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1.
Spatial and temporal variations in vegetation are examined in relation to land tenure, population increase, and rainfall variation in a part of Peddie district, Eastern Cape. Sequential aerial photographs between 1938 and 1988 are analyzed to determine trends in vegetation and population change in three different land-tenure units. The areal extent at each date of four distinct vegetation categories is determined using PC ARC/INFO GIS. Long-term annual rainfall trends for the area are analyzed and juxtaposed with vegetation changes. Extensive ground-truthing exercises are carried out to verify the present condition of vegetation condition in terms of cover and species composition. Differences in land-tenure systems are discerned as the dominant factor controlling variations in vegetation degradation. The study also reveals that neither population changes nor rainfall variations can explain the observed trends in vegetation degradation. Earlier injudicious land-use practices, sustained since the turn of the last century, may provide plausible explanations for the trends and present status of vegetation degradation in the area.  相似文献   

2.
Municipal commonages surround many small towns throughout South Africa, and are an integral component of the national land reform programme. But little is known about their extent, use or value, and most appear to have limited or no management or investment. This paper reports on a survey of randomly selected households in three small towns in the Eastern Cape to ascertain the extent and purpose of use of municipal commonages. Between 27% and 70% of urban households used commonage depending on site. Key resources used were fuelwood, medicinal plants, and grazing of livestock. Typically, commonage using households were poorer and less educated than other urban residents, although the profile of users is unique for each town. Given the extensive use of commonage resources, and their contribution to the livelihoods of the poor, local municipalities need to develop and implement sound management strategies that account for all users of commonages, rather than the oft encountered focus on livestock owners and production.  相似文献   

3.
4.
Despite the popularity of local economic development (LED) as a job creation and economic growth strategy in South Africa, many LED projects have not proved to be sustainable in the long-run, especially where human systems interact with biological ones. This article examines the relationship between sustainability and LED within the context of the emerging honeybush tea industry in the Eastern Cape. Data were gathered from provincial as well as local government policy documents and reports, and via key informant interviews. The data were analysed using Connelly’s [(2007). Mapping sustainable development as a contested concept. Local Environment, 12 (3), 259–278] three pronged approach to sustainable development as a lens through which to view the local industry. Findings showed that the industry offers many opportunities for development, including job creation in poorer, rural households; sustainable wild harvesting using a permit system; commercial cultivation; potential to develop social capital; potential for community-based LED; and product diversification. However, there are also corresponding challenges: There is currently no reliable data on the maximum sustainable yield, which is needed to guide quota allocations for entrepreneurial harvesters harvesting from wild stocks; possible biodiversity loss; and enforcing the permit scheme is proving difficult in remote rural areas.  相似文献   

5.
Heavy metal concentrations in black mussels (Mytilus galloprovincialis) collected from Cape Town Harbour were determined using energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma-mass spectrometry (ICP-MS). EDXRF showed that tissue portions of the mussels contained K, Ca, Fe, Cu, Zn, Si, Sr, Al and Au, while the shell portion contained K, Ca, Fe, Cr, Zn, Si and Sr. In addition to these metals, EDXRF also revealed the presence of Al in the shells of the largest mussels. Highest concentrations of Cu and Zn were recorded in the tissues of the smallest mussels. Due to poorer detection limits of EDXRF, ultra-trace elements (Mn, Pb, As, Hg, V, Cr, Sn, Cd, Ni and Co) were determined in mussels using ICP-MS. The average metal concentrations found in the mussels are as follows; Pb (7.30 ± 0.67), Cd (1.98 ± 0.13), Hg (4.92 ± 0.60), As (6.94 ± 0.04), Sn (2.63 ± 0.13), Ni (1.88 ± 0.05), Cr (3.54 ± 0.05), V (4.17 ± 0.23), Co (0.74 ± 0.01) and Mn (35.20 ± 1.46). ANOVAs, Pearson correlation and principal component analysis (PCA) were employed in data analysis. The order of the abundance of metals in the mussels is Mn > Pb > As > Hg > V > Cr > Sn > Cd > Ni > Co. The average metal concentrations found in the mussels were higher than the permissible Food and Agriculture Organization (FAO) limits and other international guidelines.  相似文献   

