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The paper provides a summary of three studies conducted in the eastern Free State of South Africa between 1998 and 2000. In a questionnaire-based study approximately 21% of interviewed resource-poor farmers (n = 150) indicated that they experienced problems with ticks and tick-borne diseases. About 56% of farmers indicated that tick-related problems were most severe in summer, while 32% indicated that the most problems were encountered in winter. About 12% indicated that the tick problems were experienced throughout the year. Farmers also indicated that the highest tick burdens were experienced between spring and early winter. The principal ticks infesting cattle (n = 30) were found to be Boophilus decoloratus (53.1%), Rhipicephalus evertsi evertsi (44.7%), Rhipicephalus follis (1.0%), Rhipicephalus gertrudae (0.7%) and Rhipicephalus warburtoni (0.4%). On small stock (n = 188), R. evertsi evertsi (68%) and B. decoloratus (32%) were recorded as the main ticks in the study area. A sero-epidemiological survey of cattle (n = 386) showed that 94% of cattle were sero-positive for Babesia bigemina by IFAT, while 87% were sero-positive for Anaplasma by indirect ELISA. All the animals were sero-negative for Babesia bovis and this is probably because the tick vector, Boophilus microplus, is not present in the study area. All sheep and goats were sero-positive for Theileria species by IFAT while 85% of sheep and 100% of goats tested positive for Anaplasma species by competition inhibition ELISA. The high incidence of positive serological results for B. bigemina and Anaplasma in cattle, and Theileria and Anaplasma in sheep and goats and the absence of clinical cases would indicate that this area is endemically stable for these diseases. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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Grzegorz Kopij 《Ostrich》2013,84(2-4):77-79
Kopij, G. 1997. Breeding ecology of the African Spoonbill Platalea alba in the Free State, South Africa. Ostrich 68 (2–4): 77–79.

The breeding ecology of the African Spoonbill is surprisingly little known. In the Free State, the number of nesting African Spoonbills appears to have declined; 120 nests in 11 colonies were located in 1972–1973, compared to 32 nests in four colonies in 1993–1996 (though this later survey may have missed a few small colonies). In 1976–1977, a colony with 15 active spoonbill nests was monitored for an entire breeding season. Mean clutch size was 2.6 (n = 15); 56% of eggs hatched; 91% of hatched eggs resulted in fledglings; and chicks fledged from 53% of nests. The main food of spoonbill chicks was frogs, mainly Rana angolensis and Xenopus laevis, and aquatic invertebrates.  相似文献   

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We sampled small mammal assemblage in a mosaic of Valley Thicket vegetation in the Great Fish River Reserve during the summers of 2001 and 2002. Assemblage was dominated by seven rodent species with a single nonrodent species (Elephantulus edwardii) in the 357 trapped specimens. Rhabdomys dilectus was the most abundant in both years, followed by Mus minutoides (ranking 2nd in 2001) and Mastomys coucha (2nd in 2002). These three species, which are widespread generalists, made up 85.0% of the total rodent catch in 2001 and 74.3% in 2002. Individual species were captured on 2–14 sites of a total of 17 and M. minutoides was the most widespread. The majority of samples consisted of two (ten sites in a pooled sample for 2 years) or three species (ten sites). Significant morphological structuring was found only in two‐species samples. Species turnover was high both among sites and between the 2 years. We found no evidence of significant nested structure which would suggest hierarchical sets of ecological relationships among the species. Vegetation structure explained better than species interactions, the population variables in the rodent assemblage.  相似文献   

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The impact of alien tree clearing on soil and vegetation recovery remains largely understudied. This study focused on changes in soil and vegetation properties following Acacia removal. The aim was to quantify the long‐term consequences of alien clearing. Paired cleared (old – 15 years; medium – 11 years; recent – 6 years) and uncleared sites were selected along the Palmiet catchment in Eastern Cape Province, South Africa. Various soil physico‐chemical properties (soil moisture, pH, P, N, C, K, Na, Ca, Mg and soil repellency) and vegetation diversity measures were studied on 10 m × 10 m plots. Results indicate that measured soil nutrients are significantly (P < 0.05) lower in cleared than in uncleared sites. However, comparisons among cleared sites alone indicate that soil properties are recovering with older cleared sites having higher (P < 0.05) nutrients than recent cleared sites. Soils in uncleared sites are more repellent than soil in cleared sites. Vegetation recovery in cleared sites was taking place with older cleared sites having higher native species diversity than recently cleared site. We conclude that the removal of alien plants could have caused a reduction in soil nutrients. However, as native vegetation recovers on cleared sites, soil nutrients are gradually improving.  相似文献   

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Hill slope seep wetlands are ecologically and economically important ecosystems as they supply a variety of ecosystem services to society. In South Africa, livestock grazing is recognized as one of the most important disturbance factors changing the structure and function of hill slope seep wetlands. This study sought to investigate the potential effect of livestock grazing on the resilience and vulnerability of hillslope seep wetland vegetation cover using a trait‐based approach (TBA). Changes in vegetation cover were used as a surrogate for indicating grazing intensity. The degree of human disturbances was assessed using the Anthropogenic Activity Index. A TBA was developed using seven plant traits, resolved into 27 trait attributes. Based on the developed approach, plant species were grouped into vulnerable and resilient groups in relation to grazing pressure. It was then predicted that species belonging to the vulnerable group would be less dominant at the highly disturbed sites, as well as in the winter season when grazing pressure is at its peak. The approach developed enabled accurate predictions of the responses of hillslope plant species to grazing pressure seasonally, but spatially, only for the summer season. The predicted responses during the winter season across sites did not match the observed results, which could be attributed to the difficulty in species identification and accurate estimation of vegetation cover during winter. Overall, the approach developed here provides a general framework for applying the TBA and can thus be tested and applied elsewhere.  相似文献   

