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1.
Phosphorus transport in shallow groundwater in peri-urban Kampala, Uganda: results from field and laboratory measurements 总被引：1，自引：0，他引：1
To understand Phosphorus (P) sources and transport processes in the subsurface in Bwaise III Parish, Kampala, P attenuation
and adsorption capacities of soils were studied in situ and from laboratory measurements. Relationships between sorption parameters
and soil matrix properties, rates and mechanism of the adsorption process and soil P fractions were also investigated. P was
generally higher in the wet than the dry season, but for both seasons, the maximum was 5 mgP/l. P transport mechanisms appeared
to be a combination of adsorption, precipitation, leaching from the soil media and by colloids with the latter two playing
an important role in the wet season. The sorption process comprised two phases with the first stage rate constants being about
fourfold those of the second stage. The Langmuir isotherm described the sorption data well (R
2 ≥ 0.95) with the second soil layer exhibiting the highest sorption maximum (C
max) (average value 0.6 ± 0.17 mgP/gDW). The best prediction of C
max had organic carbon, Ca, available P and soil pH. Residual P consisting mostly of organics was the main fraction in all the
layers followed by inorganic HCl-P and NaOH-P in the top and middle layers, respectively. Loosely bound P (NH4Cl-P) was the least fraction (<0.4% of total P) in all layers indicating the high binding capacity of P by the soils. The
study results suggest that P dynamics is related to Ca, Fe and organic carbon content of the soils. 相似文献
2.
LISA NAUGHTON-TREVES 《Geographical review》1997,87(1):27-46
ABSTRACT. Subsistence farmers near Kibale National Park, Uganda, fear and resent many wildlife species. In this article I compare records of crop damage by wildlife and livestock with local complaints about the worst animals and the most vulnerable crops. I discuss the concordance and discrepancies in complaints versus actual damage in light of physical parameters of risk and of social factors that shape perceptions and vulnerabilities. Crop losses were greatest at the edge of the forest, where immigrants are disproportionately represented. State proprietorship of wildlife amplifies local vulnerability and constrains traditional coping strategies, such as hunting. 相似文献
3.
Lorraine Young 《Geoforum》2004,35(4):471-488
Children have generally been afforded little attention in migration research or unsatisfactorily included within family migration. Although they are an important consideration in family decisions to move, children also engage in autonomous, independent migration. Further, researchers now argue for the need to situate migration within political, economic and social conditions to obtain a full understanding of why people migrate. Through the use of children-centred research methods, and in-depth interviews with key informants, this paper considers children's journeys to the street in Uganda. By integrating an analysis of Ugandan street children's spatial origins with the familial and societal contexts of their migration decisions, this research highlights the complexity of their migration. In addition, an exploration of the impact of changing social, spatial and temporal conditions on street children's movements illustrates that their journeys are far more than just single processes. 相似文献
4.
A model for the evolution of weathered landsurfaces in Uganda is developed using available geotectonic, climatic, sedimentological and chronological data. The model demonstrates the pivotal role of tectonic uplift in inducing cycles of stripping, and tectonic quiescence for cycles of deep weathering. It is able to account for the development of key landforms, such as inselbergs and duricrust-capped plateaux, which previous hypotheses of landscape evolution that are based on climatic or eustatic controls are unable to explain. Development of the Ugandan landscape is traced back to the Permian. Following late Palaeozoic glaciation, a trend towards warmer and more humid climates through the Mesozoic enabled deep weathering of the Jurassic/mid-Cretaceous surface in Uganda during a period of prolonged tectonic quiescence. Uplift associated with the opening South Atlantic Ocean terminated this cycle and instigated a cycle of stripping between the mid-Cretaceous and early Miocene. Deep weathering on the succeeding Miocene to recent (African) surface has occurred from Miocene to present but has been interrupted in the areas adjacent to the western rift where development of a new drainage base level has prompted cycles of stripping in the Miocene and Pleistocene. 相似文献
5.
Wetlands provide vital wildlife habitat and ecosystem services, but changes in human land use has made them one of the world’s most threatened ecosystems. Although wetlands are generally protected by law, growing human populations increasingly drain and clear them to provide agricultural land, especially in tropical Africa. Managing and conserving wetlands requires accurately monitoring their spatial and temporal extent, often using remote sensing, but distinguishing wetlands from other land covers can be difficult. Here, we report on a method to separate wetlands dominated by papyrus (Cyperus papyrus L.) from spectrally similar grasslands dominated by elephant grass (Pennisetum purpureum Schumach.). We tested whether topographic, spectral, and temperature data improved land cover classification within and around Kibale National Park, a priority conservation area in densely populated western Uganda. Slope and reflectance in the mid-IR range best separated the combined papyrus/elephant grass pixels (average accuracy: 86%). Using a time series of satellite images, we quantified changes in six land covers across the landscape from 1984 to 2008 (papyrus, elephant grass, forest, mixed agriculture/bare soil/short grass, mixed tea/shrub, and water). We found stark differences in how land cover changed inside versus outside the park, with particularly sharp changes next to the park boundary. Inside the park, changes in land cover varied with location and management history: elephant grass areas decreased by 52% through forest regeneration but there was no net difference in papyrus areas. Outside the park, elephant grass and papyrus areas decreased by 61% and 39%, mostly converted to agriculture. Our method and findings are particularly relevant in light of social, biotic, and abiotic changes in western Uganda, as interactions between climate change, infectious disease, and changing human population demographics and distribution are predicted to intensify existing agricultural pressure on natural areas. 相似文献
6.
