Ethiopian Journals Online (EJOL)
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Why does accuracy assessment and validation of multi-resolution-based satellite image classification matter? A methodological discourse
No full textThis study presents a methodological discourse about how to validate the reliability of thematic maps derived from multi-resolution satellite-based image classification. Besides, the paper examines unbiased estimates of accuracy assessment using known sampling units. Landsat and spot images were used for lulc thematic layer extraction. These thematic layers together with reference data extracted from panchromatic aerial photo interpretation and ground survey were used as input datasets for accuracy assessment and validation analysis. For each lulc unit, a minimum of 50 reference samples were derived using a stratified random sampling scheme. Consequently, error matrices were generated to validate the quality of the 1973, 1995 and 2007 lulc maps. To improve sampling biases introduced due to the stratified random sampling reference data collection scheme, accuracy assessment indices including the producer’s, user’s and overall accuracy as well as Kappa coefficient of agreement were adjusted to the known areal proportion of map categories. The computed overall accuracy, corrected for bias using known marginal proportions of the 1973, 1995 and 2007 thematic layers were 88.12%, 89.95% and 92.27%, respectively. Also, 81.20%, 82.17% and 83.11% of Kappa coefficient of agreement were achieved from the 1972, 1995 and 2007 classifications, respectively. The findings show that high resolution aerial photos are good sources of reference datasets in the absence of historical ground truth data for accuracy assessment analysis and the lulc classifications fulfilled the minimum of lulc classification standards of overall accuracy and Kappa coefficient of agreement. Consequently, all the lulc classifications could be used as an input for policy options for integrated land resource management practices in the watershed studied
New range of the African buffalo (Syncerus caffer Sparrman, 1772) in the upper Blue Nile Valley, western Ethiopia–A preliminary study
No full textA preliminary study on the distribution of the African buffalo (Syncerus caffer) was conducted in 2014 in the Didessa River Valley of the upper Blue Nile in western Ethiopia, to confirm the presence of buffaloes and other co-existing wildlives in the area, which the government considers for settlement and investment because of unconfirmed wildlife distribution. Buffaloes were located by tracking their expected ranges in the upper Blue Nile Valley and each location was marked using GPS, and superimposed on the known range of buffaloes. The result showed that the present distribution of buffaloes is further extended from their known ranges. Moreover, the presence of several other wildlife species in the study area was also been confirmed, and the new distribution range map for buffaloes was generated. The current range of African buffaloes is the last green space left in the upper Blue Nile Valley for wildlife conservation, for which urgent conservation actions are necessary
Genotype by environment interaction and grain yield stability analysis for advanced triticale (X. Triticosecale Wittmack) genotypes in western Oromia, Ethiopia
No full textGROWTH PERFORMANCE AND SURVIVAL OF LOCAL AND WHITE LEGHORN CHICKEN UNDER INTENSIVE MANAGEMENT SYSTEM
No full textThis study was conducted to evaluate the comparative growth, sexual maturity, survival, and feed utilization efficiency of local and White Leghorn chicken under intensive management condition. Five groups of each of the two breeds, with 200 baby chicks each, were subjected to appetite feeding with commercial layer's type starter's and grower's ration at day old to eight weeks and eight weeks to twenty weeks of age respectively in a completely randomised design with 5 replication. The results showed that mean daily feed intake and total feed consumption from hatching to maturity were significantly higher (P<0.05) for the local chicken the value of which seem to be overestimated due to their highly pronounced selective feeding and feed scratching behaviour. They attained 90 and 94% of the mean body weight of leghorn chicken at an age of 2 and 5 months, respectively. Mortality and the amount of feed required to raise day old baby chicks to maturity were also significantly higher (P<0.05) for the local chicken. Local chickens were inferior to the leghorn breed in terms of feed utilization efficiency and survival when kept in confinement. The results of this study suggested that there is no economic justification for keeping local chicken under intensive management systems due to their poor feed utilization efficiency and survival
Landslide Hazard Zonation Using Expert Evaluation Technique: A Case Study of the Area Between Gohatsion Town and The Abay (Blue Nile) River, Central Ethiopia
