Microsatellite analysis of genetic diversity in African buffalo (Syncerus caffer) populations throughout Africa

Genetic diversity in nine African buffalo (Syncerus caffer) populations throughout Africa was analysed with 14 microsatellites to study the effects of rinderpest epidemics and habitat fragmentation during the 20th century. A gradient of declining expected heterozygosity was observed among populations in Save Valley Conservancy (Zimbabwe), and northern and southern Kruger National Park (South Africa). This was explained by a high mortality in northern Kruger National Park during the rinderpest pandemic at the end of the 19th century followed by recolonization from neighbouring populations, resulting in intermediate heterozygosity levels in northern Kruger National Park. In other populations expected heterozygosity was very high, indicating that rinderpest and recent habitat fragmentation had a limited effect on genetic diversity. From expected heterozygosity, estimates of long-term effective population size were derived. Migration rates among populations in eastern and southern Africa were very high, as shown by a weak isolation by distance and significant correlation in allele frequencies between populations. However, there were indications that dry habitats could limit migration. Genetic distances within buffalo in central Africa were relatively large, supporting their status as distinct subspecies. Finally, it was observed that the higher polymorphic microsatellites were less sensitive at detecting isolation by distance and differences in Ne, which may be a result of the high mutation pressure at these loci.     

Necropsy and parasitic findings from an adult forest buffalo (Syncerus caffer nanus) found dead in the Republic of Congo

A field necropsy was performed on a recently dead adult forest buffalo, Syncerus caffer nanus, found in the Nouabalé-Ndoki National Park, Republic of Congo. Based on the gross and histological lesions, the cause of death was determined to be conspecific fighting. Ectoparasites collected from this forest buffalo were Amblyomma sp. (larvae) and Rhipicephalus ziemanni Neumann. Endoparasites collected included a paramphistomid trematode, Carmyerius gregarius, and oocysts of Eimeria spp., paramphistomid eggs (presumably from C. gregarius), metastrongylid lungworm larvae, and strongylid eggs. Parasitic findings from this forest buffalo were compared to previous reports from savanna and forest buffalo.     

Applicability of bovine microsatellite markers for population genetic studies on African buffalo (Syncerus caffer)

The applicability of bovine autosomal microsatellite markers for population genetic studies on African buffalo was investigated. A total of 168 microsatellite markers were tested for PCR amplification on a test panel of seven African buffalo. Amplification was observed for 139 markers (83%), and 101 markers were studied further with 91 (90%) being polymorphic. The mean number of alleles per marker was 5.0 (SE = 0.2) and the mean heterozygosity per marker was 0.61 (SE = 0.03). Considering the overall high level of polymorphism, it was concluded that most bovine microsatellite markers are applicable in African buffalo.     

Basic haematological values in the African buffalo (Syncerus caffer caffer) and in the red buffalo (Syncerus caffer nanus)

Basic haematological values in 13 African buffaloes (Syncerus caffer caffer), 11 cows and 2 bulls, and in 2 red buffaloes (Syncerus caffer nanus), 1 bull and 1 cow, are reported. In the African buffalo, the erythrocyte count--mean 9.76 X 10(12) 1(-1)--ranged from 6.72 to 12.42 X 10(12) 1(-1), the haematocrit values--mean 0.391--varied from 0.32 to 0.47 and the haemoglobin content--mean 148.17--was in the range from 122.1 to 172.5 g 1(-1). For the red buffalo only individual values are given. In the African buffaloes, the leukocyte counts--mean 7.39 X 10(9) 1(-1)--ranging from 5.1 to 12.4 X 10(9) 1(-1) were slightly increased compared with man. For the red buffalo only individual values are reported. These values are compared with data abstracted from the literature for related buffalo species. The age-dependent decrease of erythrocyte counts and the age-dependent rise of the eosinophile proportion in the differential count are discussed.     

Variation of group size among African buffalo herds in a forest-savanna mosaic landscape

Documenting within species group size variation is important to completely understand social organization within species and to interpret variation among species. Here, I investigated group size of African buffalo Syncerus caffer over 2 years in a heterogeneous landscape. African buffalo use closed continuous forest and vast open savannas, and anecdotal observations suggest that habitat type influences their social structure. While the Cape buffalo Syncerus caffer caffer is well studied, few data exist for the forest-dwelling Syncerus caffer nanus . I observed forest buffalo at Lopé National Park, Gabon, and examined variation of group size. Eighteen forest buffalo herds used the study area with an estimated population of 342 individuals (∼5 buffalo km⁻²). The mean group size for the 18 herds was 12 ± 2 (range of means=3–24), considerably smaller than Cape buffalo herds. For eight radiocollared forest buffalo, the mean group size was stable, varying little with time of day, across seasons, or between savanna and marsh habitat. However, herd size varied widely across herds, from fewer than 10 individuals in the smallest herds to more than 20 buffalo in the largest. Large herd size is associated with home ranges that contain substantial areas of open habitat, and thus more food resources than forested habitats.     

