Elevational changes in vascular plants richness, diversity, and distribution pattern in Abune Yosef mountain range, Northern Ethiopia

The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient.We found that plant species richness declines monotonically from low to high elevations.Specifically,vascular plant species richness and diversity were lower in the Afroalpine grassland(high elevation)than in the Dry evergreen Afromontane forest and Ericaceous forest(low elevations).In contrast,endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest.Elevation showed a significant impact on the richness,diversity,and endemism of vascular plants.According to Sorensen's coefficient,the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher(32%)than the similarity between Ericaceous forest and Afroalpine grassland(18%).Only 5%similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland.Growth forms showed different elevationai richness patterns.Trees and liana increased monotonically up to 3300 m.Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient.The elevation patterns of vascular plant species richness,diversity,and growth form in the present study may be attributed to differences in management intensity,spatial heterogeneity,microclimatic variations,and anthropogenic disturbances.

Floristic diversity and composition of the Biteyu forest in the Gurage mountain chain (Ethiopia): implications for forest conservation

The Afromontane forests of Ethiopia have been under a serious degradation threat. Assessment of floristic diversity and species composition in Biteyu forest of Gurage mountain chain in the central Ethiopia was conducted to examine the pattern of forest structure. Thirty plots of 30 m×30 m were used to record the vegetation and environmental data using systematic sampling technique. The local name, plant scientific names, DBH, height,species abundance and percentage canopy cover of plant species were recorded. Shannon diversity index and Sorensen's coefficients was used for comparison among communities and similar forests in the country. Threats to the forest biodiversity in Biteyu were determined by counting cattle interference and wood stumps as disturbance indicators. Relative Euclidean Distance measures by using Ward's method(linkage) was applied for cluster analysis. Environmental variables were also recorded in each plot. Woody species population structure, basal area and importance value index were analyzed using spreadsheet programs. Data on species distribution and environmental variables in the forest were analyzed by canonical correspondence analysis. A total of 190 species in 154 genera under 73 families were identified. Twenty species were found to be endemic taxa to the Flora Area. Only three plant community types were identified from the cluster analysis due to the high human influence. The Sorensen's coefficient showed the resemblance of the Biteyu forest with other Dry Evergreen Afromontane forests in the country. Moreover, altitude and slope strongly affect the species composition and structure of Biteyu forest. Given the high anthropogenic influence, high endemism, high dependence of the local community on the forest resources, forest conservation and restoration measures should be done by stakeholders.

Ethnobotanical study of forage/fodder plant species in and around the semi-arid Awash National Park, Ethiopia

We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo （Kereyu and lttu） Nations in and around the semi=arid Awash National Park （ANP）, Ethiopia. The study aimed at investigating and documenting indigenous knowledge （IK） on forage/fodder plant species and threats to their survival. Ninety-six in= formants between 20 and 80 years old were selected using prior informa- tion. Data were collected using semi-structured interview, guided field wail discussion and field observation. Preference ranking, Jaccard＇s coefficient of similarity and priority ranking were used for data analysis. One hundred twenty-six forage/fodder species of 90 genera and 43 fami- lies were collected in the study area. More than 88% of the species were reported with their vernacular names, where 68% were reported by the Afar Nation and 70% by the Oromo Nation. Family Poaceae was repre- sented by 25 species （20%）, followed by Fabaceae 18 （14%）. Preference ranking for the most preferred forage grasses as perceived by key informants revealed that Chrysopogon plumulosus was the most important forage/fodder species. Overgrazing was the major threat in the study area, scoring 22%.

Elevation patterns of woody taxa richness in the evergreen Afromontane vegetation of Ethiopia

Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100 m intervals starting from 1500 to 3400 m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r = −0.985, −0.984, −0.981, respectively; all p < 0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p < 0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.

Woody species composition and structure of Kuandisha afromontane forest fragment in northwestern Ethiopia

