Browsing by Author "Woldu, Zerihun (Professor)"
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Item Analysis of Land and Vegetation Cover Dynamics Using Remote Sensing & Gis Techiniques, A Case Study of Nechisar National Park(Addis Ababa Universty, 2008-02) Nigussie, Asaye; Woldu, Zerihun (Professor)The research aims to analyze the trend of land and vegetation cover dynamics over the period from 1976, 1986 2000 and 2007 thus examine the conservation status of the area and generate up-to-date land cover map. Information is extracted from various Satellite images of multidated Landsat, ASTER and MODIS images. The Landsat images are the basic remote sensing data to generate the thematic maps which are further analyzed to show the cover dynamics in the park for 24years. All data s from the satellite images are processesed and analyzed using digital image processing techniques. Besides, different vector data are extracted from the images as well as other thematic maps. MODIS-NDVI images are analyzed for the different land cover classes and each vegetation cover seasonal response is compared for the year 2000 and 2005. The land cover classes identified in the study area from 1976, 1986, 2000 and 2007 are water body, riparian and ground water (GW) forest, wood land, dense bush land, bushy shrubbed grass land, open grass land, degraded grass land, cultivated land, swamp vegetation and bare land. Rate of land cover change and fragmentation of habitat were discussed for the different land cover classes. Rate of land cover change, fragmentation index and land cover conversion matrix clearly shows the dynamics of the different cover classes has happened for the past decades and generally the park conservation status is found to be poor. Bush encroachment in the study area is a major challenge to the park particularly for the grass land and overgrazing on the Nechisar plain has caused expansion of invasive plants erosion and land degradation. The community livelihood dependency both in the rural and urban setting is concluded and discussed as a challenge to the park from biodiversity conservation point of view. Key Words: Land cover dynamics, National park, Vegetation cover, Remote sensing and GIS, Habitat fragmentation, degradation, biodiversity conservationItem A Comparative Ecological Study of the Miombo Woodland in Tab ora, Tanzania.(Addis Ababa University, 2004-07) Alfred, Mwilla; Woldu, Zerihun (Professor)The plant COlli/II unities oj the Igoll1be dam protected and non-protected Miombo woodlands oj Tabora were described based on thejloristic analysis ojthe data collected between October 2003 and November 2003. Floristic analysis is based on the cover abundance values ojboth trees, shrubs andfield layer which included grasses and herbs. Plant comlllunily -environment relationship was assessed based on the soil physical and chemical characteristics. A total 60 plots (releves) were analysed, and a total 145 species vascular plants were identified. The vegetation data were subjected to cluster analysis. The cluster analysis resulted into seven community types jor field layer, nine comlllunity types jor shrub layer and eight cOllllllunity types jor tree layer. The rations ojprotected and un-protected plots were subjected to two-sample t-test. The results showed that the shrub layer responded quickly to disturbance than tree and field layer. Environlllental data were subjected to Duncan mUltiple range test. These tests resulted into conclusion that the important nutrients were more in the protected sites than in the unprotected sites. 111e results showed that there is significant difference in community composition and structure between the protected and non-protected area due to the activities going 011. Also the soils of both two areas showed significant difference in nutrient contents and account jor the differences in the composition and structure.Item Comparative Floristic study on Menagesha Suba State Forest on Years 1980 and 2006(Addis Ababa University, 2017-05) Zewdie, Abate; Demissew, Sebsebe (professor); Woldu, Zerihun (Professor)A comparative study of vegetation data of Menagesha Suba State Forest between 1980 and 2006 in the central plateau of Ethiopia was conducted. The forest represents a dry evergreen Afromontane Forest. The vegetation data were correlated in previously laid 50 quadrants, each with 20 m x 20 m systematically. The presence and absence of all shrubs and trees in the stands were recorded. Density values for trees and shrubs were registered. Soil pH, altitudes, slopes and aspect were measured. The vegetation data were analyzed using Association Analysis and TWINSPAN. Results of the Association Analysis were used for matching the species used as characteristic in the determining the community types in the previous and the current study. TWINSPAN outputs are used to identify vegetation types using polythetic hierarchical approach. According to the outputs of TWINSPAN Analysis six clusters were recognized. These are: 1. cuprussus lusitanica, 2. Myrsine africana – Erica arborea, 3. Myrsine africana – Olea europaea, 4. Olea europaea – Sideroxylon gillettii, 5. Dovyalis abyssinica – Allophyllus abyssinicus, 6. Lantana trifolia - Juniperus procera . Structural analysis of the forest showed dominance of small sized species. Kyey words – community, dry evergreen montane forest, clustering, menagesha suba state forestItem The conservation status of Pterocarpus angolensis D.C in Nguru ya Ndege Forest Reserve, Morogoro-Tanzania Robert Modest M.Sc.