scholarly journals Quantifying the Evapotranspiration Component of the Water Balance of Atlantis Sand Plain Fynbos (South Africa)

10.5772/53405 ◽  
2013 ◽  
Author(s):  
Nebo Jovanovic ◽  
Richard Bugan ◽  
Sumaya Israel
Keyword(s):  
South Africa ◽  
Water Balance ◽  
Sand Plain

scholarly journals Bees get a head start on honey production

2008 ◽  
Vol 4 (3) ◽  
pp. 299-301 ◽  
Author(s):  
Susan W Nicolson ◽  
Hannelie Human
Keyword(s):  
South Africa ◽  
Head Start ◽  
Water Balance ◽  
Sugar Concentration ◽  
Honey Production ◽  
Nectar Concentration ◽  
Bee Plant ◽  
Volume Decrease

Nectar concentration is assumed to remain constant during transport by honeybees between flowers and hive. We sampled crop contents of nectar foragers on Aloe greatheadii var. davyana , a major winter bee plant in South Africa. The nectar is dilute (approx. 20% w/w), but the crop contents of bees captured on flowers are significantly more concentrated. In returning foragers, the concentration increases further to 38–40%, accompanied by a volume decrease. The doubling of sugar concentration suggests that nectar is regurgitated onto the tongue and evaporated during foraging and on the return flight. Processing of the dilute nectar into honey thus begins early, aided by low ambient humidities. This has implications for honeybee thermoregulation, water balance and energetics during foraging, and for the communication of nectar quality to recruits.

Response to nutrient additions by the plant growth forms of sand-plain lowland fynbos, South Africa

Vegetatio ◽  
1988 ◽  
Vol 79 (1-2) ◽  
pp. 89-97 ◽  
Author(s):  
E. T. F. Witkowski
Keyword(s):  
South Africa ◽  
Plant Growth ◽  
Growth Forms ◽  
Nutrient Additions ◽  
Sand Plain

Ecological studies of larval ticks in South Africa (Acarina: Ixodidae)

Parasitology ◽  
1972 ◽  
Vol 65 (3) ◽  
pp. 469-490 ◽  
Author(s):  
J. G. H. Londt ◽  
G. B. Whitehead
Keyword(s):  
South Africa ◽  
Relative Humidity ◽  
Water Balance ◽  
Field Data ◽  
Amblyomma Hebraeum ◽  
Ecological Studies ◽  
Saturation Deficit ◽  
Vegetation Height ◽  
Boophilus Decoloratus ◽  
Glass Rods

The distribution of larval ticks in relation to vegetation cover was studied on two coastal farms in the Port Alfred district of the Cape Province. The following five species were found: Boophilus decoloratus (Koch), Amblyomma hebraeum Koch, Ixodes pilosus Koch, Haemaphysalis silacea Robinson and Rhipicephalus evertsi Neumann. B. decoloratus predominated in short protected vegetation, I. pilosus and H. silacea in short covered vegetation and A. hebraeum in medium-to-tall protected vegetation. R. evertsi was collected in too small numbers to allow any correlation to be established. Both I. pilosus and H. silacea demonstrated activity peaks during the winter months. Microclimatic measurements indicated that larval ticks were not usually collected in microhabitats which experienced midday saturation deficits in excess of approximately 10 mm Hg. Behavioural studies on larval ticks climbing glass rods demonstrated the possible association of larvae with a definite vegetation height. The optimal vegetation heights were correlated with field data. The water balance of some tick species was studied and it was found that at 26 °C a relative humidity of 70% or more (i.e. above 7·53 mm Hg saturation deficit) was required by these larvae. Larvae lost water to the atmosphere at humidities lower than this value and took up water vapour from the atmosphere at values higher than 70% R.H. They were shown to be able to imbibe water through the mouthparts, and this possibly has survival value.

scholarly journals The water balance of a seasonal stream in the semi-arid Western Cape (South Africa)

Water SA ◽  
2012 ◽  
Vol 38 (2) ◽  
Author(s):  
RDH Bugan ◽  
NZ Jovanovic ◽  
WP De Clercq
Keyword(s):  
South Africa ◽  
Water Balance ◽  
Western Cape ◽  
Semi Arid

The water balance of a first order catchment in the montane grasslands of South Africa

2001 ◽  
Vol 241 (1-2) ◽  
pp. 110-123 ◽  
Author(s):  
C.S Everson
Keyword(s):  
South Africa ◽  
Water Balance ◽  
First Order ◽  
Montane Grasslands

Evidence for global teleconnections in a late Pleistocene speleothem record of water balance and vegetation change at Sudwala Cave, South Africa

