Nyala Research Articles

Ecto- and endoparasites of common reedbuck, Redunca arundinum, at 2 localities in KwaZulu-Natal Province, South Africa: community and network structure.

Parasite community structure is governed by functional traits of hosts and parasites. Notably, parasite populations and communities respond to host social and spatial behaviour. Many studies demonstrating these effects dealt with small-bodied host species, while the influence of host social patterns on parasite communities in large hosts remains understudied. In an earlier study on nyalas (Tragelaphus angasii), host age was more important than sex in structuring helminth communities and networks, but the influence of both was mediated by local environmental conditions, creating different locality patterns. Common reedbuck (Redunca arundinum) differ from nyalas in spatial and social behaviour. Based on helminth and ectoparasite data from 56 reedbuck examined at 2 localities in KwaZulu-Natal Province, we asked which patterns are similar and which differ between the 2 host species. Similar to nyalas, reedbuck age was more important than sex in structuring communities and networks. However, local environmental conditions exerted the strongest influence on transmission patterns, especially in ectoparasites. Complex interactions between reedbuck traits, parasite traits and local environmental conditions modulated the risk of infection differently at the 2 sites, confirming our earlier findings in nyalas that pooling data from different locations may obscure location-specific parasite community patterns. Similarities between patterns in reedbuck and nyalas, despite their behavioural differences, suggest some common patterns in parasite community ecology that, in turn, are determined mostly by parasite traits and population dynamics.

Modeling the drivers of large herbivore distribution in human‐dominated southern African savannas

AbstractAfrican savanna ecosystems are home to the world's richest large herbivore (LH) assemblages. However, its landscapes are changing faster than any other region on Earth due to human activities and natural events. Therefore, understanding the factors influencing the distribution of LH in these human‐dominated environments is crucial for decision‐making on wildlife and habitat management. We combined ecological aerial surveys, camera trap, and dung count data to investigate how ecological (habitat types, perennial rivers, and rainfall) and anthropogenic (human settlements and cattle grazing areas) factors influence the distribution of LH species in Limpopo National Park (LNP). We used generalized linear models fitting binary logistic regression models to distinguish 25‐km2 cells occupied (where the species were detected) by elephants (Loxodonta africana), buffalos (Syncerus caffer), zebras (Equus quagga), kudus (Tragelaphus strepsiceros), nyalas (Tragelaphus angasii), and impalas (Aepyceros melampus) from unoccupied regions (where the species were not detected) in the LNP landscape. We found that habitat type and rainfall were the most influential factors shaping the pattern of LH distribution in the LNP, except for elephants, whose prevalence was not associated with rainfall. The prevalence of zebras was positively associated with the proximity to perennial rivers, while kudus avoided these areas. While some species (zebras, kudus, and impalas) tended to avoid settlements, others (elephants, buffalos, and nyala) seemed attracted to settlements. Cattle grazing areas were the worst predictors of the distribution of all study species. Our results disclosed the role of ecological factors for the distribution of LH and showed that anthropogenic disturbances seemed to either (partially) prevent the occurrence of LH or show the potential for human–wildlife conflict risk in the study area. Therefore, the results highlight the need to investigate/quantify the potential human–wildlife conflict risk at finer spatial scales to improve future management.

Common Myna/s Acridotheres tristis extracting hair from captive Lowland Nyalas Tragelaphus angasii

This note describes observations of Common Myna/s Acridotheres tristis perching on captive Lowland Nyalas Tragelaphus angasii at Sydney Zoo, Bungarribee, New South Wales, and pulling tufts of hair. In two of 12 interactions, the Myna extracted hair, which we suspect was for replenishing nesting materials. The repetitiveness that we observed suggests that this behaviour is not uncommon in these birds.