(Addis Ababa University, 2006-07) Modest, Robert; Woldu, Zerihun (Professor)A study was carried out in Nguru ya Ndege Forest Reserve, Morogoro- Tanzania. Simple random sampling method was applied in sampling of the vegetations. Objectives of this study were to determine the spatial distribution and population structure of P. angolensis in Nguru ya Ndege Forest Reserve, and to assess the density and the extent of exploitation of P. angolensis in Nguru ya Ndege Forest Reserve. A total of 102 woody species were recorded during the study falling in 71 genera and 30 families. The results showed that; the population density of P. angolensis in Nguru ya Ndege Forest Reserve was 19 stems/ha for individuals with DBH 4 cm. The plot of DBH class distribution showed a characteristic inverted J shape for P. angolensis, although the trend seemed interrupted. From the generated ArcView map it was observed that the distribution of P. angolensis in Nguru ya Ndege Forest Reserve was not even as quadrats into which the species was recorded seemed concentrated more in the higher altitudes of the reserve than lower plains. It was also found that, mature individuals of P. angolensis in Nguru ya Ndege Forest Reserve are being selectively removed for timber sawing. This study concluded that, the store of P. angolensis in Nguru ya Ndege Forest Reserve is still promising, and its population structure might show a normal trend in future if the forest is put in a well-managed regime. This study recommended among others, to transplant seedlings of P. angolensis especially in the northern, western and southern parts in order to restore those denuded areas of the reserve.Item Distribution of the Woody Vegetation along the Altitudinal range from Abay (Blue Nile) Gorge to Choke Mountain, East Gojjam Zone, Amhara National Regional State, Northwest Ethiopia.(Addis Ababa University, 2014-06) Achiso, Zewde; Woldu, Zerihun (Professor); Demissew, Sebsebe (Professor)Distribution of Woody Vegetation along altitudinal ranges from Abay Gorge to Choke Mountain was conducted in East Gojjam Zone of Amhara Regional State, North West Ethiopia, with aim of assessing floristic composition, species diversity and structure of woody plant species in the study area. Systematic line transect sampling method was applied to collect woody vegetation data. Accordingly, 56 quadrats each with 400 m2 (20 m X 20 m) at a distance of 50 m. a. s. l. along a transect line for tree and shrubby species and subquadrats of 5 m X 5 m within the main quadrats were laid to record saplings and seedlings of woody plants and soil sample. Vegetation classification was performed by using R Software packages. Four clusters were identified and designated as local plant community types. Each community was named after two or three of the dominant tree or shrub species in the group. Shannon-Wiener diversity index was used to compute species richness and evenness of the communities. Ecological dissimilarity of communities was determined by Euclidean distance. CCA was used to correlate pH and altitude, while FSO was used to correlate environmental factors. DBH, Density, Frequency and IVI were computed to describe the structure of vegetation. A total of 120 woody plant species in 90 genera and 48 families were identified. Fabaceae and Asteraceae were the most dominant families with 16 and 14 species and with 11 and 10 genera each respectively. Shrubs were the dominant life forms. Thirteen endemic species were recorded, from which 4 are new records for FEE. Altitude and soil pH have great impact in vegetation distribution. Future research directions and recommendations were suggested for the sustainable utilization of the vegetation. Key words/Phrases: Floristic Composition, Plant Community, Species Diversity, Woody Vegetation, Tree, Shrub, Endemic species, Soil pHItem Ecological Investigation on the Afroalpine Vegetation of Guna Mountain, South Gondar(Addis Ababa University, 2004-07) Molla, Melku; Woldu, Zerihun (Professor)Ecological investigation was conducted on the afroalpine vegetation of the Guna Massif, South Gondar, Ethiopia, to characterize vegetation communities and type and extent of utilization of the area by the farming societies at lower slopes The vegetation of the afroalpine area of Guna Mountain was studied for describing the major plant communities and relationships between vegetation and topographic, climatic and edaphic factors. Vegetation composition was studied from quadrats (10 x 10 m) while quadrat size 1 m x 1 m was used for herbaceous vegetation along an altitudinal gradient extending from 3481 m up to 4041 m. From each quadrat, species presence and absence, percent cover abundance and frequency of 56 plant species from a total of 45 quadrats were recorded. Soil samples were collected from each quadrat and were analyzed for texture, pH, conductivity and soil moisture. Association analysis was performed on the vegetation data using the program SYNTAX to identify the community types. Pearson Correlation Coefficient was applied to identify four species groups. Six major plant communities, namely: Hypericum-Carex-Satureja community, EricaHypericum- Dipsacus scrub community, Festuca-Erica complex community, FestucaOestospermum meadow community type, Festuca-Lobelia-Thymus community type and Lobepa-Festuca-Helichlysum heather community type was described. Vegetation cover and species diversity decreased with an increase in altitude, Soil moisture content also decreased with altitude. The sites occupied by the major plant communities differed significantly in their soil texture and soil moisture content Socio-economic data were obtained through questionnaire, on site observation as well as using 1984 and 1994 population census results. Twenty informants were selected in each "Kebele" for the study using systematic random sampling. Chi-Square test and correlation analysis were used to relate mode of utilization of the natural resources (grazing, thatching and firewood) by the peasant associations adjoining Guna Massif. Grazing was the most important mode of utilization followed by thatching and firewood. Most respondents (60-70%) considered the Guna area as a very important source for thatching grass, while seven out of eight peasant associations depended on the Guna area as a source of fuel-wood. The biomass production showed significant seasonal variations fo !lowing rainfall. Peak biomass was obtained during the wet periods, June-October. It ranged from 85.1 g n12 to 224.9 g m-2 for mixed stands (AlldrojJogoll ([mcthystilllls + Festllc([ richardil) and 96.1 g 111- 2 for F. riclwrdii pure stand. There was relatively little growth in the dry period (October-Janumy). The annual biomass production ranged from 112 g m·2 to 82 g m·2 for F. ric/wrciii and mixed stands, respectively. The biomass production of F. richardii stand was significantly lower than the mixed stand species.Item Ecological Study of Shrubland Vegetation along the Escarpments between Addis Alem and Wolenkomi, West Shewa, Oromoia National Regional State(Addis Ababa University, 2012-06) Shentema, Abdi; Woldu, Zerihun (Professor)The study was conducted in Oromia National Regional State, West Shewa Zone, along escarpments between Addis Alem and Wolenkomi towns with objective of investigating