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Desertification and Namibia: a perpective
Abstract
Desertification is complex problem and concept. This problem has ultimate causes, for example poverty, and proximate causes, such as agricultural mismanagement. These two levels of causation lead to processes, such as overgrazing or erosion, that manifest themselves in states of environmental degradation, for example, eroded landscapes and and annual instead of perennial grasslands. A subset of factors contributing to desertification are operative in Namibia, the driest country south of the Sahel. Namibia with its rapidly increasing population, needs to develop an institutional memory of the consequences of natural rainfall variations. Awareness, education and training, based on knowledge and understanding of the causes and processes involved, are considered essential compnents of any plan to address the challenge of desertification. This must be supported by research addressing, not just the symptoms of desertification but, the socio-economic agricultural, political and educational, in addition to the biophysical aspects. Bio-physical scientists working on desertification must learn to communicate with, as well as develop skills in , disciplines such as politics, economics, journalism and social science.
... Namibia's NatKmal Programme to Combat Desertification (NAPCOD) was launched in 1994 {Wolters 1994). Since inception, it was designed as a development and community-based natural resource management programme with emphasis on supporting local level management action and national level policy making with sound and relevimt research (Seely and Jacobson 1994). The programme was to reflect the specific ecological and societal conditions prevailing in Namibia~ A key aspect ofNAPCOD'was development of reliable . ...
... fungi, interact while maintaining soil-related ecosystem functions; such as nutrient breakdown and cycling. · In dryland systems, such as the north-western pan of Namibia, tennites dominate the soil macrotauna complemented in some areas by fishmoths (Crawford and Seely 1994, andZeidler eta/. 2002 a). ...
... There is currently much concern in Namibia about the effects of various agricultural practices on productivity of the land (Quan et al. 1994, Seely and Jacobson 1994, Bester 1995, Ward 1996, Aharoni and Ward 1997. Indeed, about 60% of northern Namibia suffers from bush encroachment, while up to 90% of southern Namibia is considered to be overgrazed (Quan et al. 1994). ...
... We consider this point to be unnecessarily restrictive because grasslands tend to change from annual to perennial grasses with increasing rainfall (Shmida 1985), thereby precluding appropriate comparison along the rainfall gradient in Namibia. Additionally, annual grasses tend to replace perennial grasses in desertified grasslands, especially those suffering from heavy grazing (Kelly and Walker 1977, Frost et al. 1986, O'Connor 1991, O'Connor and Pickett 1992, Seely and Jacobson 1994, Parton et al. 1995, Parsons et al. 1997. ...
We compared the herbage standing crop on 31 farms along a rainfall gradient in Namibia (southwestern Africa) in 1997 with the results attained for the same gradient by Waiter (1939). We found that the slope for the regression of herbage yield on mean annual rainfall in 1997 was 5.93, i.e. 5.93 kg herbage was produced per hectare for every 1 mm increase in rainfall along the gradient. This regression slope is considerably lower than that in Waiter's (1939) study (slope = 10.34). Thus, current grassland productivity per unit of rainfall in Namibia is about half that of 50 years ago. There is no evidence of a change in annual rainfall over this period, nor is there any evidence that either short-term (current) or longer-term (11 years) stocking densities affect current herbage yield. We conclude that, while desertification has taken place, grazing over the last decade has not been the cause of this reduced productivity.
... This is evident in communal tenure areas, where land degradation is a growing problem (Adams and Devitt, 1992;Quan et al., 1994b;Seely et al., 1995;Wolters, 1994). According to Seely and Jacobson (1994), proximate causes of land degradation in Namibia include both biophysical and land management factors. Non-adaptive management in a highly variable climate is seen as a major cause of land degradation (Naraa et al., 1993;Van Warmelo, 1962). ...