To investigate the woody species composition,diversity and structure of Kuandisha Afromontane forest,vegetation and environmental data were collected from 53 plots of 10 m 9 50 m for trees and shrubs and 265 subplots of 2 m 9 4 m for seedlings were laid along eight transect lines. The local name, scientific name, abundance,DBH, height and percentage foliage cover of species were recorded. Environmental variables, namely altitude, latitude and longitude as well as disturbance levels were also recorded in each plot. Structure, basal area, importance value index（IVI） and species prioritization were analyzed using spreadsheet programs. Correlation coefficients, frequency, relative frequency, Shannon diversity index,Shannon evenness and vegetation classification were analyzed using an R package. Sixty-six species belonging to40 families were recorded. Fabaceae was the most diverse family consisting of seven species, followed by Euphorbiaceae and Asteraceae. In terms of habit, 29 species were trees, 28 were shrubs, and 9 were lianas. The overall Shannon diversity index was 2.5. The frequency and relative frequency of woody species with DBH C2.5 cm ranged from 1.9 to 92.5 and 0.1 to 5, respectively. Seedling density varied among species ranging from five to 9938 individuals ha-1. The total basal area of woody species having DBH C2.5 cm is 15.3 m2ha-1. The IVI of species ranged from 0.13 for Solanum giganteum Jacq. to 28.4 for Croton macrostachyus Del. The woody vegetation was classified into five community types. Species richness,diversity and evenness of communities were strongly positively correlated. On the other hand, the correlation between disturbance and seedling density, and species richness was strongly negative. Thus, among the recorded woody species, a significant portion was either lacking regeneration or selectively removed for various purposes.The lack of seedlings of those species is mainly attributed to anthropogenic disturbances particularly free grazing. As a result, 14 tree, seven shrub and one liana species were prioritized for conservation and management interventions.

Anthropogenic effects on floristic composition, diversity and regeneration potential of the Debrelibanos Monastery forest patch, central Ethiopia

This study assesses the effects of human disturbance on:(1)floristic composition,diversity,and plant community types;and,(2)the regeneration potential of woody species in the Debrelibanos Monastery forest patch in the North Showa zone of Oromia National Regional State,Ethiopia.Fifty sample quadrats were placed on parallel transect lines along altitudes in the forest using a systematic sampling design.Quadrats of 1 m^2,100 m^2 and 400 m^2 were used for recording herbaceous/seedling,sapling and tree species,respectively,with symptoms of different human disturbance effects.One hundred and thirteen species belonging to 52 families were recorded in the forest patch.The results show 459.5 stems ha^-1 of tree/shrub species present.Four community types,namely Juniperus procera–Acacia lahai,Carissa spinarum–Acacia abyssinica,Olea europaea subsp.cuspidata–Euphorbia abyssinica and Ficus sur–Allophylus abyssinicus were identified.The overall Shannon–Wiener diversity index was 3.3.The regeneration patterns of some species were poor.Slope,altitude and human activities had significant effects on vegetation patterns and imply that current management practices are not satisfactory to sustain the forest.Unless improved management interventions are made,the sustainability of forest services will be at stake.

Species composition,structure,regeneration and management status of Jorgo-Wato Forest in west Wollega,Ethiopia

Species composition,structure,regeneration,and management status of Jorgo-Wato Forest(JWF)was studied.Number of individuals,diameter at breast height(dbh)and height of woody species(dbh≥2.5 cm)were counted and measured in each plot.Group discussions with local farmers residing around JWF were carried out to understand the management of the JWF.Forest structural attributes were computed using descriptive statistics;correlation was used to assess relationships between the structural variables.A total of 4313 individuals(dbh≥2.5 cm)with a density of 1477 ha-1 were recorded,the number of species and individuals decreasing with increasing dbh classes.Species with the highest Importance Value Index(IVI)were Pouteria adolfifriedericii(37.7),Syzygium guineense subsp.afromontanum(23.6),Dracaena afromontana(20.5),Chionanthus mildbraedii(15.9),and Croton macrostachyus(12.3).Overall distribution of woody plants across size classes exhibited a reverse J-pattern,suggesting a healthy population structure and good regeneration.Nevertheless,some species were not represented in smaller diameter classes,including juvenile phases,which indicate a lack of regeneration.For these species,monitoring and enrichment planting would be necessary,along with curbing illegal cutting and coffee farming in the natural forest.Management interventions in the JWF need to consider livelihood options and to respect the rights of local communities.

Vegetation Structure and Regeneration Status of the Western Escarpment of the Rift Valley of the Gamo Zone, Southern Ethiopia

Understanding the structure and regeneration of forest resources contributes to identifying the elements of diversity, endemism, threatened and endangered species. This study was conducted in the western escarpment of the Rift valley of the Gamo Zone, Southern Ethiopia. The main objective was to investigate structure and regeneration status of the study area. A systematic sampling method was used to collect vegetation data from a total 102 quadrats, each 20 × 20 m (400 m2) and five 1 × 1 m (1 m2) sub-quadrats were established at the four corners and at the centre for sapling and seedling estimation. Tree and shrub species were listed;Height (H ≥ 1.5 m) and DBH ≥ 2 cm were measured and recorded. R-statically software and Microsoft Excel were used to record and analyse the data. A total of 126 plant species belonging to 43 families and 90 genera were identified. The most dominant families were Fabaceae, followed by Anacardiaceae and Euphorbiaceae. Most frequent species were Euclea divinorum (84.3%), followed by Rhus natalensis (83.3%), Terminalia brownii (74.5%). DBH class ≤ 5cm had highest density (63.6%) and DBH ≥ 25.1 cm had the lowest density (0.87%). Three population patterns have been observed;inverted J, J-shaped and irregular shaped. 93% of species had IVI values b/n 1 - 4, 65% of species IVI values < 1% and 7% of species had IVI values ≥ 5.28. Pappea capensis, Combretum molle, Terminalia brownii, Euclea divinorum had highest IVI values. In the vertical stratification, lower story was 91.3% of the individuals. Only a few species contributed to the high density of saplings (440.2/ha) and seedlings (825.49/ha) while most had very little or no saplings and seedlings at all. Thus, in order to revert the current forest structure and regeneration to the previous natural state, it is considered important to minimize the influence of the human interference, grazing and raising awareness to surrounding community.

