Trends in land use and land cover change in the protected and communal areas of the Zambezi Region, Namibia
- Authors: Kamwi, Jonathan , Kaetsch, Christoph , Graz, Patrick , Chirwa, Paxie , Manda, Samuel
- Date: 2017
- Type: Text , Journal article
- Relation: Environmental Monitoring and Assessment Vol. 189, no. 5 (2017), p. 1-18
- Full Text:
- Reviewed:
- Description: Land management decisions have extensively modified land use and land cover in the Zambezi Region. These decisions are influenced by land tenure classifications, legislation, and livelihoods. Land use and land cover change is an important indicator for quantifying the effectiveness of different land management strategies. However, there has been no evidence on whether protected or communal land tenure is more affected by land use and land cover changes in southern Africa and particularly Namibia. Our study attempted to fill this gap by analyzing the relationship between land use and land cover change and land tenure regimes stratified according to protected and communal area in the Zambezi Region. Multi-temporal Landsat TM and ETM+ imagery were used to determine the temporal dynamics of land use and land cover change from 1984 to 2010. The landscape showed distinctive modifications over the study period; broad trends include the increase in forest land after 1991. However, changes were not uniform across the study areas. Two landscape development stages were deduced: (1) 1984–1991 represented high deforestation and gradual increase in shrub land; (2) 1991–2000 and 2000–2010 represented lower deforestation and slower agropastoral expansion. The results further show clear patterns of the dynamics, magnitude, and direction of land use and land cover change by tenure regime. The study concluded that land tenure has a direct impact on land use and land cover, since it may restrict some activities carried out on the land in the Zambezi Region. © 2017, Springer International Publishing Switzerland.
Livelihood activities and skills in rural areas of the Zambezi Region, Namibia : Implications for policy and poverty reduction
- Authors: Kamwi, Jonathan , Chirwa, Paxie , Graz, Patrick , Manda, Samuel , Mosimane, Alfons , Katsch, Christoph
- Date: 2018
- Type: Text , Journal article
- Relation: African Journal of Food, Agriculture, Nutrition and Development Vol. 18, no. 1 (2018), p. 13074-13094
- Full Text:
- Reviewed:
- Description: This paper examined livelihood activities and skill sets available within rural households in the Zambezi Region of Namibia. Specifically, the study addressed three key questions: (i) what livelihood activities do rural people pursue? (ii) what demographic factors are associated with these activities? and (iii) what measures can be taken to diversify and sustain income from these livelihood activities? In order to address these questions, semistructured interviews covering 424 households were used to collect the data. The questionnaire consisted of questions corresponding to the sustainable livelihood framework including (1) human assets (2) financial assets and major sources of income (3) physical and natural assets and (4) social assets. A series of logistic regressions were fitted from which the estimated odds ratios (y) were derived to ascertain the effect of the predictors on the livelihood activities and skills. Odds ratios were used to measure the magnitude of strength of association or non-independence between binary data values. The results showed that the use of various livelihood activities and skills in different combinations is of significant importance to rural livelihoods. Five percent of the respondents obtained income from only one source, with 95 % of the respondents engaged in a combination of farming and non-farming activities. Most of the respondents had various reasons for diversifying into other activities vis-a-vis agricultural income, limited skills, large family size, availability of opportunities, seasonal nature of agricultural produce, favourable demand for goods and services or a combination of these. In addition, the results showed that gender, age, designation and education significantly (p < 0.05) influenced the choice of household's skills. The study concludes that a combination of rural household activities and skills influenced by a variety of factors have led to improved livelihoods in the study area. For policy purposes, this suggests that state interventions in rural livelihood skill development can play a significant role in promoting more sustainable rural livelihoods. © 2018, African Scholarly Science Communications Trust (ASSCAT).
