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1.
In order to elucidate the taxonomic status of the melanistic, girdled lizard, Cordylus cordylus niger, occurring in the Cape Peninsula and the Saldanha Bay area, South Africa, character variation among populations of the C. cordylus complex in the section of the Cape Province south of 32°3C latitude and west of 19°30' longitude was analysed. Variation for 92 external morphological characters at 54 localities was determined. Distinct patterns of interlocality variation were observed in only eight characters, but interestingly, these patterns were concordant in all eight cases. The observed patterns are interpreted as indicating that three phenotypic forms of the nominate species occur in the south-western Cape, namely a coastal melanistic form (= C. c. niger), occurring in insular and peninsular situations along the coast; a montane melanistic form occurring at relatively high altitudes along the western section of the Cape Fold Mountains; and the typical form (= C. c. cordylus), occurring commonly along the coastal lowlands, but also further inland at some places.  相似文献   

2.
Gene products of nine loci were examined by horizontal starch-gel electrophoresis in five samples of black mussels, Choromytilus meridionalis, from the south-western Cape coast. Allelic frequency variation for four polymorphic proteins suggests no racial differences between west and south coast populations. Mean heterozygosity (H) showed a non-significant increase from south to west coast populations. The duration of the pelagic larval stage and currents may both contribute to long-distance larval recruitment, although gene flow between neighbouring populations may be more important.  相似文献   

3.
本研究利用单向水平板淀粉凝胶电泳以我国5个固有地方绵羊品种包括湖羊(Hu)、同羊(Tong)、滩羊(Tan)、小尾寒羊(Han)、洼地羊(WD)为研究对象对X-蛋白遗传多样性进行了检测,并引用我国周边国家、地区绵羊品种为分析背景。结果表明以喜马拉雅山脉为界的亚洲东部和南部的北部群体和南部群体在编码的X(+)型的显性等位基因X频率上存在极显著差异(P〈0.01)。北部检测的群体中X等位基因频率范围为0~0.18,平均值为0.0878,包括属于藏羊和蒙古羊系统的小尾寒羊(Han)、不丹羊(Bhutan)、同羊(Tong)、湖羊(Hu)、滩羊(Tan)、洼地绵羊(WD)、Bhyanglung绵羊(Bhy)、Baruwal绵羊(Bar)、云南绵羊(Yunnan)、哈拉和林绵羊(Kh)和乌兰巴托绵羊(Ub)。南部检测的群体中X等位基因频率范围为0.2037~0.4655,平均值为0.3082,包括属于印度绵羊系统的孟加拉国绵羊(Ban)、Kagi绵羊(Kagi)、Lampuchhre绵羊(Lamp)、越南占部落绵羊(Cham)和缅甸绵羊(Mya)。本研究揭示X等位基因可作印度绵羊的标记,在绵羊群体尤其是亚洲东部和南部绵羊系统形成的研究中具有潜在的重要作用。  相似文献   

4.
The combined fish collection databases of the Albany Museum and the J.L.B. Smith Institute of Ichthyology are used to identify hotspots of endemism and threatened fish distributions in South Africa. Hotspots of fish species richness occur in the north-eastern lowveld sectors of South Africa and along the ecotone between the tropical/ subtropical and temperate faunal zones. Hotspots of endemic fish richness occur within both the tropical and temperate faunal regions, notably in the Olifants River system, Western Cape and in areas of high relief such as the Cape Fold Mountains, the Amatola-Wrnterberg (Eastern Cape), and the Drakensberg Escarpment {Kwazulu/ Natal-Eastern Transvaal). Threatened taxa are concentrated in the hotspots of endemic species richness which coincide largely with areas of major river conservation concern. There is limited scope for fish conservation within the ambit of formal (or informal) declared reserves, and the survival of the fauna depends on the success of river catchment conservation management. The value of museum collections in identifying areas of conservation concern for freshwater fishes is emphasized, and highlights the importance of well-preserved voucher specimens for biodiversity conservation.  相似文献   

