Comparison of satellite rainfall data with observations from gauging station networks
- Authors: Hughes, Denis A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
- Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
- Full Text:
- Date Issued: 2006
- Authors: Hughes, Denis A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
- Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
- Full Text:
- Date Issued: 2006
Cultivation of medicinal plants as a tool for biodiversity conservation and poverty alleviation in the Amatola region, South Africa:
- Wiersum, K Freerk, Dold, Anthony P, Husselman, Madeleen, Cocks, Michelle L
- Authors: Wiersum, K Freerk , Dold, Anthony P , Husselman, Madeleen , Cocks, Michelle L
- Date: 2010
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141489 , vital:37979 , ISBN 9781402054488 , https://library.wur.nl/ojs/index.php/frontis/issue/view/232
- Description: This paper describes the assumptions and results of a study to assess whether cultivation of medicinal plants can serve as a tool for combined biodiversity conservation and poverty alleviation. The study was carried out in the Amatola region of Eastern Cape, South Africa, where sustained beliefs in medicinal plant use, also under non-traditional conditions, has resulted in an increase in commercial demands. It was based on the assumption of poverty alleviation not only referring to an increase in income and labour, but also an increase in social capital and human dignity. The study assessed the local perceptions of the use and cultivation of medicinal plants and the need for conservation of these plants, as well as the features of already ongoing cultivation practices and options for increased cultivation. It consisted of participatory assessments in three villages involving around 250 persons and participatory trials with 14 rural women selling medicinal plants on urban markets. The study indicated that the growing demand for medicinal plants is related to the great cultural significance attached to medicinal plants.
- Full Text:
- Date Issued: 2010
- Authors: Wiersum, K Freerk , Dold, Anthony P , Husselman, Madeleen , Cocks, Michelle L
- Date: 2010
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141489 , vital:37979 , ISBN 9781402054488 , https://library.wur.nl/ojs/index.php/frontis/issue/view/232
- Description: This paper describes the assumptions and results of a study to assess whether cultivation of medicinal plants can serve as a tool for combined biodiversity conservation and poverty alleviation. The study was carried out in the Amatola region of Eastern Cape, South Africa, where sustained beliefs in medicinal plant use, also under non-traditional conditions, has resulted in an increase in commercial demands. It was based on the assumption of poverty alleviation not only referring to an increase in income and labour, but also an increase in social capital and human dignity. The study assessed the local perceptions of the use and cultivation of medicinal plants and the need for conservation of these plants, as well as the features of already ongoing cultivation practices and options for increased cultivation. It consisted of participatory assessments in three villages involving around 250 persons and participatory trials with 14 rural women selling medicinal plants on urban markets. The study indicated that the growing demand for medicinal plants is related to the great cultural significance attached to medicinal plants.
- Full Text:
- Date Issued: 2010
Spatial and seasonal distribution patterns of the ragged-tooth shark Carcharias taurus along the coast of South Africa
- Dicken, Matthew L, Booth, Anthony J, Smale, Malcolm J
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127008 , vital:35943 , https://doi.10.2989/18142320609504210
- Description: Off South Africa, the ragged-tooth shark Carcharias Taurus has been occasionally reported from the West Coast, but it is more commonly found along the East and South coasts from Cape Town to northern KwaZulu-Natal (KZN) (Bass et al. 1975, Smale 2002). Mating is thought to occur off the south coast of KZN from October to late November (G Cliff, Natal Sharks Board, unpublished data). Pregnant females then move northward to spend the early part of their gestation in the warmer waters of northern KZN and possibly southern Moçambique. During July and August, the near-term pregnant females begin to move southwards towards the cooler waters of the Eastern Cape (Wallett 1973, Bass et al. 1975, G Cliff, unpublished data), where they give birth from September to November (Smale 2002). After parturition, many of the females migrate back to KZN. The whereabouts of mature males outside of the mating season is unclear. These broadscale distribution and migratory habits for C. taurus have been inferred from limited catch records obtained for only parts of its range along the South African coast.
