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More Water, Less Grass?: An assessment of resource degradation and stakeholders’ perceptions of environmental change in Ombuga Grassland, Northern Namibia
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The objectives of this thesis are to assess: to what degree have natural resources deteriorated in a grazing area in northern Namibia, how do perceptions of environmental change held by local stakeholders there, correspond to scientific assessments, and how do these relate to national estimates? Analysis of the process of developing national indicators for monitoring of land degradation concluded that specific indicators should be developed on national level, and in some instances even on local level as there are no universal causes of land degradation. According to farmers overgrazing and low rainfall since the early 1990s cause negative environmental changes in the study area, partly confirming findings from national monitoring. Results also suggest that: less grazing outside the study area, improved access, permanent water supply, and fencing of large areas, also contributed. Results show that improved water supply was the most important factor. Investigation of the influence of permanent water points on grazing resources showed that perennial grasses are replaced by less palatable annual grasses as far as 6 km from water points along a water pipeline. No significant grazing induced changes in grass composition were observed around privately owned wells. Private ownership seems to be a key factor preventing over-utilization of grazing resources around the latter. A remote sensing study using Landsat TM imagery identified bare ground, saltpans and grassland with a fair accuracy. Separation of woodland from shrubland and shrubland from grassland was less accurate using supervised classification. The results show that the soil adjusted vegetation index provides valuable information about variations of green biomass over time in semi-arid environments. However, it is suggested that satellite based investigations should be supported by thorough ground based assessment due to the influence of underlying soil in this environment.

Place, publisher, year, edition, pages
Stockholm: Institutionen för naturgeografi och kvartärgeologi , 2007. , 114 p.
Series
Dissertations from the Department of Physical Geography and Quaternary Geology, ISSN 1653-7211 ; 4
Keyword [en]
Environmental monitoring, semi-arid, pastoralism, rural water supply, indicators, local knowledge, vegetation survey, satellite remote sensing
National Category
Physical Geography
Research subject
Physical Geography
Identifiers
URN: urn:nbn:se:su:diva-6707ISBN: 91-7155-381-9 (print)OAI: oai:DiVA.org:su-6707DiVA: diva2:196909
Public defence
2007-04-11, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 13:00
Opponent
Supervisors
Available from: 2007-03-20 Created: 2007-03-02 Last updated: 2010-10-21Bibliographically approved
List of papers
1. Land Degradation Monitoring in Namibia: A First Approximation
Open this publication in new window or tab >>Land Degradation Monitoring in Namibia: A First Approximation
2004 In: Environmental Monitoring and Assessment, ISSN 0167-6369, Vol. 99, no 1-3, 5-21 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:su:diva-24160 (URN)
Note
Part of urn:nbn:se:su:diva-6707Available from: 2007-03-20 Created: 2007-03-02Bibliographically approved
2. Local and national perceptions of environmental change in central Northern Namibia: Do they correspond?
Open this publication in new window or tab >>Local and national perceptions of environmental change in central Northern Namibia: Do they correspond?
2007 In: Journal of Arid Environments, ISSN 0140-1963, Vol. 69, no 3, 506-525 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:su:diva-24161 (URN)000245349300012 ()
Note
Part of urn:nbn:se:su:diva-6707Available from: 2007-03-20 Created: 2007-03-02Bibliographically approved
3. Water points and their influence on grazing resources in central northern Namibia
Open this publication in new window or tab >>Water points and their influence on grazing resources in central northern Namibia
2008 (English)In: Land Degradation and Development, ISSN 1085-3278, E-ISSN 1099-145X, Vol. 19, no 1, 1-20 p.Article in journal (Refereed) Published
Abstract [en]

Debate among scientists about ecological dynamics and appropriate management of semi-arid rangelands has led to a challenge of received wisdoms of range management and pastoral development in dryland Africa. In our study, we investigated impacts of grazing on grass composition around permanent water points along a pipeline and around a traditional hand-dug well in an important grazing area in central northern Namibia. Grass species abundance and selected environmental variables sampled along transects radiating out from these water points were analysed using Canonical Correspondence Analysis (CCA). Significant grazing-induced changes, manifested by palatable perennial grasses being replaced by less palatable annual grasses, were identified around water points along the pipeline. There annual grasses Schmidtia kalihariensis and Aristida stipioides dominate the vegetation as far as 5 km from the water points. No significant grazing-induced changes in grass composition were observed around the hand-dug well. Private ownership leading to stronger control of access to traditional wells compared to the open access water points along the pipeline seems to be a key factor preventing overutilisation of grazing resources around the former.

Keyword
semi-arid rangeland, pastoralism, water point, grazing gradient, ordination, species response curve, Namibia
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-24162 (URN)10.1002/ldr.809 (DOI)
Available from: 2007-03-20 Created: 2007-03-02 Last updated: 2012-03-26Bibliographically approved
4. Can remote sensing detect environmental changes in a grazing area in northern Namibia?
Open this publication in new window or tab >>Can remote sensing detect environmental changes in a grazing area in northern Namibia?
Manuscript (Other academic)
Identifiers
urn:nbn:se:su:diva-24163 (URN)
Note
Part of urn:nbn:se:su:diva-6707Available from: 2007-03-20 Created: 2007-03-02 Last updated: 2010-01-13Bibliographically approved

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