Spelling suggestions: "subject:"rangel condition""
1 |
Understanding Land Management and Desertification in the South African Kalahari with Local Knowledge and PerspectivesKong, Taryn M. January 2012 (has links)
Desertification, or land degradation in drylands, is a serious environmental problem in South Africa with tremendous socio-economic consequences. Land users' perspectives on land management practices and knowledge about their rangelands have been poorly represented in the discourse of land degradation in South Africa. We addressed this knowledge gap by examining three participatory methods to capture local knowledge and perspectives, as well as the relation between knowledge, attitude and practice status relative to three land management actions done by livestock farmers in the South African Kalahari. Photo elicitation captured a greater level of detail and new information compared to semi-structured interviews alone, while enhancing researchers' understanding of farmers' knowledge and perception in multiple ways. The photovoice group discussions led to farmers' engagement in reflective dialogues, which facilitated mutual learning among the farmers. We found that a high level of knowledge and positive attitude alone did not always result in actual full scale practice. Situational factors such as limited financial resources, inadequate farm infrastructure, farm size, and land tenure were given by farmers as constraints or challenges to their land management. We further examined how effective local knowledge and remotely sensed data were in assessing the veld condition in the Kalahari Duneveld. The farmers' assessment of veld condition corresponded to field measured grass, shrub and bare ground cover. The three vegetation metrics calculated from remotely sensed images (i.e., Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), and the tasseled cap greenness) all correlated poorly to the measured vegetation cover because of the excess spectral noise caused by the high iron oxide content in the Kalahari sand. Local perspectives and knowledge have potential to augment traditional ground-based rangeland assessment and contribute in the combat against desertification by offering a more holistic view of land management.
|
2 |
Best land-use strategies towards sustainable biodiversity and land degradation management in semi-arid western rangelands in southern Africa, with special reference to ants as bio-indicators / Marisa Coetzee.Coetzee, Marisa January 2006 (has links)
In South Africa, the unsustainable use of natural resources by domestic livestock has led to resource depletion and serious land degradation. Rangeland degradation, especially bush encroachment and soil
erosion, is particularly acute in the North-West Province, where all districts show signs of desertification and a loss of biodiversity resulting in a deterioration of human and animal health. This has a major
impact on livestock productivity and the economic viability of livestock farming with serious consequences for the livelihoods of pastoral communities. It is important to recognise ecological change before irreversible changes occur. The aim of this study, which falls within the Global Environmental Facility Desert Margins Programme (GEF-DMP), was to investigate to what extent vegetation in combination with ant communities can be used as indicators of ecosystem change due to anthropogenic human induced land-use patterns and how can this information be used in land degradation management and biodiversity conservation in the semi-arid western rangelands of Southern Africa. Sites, representing a degradation
gradient (relative poor and relative good rangeland condition extremes) within each of three Tribal-, three Commercial- and three Reserve areas, were surveyed. The impacts of these land uses on the
herbaceous species composition, woody-, soil- and ant components were evaluated. Both the woody and herbaceous species components reflected the existence of a rangeland condition/degradation gradient
across the larger study area. The herbaceous species composition reflected similar degradation tendencies within the Commercial and Reserve land uses, with sites being associated with low rangeland
as well as high rangeland condition scores. The tendencies differed between these two land uses based on the woody degradation gradient. The entire Tribal herbaceous- and woody species components showed a transitional shift towards another state, which differed significantly from the Commercial and Reserve land uses. Both the Tribal herbaceous and woody components were associated with low to intermediate rangeland condition ranges, with no significant rangeland condition gradient existing within the Tribal land use.
Understanding and quantification of the soil-vegetation dynamics hold important implications for rangeland degradation management. This study provided criteria for selecting the most appropriate
measures when incorporating the soil parameters as additive data in the multivariate analyses with the
vegetation, ant and nominal environmental data. Different land use practices resulted in different soil patterns, with significant gradients pertaining to the soil stratum and openness/woodiness groups. There was a significant though neglectable difference pertaining to the rangeland condition/degradation gradient based on the soil component. Ants have been extensively used as bio-indicators, also with regard to the monitoring of the environmental effects of rangeland pastoralism. Ant species compositional patterns and functional
groups displayed congruent clustering and diversity patterns as those of the vegetation and soil components. In contrast to the vegetation components, ant assemblages did not reflect a degradation
gradient, but rather reflected environmental changes (modifications) to the habitat structure and - heterogeneity as a result of different land use disturbances.
