首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 281 毫秒
1.
Whittington-Jones, C.A. 1997. Apparent range expansion of the Redbilled Quelea Quelea quelea in the Eastern Cape Province of South Africa. Ostrich 68 (2–4): 97–103.

Distribution records obtained from the South African Bird Atlas Project (SABAP) and from published literature show that the known distribution of Redbilled Quelea in the Eastern Cape has changed dramatically over the last century. Increased search effort following the initiation of SABAP may explain the range expansion, but changes in agricultural practice have probably been a contributing factor.  相似文献   

2.
《Ostrich》2013,84(3):295-296
The Red-billed Quelea Quelea quelea is a serious pest of agricultural crops throughout most of sub-Saharan Africa. Since the 1980s, it has expanded its range into the Eastern Cape and Western Cape, South Africa, facilitated by changes in agricultural practices. This note documents the first breeding of Red-billed Quelea in the winter rainfall region of South Africa. A colony of 350–600 nests was found, with evidence of recent breeding. Red-billed Quelea numbers were low in this region, but if numbers increase in the future in the Western Cape, winter crops could be under threat.  相似文献   

3.

A new chigger mite species, Schoutedenichia microcebi n. sp. is described from the grey mouse lemur Microcebus murinus (J.F. Miller) from Madagascar. The new species is closely related to S. dutoiti (Radford, 1948), a species described from a single specimen collected on a rodent in South Africa. Examination of the holotype and new material on S. dutoiti from South Africa enabled us to re-describe this species and provide new data on its hosts and geographical distribution.

  相似文献   

4.
A. Clark 《Ostrich》2013,84(4):251-253
Clark, A. 1974. Plumage changes in the male Maccoa Duck. Ostrich 45: 251–254.

Maccoa Duck Oxyura mi ccoo counts made at various waters in the Transvaal and Orange Free State, South Africa, in which the numbers are separated according to plumage, are presented and discussed in the light of the work done by Siegfried (1968, 1970) on this species. Males invariably outnumber females and the indications are that Transvaal birds move out of the area during winter when most males are in non-breeding plumage. There is little difference in the pattern of plumage changes between Transvaal and Cape birds.  相似文献   

5.
D. T. Cole 《Ostrich》2013,84(4):189-192
Boshoff, A. F. &; Palmer, N. G. 1983. Aspects of the biology and ecology of the Osprey in the Cape Province, South Africa. Ostrich 54:189-204.

Information gathered opportunistically on the distribution, habitat, density, seasonality, timing of migration, food spectrum, feeding and hunting behaviour and periodicity, flight mode, influence of weather on hunting activity, interspecific and intraspecific interaction, general behaviour and conservation status of the Osprey Pandion haliaetus in the Cape Province, South Africa, is presented. The species is confined mainly to the coastal region and was recorded most frequently from the larger estuaries. Although it is basically a non-breeding migrant to the area, with peaks of occurrence during the austral summer, birds were recorded throughout the austral winter. A maximum density of 0,0028 Osprey/ha of surface water was determined; there is some evidence for an increase in the number of birds in the main study area from 1980 to 1982. The birds are persistent hunters and forage mainly in the littoral zone at water depths of up to 1,5 m, with a hunting activity peak at mid morning and at late afternoon. The food spectrum comprised 84–91% mullet (Mugilidae) of 20–700 g and 9–14% Mozambique Tilapia Oreochromis mossambicus. Flapping flight was preferred for hunting purposes and the implications of this are discussed. The study area is considered to provide optimal foraging conditions of windspeed and cloud cover for Ospreys. There was little aggressive interaction between Ospreys and resident Fish Eagles Haliaeetus vocifer and competition between these two species was not a major factor. Kelp Gulls Larus dominicanus harassed Ospreys with grey. The conservation status of Ospreys in the Cape Province is considered to be satisfactory at present.  相似文献   

6.
7.
A. J.F.K. Craig 《Ostrich》2013,84(1-3):123-131
Craig, A. J. F. K. 1985. The distribution of the Pied Starling, and southern African biogeography. Ostrich 56:123-131.