... Non-adaptive management in a highly variable climate is seen as a major cause of land degradation (Naraa et al., 1993;Van Warmelo, 1962). Seely and Jacobson (1994) state that reduction in vegetation cover and subsequent soil denudation following intensive grazing can be found in all regions but in particular, in the Erongo, Kunene and north-central regions ( Figure 1). Sullivan has recently challenged these views on the basis of a study in Kunene, north-western Namibia, concluding that land degradation is not as widespread as commonly perceived (Sullivan, 1998;Sullivan, 2000). ...
This paper presents development of a first approximation of a Namibian, national level, land degradation monitoring system. The process involved a large number of stakeholders and led to the definition of four primary indicators that were regarded as related to land degradation in Namibia: population pressure, livestock pressure, seasonal rainfall and erosion hazards. These indicators were calculated annually for the period 1971-1997. Annual land degradation risk maps were produced for the same period by combining the indicators. A time series analysis of results generated by indicators was undertaken at two sites. The analysis revealed a general trend towards an increased land degradation risk over the period 1971-1997. A decrease in annual rainfall and an increase in livestock numbers caused this negative trend at one site, while decreased annual rainfall and increased human population were the causes at a second site. Evaluation of resulting maps through direct field observations and long-term monitoring at selected study sites with different conditions relevant for the indicators defined, is an essential next step.
... Additionally, grazing livestock can benefit woody plants by dispersing their seeds and by removing the fuel load, thereby reducing fire frequency and intensity, enhancing woody plant recruitment (Briske, 2017). This shift toward shrubland is usually accompanied by a shift from perennial to annual grasses (Schlesinger & Jasechko, 2014;Seely & Jacobson, 1994) or from palatable to less palatable species (Milton, 1994). ...
Changing climatic conditions and unsustainable land use are major threats to savannas worldwide. Historically, many African savannas were used intensively for livestock grazing, which contributed to widespread patterns of bush encroachment across savanna systems. To reverse bush encroachment, it has been proposed to change the cattle-dominated land use to one dominated by comparatively specialized browsers and usually native herbivores. However, the consequences for ecosystem properties and processes remain largely unclear. We used the ecohydrological, spatially explicit model EcoHyD to assess the impacts of two contrasting, herbivore land-use strategies on a Namibian savanna: grazer- versus browser-dominated herbivore communities. We varied the densities of grazers and browsers and determined the resulting composition and diversity of the plant community, total vegetation cover, soil moisture, and water use by plants. Our results showed that plant types that are less palatable to herbivores were best adapted to grazing or browsing animals in all simulated densities. Also, plant types that had a competitive advantage under limited water availability were among the dominant ones irrespective of land-use scenario. Overall, the results were in line with our expectations: under high grazer densities, we found heavy bush encroachment and the loss of the perennial grass matrix. Importantly, regardless of the density of browsers, grass cover and plant functional diversity were significantly higher in browsing scenarios. Browsing herbivores increased grass cover, and the higher total cover in turn improved water uptake by plants overall. We concluded that, in contrast to grazing-dominated land-use strategies, land-use strategies dominated by browsing herbivores, even at high herbivore densities, sustain diverse vegetation communities with high cover of perennial grasses, resulting in lower erosion risk and bolstering ecosystem services.
... High variability of rainfall and distinct seasonal changes of the amount and quality of rangeland fodder resources are typical characteristics of the semi-arid and arid rangelands of Namibia (Schneiderat, 2011). Reduced vegetation cover and subsequent soil denudation can be found in many regions in Namibia, particularly in Erongo (in western Namibia), Kunene (in northwestern Namibia) and north-central regions (Seely & Jacobson, 1994). ...