ecology of shrubland vegetation of the area. Vegetation data were collected from 50 quadrats which were systematically laid. Quaqrats of 20 m x 20 m (400 m2) were laid for woody species (shrub/trees). For the collection of herbaceous species, subplots of 1 m x 1 m at the four corners and the center of the large quadrat were established. Cover abundance value of all the species was estimated in the field, and then later converted to the Braun-Blanquet 1-9 scale as modified by van der Maarel (1979). One hundred and one plant species were collected and identified there were grouped into 88 genera and 48 families. Hierarchical cluster analysis was employed to analyze community type. Four plant community types: Euphorbia ampliphylla -Halleria lucida, Dovyalis abyssinica- Ficus sur, Caparris tomentosa - Maesa lanceolata and Rubus apetalus - Indigofera spicata were identified. Shannon - Wiener index of species diversity was applied in order to evaluate species diversity and richness. Accordingly, community type 2 is the highest in diversity (3.7 diversity index) while community type 1 is the lowest in diversity (2.88 diversity index). Height and diameter at breast height (DBH) of all woody species taller than 2 m and thicker than 2 cm were measured in the field. The overall density of tree or shrub species which have DBH >2cm was 874 individual/ha. Based on the computation of Importance Value Index, Croton macrostachyus, Carissa spinarum, Olea europaea subsp. cuspidata, Pterolobium stellatum and Acacia abyssinica, were identified to be the dominant woody species of the area. Key words/phrases: Addis Alem and Wolenkomi, ecological study, plant community, shrubland vegetation, species richness/diversityItem Ecological Study of the Shrubland Vegetation around Ambo, West Shewa Zone of Oromia National Regional State, Central Ethiopia(Addis Ababa University, 2012-06) Kebede, Belete; Woldu, Zerihun (Professor)The study area is located around Ambo, West Shewa Zone of Oromia Regional State. This study was carried out with the aim of compiling floristic composition, population structure and community types. Fifty two, 20 m x 20 m quadrats were selected and all the plants in the quadrats were recorded. The cover abundance values were estimated. DBH, height, and density count for woody species in all the quadrats were registered. A total of 110 species belonging to 98 genera and 48 families were recorded from 52 sample plots and identified at the National Herbarium (ETH), Addis Ababa University. The Asteraceae family was represented by the highest number of species (16) followed by Fabaceae (13) and Poaceae (8). Five community types were identified and described. The plant communities were named after two or three of the dominant species and/or characteristic species selected by their synoptic value. The plant community differed in species diversity, frequency of occurrence and botanical composition of species. The Rosa abyssinica- Galium aparinoides community type had the highest species diversities whereas Vernonia amygdalin-Erythrina brucei-Juniperus procera and Bidens pilosa - Microlepia strigosa - Capparis tomentosa communities had the lowest. Shannon-Wiener diversity indices were computed to measure species diversity and it revealed that species diversity is high in communities 1, 5, 4, 2 and 3 respectively. This is probably due to high rate of disturbance in the communities. The natural environment is under threat from various farming and grazing practices. Based on the result of the study, continuous discussion between local communities and various stakeholders as well as detailed ecological studies were recommended Keywords/phrases: Cluster analysis, Diversity, Dominant species, Floristic composition, Vegetation, Vegetation structureItem Ecological Study of the Vegetation in Choke-Koso Ber Mountain Range, Northwest Ethiopia(Addis Ababa Universty, 2015-11) Belachew, Getaneh; Woldu, Zerihun (Professor)Ecological Study of the vegetation in Choke-Koso Ber Mountain range was conducted in Gojjam, Amhara zone, Northwest Ethiopia, to identify and describe floristic composition, diversity, community types, community-environment relation, population structure and regeneration status. A total of 212 sample plots, each with a size of 20 m x 20 m, were systematically laid at 25 m altitudinal intervals along transect lines. In each plot, geographical coordination, altitude, aspect, slope and identity of woody species were recorded; percentage aerial cover of the species was estimated. Height and circumference at breast height (CBH) were measured for each woody species with height 2.5 m and CBH 7.85 cm. In five small sub-plots, herb species were recorded, percentage aerial cover of the species was estimated, seedling and sapling of woody species were counted and composite of soil samples were collected. Soil texture was determined using the Boycouos hydrometric method and USDA Soil Textural Triangle. Soil pH was measured using pH meter, while electrical conductivity and total dissolved salts of the soil samples were measured using Conductivity/TDS/Salinity/ Resistivity Meter. Diversity and multivariate analyses were conducted using appropriate packages in R program (Version 3.1.2). 243 plant species, belonging to 177 genera and 71 families, were recorded. Of these, 17 species (7%) were trees, 3 species (1.23%) shrub/tree, 37 species (15.23%) shrubs, 171 species (70.37%) herbs, 12 species (4.94%) climbers and 3 species (1.23%) mosses. Out of the total identified species, flowering plants were represented by 228 species (93.83%), non-flowering by 15 species (6.17%), dicots by 176 species (77.20%) and monocots by 52 species (22.80%). Asteraceae, Poaceae, Fabaceae and Lamiaceae were the dominant families. Of the total species, 33 species (13.58%) were endemic plants to Ethiopia. Agglomerative Hierarchical Cluster analysis resulted in three plant community types of Afroalpine vegetation and five plant community types of Dry Evergreen Afromontane vegetation. Analysis of Shannon and Weaver diversity index showed that species richness, diversity and evenness varied among the plant communities. Diversity and richness tended to decrease with increasing altitude, while species turnover tended to increase with increasing altitude. In general, community types with largest number of sample plots, diversified environment, highest altitudinal range and moderate