Wn Ekaya

Abiotic and herbaceous vegetational characteristics of an arid rangeland in Kenya

A two-year study was conducted with an overall objective of characterising the structure and function of an arid rangeland in Kenya. A plot measuring 100 × 100m was used for this study. Data on rainfall and temperature were recorded at the plot site whereas data on evaporation rates and relative humidity were obtained from the meteorological office near the study site. Herbaceous aboveground material was sampled at monthly intervals using a rectangular 0.25m2 quadrat frame. Clipped material was separated by species and classified dead or live by physical examination. A 5cm diameter metal soil corer was used to sample belowground plant material, at monthly intervals. The sampled material was washed with running water over 2mm sieves and classified dead or live using the vital staining technique. All weights and calculations were based on organic weight. Total aboveground standing crop ranged from 84.6g m−2 to 295.4g m−2, with a mean of 162.3 ± 60.6g m−2. Mean monthly aboveground standing crop for 1992 and 1993 was 142.8 ± 53.8 and 178.5 ± 63.3g m−2 respectively. The two values were significantly different (p<0.10). Aboveground biomass yield ranged from 17.7g m−2 to 242.7g m−2, with a mean of 104.3 ± 58g m−2 and a coefficient of variation of 58%. Mean aboveground standing crop was 59 ± 24g m−2 Monthly values ranged from 28.8g m−2 to 120g m−2, with a 38% coefficient of variation. The range for total belowground standing crop was from 83.3g m−2 to 232.7g m−2, and a mean of 155.2 ± 46g m−2. The values had a coefficient of variation of 30%. Mean total monthly belowground plant material yield for 1992 and 1993 was 137.6 ± 41g m−2 and 169.9 ± 46g m−2 The coefficients of variation were 59% and 28% respectively. The mean monthly belowground biomass yield was 51.6 ± 33g m−2 with a coefficient of variation of 64%. Mean monthly yield for belowground dead material was 103.7 ± 32g m−2, with a coefficient of variation of 31%. There was no significant difference (p>0.01) in the mean belowground dead material yield between 1992 and 1993. In 1992, annual NPP was 439.2g m−2, giving a net primary productivity of 1.22g m−2day−l. Monthly NPP ranged from 17.2g m−2 to 90.1g m−2 In 1993, annual NPP was 944.5g m−2, equivalent to a net primary productivity of 2.62g m−2 day−1. Monthly NPP was between 27.4g m−2 and 548.6g m−2. Over the 1992–1993 period, NPP was 1 383.7g m−2, equivalent to a productivity of 1.92g m−2day−1. Trends in monthly NPP closely followed the trend in rainfall. On the whole, herbaceous vegetation production and productivity were episodic in nature and closely linked to rainfall. The high primary productivity puts arid and semi-arid rangelands under sharp focus as CO2 sinks, whose role in the amelioration of greenhouse effect could be more important than is currently appreciated.

Indigenous Knowledge: The Basis of The Maasai Ethnoveterinary Diagnostic Skills

Abstract The Maasai indigenous knowledge of animal diseases is comparable to the conventional knowledge of the modern veterinarian. Their diagnostic skills of livestock diseases is based on indigenous symptoms of diseases, vectors of diseases, season effects and species affected. The pastoralist diagnostic skills appear to be superior to those of agropastoralists. With the advent of modern veterinary medicine, the Maasai ethnoveterinary practice appears to be on the decline. This paper focuses on indigenous knowledge basis for diagnosis, treatment and control of selected examples of livestock diseases. In addition, the impact of modern veterinary medicine on pastoral (Maasai) ethnoveterinary practice will be briefly discussed.

THE IMPACT OF RANGELAND CONDITION AND TREND TO THE GRAZING RESOURCES OF A SEMI-ARID ENVIRONMENT IN KENYA

Abstract A research study was conducted in Mashuru Division of Kajiado District, Kenya with the objective of analyzing the types of vegetation degradation, their causes and their influence on rangeland condition and trend. The study was conducted through remote sensing tools, ground truthing, interviews, community workshop and literature. The results of the study showed that excessive use of the woody species by humans for woodfuel, building and fencing materials, medicine and ornamentals had led to the deterioration of the rangeland due to a loss of cover, change in plant composition and biodiversity. On the other hand, overgrazing and ecological succession of the grazing lands had led to further vegetation degradation in form of bush encroachment and thickening. These types of vegetation degradation have had an overall effect of loss of grass cover and hence loss of grazing capacity by livestock, especially cattle. The causes of vegetation decrease or increase over the last 30 years have been due to deforestation (trees and shrubs), bush encroachment and thickening , change in plant species composition and natural calamities such as droughts, wild fires and army worm invasions at various times. The overall results indicated that there has been a downward trend in range condition over the last 30 years which has affected the livestock productivity of the area.