Land degradation has put the world's rangelands under intense pressure and reduced their capacity to provide vital services to those who solely depend on them for survival. With the current pressures on rangelands, worldwide, there is an urgent need to survey the present condition of rangelands. Such detailed surveys can identify where improvement programmes can be emphasised; whether it be reseeding, stock control, sociological restraints or other actions. To combat rangeland degradation, management systems are more effective when they account for community perceptions and practices. This study aims to assess the current status of woody plants in different categories of degradation as perceived by herders in Kunene, Namibia. Furthermore, we wished to compare the perception of degradation by herders with the measured ecological condition. With the help of herders, sites representing different categories of degradation (low, moderate, high and protected) were identified and 10 plots of 400m2 each were established in each category. Species diversity, density, basal area and regeneration of woody plants increased sequentially along the degradation gradient (high to low). Vegetation attributes such as species diversity, seedling density and standing basal area increased with increasing distances from the villages. Although the herders' perception of degradation, for high and moderate degradation, matches the ecological results, the low degradation sites show signs of bush encroachment, a type of degradation that the herders did not perceive as degradation. Colophospermum mopane, a known encroacher species across Namibia, was the dominant species in the moderate and low degradation sites. Pechuel‐loeschea leubnitziae, which is also known to be an indicator of degradation, was the dominant species in the high degradation sites. The findings highlight the present and future threats the study area is facing and form the basis for current restoration research.
... Correspondingly, numerous reports and scientific publications about the topic have been written since then. Early accounts focused on the economic impacts of desertification (Quan et al., 1994), reviewed general causes and processes of degradation (Seely and Jacobson, 1994), and developed policy recommendations to avoid desertification (Dewdney, 1996). Further research has compared degradation levels in freehold and communal land tenure systems (Ward et al., 1998), explored perceptions and realities of degradation (Katjiua and Ward, 2007;, and examined long-term vegetation and degradation dynamics in communal areas (Rohde and Hoffman, 2012;. ...
Accounts of land degradation and desertification in Namibian communal rangelands have seldom illustrated the broader historical context and structural frameworks within which these social-ecological processes have emerged. This paper aims to address this gap, and argues that it is necessary to take into account past state interventions and policies so as to thoroughly understand the drivers of land degradation problems in these parts of the country. Taking the case of Herero pastoralism as an example, the paper shows how a pre-colonial pastoral system keeping overgrazing at bay, but was radically transformed by the colonial state, and illustrates how current land degradation problems in the former Herero 'homelands' are intrinsically linked to past colonial interventions and policies. The analysis shows, however, that despite the calamities of colonialism and its legacies , key rangeland management practices of Herero pastoralism have not entirely disappeared, thus maintaining livestock rearing in the region as a viable way of life.
... Overgrazing of rangelands and its consequences for vegetation cover in the Namibian savannas are well documented (Seely & Jacobson 1994). The introduction of wildlife to arid parts of the Namibian savanna has resulted in particular challenges such as selective grazing and shortage of drought reserve grazing (Bothma & du Toit 2010). ...
The study compared abundance and diversity of small mammals between a commercial livestock and neighbouring game farm in the Kalahari Thornveld of Namibia’s Omaheke region. Sherman traps baited with standard small-mammal attractants were set out in grids in similar habitats on each land use for four trap-nights during the growing season and the non-growing season of 2015. In total, 174 individuals of five species of small mammals were trapped, 118 on the livestock farm, and 56 on the game farm. Species richness totalled five species of the order Rodentia of which the bioturbating species Gerbillurus paeba represented 79.9% (n=139). All five species were trapped on the livestock farm, and only three on the game farm. With similar stocking rates but different grazing management strategies, it is expected that rangeland condition and perennial grass cover differences influenced the densities and species richness of small mammals. This suggests that ecosystem services associated with these mammal species would be more effective on the livestock farm, leading to better soil moisture infiltration and retention, as well as more effective soil nutrient cycling and seed dispersal.
... However, the problem of modern desertification, a resource-related issue, is becoming severe in Africa. In southern Africa, the dry lands of two countries are most affected by this process [101], one is the Namibia [102]. ...