disturbance were found to have the highest species diversity, richness and evenness. Soil textural classes of the study area were sandy loam, loamy sand, sandy clay loam, clay loam and loam. The vegetation and the environmental data were subjected to direct gradient analysis. The output of CCA revealed that the most influential environmental variables that had effect on the distribution of species and segregation of some plant community types in both Afroalpine and Dry Evergreen Afromontane vegetation were Sand (%), Disturbances, Aspect and Slope. ANOVA and Turkey’s pair-wise comparison showed significant different (P < 0.05) between the community types with respect to mean of Altitude, Silt (%), Clay (%) and Disturbance in both Afroalpine and Dry Evergreen Afromontane vegetation. In addition, there was significant difference between the community types of Dry Evergreen Afromontane vegetation with regard to mean of Sand (%), pH, EC and Total dissolved Salt (TDS). Pearson’s correlation test for environmental variables of Afroalpine showed significant positive correlation (P < 0.05) occurred between Sand (%) and pH, Silt (%) and Disturbance, and EC and TDS. On the contrary, significant negative correlation occurred between Altitude and Slope, Sand (%) and Slope, Sand (%) and Silt (%), Sand (%) and Clay (%), Silt (%) and Clay (%), and TDS and Disturbance. Similarly, the correlation test for environmental variables of Dry Evergreen Afromontane vegetation showed significant positive correlation between Altitude and Aspect, Slope and pH, Sand (%) and EC, Sand (%) and TDS, and EC and TDS. In contrast, significant negative correlation occurred between Altitude and Disturbance, Sand (%) and silt (%), Sand (%) and Clay (%), Silt (%) and EC, Silt (%) and TDS, Clay (%) and EC, and Clay (%) and TDS. Structure was carried out for the Dry Evergreen Afromontane forest. In general, woody species had high density in the lower DBH and height classes, and the density gradually decreased with increasing DBH and height classes. The dominance of smallsized woody individuals in the lower DBH and height classes indicated the characteristic of a good regeneration status. Four patterns of population structure were identified: Inverted J-shaped, Gaussian-curve, J-shaped and U-shaped. The total basal area of woody species was 28.65 m2/ha. The six most important woody species were Maytenus arbutifolia, Maesa lanceolata, Acacia abyssinica, Schefflera abyssinica, Prunus africana and Pittosporum virdiflorum. These woody species represented 71.96% of the total Important Vale Index. The remaining 28.04% was contributed by eighteen woody species.Item The Floristic Composition and Diversity of Wetland Vegetation in Tello Wereda in Kefa Zone, Southwest Ethiopia(Addis Ababa University, 2006-06) Unbushe, Dikaso; Demissew, Sebsebe (professor); Woldu, Zerihun (Professor)The present study was carried out in Kaffa Zone in general and Tello Wereda in particular, southwest Ethiopia. The study in wetland vegetation of the area was conducted between October 2005 and June 2006. The vegetation and environmental data were collected from 88 quadrats (during wet season) and 77 quadrats (during dry season) from the six study sites. The Purpose of the study was to investigate floristic composition and diversity of wetland vegetation in the area. The major issues addressed include floristic diversity, vegetation description, community type identification, site diversity, measurement of aboveground biomass and wetland plant inventory. During the study, the percentage cover abundance of each species was estimated and later converted into modified Braun-Blanquet 1-9 scale. Clipping of all the aboveground vegetation was carried out in 1 m2 plot size, which is placed at the center of each 4 m2 quadrat, used for plant community description. Some environmental variables and disturbance scale was recorded for each site. A total of 69 and 56 plant species representing 28 and 27 families were identified during wet and dry seasons respectively. The families Cyperaceae, Poaceae and Lamiaceae were represented by the highest number of species. All the vegetation data were analyzed with SYNTAX-2000, computer program. Three and four reasonable plant community types were obtained and described. The resulting clusters were interpreted as community types and were given names after two dominant plant species. Shannon-wiener diversity index was employed to analyze species diversity in the plant community types and the study sites. The clusters of stands were found to show variation due to differences in altitude, moisture contents, and other site conditions. Recommendations for the sustainable utilization of the vegetation resources at the study sites are provided.Item Floristic Composition and Ecological Study of Bibita Forest (Gura Ferda), Southwest Ethiopia(Addis Ababa University, 2006-06) Denu, Dereje; Demissew, Sebsebe (professor); Woldu, Zerihun (Professor)This study was carried out at Bibita Forest (Gura Ferda), southwest Ethiopia to determine floristic composition, vegetation structure and to identify community types and to investigate the role of environmental factors in the distribution of the vegetation. 60 relevés, 20 m x 20 m at 25 m altitudinal drop along an altitudinal gradient were laid to collect the data on cover–abundance (for trees and shrubs), DBH, height, density, seedling and sapling count (for trees only). The data on herbaceous species were collected from five, 5 m x 5 m subplots laid at four corners each and one at the centre of the large relevé. Two soil samples were taken from each relevé at a depth of 0–10 cm (topsoil) and 30–50 cm (subsoil). The analysis for soil pH, % sand, % clay, % silt, and Electrical Conductivity (EC) were done. A total of 196 plant specimens belonging to 74 families and 170 genera were identified. The five most dominant families were Rubiaceae and Asteraceae (13 species each), Euphorbiaceae and Acanthaceae (9 species each) and Fabaceae (8 species). Out of 196 species 13 were endemic to Ethiopia. Ipomoea involucrata Beauv. and ? Harungana madagascariensis Lam. ex Poir. belonging to the families Convolvulaceae and Clusiaceae respectively were found to be new records for Ethiopia. Six community types were identified at 0.65 to 0.75 dissimilarity levels and each community was named after dominant tree and/or shrub species. The study on vertical