No full textThe area between Gohatsion town and the Abay River in Central Ethiopia is witnessing severe problems of landslides during rainy seasons. These landslides in the area affect the safe functioning of the road, which is an essential link between Addis Ababa and the northwestern part of the country. In the present study, an attempt is made to delineate the area into landslide hazard zones (lhz). The landslide hazard zonation was carried out by “Landslide Hazard Evaluation Factor” (lhef) rating scheme. The lhef is an expert evaluation technique that is based on the observational past experience gained over causative factors and their contribution for instability of slopes in the area. The causative factors responsible for landslide activity, which were considered during the present study, are: relative relief, slope morphometry, geology, groundwater and land use/ land cover. The information pertaining to these causative factors was collected from the field and analyzed as per the lhef scheme. The evaluated lhz revealed that most of the study area falls within the moderate and high hazard zones. The existing road that links Addis Ababa with the northwestern part of the country mostly passes through high hazard zones and some of it passes through moderate hazard zones. This seems to be the main reason for frequent landslides along the road during the rainy season. Thus, it is imperative to conduct detailed investigations to suggest proper remedial measures for slope stabilization along the road section or to realign the road section to avoid such critical slope sections
Nutrient Uptake Efficiency and Growth of Two Aquatic Macrophyte Species under Constructed Wetlands, Ethiopia
No full textThis study was carried out to investigate the growth and nutrient uptake of two wetland plants from Lake Tana. Rhizomes of Cyperus papyrus and Phragmites karaka were grown outdoors in four parallel-aligned horizontal sub-surface flow constructed wetland (hssfcw) treatment beds. The treatment beds were irrigated with wastewater sourced from students’ residence from January 21 to March 20, 2011. The results of the study showed that Cyperus papyrus had higher rate of biomass accumulation as evidenced by increase in shoot and root weights (83.93 gm) compared to Phragmites karka. It had also significantly (p < 0.05) higher root total phosphorus and leaf total nitrogen content than that of Phragmites karka. The mean removal efficiency of the papyrus-planted treatment bed was 56.37% (NO3-N), 84.04% (PO43-); the phragmites- planted treatment bed was 58.37% (NO3-N), 65.18% (PO4 3- ) and the unplanted (control) treatment bed was 36.13% (NO3-N) and 50.21% (PO4 3-). Pollutant removal efficiency differences were statistically significant (p < 0.05) between planted and unplanted treatment beds for PO43- but not for NO3-N. The study also showed that the progressive increase in the plant density, shoot length and stem diameter was positively correlated with the nutrient removal efficiency of the treatment beds. The average removal efficiency of the two planted treatment beds was higher than unplanted bed. The study proved that these macrophytes had the ability to accumulate high biomass and remove nutrients and therefore have high potential in biological nutrient removal processes
Plant Diversity, Vegetation Structure and Relationship between Plant Communities and Environmental Variables in the Afromontane forests of Ethiopia
No full textDiversity patterns of vascular plant species were studied along geographical gradients in the Afromontane region of Ethiopia. Vegetation data were sampled from five moist evergreen Afromontane forest fragments, namely Harenna (southeast), Bonga, Maji, Berhane-Kontir and Yayu (southwest). In each forest, quadrats of 20x20 m were laid along transects to collect vegetation data. The patterns of plant diversity were evaluated on the basis of species richness as the total number of species at each site and species change between and within sites and in relation to vegetation structure. Floristic analyses of five Afromontane forests altogether revealed 118 families and 653 vascular plant species, and about 5% of the species were endemic. Species richness and densities vary considerably between the forest sites. The highest beta and gamma diversities were recorded in the Berhane-Kontir forest and the lowest in Bonga. The studied Afromontane forests were floristically different but the common feature of the geographically separated forests is the occurrences of wild coffee populations. Ordination of the study quadrats of the forests forms five groups based on the species composition. Moist evergreen Afromontane forests support a high density of woody plants, which, however, differ between sites. The Ethiopian moist evergreen Afromontane forests are highly threatened due to anthropogenic factors and, thus, need immediate conservation measures. It is recommended that conservation strategies should focus on multiple-sites conservation networking in order to include a range of forests in the conservation system