5.
《African Zoology》2013,48(3):249-257
Understanding fish movement patterns and migrations is important for fisheries management as well as the identification and conservation of critical habitats. Data collected by the Oceanographic Research Institute's Cooperative Fish Tagging Project (ORI-CFTP) were used to describe the large-scale movement patterns of Lichia amia along the South African coastline. A total of 10 762 L. amia were tagged between 1984 and 2012, of which 744 (7%) were recaptured. Most tagging effort, mainly on juvenile and subadult individuals, took place along the south-eastern (i.e. Eastern Cape) and south-western (i.e. Western Cape) regions of the country during summer. Conversely, more L. amia were tagged and recaptured (mostly adults) during winter and spring (July to November) along the north-east coast (i.e. KwaZulu-Natal). Movements (dispersal distance in kilometres) by juveniles were restricted and largely confined to estuaries within the south-eastern and south-western regions of the country. There was a significant effect of fish size on distance moved (ANOVA: p<0.001), with evidence of a distinct seasonal (winter) longshore migration by adults to KwaZulu-Natal. The consequences of juvenile residency in estuarine habitats and high recapture rate of adults during a directed, seasonal spawning migration are discussed in light of improving current fisheries management.  相似文献   

6.
The giant panda faces severe threats from habitat fragmentation and isolation. Currently, giant panda populations have been fragmented into 30 habitat patches. The disappearance of isolated small populations and studies on the genetic diversity of various populations have shown that small isolated panda populations are at a high risk of dying out completely. Habitat fragmentation has seriously impaired the ability of the giant panda to resist climate changes and other natural disasters, such as large‐scale, synchronous bamboo blooming. The Min Mountains have the largest population of pandas in China, numbering 581 individuals and accounting for 52% of the total (1114) in China. Geographic isolation means that giant pandas in the Min Mountains are divided into two populations (population A in the north and population B in the south). Population B, which had only 42 individuals in 1989, is severely threatened by high‐density human populations and the loss of genetic diversity. However, we have identified an important corridor connecting the two populations. This paper explains the importance and the feasibility of reestablishing this corridor. Due to the special geographic locations of these two populations (two rivers block the migration of giant pandas between south and north), the corridor is the only passage for giant pandas in the region. Recent studies have also shown an increase of giant panda activity in the area of the corridor. However, vegetation in the corridor has been severely degraded. Bamboo forest must be restored in this area to provide food for the pandas during migration. The effects of human activities must be reduced in order to maintain panda habitat. We believe that a restored corridor will be of great benefit to the survival of giant pandas in the Min Mountains, especially for population B. Successful re‐establishment of a corridor will be a valuable model for corridor construction in the future.  相似文献   

7.
An analysis of morphological and allozyme variation in the Namaqua gecko, Pachydactylus namaquensis from southern Africa is presented. Three separately evolving lineages, well defined by morphology and allozyme variation, are identified. The isolated southern population, occurring on the southern escarpment and Cape Fold Mountains surrounding the western Little Karoo, is named P. kladamderma sp. nov., and is characterized by a slit-like ear opening, low number of granules bordering the mental (3-6) and mental and adjacent infralabials (513), the frequent (79%) occurence of the supralabial entering the nostril, and its drab brown base colouration. A northern population, occurring in southern Namibia and the Richtersveld is named P. haackei sp. nov., and is characterized by its more rounded or squared ear opening; high number of granules bordering the mental and adjacent infralabials (11-19), the general exclusion of the supralabial from the nostril (only 3.7% entry), and brighter, lighter colouration. It is further differentiated from P. kladaroderma on the basis of fixed differences at 11 allozyme loci. Both new species differ from P. namaquensis, which is mainly restricted to Little Namaqua- land, but is sympatric with P. haackei in the Lower Orange River region, by their more heterogenous dorsal scalation, smaller cloacal spurs, lack of spine-like tubercles on the lateral surfaces of the tail, and more fragile skin. The type locality of P. namaquensis is restricted to ‘the vicinity of Springbok, Little Namaqualand, Northern Cape Province, South Africa’.  相似文献   

8.
A new species of girdled lizard in the Cordylus genus is described from the south-western Cape, South Africa. Unlike other Cordylus taxa the new form usually has only two supraciliaries per side, the posterior parietals are usually separated mesially by a small post-interparietal scale and the lateral body scales are larger than the dorsal scales. The relationships of this new form to other members of the Cordylus group are discussed.  相似文献   