Livelihoods, land use and land cover change in the Zambezi Region, Namibia
- Authors: Kamwi, Jonathan , Chirwa, Paxie , Manda, Samuel , Graz, Patrick , Katsch, Christoph
- Date: 2015
- Type: Text , Journal article
- Relation: Population and Environment Vol. 37, no. 2 (2015), p. 207-230
- Full Text: false
- Reviewed:
- Description: This paper examines the socio-economic drivers of land use and land cover change and assesses the impacts of such changes to rural livelihoods in the Zambezi region of northern Namibia. We carried out a longitudinal analysis of Landsat imagery of land use and land cover. The analysis revealed that the amount of land in the region covered by forest increased significantly in the period from 1991 to 2010 whilst crop/grass land decreased. Focus group meetings, key informant interviews and semi-structured interviews covering 424 households stratified by gender were used. The results show that natural resource uses are vitally important in the rural livelihoods. The drivers of land use and land cover change are agricultural expansion, population increase and illegal logging. Livelihood coping strategies include piecework, food aid, borrowing from relatives and wild food collection. By gender stratification, piecework contributed 37 and 63 % while agriculture contributed 29 and 71 % of the income of male- and female-headed households. Logistic regression analysis showed knowledge of regulations, age group and species availability significantly (p < 0.05) influenced the choice of a household's livelihood coping strategy. The study concludes that the changes in coping strategies influenced by a variety of factors have led to the diminished use of natural resources. For policy purposes, this suggests that state interventions can play a significant role in promoting more sustainable natural resource usage. This analysis enables effective decision-making to reconcile the efforts of sustainable development and natural resource management. © 2015, Springer Science+Business Media New York.
Plant recruitment and survival as indicators of ecological success in abandoned pasture land in Nurcoung
- Authors: Florentine, Singarayer , Gardner, Jessica , Graz, Patrick , Moloney, Sean
- Date: 2013
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 2, no. 1-3 (2013), p.
- Full Text:
- Reviewed:
- Description: One of the major impediments to developing better restoration strategies is the inadequate documentation of past restoration efforts. In 2008, Greening Australia commenced ecological restoration on the Nurcoung property in Victoria to enhance local biodiversity, and in this paper we report on the habitat restoration outcomes in the three Ecological Vegetation Classes (EVC) found on this property.
A unique weed problem — the control of fairy grass Lachnagrostis filiformis seedheads on Lake Learmonth in western Victoria
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2008
- Type: Text , Conference paper
- Relation: Paper presented at 16th Australian Weeds Conference: Weed management 2008 hot topics in the tropics, Cairns, Queensland : May 18th-22nd, 2008 p. 165-167
- Full Text:
- Description: The native fairy grass (Lachnagrostis filiformis (G. Forst.) Trin.) has colonised extensive areas of dry lake beds in western Victoria during the current drought. Large numbers of the plants’ detached mature panicles (seed heads) lodge against housing, fences, railway lines and other obstacles. This can be a fire hazard, degrades township aesthetics and creates a general nuisance to communities of lakeside towns. Current control measures are costly and only provide short-term solutions. A three-year study commencing in 2006 was designed to assess current and innovative control measures and develop a potential long-term management solution to the problem. Treatments applied to the bed of Lake Learmonth during the first year of the study included late-season glyphosate herbicide at two concentrations, late-season slashing, and seed broadcasting of two native species to reduce L. filiformis inflorescence biomass through competition. Slashing reduced L. filiformis inflorescence biomass and herbicide treatments successfully killed L. filiformis plants, while having no effect on germination of seed collected from sprayed plants. Although these treatments successfully limited the impact of L. filiformis on lakeside towns during the first year, the longer term efficiency is doubted. Treatment effects will be monitored over a further two years.
- Description: 2003006269
Decade-long response of arid-land mallee vegetation to fire, flooding and grazing in south-eastern Australia
- Authors: Florentine, Singarayer , Milberg, Per , Di Stefano, Julian , Westbrooke, Martin , Graz, Patrick
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 121, no. October (2015), p. 7-14
- Full Text:
- Reviewed:
- Description: Australian arid vegetation has evolved within highly variable environments characterised by low rainfall and sporadic fire events. Episodic high rainfall events are a significant factor in plant species recruitment, but their unpredictability makes them difficult to study. We report on the response of vascular plants to a major rainfall event and flood in an arid region of south-eastern Australia. Fire that occurred two months before the flood was incorporated into the study. Paired fenced and unfenced plots were established at control locations and also in areas that had been either flooded, burnt, or flooded and burnt. Objectives were to quantify the long-term effects of fire, flood and vertebrate herbivory, and their interactions, on vegetation composition, plant life forms and species diversity. We found that relative to controls (i) there was a significant effect of flooding on vegetation composition, (ii) changes in life form abundance were driven by flooding and grazing, (iii) there was a strong positive relationship between grazer exclusion and species diversity that was maintained over time and (iv) there was little effect of fire. Understanding the long-term effects of both natural disturbances and vertebrate herbivory will benefit plant conservation in the arid zone. © 2015 Elsevier Ltd.
