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1.
J Environ Manage ; 82(4): 481-94, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16616986

RESUMO

A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (<2 years) close to the encampments. The latter constitutes the herding of bulls and immatures (>2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on traditional burning practices and recurrent droughts were seen as aggravating factors to this invasion process. The increasing practice of crop cultivation on the rangelands was identified as a serious threat to future livestock production and traditional resource management practices. Suggestions for possible interventions to improve the productivity and sustainable use of these rangelands are made.


Assuntos
Criação de Animais Domésticos/estatística & dados numéricos , Conservação dos Recursos Naturais , Opinião Pública , População Rural , Adulto , Animais , Bovinos , Etiópia/etnologia , Feminino , Humanos , Masculino , Inquéritos e Questionários
2.
J Environ Manage ; 85(2): 443-52, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17141403

RESUMO

The structure and advancement of woody vegetation was studied in a semi-arid rangeland of southern Ethiopia under three land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. A total of 54 woody plant species were identified. Based on the subjective opinions of the pastoralists, 85% of the identified woody plants have forage values to livestock. Cadaba farinsoa, Ormocarpum trichocarpum, Rhus natalensis, Acacia brevispica, Cordia gharaf and Hibiscus sparseaculeatus were reported to have fair to good palatability. Tree equivalent (TE) density of all woody plants combined was greater (P <0.01) in the government ranch (1) 188 TE ha(-1)) and the communal land (1083 TE ha(-1)) than in the traditional grazing reserve (419 TE ha(-1)), whereas this did not vary significantly (P >0.05) along the distance gradient from water. The most important encroaching woody plant species in the study areas were in descending order: Commiphora africana, Acacia drepanolobium, A. brevispica, Acacia. tortilis, Grewia tembensis and Lannea floccosa. The density of individual encroaching woody plant species along the distance gradient from water was not consistent. All encroaching woody species had the highest TE density in the communal land. The prevalence of these species followed the pattern of intensity of use within the communal grazing area. Most of the woody species had the highest abundance in the height class >0-2m regardless of land use and distance gradient from water. This study investigated the advance of severe woody encroachment in the communal and government sites as well as along the distance gradient from water. Some of the important contributing factors that can be suggested are heavy grazing pressure (in both the communal and government sites), expansion of cultivation and reduced mobility of livestock due to settlement of the pastoralists in the communal land.


Assuntos
Ecossistema , Árvores/crescimento & desenvolvimento , Água/análise , Conservação dos Recursos Naturais , Monitoramento Ambiental , Etiópia , Movimentos da Água
3.
J Environ Manage ; 85(2): 429-42, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17129661

RESUMO

The distribution and compositional pattern of the grass layer, as well as soil quality of southern Ethiopian semi-arid rangelands were examined under three land-use systems (communal land, government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. In total, 49 grass species were identified, 65% of which were perennials. Of the most commonly distributed highly desirable species, Chrysopogon aucheri showed the greatest frequency under the traditional grazing reserve (27.6%), and the lowest in the communal land (14.0%). The frequency of Cenchrus ciliaris was similar in all the study sites. The proportion of Lepthotrium senegalensis was low under the land-use systems (3.9%) and increased away from water sources (2.3%). Of the less desirable species, Sporobulus nervosus was extremely more abundant (<0.05) in the communal land (13.3%) than the traditional grazing reserve (3.3%) and the government ranch (1.9%). Sporobolus pyramidalis was dominant in the study sites, with similar (P>0.05) frequency percentages under the land-use systems and along the distance gradients from water. Basal cover was low and similar on all the study sites (3.3%). Concerning the soil texture, sand (71.1%) constituted the largest proportion, followed by silt (21.3%) and lastly, clay (7.7%). With regard to soil exchangeable cations, organic C and total nitrogen were generally low and did not show marked variation in all the study sites. The study showed significant differences for most of the vegetation variables between the communal land and the other land-uses. This suggested that grazing intensity was higher in the communal land and moderate in the government ranch and in the traditional grazing reserves (kallos). The lack of significant differences in most of the studied (vegetation) variables along the distance gradient from water could be ascribed to the fact that grazing disturbance has already exceeded a certain threshold of degradation. Under the present low states of soil nutrients and rainfall, cultivation is neither sustainable nor environmentally friendly and this will lead to further degradation of the soil in these marginal lands.