Patterns and predictors of ungulate space use across an isolated Miombo woodland reserve

AbstractUnderstanding ecological‐ and management‐related predictors of mammal space use within protected areas is critical for management planning. This is particularly true in small, fenced and isolated reserves where we hypothesised that management‐related activities will influence large herbivore space use more than ecological characteristics. We used camera trap data to assess the space use patterns for 18 ungulate species in the small and isolated Majete Wildlife Reserve (Majete) in the understudied Miombo woodland ecoregion of southern Malawi. In the 2018 dry season, the 691 km2 reserve was systematically surveyed for ungulate presence at 140 camera trap locations. Over a period of 5456 camera days, the survey yielded 11 078 independent detections of 18 ungulate species and three predators. Using a single‐species occupancy modelling framework, the probability of space use of ungulates was assessed in relation to five management (fire exposure, fire frequency, water availability, distance from fence and road) and five ecological (visibility, grass biomass, vegetation type, terrain ruggedness and predator abundance) space use covariates, while accounting for imperfect detection. Top‐ranked models contained multiple covariates for 15 of the 16 species modelled, with only nyala's (Tragelaphus angasii) space use best predicted by vegetation type only. Distance to water, vegetation type, visibility and fire frequency were predictors having strong influences on six or more species each. More management‐related covariates reflected in top models, but ecological covariates had more meaningful effect sizes making us reject the hypothesis. Importantly though, distance from the roads and fence were also identified as prominent predictors. Notably, black rhinoceros' (Diceros bicornis) probability of space use increased with distance from the reserve boundary. Beyond informing habitat management for ungulates in Majete, these results can form the basis for understanding species‐specific space use patterns in other small reserves with similar characteristics and threats.

Herd Prevalence of Mycobacterium Avium Ss. Paratuberculosis in a Comingled Population of Captive Nyala (Tragelaphus Angasii), Impala (Aepyceros Melampus) And Thomson’s Gazelle (Gazella Thomsonii)

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis, a contagious, chronic, and eventually fatal enteric disease of domestic and non-domestic ruminants. MAP is highly resistant to heat, disinfectants, and environmental agents, staying infective for a long time in the environment which makes biosecurity a challenge when trying to control this disease in domestic, zoo ruminants, and especially wild animals. The highest burden of MAP is in domestic ruminants, followed by zoo ruminant species, and then frees ranging wild ruminants. The overall physiology and pathophysiology of MAP when it occurs in all three ruminant groups is essentially identical, so environmental factors would appear to have dominant roles in explaining the differences in the prevalence among the three groups. Herd prevalence in a group of comingled managed zoo ruminants nyala (Tragelaphus angasii), impala (Aepyceros melampus) and Thomson’s gazelle (Gazella thomsonii) show a clear difference between the low prevalence of MAP in the Thomson’s gazelle compared to both he impala and nyala. When Thomson’s gazelle herd were later fed a high intake of concentrate rations in a similar fashion to the nyala and impala, the prevalence of MAP then started to approach these latter species. Feeding niches and nutrition, especially high concentrate, low fiber feeding, leads to a higher prevalence of MAP. Hypocalcemia or increased calcium demand parallels this trend in MAP prevalence amongst these three comingled species. The observation is that the more intensively managed any ruminant becomes, especially in terms of feeding, the higher the apparent prevalence of MAP. In this regards MAP infection can be more appropriately thought of as an anthropogenic condition. This perspective may allow for exploring other control measures focused on feeding practices and more specifically on calcium metabolism.

Impact of host sex and age on the diversity of endoparasites and structure of individual-based host-parasite networks in nyalas (Tragelaphus angasii Angas) from three game reserves in KwaZulu-Natal province, South Africa

In recent years, numerous studies have examined the effect of host sex and age on the structure of parasite communities in several host taxa under various environmental conditions and in different geographic regions. However, the influence of such factors on the structure of host-parasite networks has received less attention, and remarkably few studies have been carried out on large terrestrial mammals. In this study, we investigated the effects of host age and sex on the parasite infra- and component communities of nyalas (Tragelaphus angasii) and on the structure of individual-based nyala-endoparasite networks. We also aimed to evaluate to what extent these effects vary spatially and if they are mediated by conservation management. Based on a data set of internal macroparasites of 74 nyalas from three game reserves in KwaZulu-Natal province, we found that host age strongly influenced parasite community structure as well as the structure of parasite-nyala networks, whereas host sex played a minor role. However, the effects of both host sex and age were mediated by environmental conditions and thus led to different patterns at the three localities. Our findings highlight that host-parasite communities from different localities should not be pooled when conducting host-parasite network and community studies as this may bias results and mask patterns that are typical for a given locality.