stratification showed that Bibita Forest(Gura Ferda) has the upper storey (above 29 m), middle storey (15–29 m) and lower storey (below 15 m). The study on vegetation and population structure showed that the density of tree species was high at the lower class levels. Density of trees greater than 2 cm DBH (ca. 777/ha), for height greater than 6 m the tree density (ca. 673/ha), basal area (ca. 70/ha), frequency of all the tree species (716/ha) and the respective IVI values for each tree species were also calculated. The comparison of Bibita Forest (Gura Ferda) with other forests in Ethiopia with respect to tree densities, percentage distribution of tree species, basal area and phytogeographical comparison was done. Soil environmental factors such as pH of the top and subsoils, clay and sand particles of both the top and subsoils showed significant relations with altitude, species richness and diversity.Item Floristic Composition and Structure in Beschillo and Abay (Blue Nile) Riverine Vegetation(Addis Ababa University, 2006-07) Belachew, Getaneh; Demissew, Sebesebe (Professor); Woldu, Zerihun (Professor)Riverine vegetation along Beschillo and Blue Nile rivers was studied with the aim of compiling floristic composition and describing its plant communities. The area studied occurred between altitudinal gradients of 1324 and 626m. Beschillo is a tributary of Blue Nile River from which the study was started at a point between Mekdela and Tach-Gayint ‘woredas’ in Amhara Regional State (11025.232’ N & 380 42.331’ E) up to the point at which it joins the Blue Nile River (11002.121’ N & 38028.521’ E) and then continued to Sirba Abay (10007.492’ N & 35020.919’ E), which is located in Benishangul-Gumuz Regional State. A total of 580 km was covered to study the riverine vegetation along the two rivers. The data was collected in October and November 2005. Along the rivers, nested belt transects were laid at 500 or 1000 m interval from the riverbank to the adjoining upland. A total of 74 releves were analyzed within 43 transects. The number of plots in each transect was determined by the size of riverine vegetation which laid from the stream edge to the adjoining upland. Cover abundance value for each species was estimated based on Braun- Blanquet approaches as modified by Van der Maarel (1979). The number, height, and diameter at breast height (DBH) >2.5cm were measured for all tree individuals. A total of 205 vascular plant species were recorded of which, 47.32% were herbs, 6.83 % climbers, 22.44% shrubs and 23.41% were trees. A total of 53 Families and 152 Genera were registered, of these 12% were Poaceae, 10% Fabaceae, 5.4% Acanthaceae, 4.9 % Malvaceae and 4.4% Tiliaceae. The output of cluster analysis revealed 6 distinct plant community types. Structural parameters such as Density, Frequency, Dominance, and Important Value Index were calculated. Shannon-Weiner Diversity Index was also computed. The density of tree species per ha was 115 whereas the total basal area (BA) of trees species m2 / ha was 12.6. Most of the tree individuals distributed in middle diameter and height classes.Item Floristic Composition of Herbaceous Flowering Plant Species with Emphasis to Ethnobotanical Importance of Wild Grasses in Laelay and Tahtay Michew Districts, Central Zone of Tigray, Ethiopia(Addis Ababa University, 2012-06) Atsbeha, Genet; Woldu, Zerihun (Professor)This study was carried out in Laelay and Tahtay Maichew districts. Objectives of the study were to: identify herbaceous flowering plant species found in the study area, to identify community types of the vegetation of the study area, to document the ethnobotanical importance of wild grasses and to sample wild grass hosts of stem borers that can be used as trap plants in the pushpull pest management approach. Within 65 sample quadrats, different herbaceous species were collected for taxonomic identification using preferential sampling method and coded for an analysis from 1m x 1m sub-quadrats placed within 20m x 20m quadrat. For ethnobotanical importance of wild grasses data was collected using semi-structured interview, guided field walk and direct observation, preference ranking, direct matrix ranking, group discussion and informant consensus. A total of 132 herbaceous flowering plant species of vascular plants belonging to 99 genera and 34 families were identified. With regards to species number, the most dominant plant family is Poaceae (34 species), followed by Asteraceae (16 species), Fabaceae (14 species). Four community types were also identified at 47.94% to 31.42% similarity levels. With regards to ethnobotanical importance of wild grasses, preference ranking indicated that, the most preferred grasses for animal feed are Cynodon dactylon followed by Cynodon aethiopicus, Snowdenia polystathya, Pennisetum villosum and Pennisetum sphacelatum 1st, 2nd, 3rd,4thand 5th respectively. Wild grass hosts of the stem borers was searched and among the large stemmed wild grasses known from the study area larvae and pupae of Busseola fusca and Sesamia calamistis-stem borers of maize and sorghum were found in Pennisetum purpureum. Key Phrases: Laelay and Tahtay Maichew districts, floristic composition of herbaceous flowering plant species, ethnobotanical importance of wild grasses, wild grass hosts of stem borersItem Floristic Composition of Woody vegitation with Emphasis to Ethnobotanical importance of Wild Legumes in Laelay and Tahtay Maichew districts, Central zone, Tigray, Ethiopia(Addis Ababa University, 2012-06) Shumbahri, Mohammed; Woldu, Zerihun (Professor); Demissew, Sebsebe (Professor)This study was focussed on the floristic composition of woody plants and ethnobotanical importance of legumes in Laelay and Tahtay Maichew, central zone, Tigray. To study woody plants study sites were selected via preferential sampling in protected, mountains and degraded watershades following survey. At the end of the day, sixty (60) plots were laid down. Interviews were conducted with informants and field observations were made to collect Ethnobotanical data. Statistical tools like hierarchial cluster analysis and Shannon-Wiener diversity index were used for vegetation data analysis. Preferential ranking was also applied for Ethnobotanical data analysis. As a result 57 woody species and 8 herbaceous legumes were identified. The most species rich family was Fabaceae with 13 species. The result of cluster