Relationship between Prosopis juliflora invasion and livelihood diversification in the South Afar region,Northeast Ethiopia

This study assessed the effects of Prosopis juliflora invasion on livelihood diversification and evaluated the determinants of livelihood diversification in two districts in the South Afar region of Northeast Ethiopia.Using random sampling method,154 households and 2 focus groups composed of 10 individuals were selected from four sites in the two districts.The relationship between P.juliflora invasion and incomes obtained from P.juliflora varied across the study sites.In Awash Fentale District and Amibara District,11.0%and 3.2%of households,respectively,earned income from P.juliflora charcoal production.In total,14.3%of households were involved in charcoal production.In addition,19.9%of households earned income from selling P.juliflora pods and wood materials in the two districts.With the exception of income from P.juliflora charcoal production,the sex of households did not affect incomes from other livelihood activities.Moreover,household educational attainment significantly affected income obtained from vegetables,fruits,and cereal crops.Male householders were engaged in more diverse livelihood activities than female householders.Reversing the severe invasion of P.juliflora on grazing and woodlands in the region is advisable through integrated natural resources,pastoralist participation,and multidisciplinary research strategies.

牧豆树(Prosopis juliflora)入侵对埃塞俄比亚东北部阿法尔民族地区国家牧场本地物种多样性和木本植物更新的影响

调查牧豆树(Prosopis juliflora)的入侵及其对本土植物物种的影响和控制该物种入侵具有重要意义。本研究旨在评估:(1)牧豆树入侵对Awash Fentale和Amibara Woredas两地植物物种多样性的影响;(2)牧豆树入侵对本地木本植物更新潜力的影响。样品采集是在牧豆树灌丛、牧豆树与本地物种混生群落、未入侵林地和开阔放牧场进行的。植被调查按照牧豆树的入侵状况分类,然后在不同入侵状况生境中采用随机抽样技术进行数据收集。在植物种类组成中,非入侵林地记录的物种比例最高,为87个(占27.4%),而开阔放牧地记录的物种比例最低,为70个(占22%)。牧豆树的入侵降低了植物的香农多样性指数,香农多样性指数(H’)和物种丰富度(R)的平均值在牧豆树与本地物种混生群落(H’=2.22,R=14)和未入侵林地(H’=2.23,R=13)显著高于牧豆树灌丛(H′=1.96,R=12)和开阔放牧场(H′=1.84,R=10)。在牧豆树与本地物种混生的群落下,本地植物更新苗总密度最高,为358株ha-1,而在牧豆树灌丛下更新幼苗密度最低,为153株ha-1。此外,本地木本植物更新苗密度在牧豆树灌丛下仅为102株ha-1,而在未入侵林地下却高达1252株ha-1。如果牧豆树入侵及其对本地物种多样性的影响继续,外加气候干旱,阿法尔植物区系的植物多样性将受到严重影响,其生态系统服务的变化存在着不确定性。因此,所有利益相关方应参与,并采取多学科研究应用于研究区的牧豆树管理和牧场恢复。

Ecological and floristic study of Hirmi woodland vegetation in Tigray Region,Northern Ethiopia