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Wetland assessments in South Africa continue to be undertaken at the scale of individual wetlands, while ultimately a landscape assessment is required for broader regional planning. The aim of this research was to develop probability models of degradation per wetland type using landscape-scale predictor variables. Condition data for a total of 463 seep, floodplain and valley bottom (channelled and unchannelled) hydrogeomorphic (HGM) units was combined with data for 21 potential explanatory variables for land cover, infrastructure and catchment physiography. Multiple logistic regression models to estimate the probability of degradation per HGM type were investigated at three different spatial levels (1,000?m buffer radius; 100 and 1,000?km2 scales). Models at the intermediate scale were most useful and only these are reported. Percent natural vegetation, road density, population density and altitude, together with anthropogenic land use (cultivation and forestry plantation area) were important predictors of wetland condition, and differed per HGM type. Regional patterns of degradation within quaternary catchments in KwaZulu-Natal were dissimilar for each HGM type. There is potential to refine and extend the models for application at a national level, and to predict actual condition scores using ordinal logistic regression based on larger datasets.  相似文献   

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Absolute dating of several stratigraphic levels position an infant's mandible relatively to about 29,500 years ago. This mandible may represent the infant stage of an early Negroid from of Homo sapiens afer and was probably associated with cultural material belonging to the transition of the Middle Stone Age to the Late Stone Age.  相似文献   

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We used the Braun-Blanquet method to study the vegetation of coastal wetlands in South Korea. Three habitat types were found, i.e., salt marshes, salt swamps, and sand dunes. These plant communities were classified as: 1) two groups (five associations each) in the salt marshes that comprised either annual herbaceous halophytes (ClassThero-Salicornietea), or biennial/perennial herbaceous species (ClassAsteretea tripolii); 2) one group in the salt swamps consisting of five hydrophilous halo-tolerant associations (ClassPhragmitetea); and 3) three groups in the sand dunes, including one association of annual herbaceous halophytes (ClassSalsoletea komarovii), seven associations of herbaceous perennial halophytes (ClassGlehnietea littoralis), and one association of shrub perennial halophytes (ClassVrticetea rotundifoliae). These three habitat types accounted for the majority of the six main classifications of coastal vegetation distributed in South Korea.  相似文献   

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The activity patterns of springhares Pedetes capensis ( Rodentia: Pedetidae ) from the Eastern Cape Province, South Africa, were investigated by counting the number of springhares active above ground at regular intervals throughout the night at different times of the year and under different weather conditions and phases of the moon. A combination of time of year, time of night and level of illumination best explained springhare activity, accounting for 43% of the variation in springhare numbers. Springhare activity generally reached its peak soon after dark, thereafter remaining fairly constant throughout most of the night and only decreasing in the 2–4-h period before sunrise. On those nights when the moon either rose or set during the night, this pattern was modified by the level of illumination. Springhares responded to moonlight by reducing above-ground activity, shifting activity to dark, moonless periods of the night, and by reducing their use of open space. Except for extremes, other weather conditions had no significant effect on springhare activity.  相似文献   

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Specimens of the freshwater snail Bulinus tropicus (Krauss, 1848) collected in the Free State, South Africa shed cercariae with an oral collar bearing 27 spines. Tadpoles of the African clawed toad Xenopus laevis laevis Daudin, 1802 collected from the same waters harbored metacercariae with a similar collar of spines. Adults were obtained after feeding infected tadpoles to laboratory-reared reed cormorants, Phalacrocorax africanus (Gmelin, 1789). The parasite was identified as Petasiger variospinosus (Odhner, 1910), the life cycle was experimentally completed, and stages described by the use of light and scanning electron microscopy.  相似文献   

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Coastal sand dune ecosystems are subjected to many stress and disturbance factors that are particularly high in the foredunes compared to the backdunes. Although a few studies have been conducted on eastern coastline sand dunes of South Africa, none have examined the relationship between aspect and slope on vegetation composition and soil properties of coastal forest backdunes. Vegetation and soil sampling were conducted in 11 transects, each with four plots measuring 10 × 10 m, located on the seaward and landward sides and on middle and lower slopes of backdunes of Bathurst coastal forest. A total of 39 species were identified, of which 23 were trees and shrubs, thirteen were forbs and three were grasses. The data show that both aspect and slope had limited influence on vegetation community assemblage and soil properties, but had significant effects on individual species distribution. There was a grass‐dominated community on the middle slope and a tree‐ and shrub‐ dominated community on the lower slope. These two plant communities act as the required coastal forest ecosystem engineer driving variability in soil properties between the slopes, the most prominent being high soil nutrients and moisture in the lower slopes compared to the middle slopes.  相似文献   

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We compared the gastrointestinal parasites of the baboon,Papio cynocephalus ursinus, living in montane (altitude, >1800 m) and coastal lowland (altitude, 100–200 m) habitats in Natal, South Africa, using fecal analysis. While the montane animals harbored a smaller number of species, helminth egg-output rates were higher in them than in the lowland animals. The decrease in parasite diversity with increasing altitude was expected, but the difference in helminth egg output was not. It may be due to a combination of food shortage, which characterizes the montane environment, especially at the end of winter, and the high proportion of soil-contaminated items in the diets of the montane animals.  相似文献   

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There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STAT? software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the α?=?0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (p?=?0.003), breed (p?=?0.041) and the absence of a latrine (p?=?0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aOR?=?1.89; 95% CI?=?1.07, 3.35) (p?=?0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area.  相似文献   

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