Schinziophyton rautanenii (Schinz) Radcl.-Sm
- Authors: Graz, Patrick
- Date: 2007
- Type: Text , Book chapter
- Relation: Vegetable oils Chapter p.
- Full Text: false
Controlling wind blown Lachnagrostis filiformis (fairy grass) seed heads in western Victoria
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2009
- Type: Text , Conference paper
- Relation: Paper presented at Fourth Victorian Weed Conference : Plants behaving badly - in agriculture and the environment, Mercure Hotel, Geelong, Victoria : 7th-8th October 2009
- Full Text:
- Description: 2003007372
The behaviour of the measure of surround in relation to the diameter and spatial structure of a forest stand
- Authors: Graz, Patrick
- Date: 2008
- Type: Text , Journal article
- Relation: European Journal of Forest Research Vol. 127, no. 2 (2008), p. 165-171
- Full Text: false
- Reviewed:
- Description: Forestry inventory practices have, in the past, concentrated on obtaining information primarily required for timber management. To assess the ecological impact of exploitation, particularly under continuous cover forest management, diversity measures are required that consider the structural diversity in a forest stand. The measure of surround that was initially developed in Germany may be used to quantify the spatial interspersion of different tree size classes as a measure of spatial diversity. While the measure of surround has been applied to practical problems in the past, little is known about its actual performance in relation to stand compositions. This study investigate the behaviour of the index using a number of simulated age class distributions under various degrees of interspersion to provide a norm against which it may be compared. The measure of surround applied to diameter distributions is closely related to the diameter structure of a stand. When diameter classes are interspersed completely randomly within a stand the relative cumulative frequency of the diameter class provides an estimator of the size specific measure of surround. This provides a baseline from which the index may be interpreted. © Springer-Verlag 2007.
- Description: C1
Influence of selected environmental factors on seed germination and seedling survival of the arid zone invasive species tobacco bush (Nicotiana glauca R. Graham)
- Authors: Florentine, Singarayer , Weller, Sandra , Graz, Patrick , Westbrooke, Martin , Florentine, Arunthathy , Javaid, Muhammad , Fernando, Nimesha , Chauhan, Bhagirath , Dowling, Kim
- Date: 2016
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 38, no. 4 (2016), p. 417-425
- Full Text: false
- Reviewed:
- Description: Tobacco bush (Nicotiana glauca R. Graham) is an aggressive invading species, which is active after disturbances such as high rainfall events and flooding. Past studies have focussed on population dynamics and allelopathic effects associated with the species, but little is known about its seed ecology. To address this dearth of information, this study aimed to investigate: (i) the effect of various stress factors (temperature, light, osmotic potential, salt stress, heat-shock, a combination of heat-shock and smoke, pH buffer, and burial depth of seed) on seed germination and seedling emergence, and (ii) factors affecting the fate of seedlings. The results show that N. glauca was able to germinate over a broad range of temperatures with highest seed germination occurring at 30/20°C with 12h of light and 12h of dark conditions. Seed germination was greatest (89%) when seeds were placed on the soil surface and emergence decreased considerably as planting depth increased from 0.5 to 1.5cm. Water stress greatly reduced seed germination (58% germination at osmotic potentials below -0.2 MPa) and germination was completely inhibited at water potentials of -0.4 to -0.6 MPa. Although increasing salinity reduced the seed germination of this invasive species, N. glauca seed was able to germinate in both alkaline (81% at pH 10) and acidic (80% at pH 4) conditions. The trial on the effect of seed age and field seed burial on seed germination showed a slight decline in seed germination after 120 days of burial compared with non-buried seeds. Further, the combined effect of heat-shock and smoke effectively inhibited the germination of N. glauca seeds; however, our study shows that seedlings of N. glauca can withstand heat-shock of up to 130°C. Studies such as this will assist in the development of control strategies to prevent the spread of this invasive species into arid landscapes. © 2016 Australian Rangeland Society.