Both vegetation and ant diversity measures were mainly associated with the Tribal land use. These diversity indices were indicators of habitat complexity, heterogeneity and moderate disturbance, rather than indicators of a rangeland condition/degradation gradient. The diversity patterns are best described
by a dichotomy between the humped-shaped productivity/diversity and the habitat
complexity/heterogeneity models. Vegetation and ant diversity measures for this study should be considered as environmental indicators of habitat disturbance rather than as biodiversity indicators.
It is suggested that vegetation, soil and ant patterns are best described by the state-and-transition model, which encompasses both equilibrium and non-equilibrium systems. The resilient nature of these rangelands, typical of non-equilibrium systems, was reflected by the low to intermediate differences
between land uses with regard to the herbaceous, woody, soil and ant components. However, densitydependent coupling of herbivores to key resources resulted in transitional shifts and modification of the
vegetation composition and structure within and between land uses, displaying the equilibrium dynamics pertaining to these rangelands. Small disturbances in these rangelands may result in detrimental
“snowball” interactive biotic-biotic /abiotic cascades. Spatial heterogeneous patterns within and between
land uses as displayed by the vegetation, soil and ant parameters, necessitate that monitoring and management at patch, paddock and landscape scale should be conducted, cautioning against the extrapolation and over simplification of management strategies across all land uses. Because these arid rangelands are linked socio-ecological systems, it is not possible to address biophysical issues associated with land degradation without including the human dimensions. A “Key assessment matrix” is provided for monitoring and management purposes pertaining to land degradation and diversity aspects within and between the different land uses, and can be used by the land user, extension officer and scientist. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2007.
|
3 |
Best land-use strategies towards sustainable biodiversity and land degradation management in semi-arid western rangelands in southern Africa, with special reference to ants as bio-indicators / Marisa Coetzee.Coetzee, Marisa January 2006 (has links)
In South Africa, the unsustainable use of natural resources by domestic livestock has led to resource depletion and serious land degradation. Rangeland degradation, especially bush encroachment and soil
erosion, is particularly acute in the North-West Province, where all districts show signs of desertification and a loss of biodiversity resulting in a deterioration of human and animal health. This has a major
impact on livestock productivity and the economic viability of livestock farming with serious consequences for the livelihoods of pastoral communities. It is important to recognise ecological change before irreversible changes occur. The aim of this study, which falls within the Global Environmental Facility Desert Margins Programme (GEF-DMP), was to investigate to what extent vegetation in combination with ant communities can be used as indicators of ecosystem change due to anthropogenic human induced land-use patterns and how can this information be used in land degradation management and biodiversity conservation in the semi-arid western rangelands of Southern Africa. Sites, representing a degradation
gradient (relative poor and relative good rangeland condition extremes) within each of three Tribal-, three Commercial- and three Reserve areas, were surveyed. The impacts of these land uses on the
herbaceous species composition, woody-, soil- and ant components were evaluated. Both the woody and herbaceous species components reflected the existence of a rangeland condition/degradation gradient
across the larger study area. The herbaceous species composition reflected similar degradation tendencies within the Commercial and Reserve land uses, with sites being associated with low rangeland
as well as high rangeland condition scores. The tendencies differed between these two land uses based on the woody degradation gradient. The entire Tribal herbaceous- and woody species components showed a transitional shift towards another state, which differed significantly from the Commercial and Reserve land uses. Both the Tribal herbaceous and woody components were associated with low to intermediate rangeland condition ranges, with no significant rangeland condition gradient existing within the Tribal land use.