9.
One hundred and seventeen scrub hares, Lepus saxatilis, were examined for ixodid ticks in various regions of the Cape Province. They were infested with 18 tick species and the seasonal abundances of the immature stages of Amblyomma hebraeum, Amblyomma marmoreum, Hyalomma marginatum rufipes, Rhipicephalus appendiculatus and Rhipicephalus glabroscutatum and all stages of Rhipicephalus oculatus and the adults of a Rhipicephalus sp. (near R. oculatus) were determined. Seventy-two scrub hares on 3 farms in the Orange Free State harboured 10 ixodid tick species and the seasonal abundances of the immature stages of H. marginatum rufipes and Hyalomma truncatum and all stages of Rhipicephalus punctatus were determined. Thirty Cape hares, Lepus capensis, examined in the northern Cape Province harboured 5 tick species and the seasonal abundances of the immature stages of H. marginatum rufipes and H. truncatum were determined. Thirty-four Cape hares examined in the south-western Orange Free State carried 6 tick species and the seasonal abundance of immature H. marginatum rufipes was determined on these animals. Twenty-eight Smith's red rock rabbits examined on 2 farms in the south-western Orange Free State were infested with 7 tick species.  相似文献   

10.
Hymenosoma orbiculare, (Crustacea: Brachyura: Hymenosomatidae) a crab common in estuaries in south- and south east Africa occurs in freshwater in Lake Sibaya at depths down to 40 m. This is the only known freshwater record of this species. The population density in the lake is fairly uniform declining in shallow and very deep water with an a11erage- of 2,5 m-2 (134 Jm-2). The proportion of females in the population increases with depth. Females carry fewer eggs than estuarine populations and breeding appears to occur throughout the year. Both zoeae and adults differ morphologically from estuarine populations. These differences in breeding, biology and morphology raise the possibility that the Lake Sibaya population is specifically distinct from estuarine populations and this is discussed in relation to other instances of hymenosomatid invasion of freshwater habitats.  相似文献   

11.
We examined various measures of temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse Pterocles namaqua (presumably mostly for P. n. furvus) in South Africa. Bird-atlas maps indicating reporting-rates and extensive-counts showed that the majority of Namaqua sandgrouse concentrate in Bushmanland, in the north-western Cape Province, from December to March. From April to July the sandgrouse move north and east of Bushmanland and apparently return to Bushmanland from August to November. This west-east movement occurs at a relatively constant rate of 30-50 km per month. Only 15% of the sandgrouse ringed at an estate within the eastern part of this species range returned the following winter. Follicle diameter and brood-patch measurements increased significantly from July to August, at the time when the majority of birds leave the estate. Belly-soaking was more prevalent in early summer in Bushmanland than in any season in the east. South African populations of Namaqua sandgrouse are partial migrants which breed primarily in early summer (October - November) in Bushmanland.  相似文献   

12.
闽南牛遗传多样性及其系统地位的研究   总被引:1,自引:0,他引:1  
以中心产区简单随机抽样法在福建省漳州市漳浦县霞关乡抽取闽南牛64头,采集血样,按常规方法分离血浆和血细胞,冷冻后带回实验室-20℃保存备用。用垂直平板聚丙烯酰胺凝胶电泳(PAGE)和水平淀粉凝胶电泳技术检测21个编码血液蛋白(酶)的结构基因座的基因频率,同时引用国内外13个群体7个相同座位的研究资料,进行聚类分析,结果表明:在所检测的21个基因座中,有10个存在多型,多态位点百分比为47.62%,群体内遗传变异水平相对较高,平均杂合度为0.1593;闽南牛与东南亚牛种亲缘关系较近,证实了闽南牛是由南方黄牛和瘤牛的混血种,但可能不含有斑腾牛或巴厘牛的血统。目前应扩大保种群的数量,以维持群体内遗传传多样性。  相似文献   

13.
Teladorsagia davtiani in sheep in the south-western Cape, is recorded in the Republic of South Africa for the first time. The literature dealing with this helminth is briefly reviewed.  相似文献   

14.
Southern Africa has the richest diversity of land tortoises in the world, as well as an important radiation of pelomedusid terrapins. Total species richness has two epicentres, including the Transvaal lowveld and adjacent KwaZulu/Natal (owing to the prevalence of pelomedusid terrapins) and the Eastern and south-western Cape (owing to small testudinids). The area encompassing Lesotho, Transkei and adjacent regions, lacks testudinids for unknown reasons. Archaeological data indicates that this gap is natural, and not the result of man-induced extinctions. Endemic species are clustered in the Cape, whilst the few threatened species are more widely distributed. The majority of species is well protected in existing reserves. The small number of chelonian species in southern Africa and their relatively well-known distributions, test the efficacy of an iterative reserve selection algorithm. The presence of many allopatric (or nearly so) congeneric species leads to the selection of iterative reserves that protect peripheral populations. To avoid this, marginal records and isolated, peripheral populations should be excluded from the analysis.  相似文献   