analysis show that, five community types with distinct species number and the community types found in protected areas have more species than unprotected ones. The prefertial ranking for ethnobotanical study of legumes show that, widely used plants for food and farm implements are Ziziphus spina-christi and Acacia lahai respectivelly. The traditional medicinal knowledge is acquired more from parents in the area. The major threats of woody plants are cutting, continuous cultivation and overgrazing Woody. Meanwhile plantations are the main conservation practices applied in the areas to conserve and facilitate regeneration of woody plants. KEY WORDS and PHARASES: Woody plants, cluster analysis, Ethnobotany, legumes, plantationItem Floristic Composition, Structural Analysis and Land use/Land Cover Change in Bore- Anferara-Wadera Forest, Southern Ethiopia(Addis Ababa Universty, 2017-06) Woldearegay, Mesfin; Woldu, Zerihun (Professor)This study was conducted in Bore-Anferara-Wadera forest, southern Ethiopia, to investigate the floristic composition, vegetation structure, regeneration status and land use/land cover change. Vegetation data were collected from 112, 30 m x 30 m sample plots laid for trees at every 400 m distance along line transects and 5 m x 5 m and five 1 m x 1 m subplots for saplings and herbs, respectively. The regeneration status of woody species was assessed by employing total count of all seedlings within the main sample plot. Environmental variables such as altitude, slope, and exposure were measured in each sample plot. Soil samples were taken from two layers (0-25 and 25-50 cm) at five points in each sample plot and soil sample from these five points were mixed to form a composite sample. In each sample plot, woody species ≥ 3 m were counted and cover abundance values estimated as well as height and diameter at breast height were measured. Hierarchical cluster analysis was used to identify plant communities and synoptic values for identification of the dominant species for naming plant communities. Density, frequency, basal area and importance value index (IVI) of woody species were also computed. Shannon-Wiener diversity index was used to assess species richness and evenness. Sorensen's similarity coefficient was used to measure similarities among communities and between Bore-Anferara-Wadera and eight Afromontane forests in Ethiopia. Canonical correspondence analysis (CCA) was used to assess the relationship between plant community types and environmental variables. Moreover, three periods land sat images (1986 TM, 2000 ETM+ and 2014 OLI/TIRS) were acquired and analyzed by using remote sensing and GIS technologies to generate information on the temporal changes in land use and land cover types. A total of 136 vascular plant species belonging to 119 genera and 63 families were recorded. About 4.4% of the species were endemic to Ethiopia and 11.8 % of the species were new records for the Sidamo floristic region of the flora area. The overall Shannon-Wiener diversity and evenness values of Bore- Anferara-Wadera forest were 3.84 and 0.78, respectively. Size class distribution of woody species across different DBH and height classes indicated the relatively high proportion of individuals at lower classes, indicating impacts of past disturbance. Analysis of population structure and regeneration status of the forest revealed various patterns of population dynamics where some species were represented by few mature plants only suggesting that they are on the verge of local extinction and thus immediate conservation measures should be taken. Community classification using the free statistical software R version 3.1.1 resulted in four, namely Acanthus eminens - Dracaena afromontana, Syzygium guineense subsp. afromontanum - Ocotea kenyensis, Pouteria adolfi-friederici - Psychotria orophila and Scolopia theifolia - Teclea nobilis community types. Canonical correspondence analysis (CCA) result showed that altitude and slope were among the main environmental variables in determining patterns of species distribution and plant community formation. The results of land sat image analysis revealed that agricultural land and built up area are expanding rapidly at the expense of other land use and land cover types. Forest and shrub land areas have declined drastically over the last 28 years. Population pressure, deforestation, land tenure system, and forest fire were the main driving forces responsible for the change in land use and land cover types in the study area. Therefore, a joint management and conservation measures should be taken by the government, local people and other stakeholders in order to reduce and/or stop the fast rate of vegetation cover declining and sustainable utilization of the forest resources in the study area. Keywords: Anferara, Biodiversity, Conservation, Land use/land cover, Plant communityItem The Impact of Water Points on Spatial Distribution of Vegetation, Range Condition and Soil Properties in Mbirikani Group Ranch, Kajiado District, Kenya(Addis Ababa University, 2006-06) Shikuku, Martin; Woldu, Zerihun (Professor)The impact of water points on range condition, woody species density, soil properties dynamics, frequency distribution and palatability levels of shrubs and grasses was investigated around two water points. Density and frequency distribution data was collected from four transects radiating from the water points and sample plots marked at various consistent distance intervals of 0-50m, 200-250m, 400-450m and 600-650m.Whereby, 50m was used as a baseline measurement for all the transects. 