐velocity mantle anomaly appears to be linked to the crust of the Okavango Rift Zone and the location of the 3 April 2017 6.5 earthquake in central Botswana. We suggest that fluids or melt at the base of the crust from the southward continuation of the East African Rift Zone triggered the intraplate earthquake in an extensional tectonic setting.

Multistage gold mineralization events in the Archean Tati greenstone Belt, northeast Botswana: Constraints from integrative white mica Ar/Ar, garnet U-Pb and sulfides Pb/Pb geochronology

The Tati Greenstone Belt (TGB) in northeastern Botswana hosts numerous Au deposits (Shashe, Mupane and Signal Hill) associated with sulfides, garnet and white mica. In this study, integrative white mica Ar/Ar, garnet U-Pb and sulfides Pb/Pb dating techniques were combined with whole rock and sulfide Pb isotope characteristics to track the source(s) of gold and constrain the timeframes of gold mineralization events. All sulfides and arsenopyrite samples from the TGB yielded overlapping Pb/Pb errorchron ages of 2227 ± 66 Ma and 2220 ± 73 Ma, respectively, which coincide with the Shashe sulfides Pb/Pb errorchron age of 2250 ± 110 Ma. These relatively imprecise Pb/Pb dates suggest heterogeneity in the initial Pb isotope ratios of sulfides. At Mupane, whereas Au mineralization-associated hydrothermal almandine garnet yielded overlapping Tera-Wasserburg lower intercept 206Pb/238U age and a concordia age of 2119 ± 18 Ma (MSWD = 1.03) and of 2105 ± 24 Ma (MSWD of concordance = 1.10), respectively, sulfides produced an errorchron Pb/Pb age of 2873 ± 140 Ma, which despite the large error remains geologically meaningful as it coincides within error with the first Neoarchean Limpopo-Liberian Orogeny (2.70–2.65 Ga), granitoids intrusion emplacement (2.65–2.73 Ga) and deposition of banded iron formation (2.73 ± 0.15 Ga). Ore-related white mica from Signal Hill yielded an overlapping Ar/Ar plateau age of 1987 ± 24 Ma and a weighted mean Ar/Ar age of 1987 ± 13 Ma (n = 15, MSWD = 4.3), which coincide within error with the 2.05–1.95 Ga second Limpopo-Liberian tectonic cycle, herein considered to have possibly triggered the Au mineralization in this area. The obtained radiometric dates point to at least three well constrained gold mineralization events, with two of them possibly triggered by two different regional tectonic events. Lead isotope compositions of most of the sulfides overlap with those of spatially associated schists and granitoids, thus suggesting these units possibly represent Pb and by inference Au rock sources. The genetic model of the TGB Au deposits is consistent with many greenstone-hosted gold deposits worldwide, suggesting our results are not solely of local/regional interest, but can be used to characterize greenstone-hosted gold deposits worldwide.

Gender Dynamics in Household Property Inheritance among Rural Communities: The Case of BaKalanga Baka Nswazwi in North Eastern Botswana

Gender Dynamics in Household Property Inheritance among Rural Communities: The Case of BaKalanga Baka Nswazwi in North Eastern Botswana

Association with humans and seasonality interact to reverse predictions for animal space use

BackgroundVariation in animal space use reflects fitness trade-offs associated with ecological constraints. Associated theories such as the metabolic theory of ecology and the resource dispersion hypothesis generate predictions about what drives variation in animal space use. But, metabolic theory is usually tested in macro-ecological studies and is seldom invoked explicitly in within-species studies. Full evaluation of the resource dispersion hypothesis requires testing in more species. Neither have been evaluated in the context of anthropogenic landscape change.MethodsIn this study, we used data for banded mongooses (Mungos mungo) in northeastern Botswana, along a gradient of association with humans, to test for effects of space use drivers predicted by these theories. We used Bayesian parameter estimation and inference from linear models to test for seasonal differences in space use metrics and to model seasonal effects of space use drivers.ResultsResults suggest that space use is strongly associated with variation in the level of overlap that mongoose groups have with humans. Seasonality influences this association, reversing seasonal space use predictions historically-accepted by ecologists. We found support for predictions of the metabolic theory when moderated by seasonality, by association with humans and by their interaction. Space use of mongooses living in association with humans was more concentrated in the dry season than the wet season, when historically-accepted ecological theory predicted more dispersed space use. Resource richness factors such as building density were associated with space use only during the dry season. We found negligible support for predictions of the resource dispersion hypothesis in general or for metabolic theory where seasonality and association with humans were not included. For mongooses living in association with humans, space use was not associated with patch dispersion or group size over both seasons.ConclusionsIn our study, living in association with humans influenced space use patterns that diverged from historically-accepted predictions. There is growing need to explicitly incorporate human–animal interactions into ecological theory and research. Our results and methodology may contribute to understanding effects of anthropogenic landscape change on wildlife populations.

