Rangeland evaluation and perceptions of the pastoralists in the Borana zone of southern Ethiopia
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Date
2003-03
Authors
Bayene, Solomon Tefera
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
The study was conducted in the Borana rangeland of southern Ethiopia. In the last few
decades the Borana rangelands have been degraded while the pastoralists adhered to the
traditional grazing strategies. The main aims with this study were to investigate the soil
characteristics as well as aboveground plant communities and to assess the condition of
the rangeland. In addition, the pastoralists' perceptions and cattle-rangeland
management practices were evaluated.
The botanical composition of the grass layer, woody vegetation structure, soil and the
rangeland condition were studied in four communal grazing areas (Did Yabello, Did
Harra, Dubuluk and Melbana), three land use systems (communal land, government
ranch and traditional grazing reserve) and along distance gradients from water source.
Species composition and basal cover of the grass layer was estimated using frequency of
occurrence of plant species. Woody plant data were standardized to tree equivalent ha-l
(l TE = 1 tree, 1.5 m high). Rangeland condition was assessed based on ecological
condition index, weighted palatability composition of the grass layer, the structure of
woody plants and soil compaction. Soil seed bank was studied under three land use
systems and along a distance gradient from water source. Survey on cattle-rangeland
management practice and pastoral perceptions was conducted on 40 individual
households and 118 elders (7 per group).
Survey results of the pastoral households and elders indicated that the average household
in the study area was 7 members. The percentages of male and female children who
attended schools were 26 % and 9 % respectively. Livestock holding per household was
estimated to be 14 cattle, 10 goats, 6 sheep and 2 camels. Cultivation is widespread in
the study area. Major constraints in livestock production were in order of importance:
drought, feed shortage, water scarcity, animal diseases, predators and communal land
tenure. According to the pastoralists, contributing factors to rangeland degradation were
in descending order: recurrent drought, human and livestock pressure, expansion of
cultivation, ban on fire and development of water ponds.
A total of 49 grass species were identified in this study. The communal land had higher
and lower percentages (P<0.05) of annual and perennial grasses, respectively, than the
government ranch and the traditional grazing reserve. There were no marked differences
(P>0.05) among the four communal grazing sites and the three different distances from
water concerning both annuals and perennials. The occurrence of Chrysopogon aucheri
was higher (P<0.05) on the government ranch (23 %) and traditional grazing reserve (27
%) than on the communal land (14 %). The frequency of C. aucheri did not vary
between the communal grazing sites (average = 14 %) and along distance gradient from
water (average = 12 %). Leptothrium senegalensis and Chloris myriostachya did not
vary (P<0.05) between the land use systems (average = 4 % and 1 %, respectively) and
along the distance gradient from water (average = 2 % for both species). The frequency
of Sporobulus nervosus was highest (P<0.05) in the communal land (13 %), whereas the
occurrence of S. pyramidalis did not differ markedly (average = 32 %) between the land
use systems (P>0.05). Both species did not show prominent variations along the distance
gradient from water (average = S. nervosus-14 % and S. pyramidalis-36 %). Grass basal
cover was fairly low and similar in the land use systems, communal grazing sites and
distance gradients from water.
A total of 54 woody plants were identified. Total density of woody plants was higher
(P<0.001) on the communal land (l 083 TE ha-I) or the government ranch (l 188 TE hal)
than on the traditional grazing reserve site. Within the communal grazing sites, the
densities at Did Yabello (l 318 TE ha"), Did Harra (l 088 TE ha") and Melbana (1 178
TE ha") were higher (P<0.05) than on the fourth site, Dubuluk. Results from the
distance gradient from water revealed that differences were not significant (P>0.05)
between the near, middle and far sites (average = 1 150 TE ha-I). Overall figure showed
the advancement of woody encroachment in the semi-arid Borana rangelands. The most
important invaders were Commiphora africana, Grewia tembensis, Acacia
drepanolobium and A. brevispica.
Soil chemical analysis revealed low nutrient contents, which did not vary significantly
(P>0.05) in all the study areas. Similarly, differences in pH, soil texture, soil bulk
density and soil compaction were not significant.
Assessment of rangeland condition indicated that both ecological condition index (ECI)
and weighted palatability composition (WPC) were highest on the government ranch
(711 and 55 %, respectively). Along the distance gradient from water, differences in
rangeland condition (P>0.05) were not significant (average: ECI = 533 and WPC = 29
%). Within the communal grazing sites, Dubuluk and Melbana had relatively higher ECI
and WPC values (average: 602 and 36 %, respectively) than the other two sites (average
= 520 and 25 %, respectively).
The soil seed bank study revealed that a total of 44 plant species were identified. Of
these, 25 % were grasses and 75 % were non-grass plant species. As for the land use
systems, seedling and floristic density of the graminoids were higher (P<0.05) on the
traditional grazing reserve (798 seedling m-2 and 361 plants m-2, respectively) than on
the communal land and the government ranch. Along the distance gradient from water,
the differences were not significant (P>0.05). Similarity between grass flora of seed
bank and above ground plant community was low.
It can be concluded in this study that the deteriorating conditions of the Borana
rangelands were revealed by changes in the structure and composition of the grass layer,
woody vegetation, soil fertility and by the status of the soil seed bank. Bush
encroachment is the critical problem. Therefore, workable control programs need to be
devised immediately. It is also vital to develop a clear policy at national level on the use
and management of the communal rangeland resource.
Description
Keywords
Range management -- Ethiopia -- Borana Plateau, Pastoral systems -- Ethiopia -- Borana Plateau, Rangelands -- Ethiopia -- Borana Plateau, Thesis (Ph.D. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2003