Potential effects of prescribed savannah burning on the diet selection of forest buffalo (Syncerus caffer nanus) in Lopé National Park,Gabon

Seasonality and management are factors that may affect the diet selection of the forest buffalo (Syncerus caffer nanus). Fire is considered a major driving force in savannah systems and prescribed burning is a commonly applied conservation tool in protected areas such as Lopé National Park, Gabon. Prescribed annual fires contribute to the maintenance of open areas and provide high‐quality forage for forest buffalo, a major herbivore in the park. We used microhistological faecal analysis to determine the diet selection of forest buffalo and measured the extent of variation between a dry season, preburn and a wet season, postburn sampling period. The buffalo diet comprised mainly of monocotyledons, primarily grasses (Poaceae) and sedges (Cyperaceae). Intake of open‐area‐associated plant species was higher in the wet season, postburn treatment sampling period (97%) than the dry season, preburn sampling period (87%), which corresponded conversely to a reduction in forest‐associated Marantaceae plants (10% versus 1%). High proportions of grasses and sedges in the diet signify the importance of open areas for forest buffalo. Controlled burning as tool for maintenance of open areas may play a key role in the meta‐population management of the forest buffalo.     

Seasonal variation in forages utilized by the African buffalo (Syncerus caffer) in the succulent thicket of South Africa

The succulent thicket of the Eastern Cape, South Africa, is characterized by densely wooded vegetation that is dominated by succulents with little understory of ephemeral and weakly perennial grasses and forbs. Studies have developed around the question: how do bulk grazers such as the African buffalo (Syncerus caffer) survive in the succulent thicket? In this study, the diet of the African buffalo at the Great Fish River Reserve (GFRR) was studied in two seasons (wet and dry). The diet profile was assessed from faecal matter, using the micro‐histological analysis method. During the wet season, grass species contributed 72% to the diet while 28% was contributed by browse species. In the dry season there was a significant increase in the intake of browse by 5% (χ² = 19.94, df = 11, P < 0.05). There were species that were neglected in the wet season but became principal dietary items in the dry season, these included Setaria neglecta, Cymbopogon plurinodis, Capparis sepiaria and Portulacaria afra. Diet quality, as estimated from faecal samples, suggested that the buffalo were nutritionally stable; however, the presence of sarcoptic mange in the buffalo suggests nutritional stress.     

Population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) in Chebera Churchura National Park,Ethiopia

An investigation of population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) was carried out in the Chebera Churchura National Park, Ethiopia during the wet and dry seasons of 2005–2006. Sample counts of African buffaloes were carried out in an area of 1,215 km². The estimated population of buffalo was 2,617 individuals. Males comprised 35.0%, while females 52.8% of the population. The remaining 12% of the population was young of both sexes and of all ages of unknown sex. It was difficult to categorize the young into male and female in the field, as their primary sexual characteristics were not easily visible. Male to female sex ratio was 1.00 : 1.51. Age structure was dominated by adults, which constituted 72.06% of the total population. Subadults comprised 22.02%, and young accounted for 5.9% of the population. Larger herds of up to 27 individuals were observed during the wet season and smaller herds of eight individuals during the dry season. The mean herd size during wet and dry seasons was 24.81 and 7.77, respectively. The African buffaloes were distributed in four habitat types such as grasslands, woodlands, montane forests and riverine habitat in the study area. They were observed more in the riverine vegetation types during the dry season. Relative abundance of food resources, green vegetation cover and water availability in the area were the major factors governing their distribution in the present study area. They spent a greater proportion of the time in feeding and resting/ruminating activities. On the average, 49.7% of the daytime was spent in feeding, and 38.75% of the day on resting (lying down and standing). Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season.     

A comparison of the grazing preferences of buffalo (Syncerus caffer) and Ankole cattle (Bos indicus) on three different pastures

Observations of the diet of cattle and buffalo grazing three different pastures of known composition and history were made at the height of the rainy season in Acacia-Cymbopogon/Themeda dry savanna in Ankole, Uganda. Brachiara decumbens, Chloris gayana, Cynodon dactylon, Digitaria melanochila and Setaria aequalis were frequent species which were highly acceptable to both buffalo and cattle. Themeda triandra was highly acceptable to cattle but less so to buffalo. Leersia hexandra, a swamp grass, was eaten by buffalo but the cattle did not graze in wet areas. Loudetia kagerensis and Cymbopogon afronardus were largely unacceptable to both species of animal, although buffalo showed a greater tolerance of C. afronardus than did the cattle. It is suggested that both species of animal showed a need to vary their diet periodically and buffalo chose C. afronardus whereas the cattle browsed A cacia bushes for this purpose. The quantities ingested were small. Preferences of both species of animal varied with choice available and its physical condition. The pretreatment of herbage by other species of animals is considered important in affecting its acceptability. Cattle and buffalo appeared to be competitive for food in the three environments in this study but the buffalo utilized certain environments e.g. standing water, tree shade, to a greater extent than the cattle and so represented an overall improvement in the secondary productivity from the area.     