Selection of Vegetation Greenness by Nyala Antelopes on a Resource Productivity Gradient

Geographic gradients in plant productivity can present foraging large herbivores with varying resource levels across the range of a population, to which individuals can demonstrate varying intensity of selection. To investigate individually-specific responses of nyala antelopes (Tragelaphus angasii ) to vegetation greenness, we monitored the landscape use of eight telemetry-collared adult females, half at the wetter end and half at the drier end of Hluhluwe–iMfolozi Park, South Africa. We used remotely-sensed greenness as an index for plant productivity and data on canopy structure, and we compared the strength of selection for greenness between animals having different greenness averages within their home ranges. We found a decreasing pattern between home-range average greenness and strength of selection, which depended on season and presence of tree canopies. Animals in low-greenness home ranges tended to have stronger positive selection in closed-canopy vegetation in the dry season; those in high-greenness home ranges tended to have the stronger negative selection in open-canopy vegetation in the wet season. Our study emphasizes the possibility that a spatial resource gradient on a landscape might provide a valuable model of temporal change in a resource and an indication of potential for foraging animals to adapt to those changes.

Preference of intake of different tree leaves preserved with drying and ensiling by nyala antelope (Tragelaphus angasii).

It is recommended that browse should be an important part of diets for browsing and intermediate feeding type ruminants. However, provision of browse in winter time is problematic for many zoos located in the temperate climate. Drying or freezing of branches are commonly practiced solutions to this problem, but ensiling of tree leaves could also be an attractive option. The aim of this study was to determine the effect of drying and ensiling of different tree leaves on preference of their intake by nyala antelope (Tragelaphus angasii), an intermediate feeding type ruminant. A study was conducted on five nyala fed a standard diet (meadow hay, dehydrated chopped lucerne and limited concentrates) before and during the study. Preference of intake of five feeds was tested: dried maple (A. platanoides), oak (Q. robur), willow (S. alba), and ensiled maple and lime (T. cordata) leaves. Each day two tested feeds were offered to each animal. After 4 h of presentation, feed refusals were weighed and preference ratio for each tested feed and animal was calculated. Then, preferences were ranked using a pairwise comparison chart. Dried maple and oak leaves were preferred more than other leaves whereas ensiled lime leaves were the least preferred. On the other hand, ensiled and dried maple leaves were equally preferred. Results of this study showed that palatability of ensiled tree leaves should not be a concern when feeding nyala, and likely also other browsing or intermediate feeding type ruminants, but palatability of silage may depend on the species of tree.

EVALUATION OF TWO ANESTHETIC COMBINATIONS IN LOWLAND NYALA (TRAGELAPHUS ANGASII).

Fourteen lowland nyala (Tragelaphus angasii) in managed care were successfully anesthetized for a total of 17 anesthetic events using either a combination of butorphanol (0.75 ± 0.15 mg/kg), azaperone (0.25 ± 0.05 mg/kg), and medetomidine (0.30 ± 0.06 mg/kg) (BAM) or medetomidine (0.17 ± 0.01 mg/kg), azaperone (0.22 ± 0.02 mg/kg), and alfaxalone (0.52 ± 0.08 mg/kg) (MAA) delivered intramuscularly via dart. Mean time to initial effect, sternal recumbency, lateral recumbency, handling, and intubation were recorded. The nyala were maintained in sternal recumbency with supplemental oxygenation until 60 min after initial injection. Cardiopulmonary effects were recorded every 5 min after handling until reversal. Arterial blood samples were collected every 15 min for analysis. Level of sedation and quality of recovery were scored. Anesthesia was antagonized with atipamezole (at 5 mg per mg of medetomidine) for both protocols and naltrexone (at 2 mg per mg of butorphanol) for the BAM protocol delivered intramuscularly via hand injection. Mean time to extubation, head control, and standing post reversal were recorded. No hyperthermia, acidemia, apnea, or tachycardia occurred; however, animals did display hypoxemia. Two animals in the BAM cohort required supplementation to facilitate handling. These drug combinations provided satisfactory levels of sedation in most cases for safe handling and minor procedures in lowland nyala under managed care.

The <italic>Australopithecus</italic> Taun child skull: A fossil that changed human evolution history

The <italic>Australopithecus</italic> Taun child skull: A fossil that changed human evolution history

Does Competition Shape Cheetah Prey Use Following African Wild Dog Reintroductions?

