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Questions and Answers
What was the average standing 'dead grass' abundance across the catchment during the 2000 dry season?
What was the average standing 'dead grass' abundance across the catchment during the 2000 dry season?
The abundance of perennial grasses significantly increased in the wet season of 2000 compared to the dry season of 2000.
The abundance of perennial grasses significantly increased in the wet season of 2000 compared to the dry season of 2000.
False
What was the minimum standing 'dead grass' abundance observed closest to water points?
What was the minimum standing 'dead grass' abundance observed closest to water points?
0%
The 2000 wet season had a significantly greater annual grass abundance than the ____ wet season.
The 2000 wet season had a significantly greater annual grass abundance than the ____ wet season.
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Match the following grass types with their seasonal abundance:
Match the following grass types with their seasonal abundance:
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What statistical value indicates a significant seasonal difference in forb abundance?
What statistical value indicates a significant seasonal difference in forb abundance?
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Annual grasses showed a decrease in abundance within 1.0 km of a water point, which was significant.
Annual grasses showed a decrease in abundance within 1.0 km of a water point, which was significant.
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During the 2000 dry season, what was the variance of the standing 'dead grass' abundance?
During the 2000 dry season, what was the variance of the standing 'dead grass' abundance?
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What may have been a flaw in the studies referenced by Sullivan (1999)?
What may have been a flaw in the studies referenced by Sullivan (1999)?
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The average rainfall serves as a reliable predictor for seasonal rainfall in the arid north-west.
The average rainfall serves as a reliable predictor for seasonal rainfall in the arid north-west.
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What did the annual grasses and forbs usually do during the dry season?
What did the annual grasses and forbs usually do during the dry season?
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In 1995, Sesfontein received ____ mm of rain.
In 1995, Sesfontein received ____ mm of rain.
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Match the following rainfall data with its associated year:
Match the following rainfall data with its associated year:
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What type of grasses are characterized by forming tufts and retaining leaves throughout the year?
What type of grasses are characterized by forming tufts and retaining leaves throughout the year?
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What method was used for field sampling in the study?
What method was used for field sampling in the study?
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All transects were established at a distance from any water sources.
All transects were established at a distance from any water sources.
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What vegetation community dominates the 50–100 mm rainfall zone?
What vegetation community dominates the 50–100 mm rainfall zone?
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The long dry season has no impact on domestic stock and wildlife.
The long dry season has no impact on domestic stock and wildlife.
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What is one effect of below-average rainfall on grazing and browsing?
What is one effect of below-average rainfall on grazing and browsing?
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The area around water sources is dominated by __________.
The area around water sources is dominated by __________.
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Match the vegetation with the corresponding rainfall zone:
Match the vegetation with the corresponding rainfall zone:
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What type of grazing do domestic stock and wildlife rely on during drought?
What type of grazing do domestic stock and wildlife rely on during drought?
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What are animals observed eating during the dry season from previous growth?
What are animals observed eating during the dry season from previous growth?
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Vegetation diversity and abundance increase around water sources.
Vegetation diversity and abundance increase around water sources.
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Which trees were primarily observed to be browsed by wildlife during the dry season in the Hoanib River catchment?
Which trees were primarily observed to be browsed by wildlife during the dry season in the Hoanib River catchment?
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Domestic stock, particularly goats, could easily browse extensively on F.albida trees due to low browse heights.
Domestic stock, particularly goats, could easily browse extensively on F.albida trees due to low browse heights.
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What kind of vegetation was most available for livestock immediately before and right after the first rains?
What kind of vegetation was most available for livestock immediately before and right after the first rains?
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Elephants, giraffes, and gemsbok were observed consuming the bark and pods of ________ and ________ trees.
Elephants, giraffes, and gemsbok were observed consuming the bark and pods of ________ and ________ trees.
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Match the animals with their feeding habits:
Match the animals with their feeding habits:
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What type of feed was mainly obtained by livestock such as cattle?
What type of feed was mainly obtained by livestock such as cattle?
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Wildlife would prefer to graze in riverbeds only during the wet season when new vegetation was available.
Wildlife would prefer to graze in riverbeds only during the wet season when new vegetation was available.
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What was a major source of nitrogen intake for sheep and goats during the dry season?
What was a major source of nitrogen intake for sheep and goats during the dry season?
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Which of the following studies focuses on the ecological implications related to ungulate diversity in African savannas?