15.
The African Penguin (Spheniscus demersus) has suffered population declines and is listed in the IUCN Red List as Endangered. The species is endemic to the coast of southern Africa, and breeding colonies are distributed on the south-western coast of Africa. Currently, African Penguins are being kept in zoo and aquarium facilities throughout South Africa. In this study, molecular genetic data based on 12 microsatellite markers from 1 119 African Penguin samples from four facilities were generated in order to determine the level of genetic variation, population structure and differentiation, and effective population size to assist in the development of an effective captive management plan. Expected heterozygosity ranged from 0.57 to 0.62, and allelic richness from 4.2 to 5.1. However, based on differences between first- and second-generation captive birds, we conclude that the ex situ population is at risk of losing genetic variability in the future and management programmes should include exchange of birds between captive facilities in order to induce gene flow and increase effective population size. Adding individuals from in situ populations should also be considered in the future in cases where these birds cannot be rehabilitated. Molecular genetic analyses of wild penguin populations should be carried out for comparison, and to ascertain to what degree ‘in situ genetic diversity’ is represented among ex situ populations. With regular resampling and analyses, the extent of the effect of processes such as genetic drift on diversity in the ex situ penguin populations will become evident.  相似文献   

16.
A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek, motivating the government to propose establishment of an Asian elephant national park. However, planning is hampered by a lack of genetic information on the remaining populations in China. We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure. We identified 237 unique genotypes (153 females, 84 males), representing 81% of the known population. However, the effective population size was small (28, range 25–32). Historic demographic contraction appeared to account for low haplotype diversity (Hd = 0.235), but moderate nucleotide and nuclear diversity (π = 0.6%, He = 0.55) was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar, Lao PDR, and Vietnam. The 5 populations fell into 3 clusters, with Nangunhe elephants differing consistently from the other 4 populations (FST = 0.23); elephants from Mengyang, Simao, and Jiangcheng belonged to a single population (henceforth, MSJ), and differed from the Shangyong population (FST = 0.11). Interpopulation genetic variation reflected isolation by distance and female-biased dispersal. Chinese elephants should be managed as 2 distinct units: Nangunhe and another combining Shangyong and MSJ; their long-term viability will require restoring gene flow between Shangyong and MSJ, and between elephants in China and neighboring countries. Our results have the potential to inform conservation planning for an iconic megafaunal species.  相似文献   

17.
In the last decades, several endangered breeds of livestock species have been re‐established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO‐recommended microsatellites of these landraces and three phenotypically similar Nordic‐type landraces and compared these breeds with central European, Mediterranean and south‐west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south‐west Asian domestication site with a south‐east‐to‐north‐west cline that is clearly steeper than the Mediterranean east‐to‐west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land‐races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long‐horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately.  相似文献   

18.
Nematodirus abnormalis is a common nematode parasite of sheep on several farms in the Caledon district of the south-western Cape and is the major species of Nematodirus on a farm in the Riviersonderend mountains of this region, yet it has never before been recorded from domestic animals in South Africa.  相似文献   

19.
裕固族的草原游牧文化(Ⅱ)——裕固族的草原生产   总被引:1,自引:1,他引:0  
研究裕固族的生产文化对保护祁连山生态环境、促进少数民族地区经济发展具有十分重要的意义。通过查阅资料表明:裕固族是一个古老的游牧民族。传统上以畜牧业生产为主,狩猎采集和农耕为辅。最早主要生活在阿尔泰山和额尔齐斯河以北的草原上,游牧于中北亚地区及中国西北的许多地方。14世纪中叶到16世纪由于瘟疫流行、战火连绵、自然灾害频繁迫使裕固族的先民们向东迁,一部分聚居在祁连山北麓的山区草原上经营畜牧业。而另一部分聚居在河西走廊的戈壁绿洲经营农业。裕固族有自己的民族传统手工业。  相似文献   

20.
The suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-Area Model (DARLAM). DARLAM's predictions are compared with the mean outcome from two global circulation models. East Africa and South Africa are considered the most vulnerable regions on the continent to climate-induced changes in tick distributions and tick-borne diseases. More than 50% of the species examined show potential range expansion and more than 70% of this range expansion is found in economically important tick species. More than 20% of the species experienced range shifts of between 50 and 100%. There is also an increase in tick species richness in the south-western regions of the sub-continent. Actual range alterations due to climate change may be even greater since factors like land degradation and human population increase have not been included in this modelling process. However, these predictions are also subject to the effect that climate change may have on the hosts of the ticks, particularly those that favour a restricted range of hosts. Where possible, the anticipated biological implications of the predicted changes are explored.  相似文献   

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