2015 ◽  
Vol 110 ◽  
pp. 114-130 ◽  
Author(s):  
Helen Green ◽  
Robyn Pickering ◽  
Russell Drysdale ◽  
Brett C. Johnson ◽  
John Hellstrom ◽  
...  
Keyword(s):  
South Africa ◽  
Water Balance ◽  
Late Pleistocene ◽  
Vegetation Change

scholarly journals Impact of land-use change on catchment water balance: a case study in the central region of South Africa

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yali E. Woyessa ◽  
Worku A. Welderufael
Keyword(s):  
South Africa ◽  
Land Use ◽  
Water Balance ◽  
Central Region ◽  
Surface Runoff ◽  
Catchment Area ◽  
Forest Cover ◽  
Water Yield ◽  
Climatic Data ◽  
The Mean

AbstractAn assessment study on the impact of land use change through afforestation on catchment water balance was carried out in one of the semi-arid quaternary catchments (C52A) of the Modder River Basin located in the central region of South Africa. The study used ArcGIS and the Soil and Water Assessment Tool (SWAT) to create scenarios of forest cover areas and to simulate the water balance of C52A, respectively. Climatic data from 1993 to 2020 were used to simulate the catchment water balance. The climatic data from 2011 to 2020 were generated using SWAT weather generator while the rest was obtained from South Africa Weather Service at three weather stations located within C52A catchment. In the C52A quaternary catchment it was envisaged to increase forest cover by considering afforestation on pastureland that is found on slopes > 8% and > 3% which created two forest scenarios. The baseline land use [Land use 2000 (LU2000)] which is taken as the base scenario in this study has about 84% of the catchment area covered with pasture. The two forest scenarios created were: forest scenario1 (FRSE1), i.e. conversion of pastureland on slope > 8% to forest, and forest scenario2 (FRSE2), i.e. conversion of pastureland on slope > 3% to forest. The type of forest considered in these scenarios is an evergreen tree, acronym as FRSE by SWAT land use classification. The conversion increased forest cover by 8.3% and 30.5% on FRSE1 and FRSE2, respectively. The result of the water balance of the catchment based on the land use scenarios were compared with the baseline land use scenario (LU2000). The result obtained showed that FRSE1 produced a non-significant change both on the mean monthly surface runoff and water yield compared to LU2000. On the other hand, FRSE2 showed 30% decrease on the mean monthly surface runoff, but increased the mean monthly lateral flow and base flow by 110% and 254%, respectively compared to the LU2000. Thus, in the overall water balance, the mean monthly water yield of the catchment increased by 171% on FRSE2 compared to the LU2000. Although there are considerable number of research reports on the negative effect of forest on catchment water yield, this study showed a significant water yield increase when approximately 30% of the C52A catchment area, which lay on slopes > 3% and covered by grass, was converted to evergreen forest land. The result showed that having a forest cover on a suitable slope range can bring about a positive effect on the total water yield of a catchment. Therefore, this finding is important for catchment management stakeholders and policy-makers when devising land use and water resources management strategies in a catchment.

scholarly journals Rainfall, Soil Water Content, and Groundwater Levels at the Riverlands Nature Reserve (South Africa)

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Nebo Jovanovic ◽  
Richard D. H. Bugan ◽  
Sumaya Israel
Keyword(s):  
South Africa ◽  
Water Balance ◽  
Soil Water ◽  
Nature Reserve ◽  
Response Analysis ◽  
Western Cape ◽  
Groundwater Levels ◽  
Wide Range ◽  
Water Contents ◽  
Soil Water Contents

Quantified medium- and long-term hydrological datasets are scarce in South Africa, yet they are essential to gain understanding of natural systems, contribute to ecosystem conservation, and ultimately quantify water balance processes accurately. A hydrological experiment was carried out at Riverlands Nature Reserve (Western Cape, South Africa) in order to quantify the components of the soil water balance at experimental sites occupied by endemic and invasive vegetation. In two separate follow-up projects, five-year time series were collected in three treatments, namely, endemic fynbos vegetation, bare soil, and land invaded by Acacia saligna. Rainfall was recorded daily with a manual rain gauge. Groundwater levels were logged hourly at 14 boreholes. Volumetric soil water contents and soil temperatures were logged hourly at different depths in the soil profile. Groundwater levels and soil water contents responded to rainfall with very clear seasonal trends. The data can be applied in water balance and evapotranspiration studies, unsaturated flux studies, soil temperature profile studies, and rainfall-groundwater level response analysis and for calibrating and validating a wide range of hydrological models.

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