The Pied Starling is restricted to South Africa, Lesotho and Swaziland, but within this region it occupies a variety of habitats. Its modern distribution is certainly influenced by its association with man. However, a comparison with other vertebrate species, and with patterns of plant distribution, suggests that its geographical distribution has been determined primarily by its evolutionary history. A hypothesis for the origin of this species leads to several predictions concerning biogeography in southern Africa.  相似文献   

8.
Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.  相似文献   

9.
The genus Laminaria has a wide distribution range compared with other kelp genera because it is found in both the North and the South Atlantic, on both sides of the North Pacific, as well as in the Mediterranean. Hypotheses behind this biogeographical pattern have been discussed by several authors but have not yet been fully evaluated with time‐calibrated phylogenies. Based on the analysis of four molecular markers (ITS2, rbcL, atp8 and trnWI), our goal was to reassess the Laminaria species diversity in South Africa, assess its relationship with the other species distributed in the South Atlantic and reconstruct the historical biogeography of the genus. Our results confirm the occurrence of a single species, L. pallida, in southern Africa, and its sister relationship with the North Atlantic L. ochroleuca. Both species belonged to a clade containing the other South Atlantic species: L. abyssalis from Brazil, and the Mediterranean L. rodriguezii. Our time‐calibrated phylogenies suggest that Laminaria originated in the northern Pacific around 25 mya, followed by at least two migration events through the Bering Strait after its opening (~5.32 mya). Today, the first is represented by L. solidungula in the Arctic, while the second gave rise to the rest of the Atlantic species. The colonization of the North Atlantic was followed by a gradual colonization southward along the west coast of Europe, into the Mediterranean (~2.07 mya) and two recent, but disconnected, migrations (~1.34 and 0.87 mya) across the equator, giving rise to L. abyssalis in Brazil and L. pallida in southern Africa, respectively.  相似文献   

10.
Largemouth bass Micropterus salmoides are a popular North American angling species that was introduced into South Africa in 1928. To enhance the largemouth bass fisheries, Florida bass Micropterus floridanus were introduced into KwaZulu Natal, South Africa, in 1980. Knowledge on the status of M. floridanus in South Africa is required, because it lives longer and reaches larger sizes than M. salmoides, which may result in heightened impacts on native biota. Because M. floridanus are morphologically similar, but genetically distinct from M. salmoides, the distribution of this species was assessed by genetically screening 185 Micropterus sp. individuals sampled from 20 localities across South Africa using the mitochondrial ND2 gene. Individuals with mitochondrial DNA matching M. salmoides were recovered from 16 localities, whereas M. floridanus mitochondrial DNA was recovered from 13 localities. At nine localities (45%), the mitochondrial DNA of both species was detected. These results demonstrate M. floridanus dispersal to multiple sites across South Africa.  相似文献   

11.
Capsule Long-distance migrant birds show less favourable trends than sedentary/short-distance species.

Aims To use breeding bird surveys to contrast population trends amongst common species according to their migration pattern.

Methods Changes in abundance of 62 Danish breeding sedentary, short-distance (Europe/North Africa) or long-distance (trans-Saharan) migrants were described by fitting log linear regression models to point-count census data gathered during 1976–2005.

Results Trans-Saharan migrants declined by 1.3% per annum during this period, while short-distance migrants and sedentary species increased by 1.4% and 1.0% per annum, respectively. There were no significant decadal declines amongst species using different summer breeding habitats, except for wetlands, and there was no consistent variation in trends associated with wintering regions or habitats or diet.

Conclusions More information is urgently needed on diet, feeding ecology, habitat requirements, winter distribution and intra-African movements of the commoner European summer visitors to identify causes of the declines and highlight when in the annual cycle detrimental effects occur. Studies linking individuals on their breeding, staging and wintering grounds are especially needed. Danish trends resemble those from elsewhere in Europe, confirming that restoration to favourable conservation status requires inter-continental action to meet European and global targets to reduce or halt biodiversity loss.  相似文献   

12.
13.
Oschadleus, H.D., Underhill, G.D. & Underhill, L.G. 2000. Timing of breeding and primary moult of the Masked Weaver Ploceus velatus in the summer and winter rainfall regions of South Africa. Ostrich 71 (1 & 2): 91–94.