20m by 20 m and 1m by 1m plots for density and frequency respectively were used. Range condition and soil properties’ data were obtained from 0.5m by 0.5 m respectively. One way analysis of variance (ANOVA) and linear regression based on Minitab version 12.22 computer software was employed to assess the relationship between the environmental variables and the distance from the water points. For the woody species, the number of individual stems per plot increased in number with respect to distance from the water point both within and between transects, however this was tested not significant for all the transect directions. Greater density of mature individuals than saplings was recorded with respect to distance from both water points. Two methods independently followed to assess the status of range condition, revealed similar results. The method by (Naylor and Herlocker, 1987) involved a range condition scoring criteria ranging from 0-3, optimal, minimal status respectively and squarely based on estimations. Method by (Baars etal., 1996) involved actual sampling and scoring criteria ranging from 0-10 optimal, minimal status respectively. The area close to the water points (0-50) m, had poor range condition. The other three concentric zones all reflected fair condition. All the five soil nutrients (K, P, Ca, Om and N), showed a decreasing trend in values as the distance increases from the water points. Nevertheless, only Phosphorous and Organic matter showed significant variations. Fourteen shrubs and grass species selected by experienced pastoralists were used to explore the distance, frequency distribution and palatability preference relationships. Highly desirable (highly palatable and intermediate) grasses had high abundance away from the water points. Shrubs closer to the water points were found to be less palatable. Generally, it was apparent that the water points have a contribution to rangeland degradation and that the condition is likely to worsen if the trend remains unchecked.Item Urban Poverty and Poor Housing Condition in Addis Ababa Metropolice Using Remote Sensing and Geographic Information System(Addis Ababa Universty, 2008-07) Samuel, Mebrate; Woldu, Zerihun (Professor)This study explores the urban poverty and intends to contribute to the study of the phenomena of rapid urban poverty and poor housing condition in Arada and Lideta sub-cities of Addis Ababa. The study was conducted on primary and secondary data collected from various households of the sub-cities. Four hundred households were surveyed to investigate the access to toilet, the status of the house, the water supply, socio-economic and sanitation situation. The study was made urban land classification of Arada and Lideta using Remote sensing technique and poverty area map using GIS technique. In order to achieve this objective the collected sample of households, Aerial photographs, Ikonos image and other data were analyzed. An overlay analysis is carried out by evaluating the layers obtained according to their weight and the poverty susceptibility map is produced. And then classified into four classes: low, moderate, high, and very high. From the result more residential parts of Lideta sub city are found in the highest poverty area than Arada sub city. The major reason for the occurrence of poverty area is their monthly income is very low and inadequate so that they can not construct, buy, or rent decent dwelling unit. Furthermore, lack of adequate sewerage and water supply, poor housing condition, over crowdedness are among the main problems. Still more can be inferred that the surveyed households live in an unhygienic and congested environment lacking the basic necessities of a healthy life. On the other hand the remote sensing processed result reveals that the urban land classification area changed through different period of time. Between 1965 and 1984 the built up area and the road distribution had increased. During 1984 and 2004 the two sub cities had changed that built up area and road distribution increased. Generally the magnitude of their problems is worsening from day to day. To improve these conditions the community needs to be actively participation with volunteer investor and small microfinance for the construction of houses and financial advancement.Item Vegetation Ecology and Dynamics of Land Cover Change of Abune Yosef Mountain Range, Lasta District, Amhara Regional State, Northern Ethiopia(Addis Ababa University, 2020-02-02) Gebrehiwot, Kflay; Woldu, Zerihun (Professor); Demissew, Sebsebe (Professor); Teferi, Ermias (PhD); Desalegn, Temesgen (PhD)The understudied flora, Abune Yosef mountain range, is under pressure from land use changes. This research was conducted to study the vascular plant composition, plant communities, diversity, conservation status, species richness pattern along elevation gradient, and spatiotemporal land use and land cover change. A total of 85 nested sample plots measuring 20 X 20 m, 5 X 5 m and 1 X 1 m were established for trees, shrubs, and herbs respectively. Topographic, edaphic and disturbance variables were also collected from each plot. IUCN Red List and a combination of density of mature individuals, habitat specificity, and species local range was considered to assess global and local rarity respectively. Two Landsat satellite imageries from 1986 (Thematic Mapper, TM) and 2017 (Operational Land Imager, OLI) were used. Aerial photographs were used for ground referencing of the 1986 satellite image. Agglomerative hierarchical clustering and Shannon diversity index were employed to classify plant communities and quantify community diversity and evenness. Canonical correspondence analysis (CCA) was used to describe vegetation-environment-disturbance relationships. Descriptive statistics and rarity forms ratio were used for vascular plants conservation status analysis. To investigate land use land cover change (LULCC), supervised classification using Maximum Likelihood Classifier of two Landsat images from 1986 and 2017 was performed. Ground reference points and aerial photographs were used for accuracy assessment. One hundred ninety nine vascular plant species belonging to 64 families and 155 genera were recorded in five plant communities. The most species rich families were Asteraceae 42(21.1%), Poaceae 15(7.5%), Lamiaceae 12(6.03%) and Fabaceae 11(5.5%) respectively. Thirty two families were represented by a single species. The species richness followed a monotonically decreasing pattern towards higher elevation. Of the vascular plants assessed following IUCN Red List criteria, about 5% are threatened and the remaining are of least concern. Locally, only 17 species (8.54%) of the plants revealed common, and the remaining entertained six forms of rarity. The first axis explained 43.63% of the overall inertia and is correlated with Elevation, pH, slope aspect, total Nitrogen, soil organic Carbon & Clay. On the other hand, the second axis explained 32.06% of the total inertia and is correlated with bulk density, slope, logging, & available Phosphorus. The LULCC results demonstrated that the area of Afroalpine grassland has declined by -64.76% over the last 31 years, from 10, 500 ha to 3700 