Predicting site productivity of the timber tree Pterocarpus angolensis
- Authors: De Cauwer, Vera , Fichtler, Esther , Beeckman, Hans , Graz, Patrick , Mertens, Jan , Van Holsbeeck, Sam , Muys, Bart
- Date: 2017
- Type: Text , Journal article
- Relation: Southern Forests Vol. 79, no. 3 (2017), p. 259-268
- Full Text: false
- Reviewed:
- Description: Pterocarpus angolensis is an important timber tree of the miombo woodlands of sub-Saharan Africa. The species only grows in natural mixed forests and little is known about is productivity potential. This study aimed at investigating productivity of P. angolensis on a local scale in Namibia and Angola and on a regional scale in southern Africa. The most commonly accepted productivity indicator is stem diameter increment and this was used to study productivity at a regional scale. Indicators of productivity used at the local scale were basal area, proportional basal area and site form, which were derived from 217 forest inventory plots in Namibia and Angola. The productivity measures were modelled with abiotic site factors; biotic factors were added for the local scale. Results indicated that the most consistent site factors at local and regional scale were not related to climate but to forest cover, with the species having a competitive advantage in more open forests. Mean annual diameter increment in the open forests of Namibia was 0.51 cm after 50 years. Boosted regression tree models at a local scale showed that species presence can be modelled more successfully than species basal area, proportional basal area (correlation of 0.72 vs 0.56 and 0.45, respectively) and site form. The sites with the highest productivity of P. angolensis at the local scale had a temperature seasonality below 34.5 °C, a slope of less than 1.5°, tree cover less than 20% and stand basal area higher than 9 m2 ha−1. The results can assist in establishing a site-dependent growth model for the species and direct forest and fire management towards the most productive areas. © 2017 NISC (Pty) Ltd.
The Current Status Of Different Age, Direct-Seeded Revegetation Sites In An Agricultural Landscape In The Burrumbeet Region, Victoria, Australia
- Authors: Florentine, Singarayer , Graz, Patrick , Ambrose, Graeme , O'Brien, L.
- Date: 2013
- Type: Text , Journal article
- Relation: Land Degradation and Development Vol. 24, no. 1 (2013), p. 81-89
- Full Text: false
- Reviewed:
- Description: Many vegetation restoration works have been undertaken in Australia but only a few of those projects have been assessed for effectiveness. Revisiting earlier restoration attempts and analysing data from them is fundamental to the development of evidence-based prescriptions for future restoration work. Therefore, this study's objectives were to (I) compare plant species composition of different age direct-seeded revegetated sites and (II) determine the effect, if any, of different ages of revegetated sites on the natural recruitment of native plants. The study investigated four fenced restoration sites, dating from 2000, 2001, 2004 and 2005. Results showed that the density of plants surviving varied widely between plots of different ages. The highest density was found in the 2001 plot (2195·.7 stemsha-1), followed by 2000 (1877·8 stemsha-1), 2004 (197·6 stemsha-1) and 2005 (195·4 stemsha-1). An ANOVA showed that the overall amount of seed broadcast does not play a significant (p=0·437) role in the establishment rate. Overall, Eucalyptus ovata was found to be dominant in the 2000 (794·4ha-1) and 2001 (971ha-1) sites. In contrast, Eucalyptus camaldulensis and Eucalyptus viminalis densities were highest in the 2004 (41ha-1) and 2005 (60·4ha-1) sites, respectively. PERMANOVA showed highly significant differences in the present plant composition between plots (p<0·0001), despite similar species mixes used in sowing. Recruitment was not found in any of the sites. The least weed cover and the highest litter cover were found in the 2001 plot. A similar trend was found in the 2000 plot. In contrast, high weed cover and low litter cover were found in the 2004 and 2005 plots. Since one of the major impediments to developing better restoration strategies is the inadequate documentation of past practices, studies such as these may shed some light on how the direct-seeded technique operates in a farm situation. © 2011 John Wiley & Sons, Ltd.
The woody weed encroachment puzzle : Gathering pieces
- Authors: Graz, Patrick
- Date: 2008
- Type: Text , Journal article
- Relation: Ecohydrology Vol. 1, no. 4 (2008), p. 340-348
- Full Text: false
- Description: Increases in woody plant densities in savanna grazing lands worldwide have resulted in a decline in the grazing, capacity of these rangelands. At present. the actual cause of the problem is unknown although a vast body of literature deals with various aspects relevant to the issue. It is generally assumed, however. that the changes in the tree : grass ratio are a response to changes in soil-water development brought about by rangeland utilization. These utilization patterns differ from those under which the savanna system evolved. While changes in physiognomy are very prominent. these are generally preceded by changes in grass species assemblage. The development of species composition has been used as an indicator of rangeland condition for many years; the increase or decrease of individual species is considered in this context. Thus far. however, the shift from perennial to annual grasses has not been evaluated for its effect on soil moisture development, and subsequent implications for woody plant establishment and growth. The review presented here consolidates the existing information in order to provide a basis for understanding the woody weed encroachment problem. Copyright (C) 2008 John Wiley & Sons. Ltd.