6.
We studied stormwater detention basins where woody vegetation removal was suspended for 2 years in Virginia, USA to determine if woody vegetation can control Typha populations and how early woody plant succession interacts with Typha, other herbaceous vegetation, and site factors. Distribution and composition of woody vegetation, Typha and non-Typha herbaceous vegetation biomass, and site factors were assessed at 100 plots in four basins ranging in age from 7 to 17 years. A greenhouse study examined the interaction of shade and soil moisture on Typha biomass and persistence. Principal component analysis identified an environmental gradient associated with greater water table depths and decreased elevation that favored Typha but negatively influenced woody vegetation. Elevation was correlated with litter layer distribution, suggesting that initial topography influences subsequent environmental characteristics and thus plant communities. Soil organic matter at 0–10 cm ranged from 5.4 to 12.7 %. Woody plants present were native species with the exception of Ailanthus altissima and Pyrus calleryana. In the greenhouse, shade and reduced soil moisture decreased Typha biomass and rhizome length. The shade effect was strongest in flooded plants and the soil moisture effect was strongest for plants in full sun. Typha in dry soil and heavy shade had 95 % less total biomass and 83 % smaller rhizomes than Typha in flooded soil and full sun, but even moderate soil moisture reductions decreased above- and below-ground biomass by 63 and 56 %, respectively. Suspending maintenance allows restoration of woody vegetation dominated by native species and may suppress Typha invasion.  相似文献   

7.
This study presents the results of a comparative life cycle assessment (LCA) on the energy requirements and greenhouse gas (GHG) emission implications of recycling construction and demolition (C&D) rubble and container glass in Cape Town, South Africa. Cape Town is a medium sized city in a developing country with a growing population and a rising middle class, two factors that are resulting in increased generation of solid waste. The City is constrained in terms of landfill space and competing demands for municipal resources.The LCA assessment was based on locally gathered data, supplemented with ecoinvent life cycle inventory data modified to the local context. The results indicated that recycling container glass instead of landfilling can achieve an energy savings of 27% and a GHG emissions savings of 37%, with a net savings still being achieved even if collection practices are varied. The C&D waste results, however, showed net savings only for certain recycling strategies. Recycling C&D waste can avoid up to 90% of the energy and GHG emissions of landfilling when processed and reused onsite but, due to great dependence on haulage distances, a net reduction of energy use and GHG emissions could not be confidently discerned for offsite recycling. It was also found that recycling glass achieves significantly greater savings of energy and emissions than recycling an equivalent mass of C&D waste.The study demonstrated that LCA provides an important tool to inform decisions on supporting recycling activities where resources are limited. It also confirmed other researchers’ observations that strict adherence to the waste management hierarchy will not always result in the best environmental outcome, and that more nuanced analysis is required. The study found that the desirability of recycling from an energy and climate perspective cannot be predicted on the basis of whether such recycling conserves a non-renewable material. However, recycling that replaces a virgin product from an energy-intensive production process appears to be more robustly beneficial than recycling that replaces a product with little embodied energy. Particular caution is needed when applying the waste management hierarchy to the latter situations.  相似文献   

8.
应用修正过的土壤流失方程(USLE),在GIS技术的支持下,确定了淮北地区的降雨因子、土壤侵蚀因子、植被覆盖因子、水土保持因子和坡度坡长因子,估算了这一地区的水土流失模数,评价了区域内土壤侵蚀分布特征,以期为本区水土保持布局提供理论支持.  相似文献   

9.
以Landsat MSS(1976年)、TM(1990年)、ETM+(2002年)三期遥感数据为主要信息源,在RS和GIS技术的支持下,监测汾河水库上游区域在1976-2002年的水土流失变化情况。结果表明,1976—1990年研究区水土流失程度加剧;1990-2002年水土流失状况整体好转,局部区域仍在发展。目前,汾河水库仍有71.88%的水土流失面积有待治理,水土保持任务仍很艰巨。  相似文献   

10.
The attitudes and behaviours of private landholders toward the conservation of a highly transformed and critically endangered habitat, Overberg Coastal Renosterveld (OCR) (a grassy shrubland of the Cape Floral Region, South Africa) are described. Personal, semistructured interviews were conducted with landholders, representing 40 properties in the Overberg region, on topics such as management and utilisation of OCR, the depth of their knowledge of its conservation importance, what they perceive its value to be, and the extent of their willingness to conserve it. General attitudes toward conservation incentives and provincial conservation authorities were also investigated. Farmers more willing to conserve were younger, did not necessarily have a better education, and owned larger farms (>500 ha) with a greater amount of remnant renosterveld (>300 ha) than those less willing to conserve. Attitudes toward the OCR were largely negative, related to associated problem plants and animals and the fact that it is believed not to be economically advantageous to retain it. However, farmers are of the opinion that provision of incentives and increased extension support will provide practical positive inducements for conservation. Landholder education is paramount to prevent further transformation of critically endangered habitats. The success of private-conservation programs depends on the attitudes of landowners toward (1) the particular habitat or species to be conserved (which can vary depending on the type of land use practised and the associated benefits and disadvantages of that habitat type); (2) the conservation agency or extension officers responsible for that area; and (3) willingness of landowners to participate in a conservation program, which is influenced by landowner age, farm size, and the amount of natural habitat left to conserve.  相似文献   