The process of landscape fragmentation outside park borders occurs through the actions of people living near the boundaries. In the Kibale National Park landscape in western Uganda, human-landscape relationships are typified by small-scale subsistence agriculture, in which households rely on resources provided in forests and wetlands, whose use is in turn shaped by perceptions of resource availability. To understand and manage for fragmentation of resource pools, modeling and identifying the proximate drivers, and thus enacted resource extraction and utilization – is of fundamental importance. We combine landscape analysis at the household scale, using remotely sensed data, with household surveys, to understand the potential human drivers of local scale landscape change. We found strong evidence for a local household zone (LHZ) effect on fragmentation patterns with geographical and socioecological heterogeneities in LHZ impact. Differences were influenced by wealth, and in some cases, tribal identity. The perception of crop raiders – primarily baboons and small monkeys, but also elephants and other animals – may have largely shaped human-environment interactions, and were associated with fragmentation. Ninety-two percent of the best fit models included the attitude that the park should stay, but associated it with increased fragmentation, suggesting that the uncharacteristic non-hostile attitude about Kibale does not directly translate into conservation-friendly local human-environment interactions. This study provides insight into park–neighbor interactions and the influence of the LHZ on protected-area landscapes, and it points to important points in the system for collaborative opportunities to engage communities and conservation managers. 相似文献
7.
Mark Purdon 《社会与自然资源》2018,31(9):1082-1093
Carbon markets as a policy tool to mitigate emissions of greenhouse gases continue to be controversial, especially in developing countries. It is thus refreshing that Carton and Andersson (2017) undertook a field investigation of a transnational forest carbon offset project in Uganda. However, I am concerned that assumptions of structural Marxism that underwrite subsumption theory may have led the authors to see the project as inherently conflict ridden and exploitative and to neglect actual benefits. Their presentation of the project’s local impact jarred with my own empirical research into this project, undertaken in 2009, as well as more recent news accounts. While my field effort preceded the authors’ by 6 years, I attribute our different interpretations largely to theoretical and methodological differences. Evidence I present below suggests considerable alignment between the interests of transnational carbon markets and Ugandan smallholder farmers. Additional fieldwork might be able to resolve these differences in interpretation. 相似文献
8.
Sami Eria Robert B. McMaster 《International journal of geographical information science》2017,31(5):884-906
Despite myriad studies having been carried out on the diffusion of geographical information systems (GIS) technology, only a limited number have been done within the context of developing countries. This paper addresses the research question, how did the diffusion of GIS technology occur in Uganda? Mixed methods were used for data collection, and analysis was performed using a theoretical framework called the diffusion of innovations (DOI). The results of the study showed that the adoption of GIS by institutions in Uganda occurred in a classic diffusion pattern consistent with diffusion theory. Adoption of GIS was promoted by its relative advantage over, and compatibility with, existing technologies. It was characterized by both heterophilous and homophilous communication channels, and influenced by change agents and champions. Its rate of adoption followed an S-shaped diffusion curve, and was hampered by bureaucracy, and patronage-based societal norms. This study makes a contribution to literature on GIS diffusion in developing countries. 相似文献
9.
《Geoforum》2017
Assemblage approaches are increasingly being used to understand new socio-natural formations arising in relation to the multiple crises of capitalism, climate change and environmental degradation. The valuation of nature is key to these new formations, which the creation of new ‘valued entities’, through calculative practices, that can be accounted for, costed and circulated in monetised and financialised forms in order to ostensibly ‘fix’ certain environmental outcomes in relation to contemporary global crisis. This paper uses an assemblage approach in relation to the global’ transnational project of carbon forestry offsetting and REDD+ in a particular place, Uganda, arguing that it has utility in this respect. While Uganda has been named by Lang and Byakola (2005) as a ‘funny place to store carbon’ due to its contested land politics and history of violence its weak governance context paradoxically re-enforces the imperative for intervention. The paper argues that carbon forestry assemblages are inherently ephemeral and fundamentally contested in three ways: exhibiting a speculative virtuality, faltering materiality and disputed territoriality. Such analysis has the ability to go beyond technical and managerial, or solely pollical economic critiques of carbon forestry, to point at openings for alternatives. 相似文献
10.