Pathology of the Emerging Mycobacterium tuberculosis Complex Pathogen, Mycobacterium mungi, in the Banded Mongoose ( Mungos mungo).

Wild banded mongooses ( Mungos mungo) in northeastern Botswana and northwest Zimbabwe are infected with a novel Mycobacterium tuberculosis complex (MTC) pathogen, Mycobacterium mungi. We evaluated gross and histologic lesions in 62 infected mongooses (1999-2017). Many tissues contained multifocal irregular, lymphohistiocytic to granulomatous infiltrates and/or multifocal or coalescing noncaseating to caseating granulomas with variable numbers of intralesional acid-fast bacilli. Over one-third of nasal turbinates examined had submucosal lymphohistiocytic to granulomatous infiltrates, erosion and ulceration of the nasal mucosa, bony remodeling, and nasal distortion. Similar inflammatory cell infiltrates expanded the dermis of the nasal planum with frequent ulceration. However, even in cases with intact epidermis, acid-fast bacilli were present in variable numbers among dermal infiltrates and on the epidermal surface among desquamated cells and debris, most commonly in small crevices or folds. In general, tissue involvement varied among cases but was highest in lymph nodes (50/54, 93%), liver (39/53, 74%), spleen (37/51, 73%), and anal glands/sacs (6/8, 75%). Pulmonary lesions were present in 67% of sampled mongooses (35/52) but only in advanced disseminated disease. The pathological presentation of M. mungi in the banded mongoose is consistent with pathogen shedding occurring through scent-marking behaviors (urine and anal gland secretions) with new infections arising from contact with these contaminated olfactory secretions and percutaneous movement of the pathogen through breaks in the skin, nasal planum, and/or skin of the snout. Given the character and distribution of lesions and the presence of intracellular acid-fast bacilli, we hypothesize that pathogen spread occurs within the body through a hematogenous and/or lymphatic route. Features of prototypical granulomas such as multinucleated giant cells and peripheral fibrosis were rarely present in affected mongooses. Acid-fast bacilli were consistently found intracellularly, even in regions of necrosis. The mongoose genome has a unique deletion (RD1mon) that includes part of the encoding region for PPE68 (Rv3873), a gene co-operonic with PE35. These proteins can influence the host's cellular immune response to mycobacterial infections, and it remains uncertain how this deletion might contribute to observed patterns of pathology. M. mungi infection in banded mongooses is characterized by both a unique transmission and exposure route, as well as accompanying pathological features, providing an opportunity to increase our understanding of MTC pathogenesis across host-pathogen systems.

Henicovalvagen. n., a New Genus of Predominantly Afrotropical Ennominae with Unusually Complex Genitalia (Lepidoptera: Geometridae)

Henicovalva gen. n. (Lepidoptera: Geometridae: Ennominae), a new genus of ennomine geometrids characterised by unusually complex male and female genitalia, is described and illustrated. In addition to the East African type species H. xera (Prout, L. B., 1922) comb. n., which is transferred from Odontopera Stephens, 1831, nine additional members of this genus are described as new to science: H. serulensis sp. n. from northeastern Botswana, H. mpisiensis sp. n. from Swaziland, H. lebomboensis sp. n. from northern KwaZulu-Natal, H. dissoluta sp. n. from northeastern Tanzania, H. staudei sp. n. from central Kenya, H. praedicta sp. n. from southwestern Kenya, H. pulveraria sp. n. from Rwanda, H. negus sp. n. from Ethiopia, and H. yemenensis sp. n. from the Yemen Arab Republic. Although the recorded distribution of Henicovalva gen. n. is disjunct, this may be due to sampling bias. The phylogenetic position of the new genus within Ennominae is discussed, and it is tentatively placed in Ennomini. Illustrations of the adults and male and female genitalia, where known, are provided, as is a map showing the distribution of the southern African species. The study is complemented by a Gazetteer.

Regional Design Storm and Flood Modelling—Risk Implications in Ungauged Catchments

Most planned developments in a catchment for control of excess water using a culvert, bridge or dam spillway are located at a site in a stream where there are no discharge measurements. Even though, for gauged catchments a number of established flood frequency models and rainfall-runoff models do exist, for ungauged catchments mostly regional flood frequency and event-based rainfall-runoff models are used, which depend on regional parameters. In this paper, a regional approach for design floods is presented and risk implication for design of drainage structures assessed. A case study in light of the above has been considered at four ungauged sites in the Limpopo Drainage Basin in north-eastern Botswana.