Timing of breeding and moult is analysed in the Masked Weaver Ploceus velatus. It is common throughout southern Africa, which is largely a summer rainfall area. This species expanded its range into the Western Cape, a winter rainfall region, in the twentieth century. The peak breeding period is one month earlier in the winter rainfall area (September to November) than in the summer rainfall area (October to December). The mean starting date of primary moult is one month earlier in the winter rainfall area (9 January) than in the summer rainfall area (15 February). The duration of primary moult is similar in both regions (74 days in the winter rainfall area and 80 days in the summer rainfall area).  相似文献   

14.

Ecological niche modelling (ENM) has been used to quantify the potential occurrence of species, by identifying the main environmental factors that determine the presence of species across geographical space. We provide a large-scale survey of the distribution of ostracod species in South America, by using the domains of 25 river basins. From 221 known ostracod species, we estimate the potential distribution of 61 species, using ENM. Ten clusters of potential distribution patterns were found. Clusters 8 and 9 grouped most of the species, which presented high similarity of niche between them. Heterocypris paningi Brehm, 1934 (group 1) obtained higher niche variability. The minimum temperatures of the coldest month and the mean elevation of the river basin were most important to predict the potential distribution of ostracods of most groups. South America has a complex pattern of elevation, which affects species distributions indirectly through changes in local factors. For instance, the Andes mountains might impose a barrier for ostracod distribution in the southern part of South America because of the low temperatures and precipitation. The ENM indicated that some regions and/or basins of South America might be susceptible to the entry of several ostracod species, presently absent, including non-native species.

  相似文献   

15.
C. Wyndham 《Ostrich》2013,84(1):1-5
Clark, A. 1974. The status of the whistling ducks in South Africa. Ostrich 45:1-4. Since the 1920's the status of Dendrocygna viduata and D. bicolor has changed from that of an irregular to that of a regular species in the Transvaal, Zululand, Natal and Orange Free State. In more recent years their numbers have shown a steady increase and breeding has been established. D. viduata numbers built up more quickly than D. bicolor and it has become an established resident whereas D. bicolor is primarily a summer visitor.

In the Western Cape Province there has been little change in the status of either species but there are indications that D. viduata is appearing mote regularly in the Eastern Cape Province. The position in East Griqualand and the Transkei is obscure. In South West Africa, excluding the north east corner, D. viduata remains irregular and D. bicolor rare.

The preference shown by both species for areas where sewage effluent is disposed of and for new storage dams inevitably links their spread and increase with that of the human population.  相似文献   

16.

Nearly 20 000 specimens of pseudoscorpions from a full range of habitats have been examined. For New Zealand, 70 species and subspecies in 28 genera are recognised, and for Norfolk and Lord Howe Islands, 11 species in 9 genera. Endemism is very high in this area: in New Zealand, 13 out of 25 indigenous genera are endemic; 2 others (Apatochernes, Nesochernes) are shared with Norfolk Island; and 4 (Sathrochthonius, Austrochthonius, Synsphyronus, Protochelifer) extend their distribution to Australia (Austrochthonius is known also from South America and South Africa). The rest of the native genera have a wider distribution in the Pacific. Three species (Lamprochernes savignyi, Withius subruber, Chelifer cancroides) have a wide and disjunct distribution induced by human traffic, and are considered to be an introduced element.  相似文献   

17.
D. C. H. Plowes 《Ostrich》2013,84(2):111-121
Van Zyl, A.J, Jenkins, A.R. &; Allan, D.G. 1994. Evidence for seasonal movements by Rock Kestrels Falco tinnunculus and Lanner Falcons F. biarmicus in South Africa. Ostrich 65:111-121.

