Henok Kassa is currently a staff member of Mizan-Tepi University, College of Agriculture and Natural Resources. He has BSc in Horticulture from Mekelle University, MSc in Environmental Science from Ambo University and PhD in Geography from Ghent University.
Recognition of species richness spatial patterns is important for nature conservation and theoret... more Recognition of species richness spatial patterns is important for nature conservation and theoretical studies. Inventorying species richness, especially at a larger spatial extent is challenging, thus different data sources are joined and harmonized to obtain a comprehensive data set. Here we present a new data set showing vascular plant species richness in Poland based on a grid of 10 × 10 km squares. The data set was created using data from two sources: the Atlas of Distribution of Vascular Plants in Poland and the Polish Vegetation Database. Using this data set, we analysed 2,160 species with taxonomical nomenclature according to the Euro + Med PlantBase checklist in 3,283 squares covering the entire territory of Poland (ca. 312,000 km2). The species were divided into groups according to their status and frequency of distribution, and the statistics for each square were obtained. For purposes of analysis, sampling bias was assessed. The data set promotes theoretical analysis on s...
Charcoal production is one of the major challenges for sustainability management of natural fores... more Charcoal production is one of the major challenges for sustainability management of natural forest in Ethiopia. The study aimed to quantify the amount of charcoal produced and supplied from Bonga town surrounding districts and estimate its implications on the environment. Field surveys, household surveys, key informant interviews and focus group discussions were done to collect charcoal production and supply data in the study area. The result revealed that on average a total of about 499 and 60728 bags of charcoal supplied to Bonga town every day and annually from the five major inlet sites, respectively. On average, 15 tons/day and 5448.8 tons/year of charcoals supplied to Bonga from five inlet sites of Gimbo and Decha districts. The tops three preferred wood tree species for charcoal production are Millettia ferruginea (Hochst.) Baker, Ehretum cymosa Thonn and Vepris daniellii (pichi-SerrnolIi) Kokwaro, of which two are endemic to Ethiopia. About 1,716,372 m3 of green wood, 1,492,...
Surface water is one of the sources of global potable water. However, the quality of surface wate... more Surface water is one of the sources of global potable water. However, the quality of surface water has been degrading due to an increase in human activities. Hence, the present study was conducted to evaluate the spatial and temporal variability in drinking water physico-chemical and bacteriological characteristics from the different sources in Mizan-Aman, Ethiopia. The physico-chemical characteristics of water at the Kosokol site were found to be statistically different ( p < 0.05 ) from the other sites (Gacheb, Tsit, Reservoir 1, and Reservoir 2 sites). The dry and wet season temperature (27.1 and 23.8°C), turbidity (37.4 and 54.8 NTU), pH (7.6 and 8.1), biological oxygen demand (18.1 and 20.7 mg/l), phosphate (2.4 and 3.5 mg/l), and ammonia (2.2 and 4.8 mg/l) of the water were beyond the acceptable limit set for drinking water by both Ethiopian standards (temperature: <15°C; turbidity: 7 NTU; pH: 6.5–8.5; BOD: 10 mg/l; phosphate: 0.02 mg/l; and ammonia: 1.5 mg/l) and the WH...
Among the main challenges in modelling biological invasion is a lack of valid data on the absence... more Among the main challenges in modelling biological invasion is a lack of valid data on the absence of invasive species. Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially biased areas from invasive species distribution models (iSDMs) affected the models&#39; performance, and we assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote areas resulting from low propagule pressure.
Reservoir water physicochemical characteristics provide important information about water suitabi... more Reservoir water physicochemical characteristics provide important information about water suitability for fish production. Accordingly, the study aimed to characterize the physicochemical characteristics of Dembi reservoir water for sustainable fish production. The study was conducted in Dembi reservoir during the dry season. Water samples were collected in triplicate from selected 10 sampling sites of the reservoir water using manually prepared water sampler made from polyvinyl chloride (PVC) tube. The depth integrated sampling technique was employed to take water samples for all physicochemical characteristics analysis. From the selected 14 physicochemical characteristics, four (temperature, electrical conductivity, pH, and dissolved oxygen) were tested onsite using a multisystem HQ4d electronic meter (probe), whereas the rest 10 water quality characteristics were tested in the laboratory. The result showed that the current average depth of the dam was 5.6 ± 1.61 m. The overall me...
Among the main challenges in modelling biological invasion is a lack of valid data on the absence... more Among the main challenges in modelling biological invasion is a lack of valid data on the absence of invasive species. Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially biased areas from invasive species distribution models (iSDMs) affected the models' performance, and we assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote areas resulting from low propagule pressure.
