Preliminary Report on the “Humane Coyote-Getter” for the Control of the Black-Backed Jackal thos Mesomelas in the Transvaal

The diet of Canis mesomelas was studied in the central Namib Desert, South West Africa. A sample of 772 scats was collected from three main sites (coastal, dry riverine and open plains) and two minor sites (Diamond Area 2). Scats from the coastal site contained predominantly bird material whereas scats from the riverine and plains sites contained predominantly plant material. The present study is compared with other feeding studies of this species, particularly in South Africa.     

Energetics and Water Relations of Namib Desert Rodents

All the Namib rodents investigated, except Petromus, can survive without water on a diet of air-dried seed. Water turnover rates of these animals in the laboratory confirmed their low water requirements. Field water turnover rates were remarkably low, probably because Petromyscus and Aethomys aestivate and Petromus has a low daily energy expenditure (DEE). The rodents have an increased water turnover rate after advective fogs occur: Daily energy requirements for Petromyscus and Aethomys were similar to expected values in the laboratory, whereas Gerbillurus had a higher DEE, and Petromus and Mus had lower-than-predicted DEE's. Water turnover rate is coupled with energy turnover rate for the Namib rodents. These physiological attributes of the Namib rodents are consistent with the severity of their environment, are associated with their kidney structure, and reflect the evolutionary history and demography of the particular species.     

Life Histories of Frogs in the Namib Desert

Four anuran taxa inhabit the central Namib: Xenopus laevis, Tomopterna delalandei cryptotis, Phrynomerus annectens and Bufo vertebrate hoeschi. Xenopus is confined to permanent pools in the Kuiseb river canyon. Tomopterna extends further into the Namib, but is restricted to the Kuiseb river bed. The Kuiseb is normally dry, receiving water only briefly (as floods) during the rainy season. These floods are responsible for moving adults and larvae. Phrynomerus and Bufo occur on granite inselbergs. The inselbergs provide shelter mainly in the form of cracks under granite exfoliations. Large runoff surfaces collect the low rainfall (25 mm per year) in depressions in which the frogs breed. Phrynomerus is only active at night; males are aggressive towards one another; oviposition takes place in deep pools and development takes at least eight weeks. Bufo is active during the heat of the day; oviposition takes place in warm shallow pools; development takes about three weeks.     

Stable isotope analysis of diet confirms niche separation of two sympatric species of Namib Desert lizard

We used stable isotopes of carbon and nitrogen to study the trophic niche of two species of insectivorous lizards, the Husab sand lizard Pedioplanis husabensis and Bradfield's Namib day gecko living sympatrically in the Namib Desert. We measured the δ¹³C and δ¹⁵N ratios in lizard blood tissues with different turnover times (whole blood, red blood cells and plasma) to investigate lizard diet in different seasons. We also measured the δ¹³C and δ¹⁵N ratios in available arthropod prey and plant tissues on the site, to identify the avenues of nutrient movement between lizards and their prey. Through the use of stable isotope mixing models, we found that the two lizard species relied on a largely non‐overlapping but seasonally variable array of arthropods: P. husabensis primarily fed on termites, beetles and wasps, while R. bradfieldi fed mainly on ants, wasps and hemipterans. Nutrients originating from C₃ plants were proportionally higher for R. bradfieldi than for P. husabensis during autumn and late autumn/early winter, although not summer. Contrary to the few available data estimating the trophic transfer of nutrients in ectotherms in mixed C₃ and C₄/crassulacean acid metabolism (CAM) plant landscapes, we found that our lizard species primarily acquired nutrients that originated from C₄/CAM plants. This work adds an important dimension to the general lack of studies using stable isotope analyses to estimate lizard niche partitioning and resource use.     

Microclimate and activity of the lizard Angolosaurus skoogi on a dune slipface

The lizard Angolosaurus skoogi inhabits the surface and subsurface environments of sand dunes of the northern Namib Desert. We have related posture, locomotion, and other aspects of surface activity to the microclimate prevailing above and below the surface. Globe temperature was the best microclimatic correlate of surface activity. From our analysis, we concluded that surface thermoregulatory behaviour of A. skoogi is facultative, and aimed at maintaining a body temperature compatible with foraging and other obligatory surface activities.     

Biology of Larks (Aves: Alaudidae) in the Central Namib Desert

1. The biology of six species of larks in the Namib Desert near Walvis Bay, South West Africa, was studied in 1964, 1965 and 1966.

2. All species reproduced following rainfall in summer and autumn months, with the appearance of green grass and abundant insects on which the birds fed.

3. The primarily insectivorous species, Certhilauda albofasciata, shows no seasonality in moulting and testicular development, and reproduces whenever local rainfall results in favourable feeding and nesting circumstances, while the primarily granivorous Spizoeorys starki and Eremopterix verticalis have markedly seasonal testicular and moulting cycles timed so that reproduction occurs only during the late summer and autumn months. Ammomanes grayi is intermediate in food habits and in timing of moulting and reproduction, and C. albescens and Mirafra naevia may also be intermediate in this respect.