Production and decomposition of plant litter in an arid rangeland of Kenya

Data on litter production and decomposition in an arid rangeland in Kenya was collected over a two-year period. Utter sampling was carried out at monthly intervals using a rectangular 0.25m−2 quadrat frame. Utter within the quadrats was handpicked and washed with running water to get rid of soli particles, dried, and weighed. Weights were expressed on organic matter basis. Monthly litter production ranged from 31.4g m−2 to 130.0g m−2. Mean monthly yield was 92.5 ± 26g m−2, with a 28% coefficient of variation. There was no significant difference (p>0.01) in litter yield between 1992 and 1993. Rate of decomposition for aboveground material ranged from 0.005g g−1 day−1 to 0.084g g−1 day−1. The mean annual rate of decomposition was 0.026g g−1 day−1. Belowground plant material rates of decomposition spread from 0.009g g−1 day−1 to 0.062g g−1 day−1. with a mean annual rate of 0.041g g−1 day&minus1. Belowground material consistently decomposed faster than aboveground material. Peaks in both aboveground and belowground material decomposition rates coincided with rainfall peaks. Overall, in this arid environment, litter production and decomposition is pursed in nature, and trends are closely related to rainfall occurrence. Moisture is thus a limiting factor both to the production and decomposition of litter. Belowground litter plays a significant role in nutrient cycling.

Land use ecology and socio-economic changes in a pastoral production system.

Abstract This study was conducted in the northern part of Kenya, in Kakuma division, Turkana district. Kakuma is a semiarid area under nomadic pastoralism as the main activity. The presence of a refugee camp has attracted many people from within the Turkana community and also the outside community. The study aimed at documenting the effects of emergent land use changes on vegetation resources and the socio-economic environment in Kakuma. Data on vegetation density and cover was collected. Socio-economic data was collected from the local Turkana population and the settlement camp. The data was analysed using SPSS computer package and descriptive statistics. There was a significant difference (P<0.05) in vegetation cover and density with increasing distance away from the settlement camp. The mean tree crown cover was low near the settlement camp (6.2%) but high away from the settlement camp (57.7%). Mean tree density was high near the settlement camp (13 individuals/100m2). Shrub crown cover was low (0.9%) in the areas that had settlements. The need for fencing and building materials was the main cause of low shrub cover. The density of the shrub species generally increased as one moved away from the settlement camp (17 individuals/16m2). Herb species cover and density was high near the settlement camp(68% and 202 individuals/1m2 respectively) but this comprised mostly of species unpalatable to livestock like Tribulus terrestris and Portulaca oleraceae. The study revealed that droughts and livestock raids in the previous years had set in motion social and ecological changes. The loss of livestock through raids and droughts encouraged sedenterization. This affected the cultural patterns and has had an effect on the rangeland condition. Lack of mobility concentrated livestock in specific areas, thus depleting the forage resources and creating conditions for soil erosion. Trading activities between the refugees and the Turkana had both positive and negative impact on the economic, social and cultural setup of the local community. The increase in population around Kakuma and the settlement camp has set in motion changes that have affected vegetation and social structures. The immediate social and economic returns from the exploitation of resources have overridden the long-term benefits. In regard to this there is a need for education on the impacts, both short-term and long-term, of the various activities on the vegetation, livestock resources and also the pastoral lifestyle.

Genetic variation between ecotypic populations of Chloris roxburghiana grass detected through RAPD analysis

Chloris roxburghiana is an important rangeland grass in Kenya. In some areas it has disappeared due to land degradation resulting from overgrazing and drought. Efforts to re-introduce the grass through re-seeding using seeds from research stations have had little success. One possible reason for low establishment is attributed to transplanting spatially separated populations that may represent genetically distinct ecotypes. To test this hypothesis, germplasm diversity within and among four populations of C. roxburghiana from four ecologically distinct sites was analysed using random amplified polymorphic DNA (RAPD) markers. A total of 131 polymorphic markers were identified using nine RAPD primers. There was significant variation among populations, with genetic diversity (H) ranging from 0.134 to 0.206. Analysis of molecular variance (AMOVA) revealed most variance within populations (76%). However, the variation among populations was also significant (24%). The UPGMA of the population frequency indicated that the four populations of C. roxburghiana were genetically distinct, probably as a result of variation in soil fertility, geographical isolation and socio-ecological history of the study sites. Although there are differences for neutral genetic markers between the populations, it is difficult to relate this directly to ecotype since correlation does not imply causality. The implication for optimising future seed collection is discussed and potential areas for further studies identified.