Both interference and exploitative competition for prey occurs between carnivore species, which can be exacerbated if the carnivore species are of similar body size, meaning that they select for similar prey species. Studies on competition within the large carnivore guild in Africa have mainly focused on the interactions between the larger dominant (lions, Panthera leo, and spotted hyaenas, Crocuta crocuta) and smaller, submissive (cheetahs, Acinonyx jubatus, and African wild dogs, Lycoan pictus) species. However, given that cheetahs and African wild dogs are similar-sized and diurnal, they have a high overlap in dietary preference and hence scope for competition. Here, we investigate whether competition with African wild dogs shapes cheetah prey preference by comparing cheetah prey selection before and after reintroductions of African wild dogs. We show that cheetahs experienced high dietary overlap with African wild dogs but become more generalized hunters in the presence of African wild dogs. Moreover, cheetahs used three key prey species (impala, Aepyceros melampus, nyala, Tragelaphus angasii, and common duiker, Sylvicapra grimmia) differently following African wild dog reintroductions. We suggest that this reflects predominantly exploitative competition between these predators, particularly for impala. Such diet shifts may be useful indicators of resource limitations for managers conserving these two threatened small predators.

Opportunistic feeding by lions: non-preferred prey comprise an important part of lion diets in a habitat where preferred prey are abundant

Optimal foraging theory predicts less diverse predator diets with a greater availability of preferred prey. This narrow diet niche should then be dominated by preferred prey, with implications for predator–prey dynamics and prey population ecology. We investigated lion (Panthera leo) diets in Hluhluwe–iMfolozi Park (HiP), South Africa, to assess whether lions in a site with a high density of preferred prey (prey species weighing 92–632 kg as estimated from a published meta-analysis) have a narrow diet, consisting primarily of preferred prey. HiP is a useful study site to investigate this prediction because it is a productive landscape (with a high density of prey) where lion-preferred prey constitutes up to 33% of the prey available to lions. Furthermore, to investigate whether lions in HiP exhibit sex-specific diets as documented in other southern African populations, we estimated male and female lion diets separately. We were specifically interested in testing whether traditional approaches of estimating lion diets at the population level mask sex-specific predation patterns, with possible implications for management of lions in small to medium-sized fenced reserves. Lions in HiP preferred larger prey species (63–684 kg) and had diets with a larger proportion of preferred prey than reported in an African-wide meta-analysis. However, despite the high density of preferred prey species, 36% of lion diets still consisted of typically non-preferred species such as nyala (Tragelaphus angasii). This finding suggests that lions in HiP maintain a degree of opportunism even when preferred prey are abundant. Therefore, abundant, non-preferred prey are likely to be an important resource for lion populations. Sex-specific differences in lion diets were evident in HiP, suggesting that estimation of lion resource use and carrying capacity should consider opportunistic hunting and sex-specific differences in lion diets.

Co‐occurrence modelling highlights conservation implications for two competing spiral‐horned antelope

AbstractWe assessed the potential competitive exclusion of southern bushbuck (hereafter bushbuck,Tragelaphus scriptus) by nyala (Tragelaphusangasii), the larger of the two spiral‐horned browsing antelopes (members of the Tragelaphine family). It has been suggested that high concentrations of nyala, capable of browsing a greater breadth of food items, negatively influence bushbuck. Using camera trap data, we explored factors influencing spatio‐temporal activity patterns and co‐occurrence of both species within three Protected Areas (PAs) of the Maputaland Conservation Unit, South Africa. Bushbuck have gone locally extinct within one of our survey areas, likely because of competitive pressures and cascading effects. Our results indicated a segregation of activities; bushbuck was more nocturnal, particularly in areas with higher nyala occupancy. Nyala occupancy overall was higher than bushbuck. When comparing occupancies at the management level, bushbuck occupancy was higher than nyala within two survey areas: where nyala were modelled as present but populations were managed through culling, and where leopard (Panthera pardus) populations were highest. Co‐occurrence was most likely in these two survey areas, indicating a threshold of nyala occupancy up to which bushbuck were tolerant. Where nyala were present in conjunction with high leopard density, bushbuck occupancy was higher. Conversely, where leopard density was low, the cascading effect was of high nyala occupancy, with subsequent competitive exclusion of bushbuck. Our results have critical management implications for PAs, including the management of carrying capacities, the preservation of native species assemblages and habitat management. We provide evidence that a larger‐bodied sympatric species can outcompete subordinate sympatric browsers when not effectively managed, particularly where the predation effects that influence population dynamics are limited.