4. S. starki and E. verticalis are the only larks that normally drink, but flocks of both species were observed that were independent of drinking water.

5. Larks avoid heat stress during daytime by keeping to the shade of stones, tufts of vegetation and mouths of rodent burrows; and nests are nearly always placed on the shady side of a stone' or tuft of grass.

6. It is suggested that larks may be successful desert occupants because they have not become highly specialized and therefore can tolerate rapidly and severely changing environ-mental conditions associated with drought and irregular rainfall.     

The effect of defoliation on the persistence of elionurus muticus (spreng.) kunth in the highland sourveld of natal

A small plot trial with different heights of defoliation of unpalatable Elionurus muticus and other grass species was conducted over a six year period in the drier phase of the Highland Sourveld of Natal. Results indicate that moderate defoliation of the “palatable” species and little or no utilization of the E. muticus will cause the plant to decrease in size. Heavy, selective defoliation of the “palatable” species will result in an increase or thickening up of the E. muticus in the sward. No utilization of both components resulted in a marked decrease in E. muticus tuft size and heavy, uniform utilization of all herbage had little effect on the size of the E. muticus tuft.     

Activity of the Namib Desert dune ant,Camponotus detritus

The activity of the ant Camponotus detritus was studied in the dunes of the central Namib Desert. Activity was divided into two components: transit activity and honeydew collection. Temperature governed both forms, but light controlled the initiation and termination of transit activity, which was bimodal in warm conditions and unimodal in cool conditions. No transit activity occurred at night. Ants were active over a surface temperature range of 10-55°C. Owing to a steep thermal gradient above the sand surface during the day in summer, the temperatures which the ants bodies experienced at 5 mm above the sand were 10-15°C lower than surface temperatures; well within the ants' physiological limits. Winds of about 16 km h^-1 inhibited activity which ceased when wind speeds reached about 25 km h^-1. In summer, the number of ants collecting honeydew was negatively correlated with air temperature while in winter it was positively correlated.     

Reproductive cycle of the Namib giant ground gecko,Chondrodactylus angulifer (Squamata: Gekkonidae)

The reproductive cycle of the Namib giant ground gecko, Chondrodactylus angulifer, from southern Africa was described from a histological examination of gonadal material from museum specimens. Males followed a seasonal testicular cycle in which (based on available specimens) the major period of spermiogenesis occurred between September and December. The onset of spermiogenesis is not known as specimens from May to August were not available. Testes in regression were found in January, February and March. Testes in recrudescence were found in January, February, March and April. Females with enlarged ovarian follicles (>5mm length) were found in January/February and September to December. Mean clutch size for 36 females was 1.7 ± 0.47 S.D., range: 1–2. Evidence is presented that more than one clutch may be produced in the same reproductive season.     

Differences in diet between two rodent species,Mastomys natalensis and Gerbilliscus vicinus,in fallow land habitats in central Tanzania

Differences in the ecological niche requirements among rodent species competing in the same habitat may result from differences in the use of one to three resources: space, time and food or some combination of these. Alternatively, differences in resource use utilization among animal species may simply reflect availability of food, and when food is limited, different animal species compete. In this study, the diet of two rodent pest species, Mastomys natalensis and Gerbilliscus vicinus, coexisting in fallow land in central Tanzania were studied to assess the degree of diet differentiation among them. Dietary niche breadth of G. vicinus was greater than that of M. natalensis in all stages of the maize cropping seasons. The rodent species studied overlapped considerably in the food items consumed ranging from niche overlap (O_jk) of 0.77–0.89. Grains/seeds featured high in the diet of M. natalensis while plant material occurrence was high in G. vicinus. These two food categories may have contributed to differences in diet partitioning, which may, in turn, facilitate their coexistence in fallow land.     

Determination of artemisinin in Artemisia sieberi and anticoccidial effects of the plant extract in broiler chickens

Artemisinin has received much attention in the treatment of malaria in recent years, and it is now considered as a potential candidate to reduce coccidial infection in chickens. It is a sesquiterpene compound which has been isolated from Aretemisia annua for the first time. The present study aimed to investigate the occurrence of artemisinin in A. sieberi (AS) and to test the anticoccidial effects of plant extract in broiler chickens. The aerial parts of the plant were collected during different seasons from Yazd Province, in the centre of Iran. The artemisinin content of the AS was extracted with petrol ether and analysed by high-performance liquid chromatography using UV detection. Anticoccidial effects of the plant extract were tested on chicks challenged with various species of Eimeria. The infected chickens were treated with doses of 1 or 2.5 mg/kg per day artemisinin via oral administration of plant extract. The analytical results showed that the level of artemisinin in AS was 0.2% and 0.14% of dried weight (DW) of plant materials in summer and autumn, respectively. Treatment of experimentally infected chickens with AS extracts showed that artemisinin was able to reduce the severity of coccidial infection induced by Eimeria tenella and E. acervulina, but not E. maxima. The anticoccidial effects of artemisinin were shown by significant decrease in output of number of oocysts per gram of faeces in chickens challenged with different species of Eimeria. This study showed that the levels of artemisinin in AS were comparable with those in other species including A. annua, and that the extract of this plant can reduce coccidial infection in broiler chickens.     