Multi-nutrients deficiency of soil in southwest Ethiopia is among the primary constraints for the... more Multi-nutrients deficiency of soil in southwest Ethiopia is among the primary constraints for the very low productivity of potatoes (Solanum tuberosum L.). The combined use of organic and inorganic fertilizers is vital for resolving the common productivity issue. Thus, experiments were performed on potato variety “Belte” in Masha district, southwestern Ethiopia, in both Belg (February to May) as well as Meher (June to October) seasons of 2019 to evaluate the potato response to the vermicompost, mineral phosphorus, and nitrogen’s integrated applications. The experiment had three vermicompost rates with the factorial combination (2.5, 5, 7.5 t/ha) and three recommended rates inorganic NP’s 25%, 50% and 75% (124 kg N/ha and 103 kg P2O5/ha) fertilizer. Results have discovered that 75% inorganic NP and 7.5 t/ha vermicompost’s combined application significantly increase total tuber yield, marketable tuber yield, and individual tuber weight, giving the maximum net benefits and marginal ret...
Background The present study evaluated the compost quality from municipal solid waste (MSW) and o... more Background The present study evaluated the compost quality from municipal solid waste (MSW) and organic additives of coffee by-products and leaf of Millettia ferruginea. Compost sample (n = 30) was taken from fresh compost materials and MSW and different organic additive treatments (T1, T2, T3, T4, and T5). Compost treatments phytotoxicity test was conducted using lettuce seed (Lactuca Sativa L. var. crispa). Analysis of variance (ANOVA) was performed using SPSS (version 22) on major compost quality characteristics. Results The compost Physico-chemical characteristics like temperature (26.4 °C), moisture content (45.5%), electrical conductivity (4.6 mS/cm), pH (7.9), total nitrogen (1.2%) and phosphorous content (2918 ppm) in T4 and T5 were analogous but both are significantly different from T3, T2 and T1 compost treatments. Phytotoxicity test using 100% compost treatment media showed that T4 (101%) and T5 (102%) are phytonutrient for lettuce plant. While, T3 and T2; and T1 compost ...
Coffee residue (by-product) is generated from coffee processing stations and is disposed into ara... more Coffee residue (by-product) is generated from coffee processing stations and is disposed into arable land and surface water leading to environmental pollution, and environmentally friendly disposal method is needed in a useable way. The objective was to evaluate some additives on coffee residue quality as compost. The treatments: (1) coffee husk/pulp (CHP) (as control), (2) Coffee husk/pulp + cow dung (Cd), (3) Coffee husk/pulp + Millettia ferruginea (Mf), (4) Coffee husk/pulp + Cd + Mf, and (5) Coffee husk/pulp +effective microorganism (EM) were used to prepare compost. The experiment was laid out in randomized complete block design with three replications. The physico-chemical properties of the compost were determined at 25, 45 and 70 days of composting. The pH in CHP amended with Mf was highly significant (P<0.0001) compared with CHP and amended with Cd and EM. The contents of TN, av. P, exch. K and CEC of coffee compost treated with both Cd and Mf were significantly high. The...
Recognition of species richness spatial patterns is important for nature conservation and theoret... more Recognition of species richness spatial patterns is important for nature conservation and theoretical studies. Inventorying species richness, especially at a larger spatial extent is challenging, thus different data sources are joined and harmonized to obtain a comprehensive data set. Here we present a new data set showing vascular plant species richness in Poland based on a grid of 10 × 10 km squares. The data set was created using data from two sources: the Atlas of Distribution of Vascular Plants in Poland and the Polish Vegetation Database. Using this data set, we analysed 2,160 species with taxonomical nomenclature according to the Euro + Med PlantBase checklist in 3,283 squares covering the entire territory of Poland (ca. 312,000 km2). The species were divided into groups according to their status and frequency of distribution, and the statistics for each square were obtained. For purposes of analysis, sampling bias was assessed. The data set promotes theoretical analysis on s...
Charcoal production is one of the major challenges for sustainability management of natural fores... more Charcoal production is one of the major challenges for sustainability management of natural forest in Ethiopia. The study aimed to quantify the amount of charcoal produced and supplied from Bonga town surrounding districts and estimate its implications on the environment. Field surveys, household surveys, key informant interviews and focus group discussions were done to collect charcoal production and supply data in the study area. The result revealed that on average a total of about 499 and 60728 bags of charcoal supplied to Bonga town every day and annually from the five major inlet sites, respectively. On average, 15 tons/day and 5448.8 tons/year of charcoals supplied to Bonga from five inlet sites of Gimbo and Decha districts. The tops three preferred wood tree species for charcoal production are Millettia ferruginea (Hochst.) Baker, Ehretum cymosa Thonn and Vepris daniellii (pichi-SerrnolIi) Kokwaro, of which two are endemic to Ethiopia. About 1,716,372 m3 of green wood, 1,492,...