This paper focuses on the review of geomorphology and late Quaternary environmental change in the Namibia, south-western Africa. The relationship between geomorphology and climate in Namibia reveals the degree and extent to which its landscapes are determined by changing environmental conditions. Case studies of late Quaternary environmental changes in the northern, western and central Namibia are presented. Geomorphological analysis showed that the modern-scale landscape of the south and central Namibia is controlled primarily by tectonics and also by the lithology, base level and climate. At present there is debate on the behavior of Quaternary hydroclimate in the Namibia in response to precessional (19–23 kyr cycle) insolation variations and the effect of glacial versus interglacial boundary conditions. Clues from marine records regarding these debates were obtained. lower leaf-wax δD and higher δ13C (more C4 grasses) recorded in marine sediments over the last 140 ka indicates wetter summer conditions and increased seasonality during the Late Quaternary, particularly during Southern Hemisphere insolation maxima relative to minima and during the last glacial period relative to the Holocene and the last interglacial period. In the central and south-western Namibia, CNB dating suggests that the Namib Sand Sea has a residence time of at least 1 million years. Depositional ages of luminescence dating for dune sediments yields three broad areas of the sand sea, including MIS 5, later in the Pleistocene around the Last Glacial Maximum and the Holocene. The high coincidence of the luminescence ages of the linear dune complexes in the Kalahari over a distance of about 150 km suggests that dune activation in the south-western Kalahari was not the result of local effects but due to sub continental climatic changes. The major dates for dune forms in Kalahari at present are of Holocene age. In the northern Namibia, landscape degradation and desertification are developed during the Holocene. Humification of soils in this region suggests open savanna environments in the past and does not accord with the shrub lands and thornbush savanna at present. Landscape degradation seems to have started in pre-colonial times most likely as a consequence of cattle farming. These examples from different regions of the Namibia offers pointers as to how geomorphological evidence of Quaternary change can be used to assist in the better management of contemporary and future environmental conditions.
... The country does have many ephemeral rivers, most of which "flow" westwards from the central plateau towards the Atlantic Ocean. 1.2 Climate amibia is often labelled as the driest country in sub-Saharan Africa (Seely andJacobson 1994, Ashley 1996). It is therefore not surprising that rainfall, or the absence of it, is a dominant feature of Namibian life. ...
... Ever since desertification was recognized as a growing threat to humankind, scientific expertise has been a main component of attempts to reduce or reverse its impact. As a result, a fair amount is known, although not unequivocally, about the primary causes and manifestations of the processes of desertification (Ellis & Swift, 1988;Westoby et al., 1989;Behnke et al., 1993;Seely & Jacobson, 1994;Williams & Balling, 1995;Odada et al., 1996). Despite the ongoing best efforts of many scientists, the rate and extent of desertification continue to increase rather than decrease throughout the world. ...
Ever since the process of desertification was first recognized, scientific expertise has been in the forefront of attempts to reduce or reverse its impact. More recently the importance of involving indigenous knowledge and people experiencing and being directly affected by desertification has been acknowledged. In Namibia several programmes working on aspects of desertification have highlighted the importance of the planning, policy and legislative framework, the environmental framework and the socio-economic framework in combating desertification. Science and community action can connect to combat desertification, but the results are effective only if the framework conditions are conducive to these interactions.
... This approach is relevant to many other developing countries. Desertification is a major concern in Namibia ( Quan et al., 1994;Seely & Jacobson, 1994), and research and outreach activities within Namibia's Programme to Combat Desertification (Napcod) tackle this problem. Namibia has spectacular landscapes, and rich wildlife and marine resources, providing good opportunities for enhancing biodiversity conservation for tourism and sustainable utilization as well as for cultural reasons. ...
Biodiversity in developing countries is inextricably linked with development. Consequently, policies to conserve biodiversity must take into account national development objectives and vice versa. Policy makers in developing countries are forced to identify creative ways of conserving biodiversity while supporting development and eradicating poverty. Even more than elsewhere, arid countries must focus on biodiversity valuation for both direct (e.g. biotrade, biotechnology and tourism) and indirect (e.g. ecosystem function, aesthetics and cultural values) uses. While inappropriate policies can undermine the conservation of biodiversity, good policies do not ensure that it takes place. Particularly in arid regions, policy markers and managers must have diverse skills to address a wide variety of challenges. Adaptive management is essential for biodiversity conservation in arid environments. It requires regular, informed problem-solving over a wide range of issues, and this, in turn, requires adequate and accessible databases concerning appropriate indicators of environmental change.Major headaches for planners are the intrinsic variability of arid environments, the long-term, changes that occur, and the often uncharismatic biota involved. Managers must be able to handle rapid and adaptive program planning and implementation, monitoring and evaluation, dissemination of information to authorities and the general public, and, often, training of junior and volunteer staff. Management education in support of the conservation of biodiversity in arid environments must focus on problem-solving skills and information management to ensure the depth and breadth of the training.