Ecological role of the giant root‐rat (Tachyoryctes macrocephalus) in the Afroalpine ecosystem

Rodents with prevailing subterranean activity usually play an important role in the ecosystems of which they are a part due to the combined effect of herbivory and soil perturbation. This is the case for the giant root‐rat Tachyoryctes macrocephalus endemic to the Afroalpine ecosystem of the Bale Mountains, Ethiopia. We studied the impact of root‐rats on various ecosystem features within a 3.5‐ha study locality dominated by Alchemilla pasture, which represents an optimal habitat for this species, in 2 periods of a year. The root‐rats altered plant species composition, reducing the dominant forb, Alchemilla abyssinica, while enhancing Salvia merjame and a few other species, and reduced vegetation cover, but not the fresh plant biomass. Where burrows were abandoned by root‐rats, other rodents took them over and A. abyssinica increased again. Root‐rat burrowing created small‐scale heterogeneity in soil compactness due to the backfilling of some unused burrow segments. Less compacted soil tended to be rich in nutrients, including carbon, nitrogen and phosphorus, which likely affected the plant growth on sites where the vegetation has been reduced as a result of root‐rat foraging and burrowing.     

The effect of wind on foraging activity of the tenebrionid beetle Lepidochora discoidalis in the sand dunes of the Namib Desert

The foraging activity of the tenebrionid beetle, Lepidochora discoidalis, was studied in the sand dunes of the Namib Desert. The surface activity of this beetle species was found to be correlated both with time of day and wind speed. Higher numbers were observed on the dune surface between 17:00–19:00 h when wind speeds were consistently higher than 9 m/s. Noise and vibrations in the dune sand were found to be highly dependent on wind speed. Wind blowing at speeds higher than 5 m/s lifts the surface sand grains and generates vibrations in the sand. The peak frequency of these vibrations is in the range of 700–1000 Hz. The vibrational amplitude at the peak frequency is on average 40 dB higher at those wind speeds when the beetles are active compared to lower wind speeds. The results indicate that wind is an important cue for these beetles and can be perceived by buried beetles through substrate vibrations.     

Genetic variation in the feral horses of the Namib Desert, Namibia

Genetic variation at 7 blood-group and 10 biochemical genetic loci was examined in 30 horses from a feral herd from the Namib Desert of Namibia, Africa. The observed genetic variability was extremely low compared with that found in domestic horse breeds. The low variation was most probably a result of recent small population size and a small founding population size. Genetic comparison of the Namib horses, which were of unknown origins, to domestic horse breeds, showed that the Namib horses had the highest genetic similarity to Arabian type horses, although they did not closely resemble this type of horse in conformation.     

Adaptations in three species of large mammals (Antidorcas marsupialis,Hystrix africaeaustralis,Hyaena brunnea) to arid environments

Adaptations in the springbok Antidorcas marsupialis, porcupine Hystrix africaeaustralis and brown hyaena Hyaena brunnea to arid environments are discussed. Springbok evolved in the arid west of southern Africa. The proximate factor triggering the onset of oestrus is improved nutrition following rainfall and adaptations have evolved to ensure the success of year-round opportunistic breeding. The porcupine can also breed throughout the year but in the Karoo with its dry cold winters, young are only born in warmer wetter months. Following a gestation period of 93 days and lactation anoestrus lasting 120 days, the female porcupine has evolved a special adaptation whereby she will only conceive during the third to seventh oestrous cycle following the end of lactation. This period may be shortened or lengthened thereby enabling her to adjust to climatic conditions in an unpredictable arid environment. The brown hyaena is well adapted to living along the Namib coastal region where severe extremes in temperature occur and bitterly cold south-west winds sweep along the coastal strip. Long hair and pilo-erection probably assist brown hyaenas in adjusting to these adverse climatic conditions. The spotted hyaena, Crocuta crocuta, does not occur along the coast. Morphological differences between the two species are considered in the light of climatic differences between the coastal and interior desert regions.     