Surface water is one of the sources of global potable water. However, the quality of surface wate... more Surface water is one of the sources of global potable water. However, the quality of surface water has been degrading due to an increase in human activities. Hence, the present study was conducted to evaluate the spatial and temporal variability in drinking water physico-chemical and bacteriological characteristics from the different sources in Mizan-Aman, Ethiopia. The physico-chemical characteristics of water at the Kosokol site were found to be statistically different ( p < 0.05 ) from the other sites (Gacheb, Tsit, Reservoir 1, and Reservoir 2 sites). The dry and wet season temperature (27.1 and 23.8°C), turbidity (37.4 and 54.8 NTU), pH (7.6 and 8.1), biological oxygen demand (18.1 and 20.7 mg/l), phosphate (2.4 and 3.5 mg/l), and ammonia (2.2 and 4.8 mg/l) of the water were beyond the acceptable limit set for drinking water by both Ethiopian standards (temperature: <15°C; turbidity: 7 NTU; pH: 6.5–8.5; BOD: 10 mg/l; phosphate: 0.02 mg/l; and ammonia: 1.5 mg/l) and the WH...
Among the main challenges in modelling biological invasion is a lack of valid data on the absence... more Among the main challenges in modelling biological invasion is a lack of valid data on the absence of invasive species. Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially biased areas from invasive species distribution models (iSDMs) affected the models&#39; performance, and we assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote areas resulting from low propagule pressure.
Reservoir water physicochemical characteristics provide important information about water suitabi... more Reservoir water physicochemical characteristics provide important information about water suitability for fish production. Accordingly, the study aimed to characterize the physicochemical characteristics of Dembi reservoir water for sustainable fish production. The study was conducted in Dembi reservoir during the dry season. Water samples were collected in triplicate from selected 10 sampling sites of the reservoir water using manually prepared water sampler made from polyvinyl chloride (PVC) tube. The depth integrated sampling technique was employed to take water samples for all physicochemical characteristics analysis. From the selected 14 physicochemical characteristics, four (temperature, electrical conductivity, pH, and dissolved oxygen) were tested onsite using a multisystem HQ4d electronic meter (probe), whereas the rest 10 water quality characteristics were tested in the laboratory. The result showed that the current average depth of the dam was 5.6 ± 1.61 m. The overall me...
Among the main challenges in modelling biological invasion is a lack of valid data on the absence... more Among the main challenges in modelling biological invasion is a lack of valid data on the absence of invasive species. Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially biased areas from invasive species distribution models (iSDMs) affected the models' performance, and we assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote areas resulting from low propagule pressure.
Multi-nutrients deficiency of soil in southwest Ethiopia is among the primary constraints for the... more Multi-nutrients deficiency of soil in southwest Ethiopia is among the primary constraints for the very low productivity of potatoes (Solanum tuberosum L.). The combined use of organic and inorganic fertilizers is vital for resolving the common productivity issue. Thus, experiments were performed on potato variety “Belte” in Masha district, southwestern Ethiopia, in both Belg (February to May) as well as Meher (June to October) seasons of 2019 to evaluate the potato response to the vermicompost, mineral phosphorus, and nitrogen’s integrated applications. The experiment had three vermicompost rates with the factorial combination (2.5, 5, 7.5 t/ha) and three recommended rates inorganic NP’s 25%, 50% and 75% (124 kg N/ha and 103 kg P2O5/ha) fertilizer. Results have discovered that 75% inorganic NP and 7.5 t/ha vermicompost’s combined application significantly increase total tuber yield, marketable tuber yield, and individual tuber weight, giving the maximum net benefits and marginal ret...
Background The present study evaluated the compost quality from municipal solid waste (MSW) and o... more Background The present study evaluated the compost quality from municipal solid waste (MSW) and organic additives of coffee by-products and leaf of Millettia ferruginea. Compost sample (n = 30) was taken from fresh compost materials and MSW and different organic additive treatments (T1, T2, T3, T4, and T5). Compost treatments phytotoxicity test was conducted using lettuce seed (Lactuca Sativa L. var. crispa). Analysis of variance (ANOVA) was performed using SPSS (version 22) on major compost quality characteristics. Results The compost Physico-chemical characteristics like temperature (26.4 °C), moisture content (45.5%), electrical conductivity (4.6 mS/cm), pH (7.9), total nitrogen (1.2%) and phosphorous content (2918 ppm) in T4 and T5 were analogous but both are significantly different from T3, T2 and T1 compost treatments. Phytotoxicity test using 100% compost treatment media showed that T4 (101%) and T5 (102%) are phytonutrient for lettuce plant. While, T3 and T2; and T1 compost ...