Understanding and quantification of the soil-vegetation dynamics hold important implications for rangeland degradation management. This study provided criteria for selecting the most appropriate
measures when incorporating the soil parameters as additive data in the multivariate analyses with the
vegetation, ant and nominal environmental data. Different land use practices resulted in different soil patterns, with significant gradients pertaining to the soil stratum and openness/woodiness groups. There was a significant though neglectable difference pertaining to the rangeland condition/degradation gradient based on the soil component. Ants have been extensively used as bio-indicators, also with regard to the monitoring of the environmental effects of rangeland pastoralism. Ant species compositional patterns and functional
groups displayed congruent clustering and diversity patterns as those of the vegetation and soil components. In contrast to the vegetation components, ant assemblages did not reflect a degradation
gradient, but rather reflected environmental changes (modifications) to the habitat structure and - heterogeneity as a result of different land use disturbances.
Both vegetation and ant diversity measures were mainly associated with the Tribal land use. These diversity indices were indicators of habitat complexity, heterogeneity and moderate disturbance, rather than indicators of a rangeland condition/degradation gradient. The diversity patterns are best described
by a dichotomy between the humped-shaped productivity/diversity and the habitat
complexity/heterogeneity models. Vegetation and ant diversity measures for this study should be considered as environmental indicators of habitat disturbance rather than as biodiversity indicators.
It is suggested that vegetation, soil and ant patterns are best described by the state-and-transition model, which encompasses both equilibrium and non-equilibrium systems. The resilient nature of these rangelands, typical of non-equilibrium systems, was reflected by the low to intermediate differences
between land uses with regard to the herbaceous, woody, soil and ant components. However, densitydependent coupling of herbivores to key resources resulted in transitional shifts and modification of the
vegetation composition and structure within and between land uses, displaying the equilibrium dynamics pertaining to these rangelands. Small disturbances in these rangelands may result in detrimental
“snowball” interactive biotic-biotic /abiotic cascades. Spatial heterogeneous patterns within and between
land uses as displayed by the vegetation, soil and ant parameters, necessitate that monitoring and management at patch, paddock and landscape scale should be conducted, cautioning against the extrapolation and over simplification of management strategies across all land uses. Because these arid rangelands are linked socio-ecological systems, it is not possible to address biophysical issues associated with land degradation without including the human dimensions. A “Key assessment matrix” is provided for monitoring and management purposes pertaining to land degradation and diversity aspects within and between the different land uses, and can be used by the land user, extension officer and scientist. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2007.
|
4 |
Evaluation of restoration and management actions in the Molopo savanna of South Africa :|ban integrative perspective / Christiaan Johannes HarmseHarmse, Christiaan Johannes January 2013 (has links)
The loss of ecosystem resilience and rangeland (often referred to as veld in South
Africa) productivity is a major problem in the semi-arid Savanna environments of
southern Africa. The over-utilization of rangelands in the Molopo region of the North-
West Province in South Africa has resulted in profound habitat transformations. A
common regional indicator of rangeland degradation is the imbalance in the grasswoody
ratio, characterized by a loss of grass cover and density with increased shrub
or tree density. This can result in major reductions of rangeland productivity for the
grazing animal, forcing land users to apply active or passive restoration actions to
improve rangeland condition, control the thickening of woody species (bush
thickening), mitigate economic losses and restoring the aesthetical value of the
Savanna environment for ecotourism and game hunting aspects.
This study formed part of the multinational EU-funded PRACTICE project
(“Prevention and restoration actions to combat desertification: an integrated
assessment”). The first aim of the study was to evaluate locally applied restoration
actions using a participatory approach, followed by interviews with certain
stakeholders that formed part of a multi-stakeholder platform (MSP) related to the
livestock and game farming community in the Molopo. Participants of the MSP
ranked indicators according to their relative importance regarding the restoration
actions on an individual basis. The individual ranking results were combined with
quantitative bio-physical and qualitative socio-economic measurements for each
indicator in a multi-criteria decision analysis (MCDA), whereby the alternative actions
were ranked according to their relevancy and performance. The results were then
shared with members of the MSP in order to stimulate discussion among the
members and contribute to the social learning of the project outcome.
The overall positive response and acceptance of results by members of the MSP
changed the perceptions and objectives of the land users regarding rangeland
management. This type of participatory assessment was therefore found to be very
promising in helping to identify more sustainable actions to mitigate rangeland
degradation in the Molopo Savanna region. There is, however, still an urgent need to
create legal policy frameworks and institution-building, to support local-level implementation in all socio-ecological and economic settings, particularly in
communal areas.