- Full Text:
- Date Issued: 2010
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127008 , vital:35943 , https://doi.10.2989/18142320609504210
- Description: Off South Africa, the ragged-tooth shark Carcharias Taurus has been occasionally reported from the West Coast, but it is more commonly found along the East and South coasts from Cape Town to northern KwaZulu-Natal (KZN) (Bass et al. 1975, Smale 2002). Mating is thought to occur off the south coast of KZN from October to late November (G Cliff, Natal Sharks Board, unpublished data). Pregnant females then move northward to spend the early part of their gestation in the warmer waters of northern KZN and possibly southern Moçambique. During July and August, the near-term pregnant females begin to move southwards towards the cooler waters of the Eastern Cape (Wallett 1973, Bass et al. 1975, G Cliff, unpublished data), where they give birth from September to November (Smale 2002). After parturition, many of the females migrate back to KZN. The whereabouts of mature males outside of the mating season is unclear. These broadscale distribution and migratory habits for C. taurus have been inferred from limited catch records obtained for only parts of its range along the South African coast.
- Full Text:
- Date Issued: 2010
Temporal scales of variation in settlement and recruitment of the mussel Perna perna (Linnaeus, 1758)
- Porri, Francesca, McQuaid, Christopher D, Radloff, Sarah E
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
Valuation of communal area livestock benefits, rural livelihoods and related policy issues
- Dovie, Delali B K, Shackleton, Charlie M, Witkowski, Ed T F
- Authors: Dovie, Delali B K , Shackleton, Charlie M , Witkowski, Ed T F
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6627 , http://hdl.handle.net/10962/d1006819
- Description: The multiple benefits from livestock production to rural households are evaluated in Thorndale, a communal area of the Limpopo Province South Africa. Monetary values of livestock products are presented. Values from most previous studies are static (and thus outdated), as a result of conceptual and methodological shifts. The net monetary value of the direct benefits from livestock was estimated as $656 per household/annum, excluding the holding of cattle for savings. The net value is equivalent to 22.7% of the value of the other livelihood sources that were considered, and inclusive of cash income streams, crops, and secondary woodland resources. A net 168% herd increase in livestock was recorded between 1993 and 1999. More households owned goats compared to cattle, and cattle were important for use as draught power, and for milk. Households without livestock benefited through gifts and services, valued at $33 per household/annum. Policy concerns are the provision of adequate market and pricing mechanisms for communal area livestock, tailored savings, investment support, credit schemes, and infrastructure. An appropriate multipurpose benefit production model, other than a commercialised model is suggested for the sector.
- Full Text:
- Date Issued: 2006
- Authors: Dovie, Delali B K , Shackleton, Charlie M , Witkowski, Ed T F
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6627 , http://hdl.handle.net/10962/d1006819
- Description: The multiple benefits from livestock production to rural households are evaluated in Thorndale, a communal area of the Limpopo Province South Africa. Monetary values of livestock products are presented. Values from most previous studies are static (and thus outdated), as a result of conceptual and methodological shifts. The net monetary value of the direct benefits from livestock was estimated as $656 per household/annum, excluding the holding of cattle for savings. The net value is equivalent to 22.7% of the value of the other livelihood sources that were considered, and inclusive of cash income streams, crops, and secondary woodland resources. A net 168% herd increase in livestock was recorded between 1993 and 1999. More households owned goats compared to cattle, and cattle were important for use as draught power, and for milk. Households without livestock benefited through gifts and services, valued at $33 per household/annum. Policy concerns are the provision of adequate market and pricing mechanisms for communal area livestock, tailored savings, investment support, credit schemes, and infrastructure. An appropriate multipurpose benefit production model, other than a commercialised model is suggested for the sector.
- Full Text:
- Date Issued: 2006
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