Neutralizing antibodies against Rift Valley fever virus in wild antelope in far northern KwaZulu-Natal, South Africa, indicate recent virus circulation.

Rift Valley fever (RVF) is a zoonotic viral disease of domestic ruminants in Africa and the Arabian Peninsula caused by a mosquito-borne Phlebovirus. Outbreaks in livestock and humans occur after heavy rains favour breeding of vectors, and the virus is thought to survive dry seasons in the eggs of floodwater-breeding aedine mosquitoes. We recently found high seroconversion rates to RVF virus (RVFV) in cattle and goats, in the absence of outbreaks, in far northern KwaZulu-Natal (KZN), South Africa. Here, we report the prevalence of, and factors associated with, neutralizing antibodies to RVFV in 326 sera collected opportunistically from nyala (Tragelaphus angasii) and impala (Aepyceros melampus) culled during 2016-2018 in two nature reserves in the same area. The overall seroprevalence of RVFV, determined using the serum neutralization test, was 35.0% (114/326; 95%CI: 29.8%-40.4%) and tended to be higher in Ndumo Game Reserve (11/20; 55.0%; 95%CI: 31.5%-76.9%) than in Tembe Elephant Park (103/306; 33.6%; 95%CI: 28.4%-39.3%) (p=.087). The presence of antibodies in juveniles (6/21; 28.6%; 95%CI: 11.3%-52.2%) and sub-adults (13/65; 20.0%; 95%CI: 11.1%-37.8%) confirmed that infections had occurred at least until 2016, well after the 2008-2011 RVF outbreaks in South Africa. Odds of seropositivity was higher in adults than in sub-adults (OR=3.98; 95%CI: 1.83-8.67; p=.001), in males than in females (OR=2.66; 95%CI: 1.51-4.68; p=.001) and in animals collected ≤2km from a swamp or floodplain compared with those collected further away (OR=3.30; 95%CI: 1.70-6.38; p<.001). Under similar ecological conditions, domestic and wild ruminants may play a similar role in maintenance of RVFV circulation and either or both may serve as the mammalian host in a vector-host reservoir system. The study confirms the recent circulation of RVFV in the tropical coastal plain of northern KZN, providing the basis for investigation of factors affecting virus circulation and the role of wildlife in RVF epidemiology.

Detection of native interferon-γ in nyala (Tragelaphus angasii): Towards diagnosing tuberculosis.

Mycobacterium bovis is the main cause of tuberculosis in wildlife. In South Africa, African buffaloes (Syncerus caffer) are a wildlife maintenance host while a number of other species are considered spillover hosts. Nyala (Tragelaphus angasii), a large antelope species from Southern Africa, is frequently traded and can be infected with M. bovis. Interferon gamma (IFN-γ) release assays that detect cell-mediated immune (CMI) responses to M. bovis infection have shown promise in elephants, rhinoceroses and buffaloes. The BOVIGAM® assay is a commercial IFN-γ release assay designed to detect tuberculosis in cattle and has been validated in buffaloes. We tested the suitability of the BOVIGAM® assay to detect native IFN-γ release in nyala. Blood samples collected from 17 nyalas were stimulated with different mitogens and IFN-γ release measured. We found that incubating whole blood with phorbol 12-myristate 13-acetate and calcium ionophore (PMA/CaI) resulted in the highest levels of IFN-y release. Samples stimulated with tuberculin purified protein derivatives of M. bovis (PPDb) and M. avium (PPDa) did not show significant IFN-γ production. An intradermal tuberculin test (IDT) and culture of tissues from 15 of the 17 culled nyala were also performed, which supported the findings of the BOVIGAM® assay, suggesting the potential value of this assay for the diagnosis of tuberculosis in nyala.