Floristic Composition, Species Diversity and Vegetation Structure of Gera Moist Montane Forest, Jimma Zone of Oromia National Regional State, Southwest Ethiopia
No full textFloristic composition, species diversity and vegetation structure of Gera Moist Montane Forest was conducted in Jimma Zone of Oromia National Regional State, southwest Ethiopia. A total of 132 plant species in 112 genera and 59 families were identified from this forest. Fabaceae was the most dominant family with ten species and nine genera. According to Ensermu Kelbessa and Teshome Soromessa (2008), the dominance of Fabaceae and Asteraceae could be attributed to their efficient and successful dispersal mechanisms and adaptation to a wide range of ecological conditions. Plots of 30 m x 30 m were arranged at a distance of 200 m from each other for sampling woody species. To sample herbaceous plants, five sub-plots each with 1 m x 1 m were laid in the main plot. Shannon-Wiener diversity index was used to compute species richness and evenness between the plant communities. DBH, basal area, and height were computed to describe the structure of the forest. The regeneration status of some woody species of the forest was evaluated based on the number of seedlings and saplings per hectare. Vegetation classification was performed using R-2.11.1 software packages. Plant communities were named after two of the dominant woody species occurring in each group using the relative magnitude of the highest mean cover abundance within the cluster. Future research directions and recommendations are suggested for the sustainable utilization of the vegetation
ASSESSMENT OF THE PHYSICO-CHEMICAL CHARACTERISTICS OF A TANNERY WASTEWATER AND ITS POLLUTION IMPACT ON THE WATER QUALITY OF LITTLE AKAKI RIVER
No full textTannery wastewater is one of the most hazardous industrialpollutants containing organic and inorganic substances. For this reason,tanneries are required to treat their wastewater before discharging into theenvironment. The objective of this study was to evaluate efficiency of Batutannery wastewater treatment plant and the impact of the tannery affluent onthe quality of the Little Akaki River. The physico-chemical characteristics oftannery wastewater before and after treatment were determined based ontriplicate measurements for each sample. The data showed that raw tannerywastewater has high loads of pollutants. The highest COD, TDS, ammoniaN, sulfate, total nitrogen, sulfide and total chromium observed in the rawtannery wastewater was 7213 mg/l, 6236 mg/l, 228 mg/l, 352 mg/l, 310 mg/l,294 mg/l and 26 mg/l, respectively. Average removal efficiency of thetreatment system for the COD, sulfide, ammonia-N, TDS, total nitrogen was51%, 62.6%, 48%, 47%, 59.5% and 52.7%, respectively. The pH,temperature and electrical conductivity was reduced by less than 10% intreated tannery effluent, but COD, TN, sulfide, total chromium, sulfate andTDS exceeded the national discharge limit for the tannery effluent. Analysisof similar parameters in the Little Akaki River showed that insufficientlytreated tannery effluent caused an increase in the river water physicochemical characteristics except for temperature and pH. However, one-wayanalysis of variance showed that only the COD, total chromium and sulfate ofdownstream LAR water were significantly (p<0.05) different from upstreamsimilar parameters. This showed that impact of the tannery effluent on theriver water quality is insignificant for most of the studied parameters.Nevertheless, the physico-chemical data of upstream LAR water showed thatthe river is severely polluted by other upstream sources and the river water isbeyond the recommended water quality values for human, animal andagricultural uses
EFFECTS OF PH AND SALINITY ON THE SEDIMENTATION OF CLAY PARTICLES IN TURBID LAKES OF THE RIFT VALLEY OF ETHIOPIA AND KENYA
No full textSome lakes in the Rift Valley of East Africa are among themost productive in the world, while others are dystrophic, possessing astable, opaque suspension of fine silt or clay. Understanding the causes offlocculation and sedimentation of this material could provide insight into whythese lakes are so turbid. We collected samples of suspended clay from threeturbid lakes (Langano and Abaya in Ethiopia, and Baringo in Kenya),measured the size-distribution and organic content of their suspendedsediment, and performed laboratory studies of sedimentation rate as afunction of pH and salinity. Most of the turbidity in the two Ethiopian lakeswas due to particles between 0.5 and 1.5 µm, and the suspended material hada low organic content and C/N ratio in all the three lakes. Sedimentationvelocity of the material increased with both salinity and pH, with velocitiesvarying from near 0 at neutral pH and low salinity, to 3 cm h-1as pHapproached 12 or salinity approached 25 ppt in the case of Lake Abaya.These results may explain why it is only freshwater lakes that demonstratethese turbid clay suspensions, and suggest mechanisms through which theirturbidity might be altered