Feeding characteristics of sheep ( Ovis aries ) and Grant\'s gazelles ( Gazella granti ) on Kapiti ranch, Kenya

A study was conducted to determine the dietary characteristics of sheep and Grants gazelles on Kapiti Ranch, Kenya. The botanical composition of the diet was determined using the faecal microhistological technique. Plant species in the diets were categorised into grass, forb and browse classes. Shannon-Wiener and Morisitas similarity indices were used to express dietary diversity and overlap respectively. Simulated diets, based on microhistology results, were analysed for crude protein, neutral detergent fibre, acid detergent fibre, cellulose, lignin and in vitro dry matter digestibility. Sheep were predominantly grazers during both the dry and wet season while Grants gazelles were mixed feeders, with a higher consumption of grasses during the wet season and an equal consumption of both grasses and browse during the dry season. Diets of Grants gazelles were more diverse than those of sheep during both seasons. Degree of dietary overlap between the animal species was highest during the wet season. There were differences (P < 0.05) in dietary nutrient content between the animal species, within seasons. Dry matter digestibility was higher (P < 0.05) for both species during the wet season. Neutral detergent fibre, acid detergent fibre, lignin and cellulose were significantly higher (P < 0.05) during the dry season. Sheep diets were higher (P < 0.05) in crude protein during the wet season, whereas crude protein was higher (P < 0.05) in the Grants gazelles diet during the dry season than in the wet season. This study indicates that sheep and Grants gazelles are compatible in their use of vegetation on Athi Kapiti plains.

Land Use and Spatial Distribution of Two Gum And Incense Producing Tree Species In The Blue-nile Valley of Wogidi District, Ethiopia

Abstract The study was conducted in the Blue-Nile valley of Wogidi district in Ethiopia, where woody vegetation degradation associated with intensive land use activities has become a national concern. It was undertaken with an overall objective of documenting the impacts of land use and topography on the spatial distribution of two gum and incense producing tree species, Boswellia papyrifera (Del.) Hochst and Commiphora africana (A. Rich.) Engl. Five land use units, each with two slope categories (⩽ 25% and > 25%) were subjected to a 5x2 factorial arrangement and a total of 50 sample points were employed to measure density, crown cover, and age ratio of trees. Analysis of vegetation attributes revealed that, except for density of C. africana, all the vegetation attributes did show lower status in the heavily populated land use units than the control site reflecting the differential impact of intensive land use pressure against protection. In the heavily populated land use unit (Luu-3) for example, density, cover and age ratio of B. papyrifera trees were as low as 8.3 trees/ha, 7.7% and 0.21 respectively. In contrast to this, i.e. in the site of low population pressure (the control) the same attributes appeared to be measured as 77 trees/ha, 7.7% and 0.51 respectively. However, attached to the proximity ecological position, density and crown cover of B. papyrifera showed no significant difference (P. > 0.05) between Luu-1 and Luu-2. Density of C. africana, most likely due to its affinity to a specific microhabitat, it did not differ among all land use units (P > 0.05). Between the slope aspects of the area, B. papyrifera and C. africana were found to dominate the steep (>25%) and gentle (⩽ 25%) slopes respectively. Regarding density of B. papyrifera, while it was 196 trees/ha in the steep slope, 146 trees/ha were documented from the lower slope aspect. Inversely related to this, C. africana had 68 and 102 trees/ha on >25% and ⩽25% slopes respectively. Age ratio analysis of B. papyrifera trees, however, did not show significant difference (P > 0.05) between these two slope categories. In the study area therefore, land use and slope were identified as determinant factors to the spatial distribution of woody vegetation and policy frameworks to account these factors are suggested to be substantial in the management of such resources.

The nutritional value of Zizyphus spina-christi for goat production among the pastoralists of Kalu district, South Wello, Ethiopia

Fifteen yearling goats of similar weight were used to evaluate the potential of Zizyphus spina-christi leaves as a supplement to goats fed on Cynodon dactylon grass. Animals were randomly assigned to five feeding regimes and individually stall-fed for a preliminary period of 14 days, followed by 14 days of feeding to determine dry matter intake and digestibility and a 3-month feeding period to determine body weight changes. The treatments were formulated based on leaf:grass ratios of 0%, 25%, 50%, 75% and 100%. Z. spina-christi leaves had higher crude protein and lower fibre content than C. dactylon grass (P < 0.05). Dry matter intake, digestibility and body weight changes increased significantly (P < 0.05) as the level of supplementation increased. Thus, Z. spina-christi foliage is a potential feed supplement in the dry season, as the dry season grasses are deficient in the required nutrients and cannot meet goat requirements.

Woodlands and livelihoods of African pastoralists: The Maasai of Kajiado, Kenya

Abstract A survey study was conducted in Kajiado district, Kenya to document families and species of woody vegetation important in the livelihood systems of the Maasai. Data was collected from a total of 150 pastoralists comprising of the youth (< 30 years), middle-aged (31-50 years), and elderly (> 51 years) age group. The study revealed six key roles of woody vegetation, that is, medicinal, environmental signals, homestead and corral fencing, woodfuel, livestock fodder, and poisons to livestock. For each category, the most common families and species of woody plants were reported.