... In developing countries, such questions are almost invariably needs-driven, directed towards solving environmental and socio-economic problems such as overgrazing leading to loss of arable land. In Namibia, desertification is one of the major environmental problems (Seely & Jacobson 1991). Thus investigations of the underlying causes of land degradation have high priority. ...
Published and unpublished reports and a questionnaire were used to compile an overview of completed, ongoing and planned vegetation survey related projects in Namibia. The main objective of this activity was to determine gaps and identify priorities for future research accordingly.
Bisexual (sometimes unisexual), annual herbs, succulent shrubs with slender cylindrical stem and branches (rarely with spines developing from tips of branches), rarely geophytes or small trees. Leaves alternate or opposite, ovate to lanceolate and sometimes reduced to minute caducous rudiments, rarely arising on raised tubercles (these irregularly arranged along branches); small stipules often present and glandular or filiform. Synflorescences in axils of leaves towards apices of stem and branches or terminal on peduncle, peduncles usually simple, often with alternating or opposite bracts often differently shaped from leaves and sometimes larger just beneath cyathium, further peduncles with terminal cyathia rarely developing from axils of uppermost bracts. Cyathia bisexual or unisexual (then males larger than females); glands 4–5, usually elliptic and flat with entire, crenulate or few-toothed outer margins, sometimes with petaloid appendages; male florets with glabrous or pubescent pedicels. Capsule obtusely 3-lobed, smooth, glabrous to pubescent, 2–10 mm diam., sessile to exserted, dehiscing explosively. Seeds 3 per capsule, 4-angled to ellipsoidal or oblong, smooth to tuberculate, with or without caruncle.
No preserved material has been found of this species and it is difficult to be sure whether it falls under E. ferox or E. pulvinata or refers to the intermediates between them that occur widely over the eastern Karoo. It is therefore left among the names of uncertain application.
Promoting best practices for conservation and sustainable use of biodiversity of global significance in the semiarid areas of Namibia is being undertaken by a loose public, private, nongovernmental (NGO) partnership. This is being led by the public sector that manages a number of established national parks and more recently, in partnership with the NGO community, is promoting community based natural resource management through conservancies on commercial and communal farming lands. The private sector is primarily involved in tourism that provides the foreign exchange income motivating the public sector, with its many alternative social responsibilities, to retain their interest in biodiversity. In the arid areas of Namibia, a similar situation prevails with differences of emphasis but not overall pattern.
Anthropologists know that conservation often disempowers already under-privileged groups, and that it also fails to protect environments. Through a series of ethnographic studies, this book argues that the real problem is not the disappearance of "pristine nature" or even the land-use practices of uneducated people. Rather, what we know about culturally determined patterns of consumption, production and unequal distribution, suggests that critical attention would be better turned on discourses of "primitiveness" and "pristine nature" so prevalent within conservation ideology, and on the historically formed power and exchange relationships that they help perpetuate. © 2003, 2004 Eeva Berglund and David G. Anderson. All rights reserved.
Unravelling the skein of global change effects in southern Africa is a non-trivial task. It is made all the more interesting
since Africa is the birthplace of humanity. Southern Africa preserves an impressive five-million-year record of human-environmental
interaction. From the evolutionary cradle onwards, environmental change has profoundly affected the development of the early
and later hominids into Homo sapiens (Vrba et al.1995). More recently, over the past two millennia, environment was a major factor affecting migrations of Bantu
people into southernmost Africa. Until as late as the nineteenth century, environment continued to be a dominant factor affecting
the settlement and survival of the population of the region.