Stand Structure, Diversity and Regeneration Status of Woody Species in Open and Exclosed Dry Woodland Sites around <i>Molapo</i> Farming Areas of the Okavango Delta, Northeastern Botswana

Stand structure, diversity and regeneration status of woody species were investigated in open and exclosed dry woodland sites in Island Safari, Shorobe and Xobe, northeastern Botswana. A total of 105, 111 and 130 quadrats, measuring 20 × 20 m each, were laid down along parallel line transects in the three sites, respectively, to collect data. A total of 47 species, representing 16 families and 24 genera, were recorded in the study sites. Of these, 33 species representing 13 families and 20 genera, 41 species representing 15 families and 23 genera and 27 species representing 10 families and 14 genera were encountered in Island Safari, Shorobe and Xobe, respectively. The most diverse family was Fabaceae followed by Combretaceae and Tiliaceae at all the three sites. The most diverse genus was Acacia, followed by Combretum and Grewia. The diversity of woody species in the study sites were 2.18, 2.15 and 1.5 in Shorobe, Island Safari and Xobe, respectively, while their corresponding evenness values were 0.6, 0.6 and 0.5, respectively. The mean densities of the woody species encountered in Island Safari, Shorobe and Xobe were 2629, 4271 and 2745 individuals ha&#451, respectively. The five densest species were Colophospermum mopane, Dichrostachys cinerea, Acacia tortilis, Philenoptera violacea and Terminalia prunioides in Island Safari, C. mopane, A. tortilis, A. erioloba, P. violacea and D. cinerea in Shorobe and Acacia mellifera, A. tortilis, P. nelsii, A. luederitzii and A. erubescens in Xobe. The highest important value index values were exhibited by C. mopane, D. cinerea, A. tortilis, P. violacea and T. prunioides in Island Safari, C. mopane, A. erioloba, A. tortilis, P. violacea and C. imberbe in Shorobe, and A. mellifera, A. tortilis, P. nelsii and A. luederitzii in Xobe. The alarming result was the fact that 71%, 80% and 85% of the woody species recorded in Island Safari, Shorobe and Xobe, respectively, exhibited hampered regeneration and, thus, unhealthy population structures. Therefore, there is an urgent need to address the observed unhealthy population structures of the woody species through investigation of the major causes of their hampered regeneration, and also designing measures that will facilitate natural and artificial regeneration of these species at the three study sites.

No evidence for avoidance of visibly diseased conspecifics in the highly social banded mongoose (Mungos mungo)

Individual host behavior may be influenced by infectious disease in ways that can alter population-level disease dynamics. A novel pathogen in the Mycobacterium tuberculosis complex, Mycobacterium mungi, has emerged among banded mongooses (Mungos mungo) in Northeastern Botswana. This host–pathogen system provides an opportunity to study how individual behavior and social interactions in a group-living species might respond to infectious disease. We used repeated focal observations of known individuals with an extensive ethogram to identify behavioral differences and social interactions between healthy individuals and those with clinical signs of tuberculosis (TB). Clinically diseased banded mongooses exhibited a significantly smaller proportion of time active and alert, a larger proportion of time resting, and a slower behavioral transition rate compared to healthy individuals. They also showed lower reciprocation of allogrooming by approximately 50 %. Despite these strong behavioral differences that may serve as visible cues for healthy mongooses to avoid diseased conspecifics, we found no evidence for avoidance of clinically diseased mongooses by healthy individuals or vice versa: Clinically diseased individuals did not have lower levels of social behaviors than healthy individuals, and clinically diseased mongooses were allogroomed at the expected level despite their decreased reciprocation. Our results show that in contrast to prior studies of other species, avoidance of diseased conspecifics did not occur in this highly social species. We discuss hypotheses for this lack of avoidance and potential implications for pathogen transmission.

Numerals and number words in Shua

AbstractThis paper is concerned with expressions of numerical concepts in Shua, an endangered Khoe-Kwadi language spoken in north-eastern Botswana. It is demonstrated that a range of different systems of number representation are available to speakers. These differ in terms of the degrees to which they are integrated into the system of the language. A set of defining criteria for numerals as a lexical category is proposed, and it is argued that only members of one of the paradigmatic sets of number expressions satisfy all of the criteria. This is a “restricted” system of numerals distinguishing just ‘1, 2, 3, 4, few, many’. A detailed description of the morphosyntactic features of the members of this system is provided. Similarly, a detailed description is provided of features of the modern elaborated and extended set of number words, which are based primarily on borrowings from English, but also include extensions of terms for monetary units. The range of senses and uses of the numerals and other expressions of numbers is overviewed, including distributive and collective senses.