Assuntos
Ecossistema , Poaceae/crescimento & desenvolvimento , Solo/análise , Água/análise , Conservação dos Recursos Naturais , Monitoramento Ambiental , Etiópia , Geografia , Movimentos da Água
4.
J Environ Manage ; 85(2): 453-60, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17141937

RESUMO

The condition of the semi-arid Borana rangeland in southern Ethiopia was assessed by studying different land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. The assessment incorporated the soil, herbaceous and woody plant layers. Two methods were employed to evaluate the grass layer, viz. ecological condition index (ECI) and weighted palatability composition (WPC). The ECI on the government ranch was 21.7% and 26% greater than that of the traditional reserve and the communal land, respectively. The WPC on the government ranch was 83.3% and 48.6% greater than that of the communal area and the traditional reserve, respectively. Both ECI and WPC values were similar for all distance sites from water. Tree equivalent (TE) density, of all encroaching woody plants combined, was higher on the communal land (504 TE ha(-1)) than the government ranch (373 TE ha(-)1) and traditional grazing reserve (118 TE ha(-1)), but with no marked variations in the distance sites from water. Height class distribution of encroaching woody plants in the study areas showed the largest abundance (range: >50-100%) at the height class >0-2m. Tree equivalents per hectare of encroaching woody plants were negatively correlated (r = -0.60) with ECI and WPC and positively correlated (r=0.87) with percentage bare ground. The correlation (r = 0.50) between percentage bare ground and soil compaction was positive and low. Although the government ranch had a greater composition of highly palatable grass species than the other land uses, the rangeland was not in good condition due to severe bush encroachment. The communal land was generally in poor condition. In the traditional grazing reserve, bush encroachment was not a problem, but the productivity of the grass layer was poor when assessed on the basis of ecological and palatability merits. The negative interaction of TE density of all encroaching woody plants combined with ECI or WPC and the positive interaction with bare ground, may suggest that the abundance of these species is more critical in aggravating deterioration in grassland productivity. Therefore, the priority of any bush control program must be towards minimizing the abundance of these woody plants.


Assuntos
Ecossistema , Movimentos da Água , Monitoramento Ambiental/métodos , Etiópia , Geografia , Árvores/crescimento & desenvolvimento
5.
J Environ Manage ; 75(1): 21-35, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15748801

RESUMO

Pastoralism is the most dominant land use form in the arid rangelands of Sub-Saharan Africa, but this rangeland-based lifestyle is under threat. As a consequence a study was conducted in the Middle Awash Valley of Ethiopia with the main objectives of assessing and comparing the broad perceptions of two pastoral groups (the Oromo ethnic group living in Kereyu-Fantale and the Afar ethnic group living in Awash-Fantale) on the usage of the existing rangeland resources, and their views on constraints and possible solutions. Data were collected from 90 Oromo and 55 Afar households. Despite the difference in ethnicity both of these groups share common problems. They derive their main income from the sale of animals and animal products, but with the difference that milk products rank first in the case of the Afar and last in the case of the Oromo. Both pastoral groups depend heavily on native grasses for animal feed and to a lesser extent on woody plants as a source of browse. The majority of respondents were of the opinion that the condition of the rangelands is poor, mainly due to overgrazing, droughts and increases in the human population. Availability of water is also regarded as a problem, mainly by the Oromo. Migration is the first measure taken to solve shortages of livestock feed, but many of the pastoralists replied that migration is an undesirable practise which is mostly done out of necessity. Because of the limited resources most respondents of both groups still prefer communal land tenure where resources are shared. It is concluded that the problems facing the pastoralists in the Middle Awash Valley have been created over many years and the solutions will also require time. With the current approach of the communal grazing systems, sustainable utilisation of the rangeland ecosystem is not possible. Solutions to the poor condition of the existing rangelands will require a definite commitment and full participation not only of the pastoralists, but also of government and non-governmental organisations that are directly or indirectly involved in rangeland resources utilisation, management, conservation and other related activities.


Assuntos
Criação de Animais Domésticos , Conservação dos Recursos Naturais , Adulto , Idoso , Ração Animal , População Negra , Etiópia/etnologia , Humanos , Masculino , Pessoa de Meia-Idade , Plantas Tóxicas , Inquéritos e Questionários , Abastecimento de Água
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