11.
云南木本食用油料资源及其开发   总被引:2,自引:0,他引:2  
食用油料木本化对我国具有重要的战略意义。云南具有丰富多彩的木本食用油料树种,本文记述了云南具有重要开发价值的32 科84 种食用油料树种,并提出了它的三个开发利用的方向。  相似文献   

12.
13.
Lead levels in different environmental media (soil, grass leaves, water, ceramics, pencil, paint, crayons and cosmetics) were determined to assess the major sources of lead exposure in Thohoyandou, South Africa. Soil and plant leaves were used as indicators of Pb pollution from vehicle exhaust emissions. After digestion with concentrated acids (HNO3, HCl and HClO4) Pb concentrations were determined in triplicate using a flame atomic absorption spectrometer. The mean Pb concentrations at the kerb of selected busy roads were 205.5 ± 90, 273.0 ± 90 and 312.8 ± 81 μg g−1 and 154.7 ± 67, 182.9 ± 76 and 240.6 ± 66 μg g−1 for soil and plant leaves (dry weight) respectively. These concentrations were substantially higher than the values found on soils 50 m away from the roads (97.4 ± 11 μg g−1). Pb concentrations in plants collected further away from the road (50 m) were substantially lower (71.8 ± 9.0 μg g−1). The observed levels on soil are lower than the UK critical value of 500 μg g−1 for gardens and allotments; and 2000 μg g−1 for parks and open space as well as the Canadian values for agricultural (375 μg g−1), residential (500 μg g−1 and industrial (1000 μg g−1). From these data it was clear that Pb concentrations in soil samples were substantially higher than the levels obtained for plant leaves. The Pb levels in green crayons, blue crayons, pencils (from China & Germany), were 10650 ± 75.2, 8200 ± 52.4, 1160 ± 50.2, 79 ± 10.1 μg g−1 for the inner contents; and 4870 ± 58.1, 5650 ± 55.5, 1950 ± 46.6, 60 ± 12.9 μg g−1 for the outer surface paint respectively. The ceramics showed Pb levels of 630 ± 50.3 μg g−1 (saucer) and 560 ± 32.2 μg g−1 (cup), while the inner contents and outer surface paint showed 480 ± 32.4 and 318 ± 21.2 μg g−1 of Pb respectively. Early morning tap water flush gave a Pb level of 20.6 ± 5.6 μg Pb l−1. This value is higher than the WHO and FDA maximum permissible concentrations of 10 μg l−1 and 15 μg l−1 respectively.  相似文献   

14.
The human rights related controversies surrounding Anglo Platinum's Mogalakwena mine in South Africa's Limpopo Province hit the world stage in 2008, attracting public scrutiny and instigating much debate in the realm of international business and human rights discussions. We provide an in-depth analysis of the controversies at Mogalakwena, and Anglo Platinum's responses. This case study contributes to ongoing debates on mining company-community relations in the context of the emerging business and human rights agenda, specifically with respect to the notion of human rights ‘due diligence’. We argue that the Mogalakwena case study illustrates the risks of companies adhering to and emphasizing the technical and logistical facets of due diligence, without sufficient attention to the relational, communicative and emergent aspects, which are closely tied to corporate culture. We highlight the complexities of company-community relationships, with particular reference to the issues of legitimate community representation and participatory decision-making, and discuss the role that organizational culture plays in exacerbating or mitigating corporate-community conflict. The case study demonstrates how legal challenges often exacerbate rather than resolve the conflicts that arise due to a clash between corporate and community cultures. We suggest the need for corporate leaders to become more conscious of this cultural dimension of effective social management, particularly when interacting with communities whose cultures are markedly different from those of business corporations.  相似文献   

15.
This paper examines the ability of civil society actors to champion environmental justice in an industrial risk society in South Africa by way of mobilisation and protest action. This paper presents viewpoints from key stakeholders at the Durban city level and three local case study sites to examine social capital relations to achieve environmental justice. It explores how civil society engages in social capital for mobilisation with itself and subsequent protest actions to engage with government and industry. The paper highlights that social actor response to engage in social capital for mobilisation and protests is best understood in relation to the socio-economic and political positioning of individuals or organisations.  相似文献   

16.
Emerging approaches to water resources development and management typically highlight equity and productivity as two main objectives. In the context of integrated water resources management within a river basin, managers and stakeholders often need a comparative assessment of different options for water augmentation and/or allocation. Pitting such options against predefined objectives, such as equity and productivity, requires an assessment of the effects that available options will have on these objectives. Available documentation indicates that not only does the interpretation of such objectives vary widely, but also the available methods for assessing equity and productivity run into significant limitations in the availability of adequate data. This limitation has largely kept decision makers from gaining a comprehensive overview of equity and productivity scenarios, whether within or across sectors, that could facilitate better‐informed decisions. To address this methodological gap, this article scrutinizes different notions associated with equity and water productivity, and limitations in prevalent assessment methods with the view to develop and demonstrate pragmatic methodologies for assessing equity and productivity in data‐scarce contexts. The discussion and findings are based on a review of relevant literature and empirical and consultative research work in the Olifants River basin in South Africa. The demonstrated methodologies for assessing equity and productivity, besides being useful in data‐scarce contexts, are insightful for initiating several policy measures and also for exploring the relationship between equity and water productivity.  相似文献   