Patterns of seasonal movement by Rock Kestrels Falco tinnunculus and Lanner Falcons F. biarmicus in South Africa were determined using data from the Southern African Bird Atlas Project, road transect counts, ringing recoveries and other sources. Both species were found to be partial, facultative migrants, and Lanner Falcon movements involved mostly immature birds. Rock Kestrels were found to concentrate in the southwest of the country in the breeding season, and to move north and east in the non-breeding season. Lanner Falcons concentrated in the east of the country during the breeding season, and moved into the west in the non-breeding season. The movement by both species into the arid northwest of the country is probably associated with dramatic increases in prey abundance, in turn associated with summer rah events. Lanner Falcon movement into the southern Cape apparently coincides with cereal farming practices, affecting the availability of prey (granivorous birds and rodents). Rock Kestrel movement into the east of the aunt is probably to exploit increases in insect abundance mated with summer rain. The pattern of Rock Kestrel movements suggests that it does not compete for food with the Lesser Kestrel F. naumanni. a Palearctic migrant to the east of the country.  相似文献   

18.

Neoalbionella Özdikmen, 2008 comprises 10 accepted species, which all infect sharks of Squaliformes and Carcharhiniformes. Adult females belonging to species of Neoalbionella, based on the maxillule palp armed with three setae and the maxilliped subchela claw with only one secondary denticle, were collected from sharks off the coast of South Africa. Neoalbionella izawai n. sp. collected from the anterodorsal part of the spiracle opening of Centrophorus moluccensis Bleeker differs from its congeners by having maxillae that are separated except at the tapering tips where they are fused and that are longer than the trunk, uropods originating from the pointed posterior margin of the trunk and that are well developed, and maxillipeds without an additional spine at the base of the subchela barb. Neoalbionella etmopteri (Yamaguti, 1939) is herein reported from two new hosts (Etmopterus spp.) off South Africa.

  相似文献   

19.
Prevention is the best way to slow the escalation of problems associated with biological invasions. Screening of potential introductions is widely applied for assessing the risk of species becoming invasive. Despite advances in the understanding of the determinants of invasiveness, screening still relies heavily on assessments of the potential of species to ‘fit in’ to the broad environmental conditions of a target region. Most screening systems ask whether species are native to, or are known to be naturalized or invasive in, regions with ‘similar’ climatic/environmental conditions to the target region. The level of similarity required to make the species a high‐risk introduction is generally not specified. This paper describes a protocol for making such assessments more objective, using South Africa as a test case. Using nonparametric niche‐based modelling (generalized additive model; GAM) calibrated on the current distribution of each South African biome, we mapped regions of the world that are climatically similar to South African biomes. Lists were produced of countries with the largest areas climatically similar to South Africa overall, and to each biome separately. Validation of the usefulness of the approach was sought by evaluating whether the main invasive plant species in South African biomes occur naturally, or have adventive ranges, in regions mapped as analogous to South African biomes. A very large part of the world is climatically similar to South Africa, with eight countries having larger areas of land classified as climatically similar to South African biomes than the total area of South Africa. Almost all the most prominent invasive species in South African biomes occur naturally or are invasive outside their natural range in areas with similar climates to those that occur in parts of South Africa. This confirms the value of objective climate matching in screening protocols. We examined climatic conditions for a representative sample of major invasive plants from other parts of the world. The analysis identified several species that are already invasive in regions that have matched climates in South Africa but that are not yet introduced or, if already present, have not yet invaded large areas. For example, the following known invasive species should be considered high‐risk species in South African grasslands: Alliaria petiolata, Cytisus scoparius, Gleditsia triacanthos, Heracleum mantegazzianum, Hieracium pilosella, Juniperus communis, Pinus contorta, P. monticola, P. ponderosa, P. sylvestris, Prunus laurcerasus, and P. serotina. Objectively matched climatic regions are also useful as a first‐cut assessment when evaluating species with no invasive history.  相似文献   

20.
Abstract

Prevention and early detection are considered to be the most effective means of managing non-native invasive species that have serious ecological and economic impacts. Consequently, the study of those taxa that are still in an early stage of invasion but are highly likely to spread and to have a significant adverse impact in future is becoming an increasingly important issue in both the research on and management of invasive species. In Italy, one such species is Arctotheca calendula (L.) Levyns, a herbaceous plant of the Asteraceae family that is native to South Africa. Here, we present an overview of current knowledge on the distribution and potential impacts of this species in Italy, and we outline some features that are crucial to understanding and preventing its invasive spread.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号