Status and past and present distribution of elephants in the Kaokoveld,South West Africa/Namibia

The status and the past and present distribution of elephants (Loxodonta africana) in the Kaokoveld are examined. The elephants of the Kaokoveld are divided into a western and eastern ‘resident’ population with a transitional population in between. In 1983, 357 individual elephants were identified with 70 in the western desert-dwelling population, 207 in the eastern population and 80 in the transitional population. A distinction is made between permanent distribution and occasional wanderings. The available records indicate that elephants were present in the northern Namib Desert long before the advent of western man. From the present data it is also clear that man had little or no influence on the occupation of the western areas by elephants, but since 1880 man has caused a decline in elephant distribution and numbers. Currently the elephant’s status there seems relatively stable following intensified law enforcement. However, with the small population sizes, the situation remains vulnerable.     

Camera-trapping and seed-labelling reveals widespread granivory and scatter-hoarding of nuts by rodents in the Fynbos Biome

Many plant–animal interactions can be challenging to directly observe, due to species being small, cryptic and/or nocturnal. Previous research on seed predation and dispersal by rodents in the Fynbos Biome of South Africa has relied on indirect evidence, as methods for directly monitoring rodent–seed interactions were not available. The aims of the study were to determine which resident small mammals scatter-hoard nuts and the geographic, seasonal and taxonomic extent of scatter-hoarding in the Fynbos Biome. We used camera traps focused on seed stations at eight sites in the Fynbos Biome to determine the responses of small mammals to tagged nut-like fruits (nuts) of seven endemic plant species belonging to the Proteaceae (n = 3), Rosaceae (n = 2), Restionaceae (n = 1) and Cupressaceae (n = 1), as well as commercial sunflower seeds. We found Acomys subspinosus and Gerbilliscus paeba scatter-hoarded nuts, which they typically carried and buried individually. Rhabdomys pumilio and Micaelamys namaquensis only consumed nuts. Leucadendron pubescens and L. loranthifolium are added to the list of known plant species that are scatter-hoarded by rodents. Nuts of Cliffortia cuneata and C. phillipsii, and the critically endangered Widdringtonia cedarbergensis, were consumed but not dispersed by small mammals, whereas nuts of Ceratocaryum argenteum were neither consumed nor scatter-hoarded by rodents (within its native range). Gerbilliscus paeba and A. subspinosus scatter-hoarded nuts aseasonally, outside of seed-fall periods. Scatter-hoarding was widespread throughout the Fynbos Biome, although it was highly localised across and within sampled sites. The absence of scatter-hoarding rodents at sites with rodent-dispersed plants remains an important aspect for future investigation.     

Plants poisonous to horses in Europe

Poisoning of horses by plants is a relatively common veterinary problem and may occur when the fresh plant is ingested in pasture or when the plant contaminates hay, silage and feed. In Europe, horses are particularly at risk of poisoning by Cynoglossum officinale (houndstongue), Datura stramonium (jimson weed), Hypericum perforatum (St. John's wort), Nerium oleander (oleander), Pteridium aquilinum (bracken fern), Robinia pseudoacacia (black locust), Senecio jacobaea (tansy ragwort), Taxus baccata (European yew) and Thuja occidentalis (white cedar). For each of these poisonous plants the information given in this review includes plant distribution, conditions of poisoning, toxic active principles and clinical signs.     

Microbiological aspects of poultry processing

The microbiological condition of poultry carcasses is shown to be influenced by the general hygiene in the processing plant which is largely determined by (i) the quality of the raw materials, (ii) the design of plant and buildings, (iii) personal hygiene and (iv) cleaning efficiency. The standard of hygiene is dealt with under (i) assessment of contamination on surfaces, (ii) estimation of contamination on carcasses, including bacteria of public health significance and (iii) other measurements of value. Microbiological sampling of surfaces and carcasses is discussed and standards are suggested for water supplies, surfaces and carcasses. Data are presented from 430 frozen eviscerated carcasses sampled over the period of 12 months from a large processing plant.     

Plant selection and grazing activity of the invasive snail Theba pisana in coastal Algoa Bay,South Africa

The land snail Theba pisana is a coastal species native to the Mediterranean but has been introduced to regions all over the world, including South Africa and Australia, where it is considered a pest. This study examines the diet of T. pisana and its preference for certain dune plants in the Cape Recife Nature Reserve of Algoa Bay in the Eastern Cape, South Africa. Field observations identified plants being fed on by T. pisana, accounting for almost half of the dune plant species present in the study area. Five plant species, on which snails were found frequently and in high abundance, were selected for feeding preference experiments. Laboratory experiments and field observations indicate that T. pisana feed preferentially on Tetragonia decumbens over Osteospermum moniliferum, Osyris compressa and Cynanchum obtusifolium. It is clear that while T. pisana is reported to have a generalist diet, consuming a range of plant species commonly found in South African dune vegetation, it also exhibits a definite preference for T. decumbens. The reasons for this preference need to be investigated further.