17.
利用3S技术和景观生态学原理,以小流域为单元对秦皇岛市土地利用结构和土壤侵蚀等级类型进行空间分析,得出了不同土地利用结构所占面积和不同土壤侵蚀类型所占面积及分布小流域,并详细分析了秦皇岛市土壤侵蚀的主要影响因子和不同土地利用结构侵蚀现状。  相似文献   

18.
Development along the western beachfront of Port Alfred, which is situated along a sandy shoreline, increased markedly in the 1960s as the coastal town became a popular holiday resort. This development included the removal of coastal vegetation, which resulted in the destabilization of dunes and migration of sand westerly onto the road, West Beach parking lot, and lawns of the cabanas. Sand traps were constructed to collect sand blowing across the dunes over set periods, and the net sand movement along the mobile dune belt was calculated using Hunter's equation. The dunes show an easterly movement of sand at a rate of 3.5 m/yr, which is comparable with figures recorded along other areas of this coastline. Considering the wind regime and amount of sand movement along this coast, it is inappropriate to clear vegetation and develop within the dune region.  相似文献   

19.
Mining is an important part of the South African economy and has been the driver of much of the economic development of the country. However, the small–scale mining subsector still has to realise its full potential. A small–scale mine has been defined as a mining activity employing less than 50 people and with an annual turnover of less than 7.5 million Rand and includes artisanal mines. Small–scale miners are involved in many commodities but there appears to be a bias towards gold, diamonds and quarrying for construction materials, including brickclays. Small–scale mining is regulated by the same legislation (i.e., for the environment, labour, mineral rights, exploration and mining permitting, and skills development) as large–scale mining, though compliance is low, particularly where artisanal mining in concerned. The effective participation of small–scale miners in the mining sector is hampered by their lack of skills, i.e., technical, business and management, and their limited access to mineral deposits, capital and markets. Some of these hindrances have been inherited from the imbalances of the colonial and apartheid eras and continue to act as barriers, making entrance to the industry difficult. For those who have entered the industry out of desperation, as is the case with most artisanal miners, their activities result in negative impacts evident in the inefficient, unsafe and environmentally unfriendly operations. With the advent of the new political dispensation in South Africa, a new era is dawning for the country’s small–scale mining subsector. This has resulted in a change of attitude and new government policies which have led to special programmes being put in place to promote the subsector. Intervention strategies for the support of small–scale mining (some of which are already in operation) include programmes for kickstarting mineral beneficiation and value–addition projects, development of appropriate technologies and skills and technology transfer. Proponents of small–scale mining see a well–regulated industry as being the cornerstone of future rural economic development, particularly for previously disadvantaged communities in the poverty nodes.  相似文献   

20.
Despite their prevalence in both developed and developing countries, there have been surprisingly few field assessments of the ecological effectiveness of protected areas. This study aimed to assess the effectiveness of a key protected area in eastern Madagascar, Ranomafana National Park (RNP). We established paired 100 × 4-m vegetation transects (400 m2) within RNP and in remnant forests in the park’s peripheral zone. In each 400-m2 plot, all woody stems >1.5 cm in diameter at breast height were measured and identified to species. All species were also identified as native or non-native. We identified utilitarian species within all transects and they were sorted into use category. We calculated plot-level taxonomic biodiversity and functional diversity of utilitarian species; the latter was calculated by clustering the multivariate distances between species based on their utilitarian traits, and all metrics were tested using paired t-tests. Our results showed that there was significantly higher biodiversity inside RNP than in remnant forests and this pattern was consistent across all diversity metrics examined. Forests not located within the park’s boundary had significantly higher non-native species than within RNP. There was no statistically significant difference in functional diversity of utilitarian species inside RNP vs. remnant forests; however, the overall trend was toward higher diversity inside park boundaries. These findings suggested that RNP has been effective at maintaining taxonomic diversity relative to surrounding unprotected areas and restricting the spread of non-native plants. The results also suggested that low functional redundancy of forests outside of RNP might be of concern, because residents in surrounding villages may have few other substitutes for the services provided by species that are of critical importance to their livelihoods. This study highlights the challenges of trying to reconcile biodiversity conservation with human use of natural resources in economically poor, remote areas.  相似文献   

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