龙脑香热带雨林附生苔藓沿宿主垂直梯度的微生境偏好及其指示作用

该研究首次借助林冠塔吊调查了西双版纳国家级自然保护区龙脑香热带雨林样地内69棵树13个垂直高度上的附生苔藓植物,结果表明:目标样树上共记录到隶属于25科60属的90种附生苔藓,其中细鳞苔科物种数最多,占比达25.6%。13个垂直高度上共划分出三种生态类型:喜阳苔藓(散生巨树上45 m的区域),喜阴苔藓(乔木树干上15 m的区域),广布苔藓(广泛分布于宿主各个垂直高度上,生态位宽),并筛选出对微生境有特殊偏好的17种苔藓指示种(IndVal≥0.7,P0.05)。随宿主垂直高度的升高,扇型和交织型的苔藓占比降低,悬垂型苔藓占比先升高后降低,细平铺型和粗平铺型的苔藓占比升高。大气湿度、水汽压、胸径以及树皮粗糙度对附生苔藓生活型的分布偏好具有显著影响。总之,沿宿主垂直高度上的附生苔藓对微环境变化在生活型和形态结构上有着不同的响应方式,而同一种生态型的苔藓群落有相似的适应机制。因此,在森林林冠生境变化的监测和管理中,对微生境具有明显偏好的附生苔藓物种可作为有效的指示材料。     

老龄阔叶红松林下层木空间分布的生境关联分析

基于老龄阔叶红松林30 hm2(500 m×600 m)固定监测样地,分析了老龄阔叶红松林下层(1 cm≤DBH≤5 cm)14个主要树种(个体数>300)的空间分布与空间距离、地形因子及郁闭度之间关联性。结果显示:(1)14个种都显示出了聚集分布,绝大多数种呈现出了在小距离级上呈显著正空间自相关大距离级上呈现显著负空间自相关的趋势。(2)6个种显示与空间距离显著相关即存在本身的聚集效应,占被检验种的42.86%;7个种显示出与环境(地形、郁闭度)有显著相关性即存在显著的生境偏好,占50%。个体数大于1000的7优势种中有5个种空间分布与生境显著相关,5个种与空间距离显著相关。(3)色木槭、千金榆显示出了对低海拔、向阳坡生境类型的偏好,簇毛槭、花楷槭、毛榛显示出对高海拔、坡度陡、向阴坡生境类型的偏好。这表明,老龄阔叶红松林下层木多数树种为聚集分布,其聚集性的空间分布受生境及自身聚集效应的重要影响。多个树种对同种生境的偏好体现了植物利用资源的相似性和生态位的重叠,对不同生境的偏好体现了物种间的排斥性,这是长期适应不同微环境,利用不同空间资源的结果,也是生态位分离的反映。     

Habitat preferences and diet in the predatory Coccinellidae (Coleoptera): an evolutionary perspective

Coccinellids (ladybird beetles) exhibit considerable diversity in habitat and dietary preference and specificity. This is evident even when comparing species within some coccinellid genera. Resource limitation and competition are suggested as of greatest importance in the evolution of coccinellid habitat preferences. Dietary and habitat specialization has probably occurred in some lineages within broader preferences possessed by generalist ancestors, to avoid the costs associated with migration between habitats and prey switching. Feeding in atypical habitats, on alternative food, when optimal prey are scarce, is likely to have been of great importance in facilitating evolutionary shifts to novel diets and habitats. The broad host ranges of many coccinellid parasitoids and observed interspecific differences in parasitoid prevalence resulting from physiological differences between coccinellid species argue that enemy free space has been of limited importance in habitat and prey shifts in this group. Rapid change may occur in coccinellid foraging patterns, perhaps due to conditioning, and coccinellids may swiftly adapt to new habitats through selection acting on the expression pre-existing traits. Diet, as a determinant of coccinellid migration and gene flow, is likely to affect probable modes of speciation in different coccinellid groups. Parapatric speciation and possibly sympatric speciation are suggested as of possible importance in the genesis of new coccinellid species through prey and habitat shifts.