ha. Other declines were seen in grazing land (-72.15%, 5,900 ha), open woodland from (-100%, 3,900 ha) and shrubland (-7.04%, 2,500 ha). On the other hand, agricultural land area has increased from 38, 300 to 48, 700 ha (+27.15%), barren land from 5,400 to 8,900 ha (+64.81%), rivers, riverbeds and gullies from 1,100 to 3,700 (+236.56%), plantation forests from 2,500 to 4,700 ha (+88%) and urban settlements from 300 to 500 ha (+66.66%). The present study revealed that topographic variables have a profound influence on species distribution. Exclusive to church forests, the vegetation cover showed a declining trend over the study period. The main drivers of LULCC were identified as increased human population pressure, and temperature and precipitation variability. Since the majority of the plants are rare in the mountain range, landscape level conservation approach by establishing corridors between the vegetation types to maintain ecological and evolutionary processes is recommended.Item Vegetation Ecology and Plant Diversity of Hugumburda-Gratkhassu National Forest Priority Area, Northeastern Ethiopia: Habitat Fragmentation in Time and Space(Addis Ababa Universty, 2015-11) Kidane, Leul; Woldu, Zerihun (Professor)This study was conducted with the objectives of analyzing and understanding the species composition, diversity, structure and regeneration dynamics of Hugumburda-Gratkhassu NFPA in relation to land use\land cover and habitat fragmentation. A total of 77 quadrats were sampled using stratified sampling with optimum allocation method. In the quadrats, data on abundance, height and DBH of woody plant species as well as landscape variables were recorded. Within the main quadrat, five 2 m x 2 m subplots were laid to collect data on seedlings, saplings and herbaceous species. In addition, in each subplot, soil samples were collected and soil texture, electrical conductivity and pH were analyzed. In order to investigate edge effect, 17 forest patches were selected and sampling points for vegetation and environmental variables were established at 0, 50, 100, 150 and 200 m from the edge. A total of 83 quadrats were selected for this study. Furthermore, Satellite images were acquired and analyzed by using remote sensing technology and GIS mapping to generate information on the temporal and spatial changes in land use\land cover types and habitat fragmentation. A total of 326 plant species representing 238 genera and 88 families were recorded; shrub and herb species are dominant. Cluster analysis resulted in five different plant communities and this result was supported by the ordination result. CCA result showed altitude was the main environmental variable in determining the plant communities. Species richness, diversity and evenness varied among the plant communities and along the edge gradient. Analysis of population structure and regeneration status of the two Forest remnants revealed various patterns and generally dominated by small sized individuals. In addition, the results of image analysis revealed that disturbance was the major driving force for fragmentation and patchiness of the remnant natural vegetation and thus exposing plant species to various environmental effects at edge habitats. Consequently, the forest edge habitats were found to possess lower species richness, diversity, tree density and basal area compared to the inner habitats. Therefore, to adequately conserve and ensure species survival and maintain species diversity in the study area, these forest remnants and edge habitats should be maintained and well managed. Key words/phrases: dry afro-montane forest, edge effect, Hugumburda-Gratkhassu, habitat fragmentation, land use\land cover, plant community, National Forest Priority Area, species richness, vegetation ecologyItem Wetland Vegetation Composition and Ecology of Abaya and Chamo in Southern and Fincha'a Chomen and Dabus in Western Ethiopia(Addis Ababa, Ethiopia, 2013-05) Unbushe, Dikaso; Woldu, Zerihun (Professor)Wetland Vegetations ofChamo and Abaya Lakes in the sOllthern and Fincha 'a-Chomen and Dabus marshes in western Ethiopia were stlldied 10 determine floristic composition. I'egetotion ecology. plant community types and to identify environmental factors significantl), influencing the distriblltion of plant species and community types. A total of 339 relevr}s were laid along transects that were set up preferentially across areas where there were rapid changes in vegetalion or marked environmental gradients to collect data on estimate of percentage aerial cover of planl species and environmental variables. A total of 302 plant species belonging to 194 genera and 72 families were identified. The most dominant fap/ilies in all the sites were Asteraceae, Poaceae. Cyperaceae and Fabaceae. Multivariate data analyses were performed using appropriate packages in R version 2.14.0. Vegef(ltion data were analyzed by agglomerative hierarchical cluster analysis IIsing similarity ratio as a resembl{/nce index and Ward 's linkage method. Canonical Correspondence Analysis (eCA) was used to explore the relationship between the species composition and environmemal variables. The environmental data to be included in the CCA were determ ined using stepwise backward (md fonvard selection of variables by ANOVA lest. Statistical measurement regarding species diversity, richness and evenness of the plant community types was carried 0 1/1 by /Ising Shannon-Wiener (1949) diversity indices. Sample-based raref action curves were computed in the program EstimateS (Colwell. 2005) 10 estimare and compare species richness across sites of different sizes. Comparison of the floristic diversity of the wetlands showed that Dab/ls marsh had the highest alpha diversity. From all the study sites, relmively the highest number of plam community types was recorded f rom wetlands of Lake Abaya during both seasons. The most important factors influencing the plant species composition and pattern of wetland plant communities were drainage. water depth. land use, slope. altitude and hydrogeomorphology (in wetlands of ulke Abaya) and water depth. disturbance alld hydrogeomorphology (in wetlands of Lake Chamo). All of the measured faCial'S had significanl role in Dablls and Finclla 'o-Chomen marshes. Therefore, these should be considered in I ll/lire f1I(magemenl and prorection under the circumstance 01 climate chOflge and human activities.