Building suitable restoration approaches in the Brownfields
- Authors: Florentine, Singarayer , Graz, Patrick , Doronila, Augustine , Martin, Rachael , Dowling, Kim , Fernando, Nimesha
- Date: 2016
- Type: Text , Book chapter
- Relation: Sustainability in the Mineral and Energy Sectors Chapter 13 p. 223-239
- Full Text: false
- Reviewed:
- Description: Human activity has, in the recent past resulted in substantial changes in land cover, ecosystem health, and the ability of affected ecosystems to return to their original state. This necessitates further human intervention to recreate the systems functions than the present. Earlier restoration activities have not been documented extensively. This hinders our efforts to identify approaches that might support further work. "From abstract"
Spatial diversity of dry savanna woodlands : Assessing the spatial diversity of a dry savanna woodland stand in northern Namibia using neighbourhood-based measures
- Authors: Graz, Patrick
- Date: 2006
- Type: Text , Journal article
- Relation: Biodiversity and Conservation Vol. 15, no. (2006), p. 1143–1157
- Full Text: false
- Reviewed:
- Description: The dry woodland savannas of Namibia are of significant socio-economic importance. The paper tests the suitability of a number of diversity indicators developed for species poor systems in Europe in the woodland context. The indicators that were tested included the species specific mingling index, MSp, the measure of surround and the uniform angle index. The simple application of the methods permit relatively unschooled crews to conduct an enumeration in the field.The results show that the indicators do not only display current diversity status, but also reflect the ecological context of the individual species.
Modelling the effects of water-point closure and fencing removal : A GIS approach
- Authors: Graz, Patrick , Westbrooke, Martin , Florentine, Singarayer
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Environmental Management Vol. 104, no. (2012), p. 186-194
- Full Text: false
- Reviewed:
- Description: Artificial water-points in the form of troughs or ground tanks are used to augment natural water supplies within rangelands in many parts of the world. Access to such water-points leads to the development of a distinct ecological sub-system, the piosphere, where trampling and grazing impact modify the vegetation. This study aims to consolidate existing information in a GIS based model to investigate grazing patterns within the landscape. The model focuses on the closure of water-points and removal of fences on Nanya Station, New South Wales, Australia. We found that the manipulation of water-points and fences in one management intervention may change grazing activity in a way different to that which would be experienced if each had been modified separately. Such effects are further modified by the spatial distribution of the water-points and the underlying vegetation. © 2012 Elsevier Ltd.
Short-term gain and long-term pain: Lessons learnt from the control of Lachnagrostis filiformis (fairy grass) in Victoria, Australia
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2012
- Type: Text , Journal article
- Relation: Weed Biology and Management Vol. 12, no. 4 (December 2012), p. 156-167
- Full Text: false
- Reviewed:
- Description: The indigenous Lachnagrostis filiformis colonized extensive areas of dry lake beds in Victoria, Australia, during the drought from 1997 to 2009. Large numbers of the plants' detached seed heads disperse in the wind, lodging against nearby housing, fences and other obstacles. This accumulation of material creates a fire hazard, degrades townships' aesthetics and presents a nuisance to the communities of lake-side towns. This study aimed to examine the effects of various control methods on L.?filiformis in the short and long term. Although herbicide applications, slashing, grazing and burning were found to be effective in controlling the blown L.?filiformis seed heads in the short term, they failed to prevent subsequent reinvasion and can increase its abundance in the long term. The late application of herbicide resulted in an increase in the foliage cover and seed-head biomass of L.?filiformis by up to 37% and 150%, respectively, in the year following the treatment application. The results from this study highlight how management focused on achieving short-term goals, without consideration of the successional trajectory after implementation, can not only fail but be counter-productive in the long term. In order to achieve sustainable management, the fundamental ecological processes that promote the establishment and persistence of the weed need to be addressed.