Coffee residue (by-product) is generated from coffee processing stations and is disposed into ara... more Coffee residue (by-product) is generated from coffee processing stations and is disposed into arable land and surface water leading to environmental pollution, and environmentally friendly disposal method is needed in a useable way. The objective was to evaluate some additives on coffee residue quality as compost. The treatments: (1) coffee husk/pulp (CHP) (as control), (2) Coffee husk/pulp + cow dung (Cd), (3) Coffee husk/pulp + Millettia ferruginea (Mf), (4) Coffee husk/pulp + Cd + Mf, and (5) Coffee husk/pulp +effective microorganism (EM) were used to prepare compost. The experiment was laid out in randomized complete block design with three replications. The physico-chemical properties of the compost were determined at 25, 45 and 70 days of composting. The pH in CHP amended with Mf was highly significant (P<0.0001) compared with CHP and amended with Cd and EM. The contents of TN, av. P, exch. K and CEC of coffee compost treated with both Cd and Mf were significantly high. The...
The southwestern Ethiopian montane forests are one of the most species-rich ecosystems and are re... more The southwestern Ethiopian montane forests are one of the most species-rich ecosystems and are recognised globally as a priority area for the conservation of biodiversity. Particularly, in contrast to the drier central and northern Ethiopian highlands, they have received little attention by researchers, Here, we review changes to agricultural systems in and around these forests that are known as the genetic home of coffee (Coffea arabica L.) and that are important to the livelihoods of many rural people who have developed traditional management practices based on agroecological knowledge, religious taboos and customary tenure rights. We explored the impacts of conversions to agroforestry and cereal-based cropping systems on biodiversity, soil fertility, soil loss and the socioeconomic conditions and culture. The increasing trend of cereal cropping, resettlement and commercial agriculture causes the deterioration of natural forest cover in the region, and threaten biodiversity, land quality, sustainable, traditional farming practices and the livelihood of the local community. Large-scale plantations of tea, coffee, soapberry locally known as endod (Phytolacca dodecandra L'Hér.) and cereals have resulted in biodiversity loss. Following the conversion of forests, cultivated fields exhibit a significant decline in soil fertility and an increase in soil loss as compared to the tradition agroforestry system. The establishment of a sustainable agricultural system will require a change in paradigm, whereby the intrinsic values of the traditional forest-based agricultural system are recognised, rather than the ongoing mimicking of agricultural policies that were developed for the open fields of central Ethiopia.
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Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In
practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially
biased areas from invasive species distribution models (iSDMs) affected the models' performance, and we
assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for
neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land
use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution
atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred
fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed
to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding
the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an
area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the
original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and
urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares
in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest
that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas
was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote
areas resulting from low propagule pressure.
Absence data are important for assessing the reliability of models, but multiple surveys at a location are needed. In
practice, omission errors are more frequent than commission errors. We therefore quantified how eliminating potentially
biased areas from invasive species distribution models (iSDMs) affected the models' performance, and we
assessed how the distribution of biased areas correlated with environmental factors. We hypothesized that for
neophytes, the distribution of biased areas corresponds to specific land relief and/or particular landscape and land
use, but not the density of roads and urbanized areas. The data on neophytes were obtained from a distribution
atlas covering approximately 31,000 km2 in Central Europe overlaid with a 2 × 2 km square grid. One hundred
fifty-three species were used for modelling neophyte richness, and negative residuals from the model were assumed
to indicate biased squares. Twenty invasive species were used as an independent dataset for testing the effect of excluding
the biased squares on iSDMperformance. The exclusion of biased squares increased the iSDMperformance from an
area under the curve value of 0.73 to 0.78. The best results were obtained by excluding 30 % of the squares from the
original dataset. The presence of damp sites explained the distribution of biased squares; the density of roads and
urbanized areas had no impact. The applied method allows distinguishing biased, plausibly undersampled squares
in a species distribution atlas, the exclusion of which significantly improves iSDM performance. The results suggest
that the commonly observed low sampling effort in areas distant from communication routes and urbanized areas
was not crucial in modelling invasive species distribution, which can be related to smaller neophyte richness in remote
areas resulting from low propagule pressure.