Which of the following studies focuses on the ecological implications related to ungulate diversity in African savannas?
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The document includes a study on seasonal vegetation changes in the Hoanib River catchment.
The document includes a study on seasonal vegetation changes in the Hoanib River catchment.
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What is the primary focus of the study conducted by Jacobson, Jacobson, and Seely in 1995?
What is the primary focus of the study conducted by Jacobson, Jacobson, and Seely in 1995?
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The study by Giess in 1971 provides a preliminary vegetation map of __________.
The study by Giess in 1971 provides a preliminary vegetation map of __________.
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Match the following authors with their respective studies:
Match the following authors with their respective studies:
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What aspect of Namibia's ecology does the study by Maggs, Craven, and Kolberg (1998) investigate?
What aspect of Namibia's ecology does the study by Maggs, Craven, and Kolberg (1998) investigate?
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The Ministry of Agriculture, Water & Rural Development published a comprehensive land use plan for the Sesfontein Constituency in 1997.
The Ministry of Agriculture, Water & Rural Development published a comprehensive land use plan for the Sesfontein Constituency in 1997.
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Who authored a rapid survey method for estimating density and cover in desert plant communities?
Who authored a rapid survey method for estimating density and cover in desert plant communities?
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Study Notes
Overview of Grazing Impact Studies
- Previous studies indicated significant grazing impact due to local herdsmen overuse, with flawed methodologies cited by later researchers.
- Flaws include neglecting spatial and temporal interpretations of ecological data, the role of abiotic factors, and misconceptions about traditional farming practices.
Rainfall Variability in the North-West
- Rainfall is highly variable both spatially and temporally, complicating agricultural predictions.
- Example: Sesfontein recorded an average rainfall of 107 mm, but extreme values of 0 mm (1981) and 335 mm (1995) were noted.
- Seasonal rainfalls fluctuate, affecting vegetation growth and species survival.
Vegetation Types and Dynamics
- Annual grasses and forbs thrive during wet seasons but typically die out in dry seasons.
- Perennial grasses maintain a tufted structure and retain leaves throughout the year, showing less seasonal variation.
- The abundance of grass species (annual vs. perennial) fluctuates significantly between wet and dry seasons.
Field Sampling Techniques
- Vegetation transects were established in eight focal areas, mostly originating from permanent water sources.
- Surveys during dry seasons noted standing ‘dead grass’ abundance ranging from 0.5% to 12.5% across distances from water sources.
- Proximity to water affects standing grass abundance with the closest areas showing reduced ‘dead grass’ levels.
Seasonal Changes in Grass and Forb Abundance
- Annual grass abundance was notably higher during the 2000 wet season compared to 1999 as indicated by statistical significance.
- Perennial grass abundance showed no significant annual variation, remaining consistently low.
- A significant increase in forb abundance occurred during wet seasons compared to dry seasons; however, annual differences were not significant.
Impact of Grazing on Conservation
- Areas with high concentrations of domestic stock experienced limited grazing options during the dry season.
- Both wildlife and domestic stock forage on dried leaves, pods, and other plant materials, affecting overall vegetation patterns.
Browsing Behavior of Domestic and Wild Animals
- Various species, including elephants and giraffes, were observed feeding on specific trees (F.albida, C.mopane) during dry seasons.
- Domestic stock, particularly goats, require diverse diets, including browsing on shrubs and trees, impacting vegetation health and diversity.
Response of Vegetation to Rainfall Patterns
- Vegetation in the Hoanib River catchment is influenced by annual rainfall variability rather than land use.
- Four vegetation communities correspond to varying rainfall zones, showcasing a mix of woodland and grassland types.
- The presence of annual forbs dominates near water sources, with reduced vegetation diversity.
Environmental Challenges
- Long dry seasons pose significant grazing challenges; animals resort to consuming dried vegetation and tree pods.
- Rainfall fluctuations lead to variability in grazing intensity, with browsing becoming more crucial during drought periods.
- Severe droughts result in catastrophic losses within animal populations due to inadequate feed sources.
Acknowledgements
- Appreciation extended to various organizations and individuals aiding in the study, including DRFN staff and local communities of the Hoanib River catchment.
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Description
This quiz explores the ecological implications of traditional communal farming practices, particularly in arid regions. It discusses research critiques regarding the assessment of spatial and temporal scales in ecological studies, and examines the influence of abiotic factors on local ecosystems.