Physiological response of soybean [Glycine max (L) Merrill] to soil moisture stress

This study was done to determine the effects of varying soil moisture regimes on CO2 assimilation of soybean [Glycine max (L.) Merrill] in pots under greenhouse conditions during 2017 and 2018 cropping seasons. The experiment was conducted as a Randomized Complete Block Design (RCBD) in a 4 x 6 factorial treatment arrangement and replicated 3 times. Soil moisture regimes (80, 60, 40 and 20% of field capacity) and cultivars (Gazelle, Nyala, EAI 3600, DPSB 8, Hill and DPSB 19) were first and second factors, respectively. Collected data were subjected to Analysis of Variance (ANOVA) using Linear Mixed Model in GENSTAT. Significantly different treatment means were separated using Tukey’s test at 0.05 significance level. Leaf relative water content, stomata conductance, photosynthesis rate and sub-stomatal CO2 concentrations significantly (P < 0.001) declined with increasing soil moisture stress. Total leaf chlorophyll content increased (P < 0.001) with increased soil moisture stress. Cultivars DPSB 19 and DPSB 8 had relatively higher leaf relative water content and stomata conductance at reduced soil moisture regime at 20% moisture from field capacity indicating moisture stress tolerance potential of the cultivars. Key words: Flowering stage, podding stage, seasons, soil moisture regimes, soybean cultivars.

The foraging ecology of reintroduced African wild dog in small protected areas

Restoring large predators to small confined areas (&lt; 400 km2) is inherently complex and therefore any data on the foraging behaviour and top–down influences hold significant value for the conservation and reintroduction planning of the species. Conservation efforts are increasingly applied to small or fragmented landscapes. However, it is unclear what the effect of these small areas have on processes such as foraging behaviour as these spatial constraints may reduce the likelihood of innate predator–prey dynamics. We investigated African wild dog Lycaon pictus foraging patterns on five small fenced protected areas in South Africa. We report on the diet composition, prey preferences and potential influence of pack size and fences on the diet of African wild dogs. Data from 553 kills collected by direct observations at the five sample sites were analysed. Sixteen species of prey were recorded. A narrow dietary niche breadth was determined. Impala Aepyceros melampus and nyala Tragelaphus angasii collectively, form 75% of diet, and 67% of edible biomass. However, only nyala were significantly selected for. The mean wild dog pack sizes in our sample sites were relatively smaller than those frequently encountered in larger systems. We found that larger wild dog pack sizes did not select for larger prey. Contrary to studies investigating the influence of hard boundaries on smaller protected areas, the upward bias caused by fences on prey mass selection was inconsistent across sample sites. By characterising African wild dog diet on smaller protected areas, our results are suggestive of potential top–down influences that should be investigated by future studies. The results add to a growing body of literature that aims to assist in the reintroduction planning of endangered carnivore species.

Investigation on Theileria lestoquardi infection among sheep and goats in Nyala, South Darfur State, Sudan

اجريت هذه الدراسة فيمدينة نيالا ولاية جنوب دارفور للتقصي عن مرض الثايليريا في الضأن والماعز،. الحيونات الموجودة بصورة رئيسية هي السلالات المحلية (الصحراوى) وقليل من الهجين (السعانين والقبرص) في مختلف الاعمار، السلالة والجنس. قسمت هذه الحيوانات الي ثلاث مجموعات عمرية هي: المجموعة الاولي أقل من عمر سنة, المجموعة الثانية من عمر سنة الي سنتين, المجموعة الثالثة أكبر من سنتين. بإستخدام تقنيتين للتشخيص وهى: المسحات الدموية واختبار الاجسام المضادة المشع غير المباشربالاضافة الي تصنيف انواع القراد في الضان والماعز. جمعت 150 عينة دم لغرض المسحات الدموية والامصال. وايضا تم جمع القراد المتطفل على الحيوانات. تم فحص العينات باستخدام صبغة جيمسا للمسحات الدموية. عينات الامصال تم تحليلها باستخدام اختبار الاجسام المضادة المشع غير المباشر. اظهرت النتائج أن 9 (6%) عينة من 150 بها طور البايروبلازم للثايليريا في المسحات الدموية, 81 (54%) حالة موجبة للاجسام المضادة لثايليريا لستوكوردي. في الضأن اظهرت النتائج ان 3 (4.9%) عينة من 61 بها طور البايربلازم للثايليريا, 25 (41%) حالة موجبة للاجسام المضادةTheileria lestoquardi. بينما في الماعز نجد 6 (6.7%) عينة من 89 بها طور البايروبلازم للثايليريا، 56 (62.9%) حالة موجبة للاجسام T. lestoquardi. اعلى انتشار للبيروبلازم الثايليريا و الاجسام المضادة T. lestoquardi في الضأن سجل في الفئة العمريةاكبر من سنتين باستخدام كلا التقنيتين. اظهرت الدراسة وجود جنسين واربعة انواع من القراد الصلب في الضان والماعزهي:Rhipicephalus e. evertsi، R. s. sanguineus, Amblyommavariegatumو A. lepidum. تعتبر هذه اول دراسة تجرى لتقصي تواجد الاجسام المضادة لطفيل الثايليريا ليستوكوردي في الضان والماعز في مدينة نيالا. تواجد الاجسام المضادة لهذا الطفيل يعني ان مرض الضان الخبيث متواجد في مدينة نيالا ولا بد من وضع ذلك في الاعتبار عند تربية المجترات الصغيرة وعند إدخال هذه الحيوانات من مناطقة خالية من مرض الضان الخبيث. نواقل هذا المرض غير H. anatolicum تحتاج لتقصي خاصة في الضان والماعز والتي وجدت خالية من هذا النوع من القراد بالرغم من رصد الاجسام المضادة فيها.