Range condition at sites of differing land-use intensity at a communal farm was assessed. Vegetation, soil and termite parameters were tested for their potential as indicators. The vegetation indicators did not discriminate between two sites of high and low land-use intensity. However, the soil fertility parameters provided interesting results. The phosphorus (P), nitrogen (N), organic carbon (OC), light fraction (LF), C:N and C:LF data indicate that nitrogen limitation is more critical under high land-use and grazing pressure. Organic carbon levels are generally low but reduced to critical levels under high land-use intensity; nutrients such as phosphorus and nitrogen are conserved in the system, whereas organic carbon losses are high and inputs low. The conversion of the ‘active carbon pool’ into the ‘slow pool’, a prerequisite for long-term soil resilience, is not taking place under high land-use intensity. Termites might play an important role in maintaining range condition.
Vegetation ecological research was conducted in Kaokoland along three transects during the rainy seasons of 1997 and 1998. The transects follow the predominately east-west leading gradients of decreasing precipitation and increasing variability in rainfall. A total of 387 releves was recorded in order to describe the diversity of the vegetation along the transects. Besides the gradient of climate elements edaphic and topographic factors have a strong influence on vegetation patterns. Furthermore, the pastoral utilisation by semi-nomadic Herero-speaking people has an impact on the vegetation. Forty-five plant communities were derived from 4 identified main vegetation units. These vegetation units comprise different types of savannas and ephemeral grasslands. The classification of vegetation units and communities is presented in several tables. Using the whole data set, the influence of precipitation on the vegetation units was analysed using ordination techniques.
Increased interest in environmental change issues has led researchers to consider more integrated approaches to change dynamics. This paper examines change in terms of land degradation in north-central Botswana from both biophysical and human perspectives. Although seasonal and periodic droughts were prevalent, analysis of rainfall data over the past 70 years revealed no downward trend. However, indicators of declining productivity such as soil erosion, loss of vegetation cover, and a declining groundwater table were amply evident. The GIS analysis of remotely sensed data has shown that complete vegetation recovery after drought is not taking place, particularly in the south-central part of the study area. These areas contained the highest human and livestock population densities. The local people acknowledged facing increasing resource depletion and indicated drought as the main cause. Pressures on available resources, particularly during drought periods, appeared to have impeded the regenerative capacity of the natural vegetation cover, thereby inducing land degradation. This situation may not easily be rectified because of widespread poverty and inappropriate local perceptions of the solutions. Both of these hinder the adoption of sustainable land management.
In the Otjiwarongo region (Northern Namibia), Vertisol- Kastanozem-Calcisol soil associations occur as patches of several hundred hectares in extent. They have formed in fine- grained Mid-Holocene sediments which accumulated on both sides of the subcontinental watershed between the Ugab River draining into the South Atlantic and the Omatako Omuramba draining into the Kalahari Basin. Kastanozem formation cannot be explained by the environments that exist at present. The humification suggests open savanna environments in the past and does not accord with the shrublands and thornbush savanna at present. Using AMS C-14 and OSL data, it is possible to distinguish two periods of soil degradation during the recent past. Initially, most of the Kastanozems and Vertisols were buried by slope wash sediments to a depth of several decimetres. This process started in the mid-19th century at the latest. In a second phase, the soils were affected by rill and gully erosion, indicating increased runoff. This occurred during the last decades of the 19th and the first decades of the 20th century, probably as a result of intensified cattle farming. In contrast to other parts of Namibia, the prominent river channels of the Otjiwarongo region, most of them up to 20 in wide and 3-4 in deep, are a result of recent erosion. Degradation of vegetation and soils, and river channel formation, seem to be the main causes of farmland aridification. (C) 2002 Elsevier Science B.V. All rights reserved.
With and without the encouragement of the United Nations Convention to Combat Desertification and its Committee on Science and Technology, scientific research has been undertaken throughout the drylands with the expectation of contributing to combating desertification. Little of this research has been applied in developing countries for its identified purpose. The main reason for this is the limited translation of scientific research into an accessible format for application by development agencies or rural communities.
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