The second aim was to evaluate the effect of two chemical bush control actions
(chemical hand- (HC) and aeroplane control (AC)) as well as rotational grazing
(RGM) on the Molopo Savanna vegetation.
Results show that rangeland productivity, i.e. forage production and grazing
capacity, was found to be negatively related to the woody phytomass in the savanna
system studied. Bush thickening influenced grass species composition which was
commonly associated with a decline in the abundance of sub-climax to climax
grasses, respectively. All three actions (HC, AC & RGM) significantly reduced the
woody phytomass and increased forage production and grazing capacity.
Although AC resulted in the highest reduction of woody phytomass, the highest
forage production and grazing capacity was found under RGM. The second highest
grazing capacity was found in HC sites, which was due to a high abundance of
perennial, palatable climax grass species. Results from this study also show that the
patterns and compositions of grass species, grass functional groups (GFGs) and
woody densities indicated by RGM and chemical HC, best resemble a productive
and stable savanna system that provides important key resources to support both
grazing and browsing herbivores. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
|
5 |
Evaluation of restoration and management actions in the Molopo savanna of South Africa :|ban integrative perspective / Christiaan Johannes HarmseHarmse, Christiaan Johannes January 2013 (has links)
The loss of ecosystem resilience and rangeland (often referred to as veld in South
Africa) productivity is a major problem in the semi-arid Savanna environments of
southern Africa. The over-utilization of rangelands in the Molopo region of the North-
West Province in South Africa has resulted in profound habitat transformations. A
common regional indicator of rangeland degradation is the imbalance in the grasswoody
ratio, characterized by a loss of grass cover and density with increased shrub
or tree density. This can result in major reductions of rangeland productivity for the
grazing animal, forcing land users to apply active or passive restoration actions to
improve rangeland condition, control the thickening of woody species (bush
thickening), mitigate economic losses and restoring the aesthetical value of the
Savanna environment for ecotourism and game hunting aspects.
This study formed part of the multinational EU-funded PRACTICE project
(“Prevention and restoration actions to combat desertification: an integrated
assessment”). The first aim of the study was to evaluate locally applied restoration
actions using a participatory approach, followed by interviews with certain
stakeholders that formed part of a multi-stakeholder platform (MSP) related to the
livestock and game farming community in the Molopo. Participants of the MSP
ranked indicators according to their relative importance regarding the restoration
actions on an individual basis. The individual ranking results were combined with
quantitative bio-physical and qualitative socio-economic measurements for each
indicator in a multi-criteria decision analysis (MCDA), whereby the alternative actions
were ranked according to their relevancy and performance. The results were then
shared with members of the MSP in order to stimulate discussion among the
members and contribute to the social learning of the project outcome.
The overall positive response and acceptance of results by members of the MSP
changed the perceptions and objectives of the land users regarding rangeland
management. This type of participatory assessment was therefore found to be very
promising in helping to identify more sustainable actions to mitigate rangeland
degradation in the Molopo Savanna region. There is, however, still an urgent need to
create legal policy frameworks and institution-building, to support local-level implementation in all socio-ecological and economic settings, particularly in
communal areas.
The second aim was to evaluate the effect of two chemical bush control actions
(chemical hand- (HC) and aeroplane control (AC)) as well as rotational grazing
(RGM) on the Molopo Savanna vegetation.
Results show that rangeland productivity, i.e. forage production and grazing
capacity, was found to be negatively related to the woody phytomass in the savanna
system studied. Bush thickening influenced grass species composition which was
commonly associated with a decline in the abundance of sub-climax to climax
grasses, respectively. All three actions (HC, AC & RGM) significantly reduced the
woody phytomass and increased forage production and grazing capacity.
Although AC resulted in the highest reduction of woody phytomass, the highest
forage production and grazing capacity was found under RGM. The second highest
grazing capacity was found in HC sites, which was due to a high abundance of
perennial, palatable climax grass species. Results from this study also show that the
patterns and compositions of grass species, grass functional groups (GFGs) and
woody densities indicated by RGM and chemical HC, best resemble a productive
and stable savanna system that provides important key resources to support both
grazing and browsing herbivores. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
|
Page generated in 0.1185 seconds