The dryland area in Ethiopia covers a substantial region endowed with diverse plant resources.However,the landmass has received less attention even if it has high ecological,environmental,and economic uses.The present study was conducted in Hirmi woodland vegetation,which is one of the dryland areas in Ethiopia,with the objective of investigating the floristic composition,plant community types,vegetation structure,communityenvironment relations and its regeneration status.Vegetation and environmental data were collected from 80 sampling plots with a size of 25 m×25 m designated as the main plots.Diameter at breast height(DBH),height,basal area,density,vertical structure,importance value index(IVI),and frequency were computed.Species diversity and evenness were analyzed using Shannon diversity and evenness indices.The plant community types and vegetation-environment relationships were analyzed using classification and ordination tools,respectively.A total of 171 vascular plant species belonging to 135 genera and 56 families were recorded.About 5.3%of the species were endemic and near-endemic to Ethiopia.The highest number of species was recorded in families Fabaceae(16.4%)and Poaceae(11.7%)followed by Asteraceae(7.0%),Combretaceae,Lamiaceae,and Moraceae(3.5%each).Five plant communities were identified.According to the results from ordination analysis,the floristic composition of these plant communities was significantly affected by altitude,slope,sand,silt,soil organic matter,total nitrogen,and disturbance.The vegetation structure reveals that a large number of individual species was categorized in the lower DBH,frequency,and height classes.The highest Shannon diversity index and evenness values of the study area were 4.21 and 0.95,respectively.Anogeissus leiocarpa,Combretum hartmannianum,Ziziphus mucronata,Terminalia macroptera,and Acacia polyacantha were the species with high IVI.Some endemic plants were in the IUCN red list categories of Ethiopia and Eritrea.The overall regeneration status of the study area was poor because of anthropogenic disturbances and grazing pressures.Although the study area is endowed with high plant species diversity including endemism,it is under poor regeneration status due to various disturbances.To overcome this challenge,integrated management measures including monitoring and application of restoration techniques by taking into consideration the significant environmental factors associated with species diversity as well as observed regeneration status and IUCN threat level of the species are highly recommended.

Soil organic carbon stock in Abune Yosef afroalpine and sub-afroalpine vegetation,northern Ethiopia

Introduction:Soil is the major reservoir of organic carbon.There is a paucity of soil organic carbon(SOC)stock data of afroalpine and sub-afroalpine vegetation in Ethiopia.Hence,this study was conducted to estimate the SOC stock and correlate it with soil physicochemical properties in Abune Yosef afroalpine and sub-afroalpine vegetation.Systematic sampling was employed to collect soil samples from upper 30 cm.Dry bulk density soil pH(1:2.5 water);organic carbon(Walkley and Black),and total nitrogen(Kjeldahl)were the methods used for soil analysis.Pearson correlation and linear regression analysis were performed in SPSS 24 statistical software.Results:The SOC stock of the study area was found to be 79.57 t C ha−1.Soil organic carbon stock showed statistically significant positive correlation with vegetation type(r=0.522,p<0.01),bulk density(r=0.62,p<0.01),total nitrogen(r=0.41,p<0.01),and altitude(r=0.468,p<0.01)and negative correlation with slope(r=−0.298,p<0.05).The present study revealed similar soil organic carbon stock(SOCS)with the Intergovernmental Panel on Climate Change(IPCC)default estimate for similar regions.Positive correlation of SOCS and altitude could be resulted from the variations in anthropogenic disturbances,temperature,and precipitation vegetation types.The negative correlation between SOCS and slope is the result from the predictably higher soil erosion at steeper slopes.Temporal livestock trampling increased the bulk density but never affected the SOCS to decline.Aspect did not show any significant relationship with SOCS due to either the under surveying of all aspects or similar solar radiation found in the study area.Moreover,gazing,aspect,and soil pH did not show statistically significant impact on SOCS.Conclusion:The SOCS of Abune Yosef afroalpine and sub-afroalpine vegetation is similar to the IPCC default estimate for similar regions.This is a great contribution both to the global and local terrestrial carbon sink.

Invasion of Prosopis juliflora and its effects on soil physicochemical properties in Afar region,Northeast Ethiopia

Woody species within pastures and savannas are often associated with‘resource islands’characterized by higher fertility under canopies trees.The aims of this study were to evaluate(1)the effects of Prosopis juliflora on some soil physicochemical properties and(2)the impacts of Prosopis invasion on soil salinity.For soil physicochemical analysis,a total of 104 soil samples from Teru and Yalo Districts were collected.The soil samples were collected from soil depths of 0-15 cm and 15-30 cm in Prosopis invaded and non-invaded open grazing lands.Invasion of Prosopis had significantly affected soil pH,exchangeable Na^(+),water soluble Ca^(2+)+Mg^(2+),water soluble Na^(+),and exchangeable sodium percentage in Teru and Yalo Districts(p<0.05).The invasion of Prosopis significantly increased soil pH(1.5%),but decreased exchangeable Na^(+)(24.2%),exchangeable sodium percentage(21.6%),and water soluble Ca^(2+)+Mg^(2+)(39.9%)than non-invaded lands.Clay content of Prosopis invaded lands was higher by 19%than non-invaded lands.However,sand content of soil was higher under non-invaded lands by 5.6%than Prosopis invaded lands.Most results indicated that invasion of Prosopis had positive effects on physicochemical properties and thus conducive for cereal crops and forages.