Interspecific hybridization between greater kudu and nyala.

Hybridization of wildlife species, even in the absence of introgression, is of concern due to wasted reproductive effort and a reduction in productivity. In this study we detail an accidental mating between a female nyala (Tragelaphus angasii) and a male greater kudu (T. strepsiceros). The hybrid was phenotypically nyala and was identified as such based on mitochondrial DNA. Further genetic analysis based on nine microsatellite markers, chromosome number and chromosome morphology however, confirmed its status as an F1 hybrid. Results obtained from a reproductive potential assessment indicated that this animal does not have the potential to breed successfully and can be considered as sterile.

Livestock-wildlife conflicts in the Ethiopian highlands: assessing the dietary and spatial overlap between mountain nyala and cattle

Livestock grazing is an increasing conservation challenge throughout protected wildlife areas in Africa. We report here on a negative correlation in abundance between cattle and the mountain nyala across seven study areas in the Bale Mountains of Ethiopia, and investigate if this can be explained by similarity in feeding ecology and spatial overlap. Mountain nyala foraging behaviour was studied using scan sampling of 17 GPS/VHF-collared animals, while faecal sampling of both species was used to quantify abundance and spatial overlap. We found that female and male mountain nyala grazed during 87% and 50% of the feeding observations respectively. Although mountain nyala has earlier been classified as a browser, our findings indicate a feeding ecology closer to a grazer. The overall spatial overlap between mountain nyala and cattle was 22%, with a range of 2.4–100% among areas, and illegal cattle grazing was common. Based on the negative correlation in abundance, the similarity in feeding ecology and the relatively high spatial overlap we speculate that a competitive interaction between mountain nyala and cattle might occur. Our findings points to the potential for existence of a wildlife-cattle conflict also in the Ethiopian highlands, as frequently reported in savannah ecosystems. Resume Le pâturage du betail est un defi croissant pour la conservation dans toutes les aires protegees d'Afrique. Nous exposons ici une correlation negative entre l'abondance du betail et celle des nyalas de montagne dans sept zones d'etudes des Bale Mountains, en Ethiopie, et nous cherchons si cela peut s'expliquer par des similitudes d'ecologie alimentaire et par un recouvrement spatial. Le comportement alimentaire des nyalas de montagne a ete etudie par l'echantillonnage par balayage (scan sampling) de 17 individus equipes de colliers GPS/VHF, et des echantillons fecaux des deux especes furent utilises pour quantifier l'abondance et le recouvrement spatial. Nous avons decouvert que les nyalas femelles et mâles mangeaient de l'herbe pendant respectivement 87% et 50% des observations. Alors que le nyala de montagne a ete auparavant classe comme brouteur, nos resultats indiquent une ecologie alimentaire plus pres de celle d'un pâtureur. Le recouvrement spatial general entre nyalas de montagne et betail etait de 22%, l'eventail allant de 2,4 a 100% selon les endroits, et le pâturage illegal du betail etait frequent. Nous basant sur la correlation negative des abondances respectives, sur la similitude de l'ecologie alimentaire et sur le recouvrement spatial relativement eleve, nous emettons l'hypothese qu'il pourrait y avoir une interaction competitive entre les nyalas de montagne et le betail. Nos resultats indiquent qu'il est possible qu'il existe des conflits entre faune sauvage et betail aussi sur les hauts-plateaux ethiopiens, comme il y en a de frequents dans les ecosystemes de savane.